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Washington: The newly pictured super massive black hole is a beast with no name, at least not an official one. And what happens next could be cosmically confusing.
The team of astronomers who created the image of the black hole called it M87*. (The asterisk is silent.) A language professor has given it a name from a Hawaiian chant - Powehi - meaning "the adorned fathomless dark creation". And the international group in charge of handing out astronomical names? It has never named a black hole.
The black hole in question is about 53 million light years away in the centre of a galaxy called Messier 87, or M87 for short. On Wednesday, scientists revealed a picture they took of it using eight radio telescopes, the first time humans had actually seen one of the dense celestial objects that suck up everything around them, even light.
The International Astronomical Union usually takes care of names, but only for stuff inside our solar system and stars outside it. It doesn't have a committee set up to handle other objects, such as black holes, galaxies or nebulas.
The last time there was a similar situation, poor Pluto somehow got demoted to a dwarf planet, leading to public outcry, said Williams College astronomer Jay Pasachoff, a star-naming committee member.
Technically, our own galaxy - the Milky Way - has never been officially named by the IAU, said Rick Fienberg, an astronomer and press officer for the American Astronomical Society. He said, "That's just a term that came down through history.
"Virtually every object in the sky has more than one designation.
"The constellations have their official IAU sanctioned names but, in other cultures, they have other names."
When it comes to the black hole we saw this week , University of Hawaii-Hilo Hawaiian professor Larry Kimura stepped up even before the photo was unveiled.
Powehi (pronounced poh-veh-hee) is the black hole's Hawaiian name, not its official name, explained Jessica Dempsey, who helped capture the black hole image as deputy director of the James Clerk Maxwell Telescope on Mauna Kea, Hawaii's tallest mountain.
Hawaii Governor David Ige proclaimed April 10 as Powehi day, she said.
"This isn't astronomers naming this," she said. "This is coming from a cultural expert and language expert. This is him coming to the table and giving us a gift of this name. It's a gift from Hawaiian culture and history, not the other way around."
When asked about Kimura's idea, Pasachoff said: "That's the first I heard of it."
Eric Mamajek, chairman of the IAU working group on star names, called it a "wonderful, thoughtful name".
But Mamajek said his committee may not be the right one to grant the black hole a name. It only does stars.
"This is exactly the Pluto situation," Pasachoff said.
In 2006, astronomers at the IAU were discussing naming a large object in our solar system that eventually got called Eris. It wasn't considered a planet, so it wasn't the job of the planet committee. But some experts pointed out that it was bigger than Pluto, which added some confusion.
The conference decided to reclassify planets, kicked Pluto out of the club of regular planets and made it join the newly established dwarf planets category with Eris, Pasachoff said.
The same day the photograph of the black hole was unveiled, the IAU asked the public to choose between three names for an object astronomers call 2007 OR10. It's an icy planetesimal that circles the sun but gets 100 times further from our star than Earth does.
The three proposed names are Gonggong, a Chinese water god with red hair and a serpent tail; Holle, a European winter goddess of fertility; and Vili, a Nordic deity and brother of Odin.
In 2017, a reddish cigar-shaped comet, about 800 metres long and named 'Oumuamua was detected, the first interstellar object found found in our solar system.
'Oumuamua (pronounced oh-MOO-uh-MOO-uh) was found by the University of Hawaii's Pan-STARRS1 telescope. Its name refers in the native Hawaiian language to a messenger arriving from a great distance.
Astronomers said they closely examined the trajectory of 'Oumuamua as it speeds through our cosmic neighbourhood after being evicted somehow from a distant star system.
It swung past the sun like a slingshot, travelling at roughly 315,000km/h and is heading out of the solar system in the direction of the constellation Pegasus.
The IAU is trying to bring in more languages and cultures into the naming game, Pasachoff and Fienberg said. And soon the IAU will ask the public to help name 100 planets outside our solar system.
As astronomers gaze further into the cosmos, Pasachoff said, "We will need more names." | 0.909737 | 3.093497 |
Venus is often referred to as our “sister planet,” due to the many geophysical similarities that exist between it Earth. For starters, our two planets are close in mass, with Venus weighing in at 4.868 x 1024 kg compared to Earth’s 5.9736×1024 kg. In terms of size, the planets are almost identical, with Venus measuring 12,100 km in diameter and Earth 12,742 km.
In terms of density and gravity, the two are neck and neck – with Venus boasting 86.6% of the former and 90.7% of the latter. Venus also has a thick atmosphere, much like our own, and it is believed that both planets share a common origin, forming at the same time out of a condensing clouds of dust particles around 4.5 billion years ago.
However, for all the characteristics these two planets have in common, average temperature is not one of them. Whereas the Earth has an average surface temperature of 14 degrees Celsius, the average temperature of Venus is 460 degrees Celsius. That is roughly 410 degrees hotter than the hottest deserts on our planet.
In fact, at a searing 750 K (477 °C), the surface of Venus is the hottest in the solar system. Venus is closer to the Sun by 108 million km, (about 30% closer than the Earth), but it is mainly due to the planet’s thick atmosphere. Unlike Earth’s, which is composed primarily of nitrogen, oxygen and ozone, Venus’ atmosphere is an incredibly dense cloud of carbon dioxide and sulfur dioxide gas.
The combination of these gases in high concentrations causes a catastrophic greenhouse effect that traps incident sunlight and prevents it from radiating into space. This results in an estimated surface temperature boost of 475 K (201.85 °C), leaving the surface a molten, charred mess that nothing (that we know of) can live on. Atmospheric pressure also plays a role, being 91 times that of what it is here on Earth; and clouds of toxic vapor constantly rain sulfuric acid on the surface.
In addition, the surface temperature on Venus does not vary like it does here on Earth. On our planet, temperatures vary wildly due to the time of year and even more so based on the location on our planet. The hottest temperature ever recorded on Earth was 70.7°C in the Lut Desert of Iran in 2005. On the other end of the spectrum, the coldest temperature ever recorded on Earth was in Vostok, Antarctica at -89.2 C.
But on Venus, the surface temperature is 460 degrees Celsius, day or night, at the poles or at the equator. Beyond its thick atmosphere, Venus’ axial tilt (aka. obliquity) plays a role in this temperature consistency. Earth’s axis is tilted 23.4 ° in relation to the Sun, whereas Venus’ is only tilted by 3 °.
The only respite from the heat on Venus is to be found around 50 km into the atmosphere. It is at that point that temperatures and atmospheric pressure are equal to that of Earth’s. It is for this reason that some scientists believe that floating habitats could be constructed here, using Venus’ thick clouds to buoy the habitats high above the surface. Additionally, in 2014, a group of mission planners from NASA Langely came up with a mission to Venus’ atmosphere using airships.
These habitats could play an important role in the terraforming of Venus as well, acting as scientific research stations that could either fire off the excess atmosphere off into space, or introduce bacteria or chemicals that could convert all the CO2 and SO2 into a hospitable, breathable atmosphere.
Beyond the fact that it is a hot and hellish landscape, very little is known about Venus’ surface environment. This is due to the thick atmosphere, which has made visual observation impossible. The sulfuric acid is also problematic since clouds composed of it are highly reflective of visible light, which prevents optical observation. Probes have been sent to the surface in the past, but the volatile and corrosive environment means that anything that lands there can only survive for a few hours.
What little we know about the planet’s surface has come from years worth of radar imaging, the most recent of which was conducted by NASA’s Magellan spacecraft (aka. the Venus Radar Mapper). Using synthetic aperture radar, the robotic space probe spent four years (1990-1994) mapping the surface of Venus and measuring its gravitational field before its orbit decayed and it was “disposed of” in the planet’s atmosphere.
The images provided by this and other missions revealed a surface dominated by volcanoes. There are at least 1,000 volcanoes or volcanic centers larger than 20 km in diameter on Venus’ harsh landscape. Many scientists believe Venus was resurfaced by volcanic activity 300 to 500 million years ago. Lava flows are a testament to this, which appear to have produced channels of hardened magma that extend for hundreds of km in all directions. The mixture of volcanic ash and the sulfuric acid clouds is also known to produce intense lightning and thunder storms.
The temperature of Venus is not the only extreme on the planet. The atmosphere is constantly churned by hurricane force winds reaching 360 kph. Add to that the crushing air pressure and rainstorms of sulfuric acid, and it becomes easy to see why Venus is such a barren, lifeless rock that has been hard to explore.
We have written many articles about Venus for Universe Today. Here are some interesting facts about Venus, and here’s an article about Venus Greenhouse Effect. And here is an article about the many interesting pictures taken of Venus over the past few decades.
We’ve also recorded an entire episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus. | 0.907394 | 3.905163 |
Using data from NASA's Kepler space telescope, astrophysicists from the University of Birmingham have discovered extra-solar planets whose atmospheres have been stripped away by their host stars.According to them, planets with gaseous atmospheres that lie very close to their host stars are bombarded by a torrent of high-energy radiation. Due to their proximity to the star, the heat that the planets suffer means that their "envelopes" have been blown away by intense radiation. This violent "stripping" occurs in planets that are made up of a rocky core with a gaseous outer layer."The results show that planets of a certain size that lie close to their stars are likely to have been much larger at the beginning of their lives. Those planets will have looked very different," said Dr Guy Davies from the University of Birmingham's school of physics and astronomy. The findings have important implications for understanding how stellar systems, like our own solar system, and their planets, evolve over time and the crucial role played by the host star.Scientists expect to discover many such "stripped systems" using a new generation of satellites including the NASA TESS Mission which will be launched next year. The paper was published in the journal Nature Communications. | 0.876963 | 3.461694 |
Science, Tech, Math › Science The Woman Who Explained the Sun and Stars Meet Cecelia Payne-Gaposchkin Share Flipboard Email Print Dr. Cecelia Payne-Gaposchkin at work at Harvard Observatory. She discovered hydrogen as a major component of the Sun and other stars. Smithsonian Institution Science Astronomy Important Astronomers An Introduction to Astronomy Solar System Stars, Planets, and Galaxies Space Exploration Chemistry Biology Physics Geology Weather & Climate By Carolyn Collins Petersen Astronomy Expert M.S., Journalism and Mass Communications, University of Colorado - Boulder B.S., Education, University of Colorado Carolyn Collins Petersen is an astronomy expert and the author of seven books on space science. She previously worked on a Hubble Space Telescope instrument team. our editorial process Facebook Facebook Carolyn Collins Petersen Updated April 01, 2019 Today, ask any astronomer what the Sun and other stars are made of, and you'll be told, "Hydrogen and helium and trace amounts of other elements". We know this through a study of sunlight, using a technique called "spectroscopy". Essentially, it dissects sunlight into its component wavelengths called a spectrum. Specific characteristics in the spectrum tell astronomers what elements exist in the Sun's atmosphere. We see hydrogen, helium, silicon, plus carbon, and other common metals in stars and nebulae throughout the universe. We have this knowledge thanks to the pioneering work done by Dr. Cecelia Payne-Gaposchkin throughout her career. The Woman Who Explained the Sun and Stars In 1925, astronomy student Cecelia Payne turned in her doctoral thesis on the topic of stellar atmospheres. One of her most important findings was that the Sun is very rich in hydrogen and helium, more so than astronomers thought. Based on that, she concluded that hydrogen is THE major constituent of all stars, making hydrogen the most abundant element in the universe. It makes sense, since the Sun and other stars fuse hydrogen in their cores to create heavier elements. As they age, stars also fuse those heavier elements to make more complex ones. This process of stellar nucleosynthesis is what populates the universe with many of the elements heavier than hydrogen and helium. It's also an important part of the evolution of stars, which Cecelia sought to understand. The idea that stars are made mostly of hydrogen seems like a very obvious thing to astronomers today, but for its time, Dr. Payne's idea was startling. One of her advisors — Henry Norris Russell — disagreed with it and demanded she take it out of her thesis defense. Later, he decided it was a great idea, published it on his own, and got the credit for the discovery. She continued to work at Harvard, but for time, because she was a woman, she received very low pay and the classes she taught weren't even recognized in the course catalogs at the time. In recent decades, the credit for her discovery and subsequent work has been restored to Dr. Payne-Gaposchkin. She is also credited with establishing that stars can be classified by their temperatures, and published more than 150 papers on stellar atmospheres, stellar spectra. She also worked with her husband, Serge I. Gaposchkin, on variable stars. She published five books, and won a number of awards. She spent her entire research career at Harvard College Observatory, eventually becoming the first woman to chair a department at Harvard. Despite successes that would have gained male astronomers at the time incredible praise and honors, she faced gender discrimination throughout much of her life. Nonetheless, she is now celebrated as a brilliant and original thinker for her contributions that changed our understanding of how stars work. As one of the first of a group of female astronomers at Harvard, Cecelia Payne-Gaposchkin blazed a trail for women in astronomy that many cite as their own inspiration to study the stars. In 2000, a special centenary celebration of her life and science at Harvard drew astronomers from around the world to discuss her life and findings and how they changed the face of astronomy. Largely due to her work and example, as well as the example of women who were inspired by her courage and intellect, the role of women in astronomy is slowly improving, as more select it as a profession. A Portrait of the Scientist Throughout her Life Dr. Payne-Gaposchkin was born as Cecelia Helena Payne in England on May 10, 1900. She got interested in astronomy after hearing Sir Arthur Eddington describe his experiences on an eclipse expedition in 1919. She then studied astronomy, but because she was female, she was refused a degree from Cambridge. She left England for the United States, where she studied astronomy and got her PhD from Radcliffe College (which is now a part of Harvard University). After she received her doctorate, Dr. Payne went on to study a number of different types of stars, particularly the very brightest "high luminosity" stars. Her main interest was to understand the stellar structure of the Milky Way, and she ultimately studied variable stars in our galaxy and the nearby Magellanic Clouds. Her data played a large role in determining the ways that stars are born, live, and die. Cecelia Payne married fellow astronomer Serge Gaposchkin in 1934 and they worked together on variable stars and other targets throughout their lives. They had three children. Dr. Payne-Gaposchkin continued teaching at Harvard until 1966, and continued her research into stars with the Smithsonian Astrophysical Observatory (headquartered at Harvard's Center for Astrophysics. She died in 1979. | 0.840964 | 3.599245 |
An international team of astronomers led by Peter brown from Texas A&M University, USA, noticed an amazing re-increase brightness in the ultraviolet range distant super-bright supernova, known as ASASSN-15lh. This event has led scientists to confusion because it does not demonstrate the characteristic features of super-bright supernova or tidal event of the rupture of the cosmic bodies in the emission spectra of hydrogen.
Super-bright supernova, Hypernova is also called, usually ten times brighter compared to ordinary supernovae. Hypernova ASASSN-15lh, discovered with the help of sky survey All Sky Automated Survey for SuperNovae (ASAS-SN) to 2015, justifying its name, is a true “assassin” among the cosmic explosions of this type. It exceeds the power of conventional supernovae are about 200 times and about 570 billion times greater than the brightness of our Sun. She is the winner of the title of the brightest supernovae discovered by scientists today.
In their study, brown and his colleagues used data obtained by the spacecraft NASA swift space telescope and the NASA/ESA Hubble”, for a detailed study of the system ASASSN-15lh. They found that the flow of energy, coming from this supernova in the ultraviolet range, has increased significantly, while the luminosity of this object a hundred times higher than the luminosity of the hydrogen rich, colorful in the UV range of SN II supernovae SLSN 2008es. According to the researchers is the repeated increase in brightness is observed two months after maximum brightness was comparable with the flash of super-bright supernova.
Currently the authors are unable to give a theoretical explanation of their findings and urge theorists to pay attention to these observational results and to develop a theory of the phenomenon, given the restrictions imposed by the observations, such as the shape of the explosion, the optical/UV light flux, the x-ray flux and the lack of hydrogen – most common element in the Universe.
The study presented on the server prior scientific publications arxiv.org. | 0.874991 | 3.789776 |
If you can teach computers to learn, NASA needs your help.
Cosmologists hope gamers, programmers, computer scientists and geeks-of-all-trades can help them identify evidence of dark matter. An international group of astronomers are hosting a competition, called GREAT10 (for GRavitational lEnsing Accuracy Testing), to come up with better ways to analyze distorted images of galaxies – the signatures of invisible dark matter lurking in the universe.
Massive clumps of matter can act as a giant cosmic magnifying glass, distorting space-time in their immediate vicinity. Light traveling through the matter clump is warped and distorted, a phenomenon called gravitational lensing.
Sometimes the distortions are obvious, like in the Hubble image of a distant galaxy cluster above. But sometimes they're too subtle to be picked out by human eyes, and can even be confused with noise from the telescope used to take the galaxies' picture.
So cosmologists have turned to machine learning algorithms that teach computers to recognize patterns.
"We're trying to teach computers to pick out the correct shape given all sorts of other noise around the galaxy's shape," said NASA cosmologist Jason Rhodes, who is helping to organize the challenge. "We have our ideas as a community about how to do this, but we realized a few years ago that it was quite possible there were ideas we weren't familiar with."
The competition is designed to bring fresh ideas from machine learning and computer science experts. But the challenge is open to anyone.
"The image manipulation software and techniques used in gaming and some digital cameras are very similar," said astrophysicist Thomas Kitching of the University of Edinburgh, which is helping to sponsor the event. "Anyone with experience in image manipulation and software development would be in a good position to enter the competition."
Rhodes compares GREAT to other citizen science and engineering challenges, like the X-Prize private spaceflight competitions or the Netflix Prize to improve the movie rental website's recommendation algorithms. Those challenges promised million-dollar prizes, which is beyond the cosmology community's budget. But the GREAT10 winner will probably get an iPad or a Mac laptop.
And the real grand prize is helping to solve one of the trickiest and most fundamental puzzles in astronomy: What is the universe made of?
Ultimately, the computer programs developed for the GREAT challenge will be used to help unmask dark matter and dark energy, the mysterious stuff that makes up 95 percent of the universe.
By studying slightly distorted galaxies, scientists can make detailed maps of dark matter, the stubbornly invisible stuff that makes up 24 percent of the universe and makes itself known through gravitational tugs on regular visible matter. Knowing where the dark matter is and how it changes over time will help astronomers decipher dark energy, an even more mysterious substance that makes up 72 percent of the universe.
"The most exciting thing about this is that we are taking an interdisciplinary approach to one of the most pressing problems in all of science," Rhodes said. "The ultimate goal here is really to develop methods for studying the composition of the universe and the ultimate fate of the universe. People who haven’t spent their lives studying cosmology can make a real contribution via the GREAT10 challenge."
Image: Light bends around the massive galaxy cluster Abell 2218 in this image from the Hubble Space Telescope. Credit: Andrew Fruchter (STScI) et al., WFPC2, HST, NASA
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In Institute for extraterrestrial physics, max Planck Society and the University Observatory of Munich have found a black hole mass of 40 billion Suns. It is reported Phys.org.
Supermassive black hole is almost extinct in the galaxy Holm 15A in the cluster of galaxies Abell 85. It is distant from the Earth at a distance of 700 million light years and has a mass of about two trillion Suns.
The analysis of the photometric data showed that the detected object is the most massive black hole in the local Universe. Such masses have only black holes located in quasars at a distance of about 10 billion light years from Earth.
Holm 15A mass calculated on the basis of the movements of stars around the galactic core. Previously, a similar method was used for calculations with objects twice as closer to the Ground.
Such a supermassive black hole could be formed after the collision of several galaxies merge and their black holes. | 0.83446 | 3.109974 |
2035: Dark Matter Candidates
|Dark Matter Candidates|
Title text: My theory is that dark matter is actually just a thin patina of grime covering the whole universe, and we don't notice it because we haven't thoroughly cleaned the place in eons.
Dark matter is a hypothetical, invisible form of matter used by the vast majority of astronomers to explain the far too high apparent mass of objects at large scales in our universe. In galaxies, stars are orbiting faster than the gravitational force of the sum of the masses of visible matter in the galaxy could cause, and entire galaxies are observed moving much faster around each other than their visible masses could explain. In galactic collisions, the mass can appear to separate from the visible matter, as if the mass doesn't collide but the visible matter does. A small handful of galaxies have been observed to not have this property, suggesting that it is a *thing* that a galaxy can have more or less of and is separable from. At scales of our solar system, those effects are too small and can't be measured. The most plausible explanation for all of these phenomena is that there is some "dark matter" that has gravity, but is otherwise undetectable. In cosmology, dark matter is estimated to account for 85% of the total matter in the universe.
This comic gives a set of possibilities for what dark matter could possibly be, charted by mass from smallest (given in electronvolts) to largest (given in kilograms). Masses in the range 10-15 kg to 10-3 kg are given in grams together with appropriate prefixes, while the ton takes the place of 103 kg.
Only massive objects ranging from subatomic particles up to super massive ones are covered in this comic. There are also alternative hypotheses trying to modify general relativity with no need of additional matter. The problem is that these theories can't explain all different observations at once. Nonetheless dark matter is a mystery because no serious candidate has been found yet.
The joke in this comic is that the range of the mass of the possible particles and objects stretch over 81 powers of ten, with explanations suggested by astronomers covering only some portions of that range. Randall fills the gaps with highly absurd suggestions.
An axion is a hypothetical elementary particle postulated in 1977 to resolve the strong CP problem in quantum chromodynamics, a theory of the strong force between quarks and gluons which form hadrons like protons or neutrons. If axions exist within a specific range of mass they might be a component of dark matter. The advantage of this particle is that it's based on a theory which could be proved or also disproved by measurements in the future. Other theories, not mentioned in this comic, like the Weakly interacting massive particles (WIMPs) are much more vague.
Sterile neutrinos are hypothetical particles interacting only via gravity. It's an actual candidate for dark matter. The well known neutrinos are also charged under the weak interaction and can be detected by experiments.
Electrons painted with space camouflage
Electrons are fundamental particles which compose the outer layers of atoms. A large number of electrons in the galaxy would be relatively easy to detect, as they not only interact with light (which dark matter does not appear to), but also have a strong electric charge. Presumably, space camouflage is a positively-charged coating which prevents electrons from interacting with light. (Needless to say, this is not an actual candidate for dark matter.) The mass of an electron is about 0.5 MeV which fits well into the graph.
A neutralino is a hypothetical particle from supersymmetry and is also a current candidate for dark matter. But there is not evidence whether or not supersymmetry is correct and none of the predicted particles have been found yet.
In theoretical physics, a Q-ball is a stable group of particles. It's an actual candidate for dark matter.
(In billiards, a cue ball is the white (or yellow) ball hit with the cue in normal play. In addition, Cueball is the name explainxkcd uses for the most common xkcd character.)
Pollen is a joke candidate, though people with seasonal allergies may suspect that the universe is genuinely made up entirely of pollen in the springtime.
No-See-Ums are a family (Ceratopogonidae) of small flies, 1–4 mm long, that can pass through most window screens. Another joke candidate, because dark matter is invisible and the name "no-see-ums" implies that the flies are invisible.
Insects of the clade Antophila are major pollinators of flowering plants. In recent years bees have been disappearing at an alarming rate; Doctor Who explained that they are in fact aliens leaving Earth prior to a Dalek invasion.
In pool, the 8-ball is a black ball numbered 8. It's a pun with Q-ball/cue ball. Unless undetected aliens have discovered billiards and become addicted to it, 8-balls are found only on Earth and are, hence, unlikely dark matter candidates. The 8-ball is also a popular unit of sale for black market pharmaceuticals like cocaine, where it stands for 1/8th of an ounce (3.5g). This doesn't make sense as a dark matter candidate either -- unless dark matter is hard to detect because it's illegal & trying to avoid the cops.
Cows are bovines extensively farmed on Earth for milk and meat. Although there is folklore concerning cows achieving circum-lunar orbits, not to mention their appearance on a beloved space western TV show, as Muppet cow Natalie in the Sesame Street News Flash (and others less-remembered), they have yet to be found elsewhere in the Universe. In the television show "Too Close for Comfort", one of the characters is the cartoonist of a comic strip called "Cosmic Cow". Spherical cows have also been used (humorously) by physicists needing to simplify some source of mass in a given problem.
Obelisks, Monoliths, Pyramids
While those human constructions are huge on a human scale, they're negligible at universe-scale. It would take a large number of such constructions, distributed through space, to replicate the effects of dark matter; while a scenario could be envisioned where enough such constructs existed, with properties and distribution allowing them to match observations, this is obviously not a likely explanation. They often show up in fiction and pseudo-scientific literature as alien artifacts generating immense unknown power out of nowhere, with the most famous and influential example being the three monoliths from 2001: A Space Odyssey (with the largest having a mass of about 500,000 tonnes).
Black Holes ruled out by:
Black holes are known to occur in sizes of a few solar masses (about 1030-1031 kg) as remnants of the core of former big stars, as well as in quite large sizes at the centers of galaxies (millions or even billions of solar masses). But recent gravitational wave detections indicate that black holes at 50 or 100 solar masses also exist, though their origin is still not understood. Randall doesn't mention this but some astronomers hope that these could fill at least a part of the gap. While black holes are widely reported to be ruled out as a candidate for dark matter for various reasons Randall has listed, such constraints are based on "monochromatic" mass distributions -- meaning that all such black holes are assumed to have the same mass -- which is considered physically implausible for populations of merging bodies which are known to have vastly different masses. See: Primordial Black Holes as Dark Matter (2017) and Primordial black hole constraints for extended mass functions (2017) (That this is a common practice in cosmology may be part of the reference to "buzzkill" astronomers.) He rules out all black holes in the range of approximately 1010 kg to 1033 kg even when below some gaps at the bars appear.
Except the last item, all range below the mass of the sun (2x1030 kg) while the smallest known black hole is about four solar masses.
- Gamma rays: If dark matter were black holes of this size, the black holes could be evaporating by the predicted Hawking radiation, and we'd see a buzz of gamma rays from every direction if many of those objects would exist. Nonetheless this radiation is still hypothetical and not been observed on any known black holes. Furthermore those objects would be very small because the Schwarzschild radius of a 1012 kg black hole is approximately 148 fm (1.48×10−13 m), which is between the size of an atom and an atomic nucleus.
- GRB lensing: Gamma-ray bursts (GRBs) are the brightest events in the universe and have been observed only in distant galaxies. While gravitational microlensing (see below) is an astronomical phenomenon, it doesn't make much sense here. GRBs are short (milliseconds to several hours) and are often detected only by space-borne sensors for gamma-rays -- rarely at any other wavelengths. Measuring lensing effects would be very difficult. This paper discusses the probability of detecting lensing effects caused by galactic halo objects among the known GRBs given sufficient objects to represent the missing mass.
- Neutron star data: Neutron stars aren't black holes, but they're also very small highly compact objects at about 1.4-2.16 solar masses. While black holes can't be observed directly, neutron stars are detectable in many wavelengths. The number of them gives a clue about the number of black holes close to the mass of the sun, a number which is far too low to make up dark matter.
- Micro lensing: Gravitational microlensing is a gravitational lens effect, (the path of radiation is changed by passing through space bent by nearby mass). This was predicted by Einstein's Theory of General Relativity and was first confirmed in 1919 during a solar eclipse, when a star which was nearly in line with the sun appeared more distant to the sun than usual. Astronomers have found many so called Einstein rings or Einstein crosses where a massive object in front of other galaxies bends the light toward us. Those massive objects may be black holes, but the number is far too low to explain dark matter.
- Solar system stability: Our solar system is 4.5 billion years old and has been very stable since shortly after its formation. If not, we wouldn't exist. If dark objects at 1024 kg - 1030 kg (mass of Earth up to mass of Sun) accounted for dark matter and were distributed throughout galaxies, there should be many of them in the vicinity of our solar system and the system wouldn't be stable at all.
- Buzzkill Astronomers: Black holes above a certain size are thought by some astronomers to be impossible to miss, due to the effects they have on nearby matter. At the mass of some 1030 kg there must be many supernova remnants we still haven't found. Black holes of about 1035 kg have long been considered dark matter candidates by a minority group of cosmologists, as could be seen here Primordial Black Holes as All Dark Matter (2010) and the Milky Way's first discovered intermediate mass black hole falling in this range shown here Signs of Second Largest Black Hole in the Milky Way.
Not covered by this comic are massive astrophysical compact halo objects (MACHOs) composed of hard to detect dim objects like black holes, neutron stars, brown dwarfs, and other objects composed of normal baryonic matter. Nevertheless observations have shown that the total amount of baryonic matter in our universe on large scales is much smaller than it would be needed to explain all the measured gravitational effects.
Maybe those orbit lines on space diagrams are real and very heavy
Diagrams of our solar system (or any planetary system) often show lines representing the elliptical paths the planet takes around its sun. These lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be huge (Earth's would be 940 million km long (2π AU) and Neptune's would be 28 billion kilometers long). Powers of Ten (1977) gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the planets, including the Earth, which would probably be a problem. Their mass would also affect planetary motions in ways which we would detect. A related worry about space travel was expressed in previous centuries; it was thought that the planets were embedded within crystal shells (spheres or Platonic solids), and a rocket into space could smash the shells and send planets plummeting to Earth. Another joke candidate.
The title text refers to the fact that space is just vast emptiness where a little bit of dirt could be overlooked. Actually the mean density of detectable matter in the universe, according to NASA, is equivalent to roughly 1 proton per 4 cubic meters. And because this matter is mostly located in galaxies -- and inside there in stars and clouds -- the space between is even more empty. For comparison, one gram hydrogen consists of 6.022 x 1023 atoms. Like at home wiping with a cleaning cloth in which we can see the dirt that wasn't clearly visible on the surface we have wiped, Randall believes that some few atoms more per cubic meter could stay undetected in the same way. This isn't true because in the space between galaxies astronomers can detect matter as it spreads over thousands or millions cubic light years. Atoms can't hide; there is always radiation.
- Dark matter candidates:
- [A line graph is shown and labeled at left quarter in eV and further to the right in g together with some prefixes.]
- [The labels read:]
- µeV, meV, eV, keV, MeV, GeV, TeV, 10-18kg, ng, µg, mg, g, kg, TON, 106kg, 1012kg, 1018kg, 1024kg, 1030kg
- [All items are shown in bars ranging between two approximately values:]
- < 1 µeV - 10 meV: Axion
- 1 eV - 10 keV: Sterile neutrino
- 0.5 MeV (exactly): Electrons painted with space camouflage
- 10 GeV - 10 TeV: Neutralino
- 100 TeV - 10-17 kg: Q-ball
- 1 ng - 100 ng: Pollen
- 0.1 mg - 1 mg: No-See-Ums
- 10-1 g (exactly): Bees
- 10 g - 100 g: 8-balls
- 100 kg - TON: Space cows
- TON - 109 kg: Obelisks, monoliths, pyramids
- 109 kg - 1033 kg: Black holes ruled out by:
- 109 kg - 1013 kg: Gamma rays
- 1013 kg - 1017 kg: GRB lensing
- 1015 kg - 1022 kg: Neutron star data
- 1021 kg - 1030 kg: Micro lensing
- 1024 kg - 1030 kg: Solar system stability
- 1030 kg - 1033 kg: Buzzkill astronomers
- 1033 kg - >1036 kg: Maybe those orbit lines on space diagrams are real and very heavy
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Alternate Names: Lunar Orbiter-D, 02772
Launch Date: 1967-05-04
Launch Vehicle: Atlas-Agena D
Launch Site: Cape Canaveral, United States
Mass: 385.6 kg
Nominal Power: 375.0 W
Launch/Orbital information for Lunar Orbiter 4
Experiments on Lunar Orbiter 4
Data collections from Lunar Orbiter 4
Lunar Orbiter 4 was designed to take advantage of the fact that the three previous Lunar Orbiters had completed the required needs for Apollo mapping and site selection. It was given a more general objective, to “perform a broad systematic photographic survey of lunar surface features in order to increase the scientific knowledge of their nature, origin, and processes, and to serve as a basis for selecting sites for more detailed scientific study by subsequent orbital and landing missions. It was also equipped to collect selenodetic, radiation intensity, and micrometeoroid impact data. The spacecraft was placed in a cislunar trajectory and injected into an elliptical near polar high lunar orbit for data acquisition. The orbit was 2706 km x 6111 km with an inclination of 85.5 degrees and a period of 12 hours.
After initial photography on 11 May 1967 problems started occurring with the camera’s thermal door, which was not responding well to commands to open and close. Fear that the door could become stuck in the closed position covering the camera lenses led to a decision to leave the door open. This required extra attitude control manuevers on each orbit to prevent light leakage into the camera which would ruin the film. On 13 May it was discovered that light leakage was damaging some of the film, and the door was tested and partially closed. Some fogging of the lens was then suspected due to condensation resulting from the lower temperatures. Changes in the attitude raised the temperature of the camera and generally eliminated the fogging. Continuing problems with the readout drive mechanism starting and stopping beginning on 20 May resulted in a decision to terminate the photographic portion of the mission on 26 May. Despite problems with the readout drive the entire film was read and transmitted. The spacecraft acquired photographic data from May 11 to 26, 1967, and readout occurred through June 1, 1967. The orbit was then lowered to gather orbital data for the upcoming Lunar Orbiter 5 mission.
A total of 419 high resolution and 127 medium resolution frames were acquired covering 99% of the Moon’s near side at resolutions from 58 meters to 134 meters. Accurate data were acquired from all other experiments throughout the mission. Radiation data showed increased dosages due to solar particle events producing low energy protons. The spacecraft was used for tracking purposes until it impacted the lunar surface due to the natural decay of the orbit no later than October 31, 1967, between 22–30 degrees W longitude.
Spacecraft and Subsystems
The main bus of the Lunar Orbiter had the general shape of a truncated cone, 1.65 meters tall and 1.5 meters in diameter at the base. The spacecraft was comprised of three decks supported by trusses and an arch. The equipment deck at the base of the craft held the battery, transponder, flight progammer, inertial reference unit (IRU), Canopus star tracker, command decoder, multiplex encoder, traveling wave tube amplifier (TWTA), and the photographic system. Four solar panels were mounted to extend out from this deck with a total span across of 3.72 meters. Also extending out from the base of the spacecraft were a high gain antenna on a 1.32 meter boom and a low gain antenna on a 2.08 meter boom. Above the equipment deck, the middle deck held the velocity control engine, propellant, oxidizer and pressurization tanks, Sun sensors, and micrometeoroid detectors. The third deck consisted of a heat shield to protect the spacecraft from the firing of the velocity control engine. The nozzle of the engine protruded through the center of the shield. Mounted on the perimeter of the top deck were four attitude control thrusters.
Power of 375 W was provided by the four solar arrays containing 10,856 n/p solar cells which would directly run the spacecraft and also charge the 12 amp-hr nickel-cadmium battery. The batteries were used during brief periods of occultation when no solar power was available. Propulsion for major maneuvers was provided by the gimballed velocity control engine, a hypergolic 100-pound-thrust Marquardt rocket motor. Three-axis stabilization and attitude control were provided by four one-lb nitrogen gas jets. Navigational knowledge was provided by five Sun sensors, Canopus star sensor, and the IRU equipped with internal gyros. Communications were via a 10 W transmitter and the directional 1 meter diameter high gain antenna for transmission of photographs and a 0.5 W transmitter and omnidirectional low gain antenna for other communications. Both antennas operated in S-band at 2295 MHz. Thermal control was maintained by a multilayer aluminized mylar and dacron thermal blanket which enshrouded the main bus, special paint, insulation, and small heaters.
Results of the Lunar Orbiter Program
The Lunar Orbiter program consisted of 5 Lunar Orbiters which returned photography of 99% of the surface of the Moon (near and far side) with resolution down to 1 meter. Altogether the Orbiters returned 2180 high resolution and 882 medium resolution frames. The micrometeoroid experiments recorded 22 impacts showing the average micrometeoroid flux near the Moon was about two orders of magnitude greater than in interplanetary space but slightly less than the near Earth environment. The radiation experiments confirmed that the design of Apollo hardware would protect the astronauts from average and greater-than-average short term exposure to solar particle events. The use of Lunar Orbiters for tracking to evaluate the Manned Space Flight Network tracking stations and Apollo Orbit Determination Program was successful, with three Lunar Orbiters (2, 3, and 5) being tracked simultaneously from August to October 1967. The Lunar Orbiters were all eventually commanded to crash on the Moon before their attitude control gas ran out so they would not present navigational or communications hazards to later Apollo flights. The Lunar Orbiter program was managed by NASA Langley Research Center and involved building and launching 5 spacecraft to the Moon at a total cost of $163 million.
Original source: NASA – NSSDC | 0.818565 | 3.177451 |
ALMA: A look into the universe’s soul
ALMA, or “soul” in Spanish, is the name of the world’s largest telescope, located over 5,000 metres above sea level in the Atacama desert, Chile. The facility’s 66 mobile parabozlic antennas provide ALMA with a variable diameter that ranges from 150 metres to 16 kilometres. This serves as a gigantic zoom lens and allows the telescope to peer deep into the universe’s soul. ALMA will be officially inaugurated on 13 March 2013. At its heart lie fiber optic connections from HUBER+SUHNER.
The abbreviation ALMA actually stands for Atacama Large Millimeter Array. The installation site was chosen for a very specific reason: the Atacama is the world’s driest desert, the Chajnantor plateau is flat and lies 5100 metres above sea level. No other place on Earth offers a clearer view of the stars. Institutions from North America, Japan and Europe are working together at this location to discover how the very first galaxies formed in the early universe.
66 antennas – one telescope
ALMA is what is referred to as an “array” telescope. Instead of one massive parabolic antenna, it is comprised of 66 individual satellite dishes, most of which have a diameter of just 12 metres. Some are even 7 metres or smaller. They can, however, be distributed across the Chajnantor Plateau in different configurations and, when taken together, form one gigantic telescope. The diameter of this mega-telescope varies from 150 metres to 16 kilometres, with the mobile antennas acting as a type of zoom lens. The researchers can rearrange the dishes to give them the best view of the object they are currently interested in. The antennas, which each weigh over 100 tonnes, are moved on a rotating basis by two gigantic transporters. This allows some antennas to be relocated each day while the remainder continue to operate and provide information. Over a period of months, the entire array can be reconfigured from a compact arrangement to a distributed group, and vice versa.
Interferometry with LiSA and MASTERLINE
In order for the numerous antennas, which operate at millimeter wavelengths, to function as a single unit, they need to be linked together and their various signals merged into one. This process is referred to as interferometry and requires the utmost precision. To this end, 191 concrete pedestals that allow the antennas to be anchored with millimetre accuracy are distributed across the plateau. The pedestals are connected to the power supply and a fiber optic network for collating the signals emitted by the various telescopes. This star-shaped network centres around a technology building on the antenna field. And, at the heart of this building at a height of 5,100 metres, you can find earthquake-resistant LiSA cabinets from HUBER+SUHNER. Here, the fiber optic cables converge before splitting again in some cases. They are then distributed to the active systems of the central computer using preassembled MASTERLINE fiber optic cable systems, also from HUBER+SUHNER. These systems are highly robust and are able to withstand the low temperatures that can cause problems at such heights. They also have extremely low fiber length tolerances to prevent time differences occurring during signal transfer that could have a detrimental effect on interferometry. Since all connections need to be reattached whenever the dishes are moved to a new position, the plug-and-play concept greatly simplifies the relocation of individual antennas.
Data centre at just 2,900 metres
Since neither humans nor computers are able to operate effectively above 5,000 metres, the massive amounts of data generated are processed and analysed at a different location. The bundled signals are therefore transferred through a fiber optic connection to a data centre 28 kilometres away that lies just 2,900 metres above sea level. Upon arrival, they are analysed by a host of high-performance computers and around 500 astronomers and engineers. To facilitate this, the incoming signals pass through another set of LiSA distribution cabinets and MASTERLINE cable systems from HUBER+SUHNER. Together, these provide a complete, customer-specific solution for all passive fiber optic components used at ALMA, including support.
Inauguration on 13 March 2013
It has, however, taken a long time to reach this stage. The first surveys of the Chajnantor Plateau were conducted in the mid-1990s. Once it had been determined that the location was suitable, North America, Japan and Europe agreed to joint implementation of the project in 2001. Construction started in November 2003. It was not possible to obtain the first scientific readings until 2011, and this was with a heavily reduced infrastructure. The official inauguration ceremony for ALMA will be held on 13 March 2013, almost ten years after the start of construction. Only then will it enter full operation. By this date, all 66 antennas will be on site, mostly in operational use, as well as all main systems in the observatory. The entire team will also start work on the project, from system maintenance to research. Only then will ALMA be able to take up its true calling: revealing the soul of our universe. | 0.806102 | 3.678141 |
NASA scientists discovered the mystery of the Ocean of Storms formation of the moon, which is a region located on the moon, has a rough outline, the original studies suggest that the formation of the Ocean of Storms from the asteroid impact.
Moon Ocean of Storms has a clear edge rectangular polyline, NASA scientists believe that it is not formed in a celestial collision
According to foreign media reports, NASA scientists discovered the mystery of the moon on the ocean storm formation, which is a region located on the moon, has a rough outline, the original studies suggest that the formation of the Ocean of Storms from the asteroid impact, if this theory is correct, then the Moon basin formed thereby also from the asteroid impact, thus introduce more asteroid impacts associated with the formation mechanism of the lunar terrain, and therefore determine the Ocean of Storms formed from research in favor of impact craters on the moon type But NASA Gravity Recovery and Internal Laboratory (GRAIL) probes mission specialists found new evidence that the Ocean of Storms formed not from the impact, but the results of the lunar evolution of ancient rift.
Moon Ocean of Storms formed around the rugged contours, spans about 1,600 miles, that is 2600 km, which is located close to the Earth side of the moon, the terrain is characterized by lower elevations to more ancient volcanic plains. In fact, our side of the moon near the planet a lot of observation and research, also found that the distribution of lunar magma flow inside the system, leading researchers from the Massachusetts Institute of Technology scientist Maria Zuber also NASA GRAIL mission She thought we noticed the presence of the moon magma system trails gravity anomaly part, this is because the ancient lunar volcanic eruption of lava into the underground passage near the ground, and the distribution of the location of these rifts in the area covered by lava, Therefore, we found that they can be by gravity anomalies.
Scientists also discovered on the moon magma inside the submerged ancient rift formation mechanism and other celestial bodies in the solar system is somewhat different, such as rift zone we found on Mars and Venus on a distinction, but we can still reveal anomalies of gravity data rectangle patterns. The theory of the impact that the previous scientists is contrary, that the latter is formed from Ocean storm celestial collision, as such tend to form a circular impact shock structure, and has sharp edges Ocean storm fold, indicating that Another strength is the formation of the Ocean of Storms.
Although the Ocean of Storms rift Mars, Venus and other celestial bodies are different, but scientists have found very striking similarities in the structure of Enceladus south pole region, where there are huge giant terrain, so these two regions are subject to their own internal volcano and tectonic movements influence. Scientists believe we uncover the history of lunar gravity data, showing the moon’s interior more dynamic, probing the distribution of values GRAIL lunar gravity detector in December 2012 ended the mission, the task for the scientists to learn about the solar system, rocky the formation and evolution of celestial chance. | 0.837232 | 3.591349 |
by Pamela Welch
(Originally published in The Mountain Astrologer magazine. Republished in remembrance of Pamela, who passed away in March 2012.)
Everyone has probably heard that old familiar sports term: “Out-of-bounds!” Regardless of the sport involved, these words mean that the ball or player has gone beyond the limits of the established field of play. Could a similar dynamic be impacting the planetary play on the field of your birth chart? You bet! Out-of-bounds planets can take us beyond the established limits of thought and action. They can signify extraordinary genius or point to volatile and aberrant behavior. This article will explain the principles involved in out-of-bounds dynamics, show how these planetary elements can operate in a person’s life and discuss ways to interpret how these natal energies will manifest.
How Planets Go Out of Bounds
Out-of-bounds planets involve two dynamics: declination and the ecliptic. The ecliptic is the apparent path of the Sun in its yearly motion across the sky. Of course, in reality we know that it is not the Sun that is moving, but rather the Earth that is orbiting around the Sun. Thus, the ecliptic is actually the plane of the Earth’s orbit. Usually when we speak of astrological coordinates − for example, “My natal Saturn is at 14° Virgo” − we are giving the planet’s position in geocentric celestial longitude. This measurement, which is part of the ecliptic coordinate system, expresses the planet’s distance along the ecliptic from 0° Aries as viewed from Earth. However, in addition to this system which uses the ecliptic as its reference point, we also have what’s called the equatorial coordinate system which uses the Earth’s equator rather than the ecliptic as its plane of reference. Declination, which measures the angular distance of a heavenly body north or south of the celestial equator, is part of this equatorial system.
An easy way to comprehend declination is to simply imagine the parallels of latitude on a terrestrial map extended out into celestial space. The latitude lines that are projected in this way beyond our planet’s surface are called parallels of declination in the equatorial coordinate system. If you think of the Earth’s equator extending out into space to create the celestial equator at 0°, the parallels of declination involve those coordinates north or south of this plane.
Due to the tilt of the Earth on its axis, the Sun’s path varies in declination between about 23°27’ north of the equator at the Tropic of Cancer (summer solstice in the northern hemisphere) and 23°27’south at the Tropic of Capricorn (winter solstice). (See the Diagram at the end of this article.) When a celestial body goes beyond this maximum declination of 23°27’, either north or south, it is considered out-of-bounds. In that position, the planet is outside the boundary limits of the ecliptic plane − that is, beyond the plane of the Earth’s orbit around the Sun. The exact maximum declination of the Sun, which varies slightly by seconds from year to year, is now actually a little less than 23°27’. However, even at 23°27’01”, a planet is just beginning to go out-of-bounds without much noticeable effect. Because of this and the fact that many ephemerides and computer programs only give declination in degrees and minutes, I find it easier and more measurably significant to simply use planetary positions of at least 23°28’ declination.
Because the Moon and inner planets achieve higher declinations, they are the ones more frequently considered in working with the out-of-bounds phenomenon. (The asteroids can also go out-of-bounds; however, they won’t be specifically mentioned in this article.) Uranus and Pluto go out-of-bounds less frequently and stay there for longer periods. Saturn and Neptune have practically the same declination as the Sun while Jupiter only goes a few minutes beyond 23°27’. The Moon, on the other hand, can reach a declination of almost 29° every 18.6 years when the North Node is near 0° Aries. Mercury achieves a declination of 27°. Mars can usually only reach 27° too. However, in 1907 Mars got out to 28S54. On rare occasions, Venus will also reach 28°. I’ve found that generally the higher the degree of declination, the more pronounced the effect of the out-of-bounds planet will be, whether this is expressed in terms of greater accomplishment for the native or in some type of abnormal behavior.
The Influence of Out-of-Bounds Planets
Let’s take a more specific look now at exactly how an out-of-bounds planet will operate in an individual’s life. In most cases, my discussion will include both a planet’s declination and its sign placement in the more familiar geocentric longitude to help you integrate out-of-bounds dynamics into your astrological chart analysis.
As you might guess, people with an out-of-bounds planet tend to know no boundaries and accept no limits. Often there’s no stopping them. This can result in boundless creativity and success, allowing the native to go way beyond the potential that one might normally expect. For example, Albert Einstein who has an out-of-bounds Moon in Sagittarius near the 6th house cusp, creatively provided a whole new paradigm in regards to time and space through his work on the theory of relativity. His philosophical beliefs weren’t constrained by his era’s prevailing system of thought. Natives with an out-of-bounds planet like to break the rules in this way and color outside the lines. A client of mine with an out-of-bounds Moon in Sagittarius in the 1st house is currently in the process of writing an epic narrative poem akin to Beowulf. When was the last time anyone attempted that? This is the kind of unconventional and “outside the norm” expression you often see in someone with an out-of-bounds planet. Such individuals can often achieve extraordinary things and overcome great obstacles in life.
However, an out-of-bounds planet can also be negatively expressed, leading to abnormal or unstable behavior which is outside the accepted standards of society. Its energy can indicate a tendency toward mental imbalance or at the very least create a lot of pressure and stress in an individual’s life. The highest declination Moon I’ve ever seen in my astrology practice (28°S18’) was in the chart of a man suffering from bipolar disorder (manic-depression).
There is a fine line between genius and insanity and sometimes you will see both positive and dysfunctional elements in the lives of those with out-of-bounds planets. Judy Garland, for example, had two out-of-bounds planets – Venus in Cancer in the 1st house and Mars in Sagittarius in the 6th. Garland was certainly a sensitive beauty. However, she was also overworked as a child star and encouraged to take amphetamines. Venus is quincunx Mars in her chart and it may have been difficult for her to reconcile her emotional insecurities and desire for a loving, peaceful environment (Venus in Cancer) with the demands for her to be an energetic and exuberant working star (Mars in Sagittarius). Although she had tremendous success as an actress and singer from a young age, she also suffered from health problems and depressive mental illness accompanied by an addiction to prescription medications. This resulted in several suicide attempts and finally death. Although Venus is only at 23°N 49’declination, Mars is at 25°S 55’, creating greater instability. Mars opposite her Sun in Gemini in the 12th house is an indicator of subconscious anger directed inward in aggression towards herself. Such suppression of deeper feelings may have led to Garland’s depression as well as the ultimate act of brutality toward the self — suicide.
Often, people with out-of-bounds planets seem to get away with more somehow, or try to. They can be those individual’s that are always pushing the limits of what we commonly accept in society. With an out-of-bounds Mercury in Gemini, Dr. Jack Kevorkian, the physician who believes in euthanasia for the terminally ill, is certainly one of these people. He has had repeated conflict with the law for his belief in assisted suicide. Mercury is related to the physician and healing. However, mythically the Roman god Mercury could also put people asleep with his magic wand or be a messenger of death. Kevorkian has certainly taken on this aspect of Mercury’s expression. With Mercury at 25°>N39’ declination, we would expect to see this type of more radical behavior in support of his extremely adamant opinions.
American talk-show host, Howard Stern, also with an out-of-bounds Mercury (23°S41), is another iconoclast pushing the envelope of societies accepted norms. He loves to shock his radio audience with sexually oriented and socially unacceptable topics such as flatulence and penis size. Stern’s natal Mercury in Capricorn is conjunct Venus, Sun, Chiron and North Node, all in that same sign. He’s certainly achieved fame and star status with his irreverent radio show, biographical book, “Private Parts,” and subsequent movie by the same name. His Capricorn coldness is evident as he talks about people as little more than objects for appraisal. Stern’s out-of-bounds Mercury is in opposition to Uranus and South Node in Cancer and this definitely fits his shock jock demeanor which loves to upset the “status quo.” However, Cancer can be a vulnerable sign and his movie, “Private Parts” illustrated his early anxiety and self-doubt. To this day, when Stern is out of the sound booth and no longer on air, he’s said to be full of insecurities. His outrageous and domineering style may be a front for deeper vulnerabilities.
Daredevil Evel Knievel had an out-of-bounds Venus in Sagittarius within two degrees of his Midheaven at the high declination of 26°S17. His somewhat bizarre stunts went way beyond even the extreme end of adventure sports. Adventure was certainly his indulgence as well as his career and the way he attracted money along with admiring women. No doubt, there was a kind of grace he exhibited as his motorcycle flew like an arrow over a row of cars or a tank full of sharks. Out-of-bounds Venus is also quintile Neptune which is conjunct Mars in Virgo in his chart. The quintile (72°) indicates spontaneous creative expression and mental or artistic talents. You could say that Knievel had a creative talent for dissolving the boundaries of what is normally considered possible for the physical body. The mental energy of quintiles also excels at the kind of exact engineering calculations which were probably required as part of the preparations for his stunts.
However, Venus in Sagittarius can lead to a vain belief that you can do anything and a Mars-Neptune conjunction can also characterize a weakening of one’s physical condition. Consequently, with Venus trine Pluto (destruction, death) in Leo in the 6th-house of health, in addition to Saturn square 6th-house Chiron, Evel had numerous injuries, broken bones, and subsequent operations during his career. With out-of-bounds Venus in the sign that rules the Liver, in addition to a 1st-house Jupiter in Aquarius, it is not surprising that during one of these operations, he contracted Hepatitis C from a blood transfusion. This resulted in a liver transplant operation for him in 1999. Venus is also in a quindecile aspect to 3rd-house Uranus in Taurus. The quindecile aspect (165°) represents a disruption or compulsion, an obsessive influence which can draw one away from the main thrust of life development. Knievel’s stubborn obsession with adventure and his vain compulsion to do anything to shock his admiring fans resulted in many damaging jolts to his body.
Knievel also had a reputation for being an out of control hell-raiser, an excessive behavior associated with his out-of-bounds Venus in Sagittarius. It helps that in addition to the quindecile to Uranus and trine with Pluto, Venus is also sextile his Aquarius Ascendant which opposes Pluto. He had a history of aggression and was once arrested on charges of beating (Pluto) his girlfriend (Venus).
An out-of-bounds Mars is found in the natal chart of diplomat Henry Kissinger. Considering the assertive nature of Mars, this might seem strange for someone who was recipient of the Nobel Peace Prize in 1973. In actuality, Kissinger is an interesting mix. With a 1st-house OOB Mars in Gemini, he courageously negotiated diplomatic dialogues with heads of state in order to end aggressive conflicts such as the Vietnam War. This is supported by his 12th-house Sun-Mercury conjunction in Gemini (secret talks in closed sessions) trine Saturn in Libra and the trine of Kissinger’s Mars to his Moon in Libra, which potentially keeps its bellicose nature more peacefully directed. With Saturn also broadly conjunct his Libra Moon, he was able to make his lack of emotion work for him by asserting himself with peaceful words. At 28° Gemini in the third decan of this sign, Mars can also be less impulsive, more ruled by reason and the power of the objective mind. Kissinger was thus able to summon great courage and overcome difficult obstacles in dealing with many tense political situations.
However, we now know that Kissinger also covertly initiated atrocities and violent acts in Vietnam. In addition, he brought the downfall of the democratic Allende government in Chile in the ‘70’s to support the Chilean leader, General Augusto Pinochet, who tortured his people. (See The Trial of Henry Kissinger by Christopher Hitchens.) In this respect, Kissinger’s lack of emotion may have created an “end justifies the means” mentality.
Nevertheless, out-of-bounds Mars is found more frequently in the charts of courageous or creative individuals and great leaders than it is in violent criminals. It can also indicate an “off the charts” type of athletic ability as it does with golfer Tiger Woods, who has Mars in Gemini opposite the Moon in Sagittarius square a Virgo Ascendant.
The Out-of-Bounds Moon
Individuals with an out-of-bounds Moon are usually very unique and independent people who enjoy their freedom and solitude. However, because the Moon represents the subconscious emotional imprint, its energy can be deeply felt by the native who has this luminary out-of-bounds. People sometimes suffer from the pressure of its turbulent effects and often there is a tendency to experience loss or unsettling conditions, especially within one’s family. Due to the Moon’s changing nature and association with emotions, there is an increased likelihood for extreme sensitivity, emotional instability or mood swings, and feelings of doubt, guilt or depression when it is found out-of-bounds. Also, the Moon’s tendency toward insecurity can become a full blown paranoia. There may be an underlying sense that one’s basic security is being undermined or threatened in some way. This is often accompanied by an instinctive and irrational reaction of fear or suspicion. For instance, a client of mine with an out-of-bounds Moon in Taurus, desperately and tenaciously works for material success out of fear that she will end up like her father, a Pisces, who followed his dream but was financially unsuccessful.
Sometimes the insecure feelings will manifest physically as health issues. Frequently, this comes in the form of food compulsivity or weight problems because of the subconscious link between food and emotional nourishment. A larger size or the insulation of weight can also unconsciously represent protection from any perceived threat.
Linda Tripp, for example, has an out-of-bounds Moon (25°S28’) conjunct out-of-bounds Venus (25°S12’) in Capricorn. Her political paranoia and maternal over protection of White House intern, Monica Lewinsky, led to extreme measures. Tripp taped intimate conversations that she had with Lewinsky about her affair with President Clinton for prosecutor Ken Starr. True to her out-of-bounds Moon, Tripp later said she did it for her own protection and because she felt it was her “patriotic duty.” She claims to have received threatening messages from President Clinton via Monica in regards to testifying in the Paula Jones sexual harassment case. According to Tripp, she feared that she would lose her job or be charged with perjury because she was being pressured by Lewinsky to be a team player and lie for the president in the case.
In Tripp’s natal chart, the Moon and Venus are conjunct Jupiter in Capricorn. Tripp may have had big plans for political favors or money from a book deal in mind when she secretly taped her friend (Venus semisquare 12th–house Sun-Mercury), although she now says she’s never profited in any way. Jupiter conjunct 2nd-house Venus-Moon and Venus quincunx Pluto in the 9th-house made the righteous subterfuge that much bigger. These planetary placements show the potential for zealous beliefs and a rigidly judgmental value system along with a subconscious desire for a powerful or prominent social position. In fact, in an interview in George magazine, Tripp admits to her judgmental inflexibility and states that she dreamed of working at the White House since she was eight years old.
The ambition of a Capricorn Moon can be callous and many Americans considered Tripp’s taping of private conversations with Monica the ultimate betrayal of a friend. Venus square Neptune in Libra often shows such deception in a relationship and Neptune’s wider orb square to the out-of-bounds Moon added to Tripp’s paranoia regarding her enemies in power. With Venus square 4th-house North Node in Aries as part of the t-square to Neptune, she felt compelled to use the deceit for her own safety and self-preservation. The quindecile between Venus and Uranus in Cancer in the 7th-house gave her the obsession with love life in Washington as well as the emotional detachment to perform such a breach of a friend’s personal trust. The Venus trine to 9th-house Saturn and Mars in Virgo helped Tripp participate in the critical attack on the President who she felt was misusing both political and sexual power.
As is sometimes seen with an out-of-bounds Moon, Tripp’s actions may have been subconsciously motivated by a need for security and love. This is especially true in her case with the Moon conjunct Venus. She admits to lacking a personal self-confidence (Sun in the 12th-house), although she’s experienced it professionally (Jupiter conjunct the Moon in Capricorn). The New York Times reported that in her high school yearbook she describes her pet peeve as “a certain fair-weather friend.” This is telling not only because of what she later did to Monica Lewinsky, but also because of the much earlier fear of betrayal it shows related to the out-of-bounds Moon.
Venus quindecile Uranus in Cancer indicates that these issues may be rooted in some disruption of the basic home life in childhood that affected her sense of emotional security with others. The Capricorn Moon often indicates a mother or caretaker who was more of a drill sergeant than a nurturer and Venus trine Saturn and Mars in Virgo can relate to a critical father. Linda’s mother, who was staunchly German, was intimidated by her father who ruled the family with an iron fist. Tripp has stated that no matter how much she tried she couldn’t get the approval of her strict father. He deserted the family for another woman when she was still in high school and Linda suffered through the subsequent painful divorce of her parents. Tripp’s obsession with bringing down the powerful philanderer, Clinton, may have been based on her need to rebel against her father’s earlier actions of infidelity (Uranus quindecile Venus in Capricorn).
These emotional issues probably contributed to Tripp’s weight problem and she was insecure (Moon) about her looks (Venus). She admits that she deals with the difficulties in her life through food, a symptom of her out-of-bounds Moon, and that she was horrified by how unattractive she looked. After being scandalized by the press and ridiculed by late night comedians, Tripp had expensive cosmetic surgery that was paid for by a supporter. Considering the extreme emotional sensitivity of individuals with out-of-bounds Moon, the constant derision about her appearance must have been devastating for her. I’m sure she suffered greatly. Consequently, she had two plastic surgeries to reconstruct her face, making her more attractive (Capricorn Venus trine Saturn-Mars in Virgo), along with losing 30 pounds and having a total makeover to change her entire look.
Tripp was indicted by a grand jury for illegal wiretapping on July 30, 1999 when her solar arc directed Moon in Pisces opposed natal Saturn. Contacts involving the progressed or directed Moon are particularly important for people born with it out-of-bounds. They can often signify pivotal events such as this in the native’s life. These felony charges have since been dropped. However, Tripp is currently suing the White House and the Defense Department, her former employer, for leaking information to the press from her personal file for purposes of discrediting her.
Oprah Winfrey is another woman with an out-of-bounds Moon (24°S59’) who has struggled with her weight. Her Moon in Sagittarius on the 12th-house cusp quindecile Jupiter in the 6th shows both the subconscious compulsion to eat, accompanied by the expanding physical size, and also the obsession with diet. The sometimes wildly erratic nature of the out-of-bounds Moon contributed to the changing fluctuations in Oprah’s weight. Often a native with an out-of-bounds Moon will resist any thing that even feels like a limitation or restriction, an inconvenient trait if you’re dieting. Oprah admittedly prefers the freedom of spontaneity and even refuses to set future goals because she feels it is too confining.
Influence of the Mother
The out-of-bounds Moon often reveals an overachiever who is unconsciously seeking success, prominence or material security as a substitute for the love and attention that was not received from the mother during childhood years, something that may have plagued both Oprah and Linda Tripp. Oprah was born illegitimate and poor in the Deep South. At a young age, she was abandoned by her mother who went North to work and left to live with her grandmother. Oprah has tremendous drive and does the job of four people as she hosts a TV show, acts, spearheads a magazine, and runs her own production company, Harpo. She has also taught a “Dynamics of Leadership” class at Northwestern University and served as a philanthropist providing over five million dollars in scholarships through her Angel Network (benevolent Jupiter in the 6th house of service). In addition to the weight issue, Oprah’s Moon-Jupiter quindecile can indicate a compulsion to overwork (6th house). It is no secret that she works long hours, sometimes 16-hour days, and that she can be a hard driving worker obsessed with perfection. Oprah also admits that an inability to say “No” in former years was due to wanting to be liked by others. Part of Oprah’s drive to succeed may have been due to the hidden emotional wound resulting from the earlier abandonment by her mother.
The 12th-house Moon in Sagittarius gives Oprah the need to tell the truth and an impetus to nurture and educate society spiritually. Anyone who watches Oprah’s TV show, reads her magazine, or has attended one of her personal growth summits is familiar with the emphasis she puts on the spiritual aspect of life. She says a prayer before every show. Oprah is a truth seeker who listens to an inner voice and she has the ability to uplift and encourage others with her spiritual philosophy. On the boundary between the 11th and 12th houses, the Sagittarius Moon helps her to be a bridge bringing spiritual ideals (12th) to many diverse groups (11th). She is an inspirational teacher to many.
Not surprisingly, Oprah got her first talk-show job in Baltimore as co-host of WJZ-TV’s “People are Talking” when her solar arc directed Moon conjunct her Ascendant in 1978. This was especially momentous in Oprah’s case since her Ascendant is at 29°42’ Sagittarius and close to the 0° Capricorn winter solstice point. Directed to this point, Oprah’s out-of-bounds Moon was announcing that her career success was just beginning to germinate and would soon be on the rise. Interestingly, the Sabian symbol for 30° Sagittarius is “The Pope, blessing the faithful,” and she has since been accused of trying to start the “church of Oprah” with segments like “Remembering your Spirit” on her current television show.
Moon and Ascendant in Sagittarius as well as Jupiter in Gemini gives Oprah the ability to expand the dimensions of other people’s lives, to educate them, and communicate broader philosophies of life to society. 6th-house Jupiter can work hard at the truth and Oprah has made this her job. She has said that it is the educational aspect of her TV show and the ability to change lives that she most enjoys. Jupiter in Gemini indicates the communication of faith and optimism and Oprah’s out-of-bounds Moon in Sagittarius amplifies this to the maximum. This belief in something better has been a foundational part of Oprah’s own life and a motivation for others. Characteristic of her out-of-bounds Moon, she never recognized or even considered that any of her challenging life circumstances might limit her in any way. She started her public speaking career reciting inspirational sermons in church at the remarkably young age of three and a half years old, part of the atypical expression of the out-of-bounds Moon in Sagittarius. In fact, in the fourth grade Oprah was known as “preacher.” Her out-of-bounds Moon is also quintile Mercury, resulting in the extraordinary intellectual gifts and talented abilities as a child orator and adult talk-show host.
Jupiter also represents one’s inner teacher and with this planet in a quindecile aspect to her out-of-bounds Moon, it has been a life long process for Oprah to trust hers. After years of codependence seeking to please others, a symptom of her childhood abandonment and the victimization of sexual abuse, she has learned to speak her truth and listen to her inner voice as well as her lunar instincts. The Novile (40°) aspect between her Moon and the often codependent Neptune in Libra provided the creative inspiration that enabled her to find a spiritual rebirth out of the captivity of this old pattern. Oprah’s life definitely shows how the energy of the out-of-bounds Moon can be used to overcome great obstacles.
Transiting planets can be significant activators for a natal out-of-bounds energy. When transiting Pluto completed its long conjunction to her natal Moon in 1998, Oprah was devastated and depressed by the public’s negative response to her movie, Beloved. This film project was her baby. She nurtured the movie’s unfolding and then, at its birth, the product of her labor was rejected. Perhaps, the grief of a much older and deeper rejection linked with her out-of-bounds Moon was surfacing for her at that time. On the other hand, when transiting Jupiter opposed her out-of-bounds Moon, Oprah’s new publication, “O,” went over the top to become the most successful magazine start-up ever.
Working With Out-of-Bounds Planets
As this article illustrates, out-of-bounds planets signify one important aspect of astrological interpretation, especially in relationship to psychological factors and the potential for achievement. Today, planetary declination positions are available as part of most astrology computer programs. “Current declination positions can also be found in The American Ephemeris (2001-2010), the Astrolabe World Ephemeris (2001-2050) as well as the Raphael and Rosicrucian Ephemerides.” A plus sign (+) is used to indicate a northern declination and a minus (-) denotes a southern declination.
To identify out-of-bounds planets, note if the Moon or planet is beyond 23°27’declination and to what extent. As mentioned earlier, planets with higher declination numbers may have more of an impact than those that aren’t significantly beyond 23°27’. To interpret the planet’s effect, consider the qualities and characteristics normally associated with the planet involved and then think how it might manifest if it was behaving in a very extreme way. For example, when Mars is out-of-bounds, its natural assertion and physical energy can become violently aggressive or produce extraordinary courage and physical abilities. The alluring charm and aesthetic beauty of Venus can produce extremely vain indulgence or exceptional artistic talent. The planet’s sign and house placement will, of course, give more specific information about its expression.
As I have illustrated here, always look at the chart as a whole along with the aspects that are formed with the out-of-bounds planet. Positive aspects can mitigate the potential for a dysfunctional expression of the out-of-bounds planet by directing the energy in more productive ways. Challenging aspects can increase the likelihood of more abnormal behavior. For example, Oprah’s quintile aspect between out-of-bounds Moon and Mercury indicate her intelligence and talent for talk. The 1st-house Chiron conjunct North Node in Capricorn provided the opportunity for her to heal the lack of empowerment from childhood so that she could become a successful business maverick in the field of communications. Even so, the challenging Moon-Jupiter quindecile shows where the Moon’s out-of-bounds energy has had its most extreme expression through her weight problems and the insatiable energy she has for work on numerous projects. There may have been times that she needed to cut back on her workload, but just couldn’t stop.
On the other hand, even though he experienced professional success, Evel Knievel’s grand square in fixed signs, in addition to his quindecile between out-of-bounds Venus and Uranus as well as between Mercury-Uranus and Mercury-Saturn, indicate the chance for getting stuck in more compulsive or erratic thinking and behavior. Also, having more than one out-of-bounds planet in the chart increases the odds that the influence will be highly stressful. This is especially true when there are challenging aspects (square, opposition, quindecile, quincunx) between the two out-of-bounds planets, as in the case of Judy Garland.
Hopefully, this article has been an informative introduction to out-of-bounds planets that has also sparked your interest in declinations. There is certainly much more in this exciting world to explore. For example, even if a person does not have a natal planet out-of-bounds, through progression the Moon or planet may at some point step out-of-bounds. Depending on the planet’s length of time beyond the maximum declination of the Sun, this could be a short or long term influence on the native’s life. Begin to utilize these elements in your chart interpretation and see what you discover. Remember, even though an out-of-bounds Moon or planet can be challenging, it can also indicate your most extraordinary qualities. By becoming conscious of out-of-bounds planets, you can tap into their unlimited potential. So, have fun coloring outside the lines!
© 2001. Pamela Welch. All Rights Reserved.
Chart Data and Source
Albert Einstein, March 14, 1879; 11:30 a.m. LMT; Ulm, Germany (48°N24’, 10°E00’); Lois Rodden reports AA: Birth Record quoted by Ebertin, AstroDatabank www.Astrodatabank.com.
Judy Garland, June 10, 1922; 6:00 a.m. CST; Grand Rapids, MN (47°N14’, 93°W32’); Rodden Reports AA: Birth Record, AstroDatabank.
Dr. Jack Kevorkian, May 26, 1928; Pontiac MI (83°W17’, 42°N38’); Rodden reports X: Joanna Shannon quotes New York Times date with no time of birth, AstroDatabank – www.Astrodatabank.com.
Howard Stern, January 12, 1954; New York, NY (74°W00’, 40°N43’); Rodden reports X: Media quotes date, time unknown, AstroDatabank – www.Astrodatabank.com.
Robert Craig (Evel) Knievel – October 17, 1938; 2:40 p.m.; Butte, MT (112°W32’, 46°N00’); Rodden reports B: Birth data from Contemporary American Horoscopes, Gauquelin Book of American Charts; AstroDatabank – www.Astrodatabank.com.
Henry Kissinger, May 27, 1923; 5:30 a.m. CET; Furth, Germany (10°E59’, 49°N28’); Rodden reports AA: Birth Certificate data confirmed by cousin, AstroDatabank.
Tiger Woods, Dec. 30, 1975; 10:50 p.m.; Long Beach, CA (118°W11’, 33°N46’); Rodden reports AA: Birth Certificate in hand.
Linda Tripp – November 24, 1949; 8:00 a.m. EST; Jersey City, NJ (40°N44’, 74°W05’); Rodden reports AA: Birth Certificate in hand, AstroDatabank – www.Astrodatabank.com.
Oprah Winfrey, January 29, 1954; 4:30 a.m. CST; Kosciusko, MS (33°N03’, 89°W35’); Rodden reports A: Astrologer Robert Marks quotes Oprah from when he was on her show in 1988, AstroDatabank – www.Astrodatabank.com. Note: this is an updated birth time reported by Marks to Lois Rodden on 10/02/2000.
References & Notes
1. I would like to thank Kt Boehrer, pioneer of the Out-of-bounds concept, and Leigh Westin for their helpful works on declination and out-of-bounds planets. See, Kt Boehrer’s book, Declination: The Other Dimension (available from AFA, P.O. Box 22040, Tempe, AZ, 85285 USA, (888) 301-7630) and Leigh Westin’s book, Beyond the Solstice by Declination (available from Gheminee, P.O. Box 3874, Brookhaven, MS, 39603 USA) for more information.
2. The exact angular distance between the ecliptic plane and the celestial equator, called the obliquity of the ecliptic, varies over time. Since this also marks the maximum angular distance that the Sun can reach north or south of the celestial equator at the times of the solstices, the Sun’s maximum declination changes as part of this process. It can vary somewhat from year to year, moving forward and then backwards a few seconds until it finally moves past a certain point permanently. For example, at winter solstice 1999 it was at 23°26’15”, but in winter 2001 it was back up to 23°26’20”. Then, at winter solstice 2004, it will reach 23°26’27” and by 2010 it will be back down to 23°26’17”. Over an approximate period of 40,000 years, it varies from 21°59’ to 24°36’.
3. Pluto, for example, was out-of-bounds for 15 years from 1938-1953. The fact that it was out-of-bounds while in Leo may be one of the reasons why the Pluto in Leo age group has been such an out there “me” generation. Because Pluto and Uranus are out-of-bounds for longer periods, there is a collective level significance to such times. In their article, “Uranus and Pluto Out of Bounds,” Geocosmic Magazine (Spring 1998), Charles and Lois Hannan point out the importance of out-of-bounds Uranus and Pluto in regards to world war and revolution. Because Uranus and Pluto are outer transpersonal planets that carry more of a celestial punch, they have an important impact for individuals when out-of-bounds as well. They both go beyond 23°30’, an astrological indicator that Mitchell Gibson considers important in determining extreme behavior. (Uranus stays within about 24°. Pluto has been around 24° in the 1900’s, but got out to 26S33 in the 1200’s.) He discusses this elevation by extreme declination in his book, Signs of Mental Illness (Llewellyn 1998).
4. Kt Boehrer, Declination: The Other Dimension, El Paso, TX: Fortunata Press, 1994.
5. In his book, Signs of Mental Illness (Llewellyn 1998), Mitchell Gibson also utilizes such planetary declination in his examination of what determines psychopathology.
6. Garland had additional planetary placements significant of depression. See Barbara Banfield’s article, “The Astrology of Depression” in The Mountain Astrologer (Aug/Sept 2000).
7. Lois Rodden, from her AstroDatabank web site – www.Astrodatabank.com. Mentioned in the biographical data for Howard Stern.
8. Lois Rodden, from her AstroDatabank web site – www.Astrodatabank.com. Mentioned in the biographical data for Evel Knievel.
9. The subdivision of the signs into 10° arcs is referred to as the first, second and third decans or decanates. Interpretation is based upon a system of planetary rulership assigned to each decan.
10. I was first introduced to this information regarding the nature of the out-of-bounds Moon through Kt Boehrers article, “The Moon Has Her Reasons,” Geocosmic Magazine (Spring 1998). Also see her book, Declination: The Other Dimension.
11. Moon and Venus are also parallel since they are both south in the same degree of declination.
12. Biographical information comes from Nancy Collins’ interview of Linda Tripp in George magazine, Dec/Jan, 2001 and her Tripp interview on ABC’s 20/20 TV show on Jan 12, 2001.
13. Nancy Collins, “I’d Do It All Over Again,” George, Dec/Jan, 2001.
14. Elaine Sciolino and Don Van Natta Jr., “Testing Of A President: The Confidant; Linda Tripp, Elusive Keeper Of Secrets, Mainly Her Own,” New York Times, Sunday, March 15, 1998, http://nytimes.com.
15. Solar arc is a direction technique in which the arc distance in longitude between the natal and progressed Sun position is calculated and then added to all relevant natal positions.
16. Bibliographical information on Oprah’s life was found in the article by Lynette Clemetson, “Oprah On Oprah,” Newsweek, Jan 8, 2001 and on the Academy of Achievement web site http://www.achievement.org/autodoc/page/win0int-1.
17. See footnote 10.
18. The Novile (40°) represents inspiration, initiation and the birth that comes out of a spiritual stillness, or out of captivity as Dane Rudyar expressed it, as well as a means to nourish that birth.
19. Tools for working with challenging natal issues in order to come into alignment with the planet’s true intent can be obtained through a personal astrological consultation with me or found in my book, The Energy Body Connection: The Healing Experience of Self-Embodiment, St. Paul, MN: Llewellyn Publications, 2000.
Venus Out of Bounds
Want to learn more about Venus out of bounds? Join Tony Howard for a complete webinar class exploring several charts of key figures with natal Venus out of bounds. | 0.866774 | 3.6482 |
NASA's MAVEN enters Mars orbit
A NASA robotic spacecraft fired its braking rockets on Sunday, ending a 10-month journey to put itself into orbit around Mars and begin a hunt for the planet’s lost water.
After traveling 442 million miles (71 million km), the Mars Atmosphere and Volatile Evolution, or MAVEN, spacecraft fired its six rocket thrusters, trimming its speed from 12,800 mph (20,600 kph) to 10,000 mph (16,093 kph).
The 33-minute engine firing left MAVEN in the clutches of Mars’ gravity as it flew over the planet’s north pole and slipped into a looping 236-mile by 27,713-mile (380-km by 44,600-km) high orbit.
"I don’t have any fingernails anymore, but we made it," Colleen Hartman, NASA deputy director for science at Goddard Space Spaceflight Center in Greenbelt, Md., said during a NASA Television broadcast of MAVEN’s arrival.
Flight control teams burst into cheers and applause as radio signals from MAVEN confirmed it was in Mars orbit at 10:25 p.m. EDT/0225 GMT. Over the next several weeks, MAVEN will lower its altitude until it reaches its 93-mile by 3,900-mile (150-km by 6,200-km) operational orbit.
MAVEN will study how the solar wind strips away atoms and molecules in the planet’s upper atmosphere, a process that scientists believe has been underway for eons.
"By learning the processes that are going on today we hope to extrapolate back and learn about the history of Mars," MAVEN scientist John Clarke, with Boston University, said in an interview on NASA Television.
Scientists strongly suspect that Mars was not always the cold and dry desert it is today. The planet’s surface is riddled with what appear to be dry riverbeds and minerals that form in the presence of water.
But for water to pool on the planet’s surface, its atmosphere would have had to be much denser and thicker than it is today. Mars’ atmosphere is now about 100 times thinner than Earth’s.
Scientists suspect Mars lost 99 percent of its atmosphere over millions of years as the planet cooled and its magnetic field decayed, allowing charged particles in the solar wind to strip away water and other atmospheric gases.
Learning about how Mars lost its water is key to understanding if the planet most like Earth in the solar system ever could have supported life. The $671-million MAVEN mission is scheduled to last one year. The spacecraft joins two other NASA orbiters, two NASA rovers and a European orbiter currently working at Mars.
A seventh Mars probe owned by India is scheduled to arrive on Wednesday. | 0.830909 | 3.23787 |
GREENBELT, Md. (NASA PR) — NASA’s continued quest to explore our solar system and beyond received a boost of new information this week with three key missions proving not only that they are up and running, but that their science potential is exceptional. On Sept. 17, 2018, TESS — the Transiting Exoplanet Survey Satellite — shared its first science observations. Later in the week, the latest two missions to join NASA’s heliophysics fleet returned first light data: Parker Solar Probe, humanity’s first mission to “touch” the Sun, and GOLD, a mission that studies the dynamic boundary between Earth and space.
Part of the data from TESS’s initial science orbit includes a detailed picture of the southern sky taken with all four of the planet-hunter’s wide-field cameras. The image captures a wealth of stars and other objects, including systems previously known to have exoplanets, planets beyond our solar system. TESS will spend the next two years monitoring the nearest, brightest stars for periodic dips in their brightness, known as transits. Such transits suggest a planet may be passing in front of its parent star. TESS is expected to find thousands of new planets using this method.
Together, the two other missions represent two key observation points in the giant system of space — dominated by particles and magnetic energy from the Sun — studied by the field of heliophysics. Parker Solar Probe will help us understand how the Sun’s atmosphere drives particles out into space; GOLD monitors changes in the space close to Earth, much of them driven by ever-changing solar activity. The two viewpoints support heliophysics’ focus on our star and how it influences the very nature of space — and, in turn, the atmospheres of planets and human technology.
In early September, each of Parker Solar Probe’s four instrument suites powered on and returned their first observations on the spacecraft’s journey to the Sun. While the data are not yet examples of the key science observations the spacecraft will take closer to the Sun, they show that each of the instruments is working well.
The instruments work in tandem to measure the Sun’s electric and magnetic fields, and particles from the Sun and solar wind. They also capture images of the solar wind environment around the spacecraft. The mission’s first close approach to the Sun will be in early November 2018, but even now, still outside the orbit of Venus, the instruments indicate they’re ready to gather measurements of what’s happening in the solar wind.
“All instruments returned data that not only serves for calibration, but also captures glimpses of what we expect them to measure near the Sun to solve the mysteries of the solar atmosphere, the corona,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland.
WISPR, the mission’s only onboard imager, captured the first snapshots from its journey to the Sun on Sept. 9, 2018. Similarly, the FIELDS instrument suite provided the first magnetic field observations and even captured a burst of radio waves, signatures of a solar flare. One of the SWEAP instruments sampled its first gust of solar wind, and the ISʘIS instrument — pronounced “ee-sis” and including the symbol for the Sun in its acronym — successfully measured the energetic particle environment.
GOLD’s first light closely followed Parker Solar Probe’s. On Sept. 11, the GOLD — short for Global-scale Observations of the Limb and Disk — instrument powered on and opened its cover to scan Earth for the first time, returning a full-disk image of the Western Hemisphere in ultraviolet. In this wavelength of light, which is invisible to the human eye, GOLD enables researchers to view global-scale temperature and composition at the dynamic region where Earth’s upper atmosphere meets space.
GOLD commissioning began Sept. 4 and will run through early October, as the team continues to prepare the instrument for its planned two-year science mission.
“The GOLD mission is a game-changer, providing never-before-seen footage of upper atmospheric weather similar to the very first terrestrial weather satellites,” said Sarah Jones, GOLD mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These global-scale pictures of the boundary between Earth and space will allow scientists to start teasing out the effects coming from the Sun versus those coming from Earth’s weather below.”
With missions both near and far, like bookends in the vast stretch of space between the Sun and Earth, researchers are eager to fill knowledge gaps in our understanding of the complex relationship between solar activity and conditions at Earth.
Historically difficult to observe, the region GOLD studies is little-understood and can undergo dramatic change in as little as an hour. GOLD — which occupies geostationary orbit, hovering 22,000 miles over the Western Hemisphere — will provide hour-by-hour updates on the ever-changing conditions in near-Earth space, known as space weather. Shifts in space weather can garble space-traveling communications signals, interfere with electronics onboard satellites, endanger astronauts and at their most severe, disrupt power grids.
Meanwhile, Parker Solar Probe will travel into the blazing corona, closer to the Sun than any spacecraft before it. The mission seeks to answer fundamental questions about the Sun — questions that lie at the root of understanding how solar activity shapes space weather across the solar system.
TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by Goddard. Dr. George Ricker of MIT’s Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory in Lexington, Massachusetts; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.
Parker Solar Probe is part of NASA’s Living with a Star Program, or LWS, to explore aspects of the Sun-Earth system that directly affect life and society. LWS is managed by Goddard for the Heliophysics Division of NASA’s Science Mission Directorate in Washington. Johns Hopkins APL manages the Parker Solar Probe mission for NASA. APL designed, built and operates the spacecraft.
GOLD is a NASA mission of opportunity as part of the heliophysics Explorer Program. Goddard manages the Explorer Program for the Heliophysics Division of NASA’s Science Mission Directorate in Washington. It is designed to provide frequent, low-cost access to space using principal investigator-led space science investigations relevant to the agency’s astrophysics and heliophysics programs. GOLD is led by the University of Central Florida. The Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder built and operates the instrument. The GOLD instrument is hosted on a commercial communications satellite, SES-14, built by Airbus for Luxembourg-based satellite operator, SES.
- TESS Shares First Science Image in Hunt to Find New Worlds
- Illuminating First Light Data from Parker Solar Probe
- GOLD Instrument Captures Its First Image of the Earth | 0.834723 | 3.680872 |
Astronomers using NASA's Swift X-ray Telescope have observed a spinning neutron star suddenly slowing down, yielding clues they can use to understand these extremely dense objects.
A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. A neutron star can spin as fast as 43,000 times per minute and boast a magnetic field a trillion times stronger than Earth's. Matter within a neutron star is so dense a teaspoonful would weigh about a billion tons on Earth.
This neutron star, 1E 2259+586, is located about 10,000 light-years away toward the constellation Cassiopeia. It is one of about two dozen neutron stars called magnetars, which have very powerful magnetic fields and occasionally produce high-energy explosions or pulses.
Observations of X-ray pulses from 1E 2259+586 from July 2011 through mid-April 2012 indicated the magnetar's rotation was gradually slowing from once every seven seconds, or about eight revolutions per minute. On April 28, 2012, data showed the spin rate had decreased abruptly, by 2.2 millionths of a second, and the magnetar was spinning down at a faster rate. (read more) | 0.836224 | 3.458659 |
HiCIAO near-infrared image of the protoplanetary disk around PDS 70. The circular mask hides the star itself, as well as a smaller internal disk structure. (Credit: NAOJ)
Over the past couple of decades astronomers have figured out several methods for finding planets around other stars in our galaxy. Some have revealed their presence by the slight “wobble” they impart to their host stars as they orbit, while others have been discovered as they pass in front of their stars from our perspective, briefly dimming the light we see.
Now, some astronomers think they may have identified the presence of multiple planets, based on a large gap found in the disk of gas and dust surrounding a Sun-like star 460 light-years from Earth.
Using the High Contrast Instrument for the Subaru Next Generation Adaptive Optics (HiCIAO) mounted on Japan’s 8.2-meter optical-infrared Subaru telescope atop Mauna Kea in Hawaii, an international team of astronomers targeted PDS 70, a young star (10 million years old) about the same mass as the Sun located 460 light-years away in the constellation Centaurus.
The near-infrared observations made by HiCIAO reveal a protoplanetary disk surrounding PDS 70. This disk is composed of gas and dust and extends billions of miles out from the star. Quite literally the stuff that planets are made of, it’s a disk much like this that our solar system likely started out as over 4.6 billion years ago.
“Thanks to the powerful combination of the Subaru Telescope and HiCIAO, we are able to probe the disks around Sun-like stars. PDS 70 shows how our solar system may have looked in its infancy. I want to continue this kind of research to understand the history of planetary formation.”
– Team Leader Jun Hashimoto (NAOJ)
Within PDS 70’s disk are several large gaps positioned at varying distances from the star itself, appearing as dark regions in the near-infrared data. These gaps — especially the largest, located about 70 AU from the star — are thought to be the result of newly-formed planets having cleared the surrounding space of dust and smaller material. It’s also believed that multiple planets may be present since, according to the team, “no single planet, regardless of how heavy or efficient it is in its formation, is sufficient to create such a giant gap.”
In addition to the large disk structure and outer gap, PDS 70 also has a smaller disk located only 1 AU away. (This disk is obscured by the HiCIAO mask in the image above.)
Further observations will be needed to locate any actual exoplanets directly, since the light from the star and scattered light within the disk makes it difficult — if not impossible with current technology — to detect the incredibly faint light reflected by planets.
Still, it’s fascinating to come across what may very well be a solar system in its infancy, giving us a glimpse back in time to our own formation.
“Direct imaging of planets in the process of forming in protoplanetary disks would be ideal so that we can learn when, where, and how planets form,” said team leader Ruobing Dong of Princeton University.
Read more on the NAOJ website for the Subaru Observatory here.
The goal of the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) Project is to study the disks around less massive stars like the Sun.
Inset image: Artist’s rendition of PDS 70 and its two protoplanetary disks (NAOJ) | 0.899251 | 3.961488 |
Flecks of glimmering gold scattered on a black background. It isn’t a description of a new line of clothes, but a beautiful globular cluster that was recently photographed.
The star cluster, named Liller 1, is certainly one of the haute couture models of the sky, but it has been a tricky star system to snap. When we look out at it from Earth, Liller 1’s angle from us is almost in line with the center of the Milky Way. This means there’s a lot of dust muddying our view of it.
If this didn’t make it difficult enough to see, the cluster is also located 3,200 light-years away from the Milky Way and impossible to observe in the visible spectrum. The photograph therefore had to be taken in the infrared range using a powerful infrared camera: the Gemini South Adaptive Optics Imager. Infrared light can penetrate through the dust and reach Earth, which is how the imager can capture this beautiful celestial image.
“Only infrared radiation can travel across these clouds and bring us direct information on its stars,” commented study author Emanuele Dalessandro of the University of Bologna. The paper has been published in The Astrophysical Journal.
Liller 1 is a tight sphere of stars known as a globular cluster. The proximity of the stars means that there is the possibility for star collisions. Stellar collisions are otherwise rather rare in the universe since most stars are somewhat solitary. For example, the sun’s nearest stellar neighbor is Proxima Centauri, which is a ‘mere’ 4.2 light-years away. There’s no chance of a sun-Proxima Centauri collision anytime soon.
“Although our galaxy has upwards of 200 billion stars, there is so much vacancy between stars that there are very few places where suns actually collide,” said Douglas Geisler, principal investigator of the original observing proposal. “The congested overcrowded central regions of globular clusters are one of these places. Our observations confirmed that, among globular clusters, Liller 1 is one of the best environments in our galaxy for stellar collisions.”
Hopefully, this globular cluster will be a source of star explosions that we can study. These sorts of explosions, since they are not commonplace, could be the source of exotic galactic objects and a rare chance to examine their origins.
Learn more here http://arxiv.org/abs/1505.00568 | 0.844808 | 3.779833 |
The Moon and Uranus will make a close approach, passing within 0°44' of each other. The Moon will be 23 days old.
The Moon will be at mag -11.9; and Uranus will be at mag 5.8. Both objects will lie in the constellation Pisces.
They will be a little too widely separated to fit comfortably within the field of view of a telescope, but will be visible through a pair of binoculars.
A graph of the angular separation between the Moon and Uranus around the time of closest approach is available here.
The positions of the pair at the moment of closest approach will be as follows:
|Object||Right Ascension||Declination||Constellation||Magnitude||Angular Size|
The coordinates above are given in J2000.0. The pair will be at an angular separation of 86° from the Sun, which is in Gemini at this time of year.
|The sky on 08 July 2015|
22 days old
All times shown in EDT.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
|06 Apr 2015||– Uranus at solar conjunction|
|11 Oct 2015||– Uranus at opposition|
|09 Apr 2016||– Uranus at solar conjunction|
|15 Oct 2016||– Uranus at opposition| | 0.895513 | 3.102531 |
New Research Suggests Earth Started Its Days as a Giant Ball of Mud
Giant Convecting Mud Balls of the Early Solar System might sound like a horror movie from the 1960s, but as a recently published paper it’s got fewer rubber alien suits and more evidence on how our planet might have formed 4.5 billion years ago.
A recent study suggests that as terrestrial planets like ours formed from a swirling maelstrom of dust and asteroid, heat would have melted the asteroid’s ice before the material squeezed into solid rock. In other words, little Earth was more like a growing ball of mud.
Researchers from Australia’s Curtin University and the Planetary Science Institute in Arizona took a closer look at the assumption that the rocks making up primordial Earth were more or less like meteorites that strike its surface today.
The current model paints a picture of a planet forming as meteorite-like rocks and dust aggregates under the force of gravity.
In particular, we’re talking about a class of meteorites called carbonaceous chondrites that while relatively rare as far as falling space rocks go, are primitive samples of the early Solar System.
The composition of certain sub-types of carbonaceous chondrite is one of the biggest clues on how Earth formed.
“The unusual chemistry of CI and CM chondrites, abundant water, and mix of complex organics have led many to identify these meteorites as plausible terrestrial planet precursors or candidates for delivery of terrestrial volatiles,” the researchers write.
Unfortunately, there isn’t a whole lot of agreement on how water might have behaved in these rocks billions of years ago.
While the chemistry of some meteorites could be the result of small amounts of water trapped in tiny holes, other studies have indicated water might flow over long distances inside large asteroids.
A consistent model would help explain the hydrothermal properties of baby terrestrial planets like ours.
“The assumption has been that hydrothermal alteration was occurring in certain classes of rocky asteroids with material properties similar to meteorites,” says Bryan Travis from the Planetary Science Institute.
And as such, there was a general assumption that the rock had to be solid, with small volumes of water ice restricted to tiny pockets.
So Travis and his colleague Phil Bland from Curtin University decided to go with a different idea. What if on accretion, tiny bits of dust, ice, and rock clung together without melting and cooling into a solid expanse?
Water could still melt in this highly porous body thanks to nearby radioactive elements, and even pull tiny particles along in their warm currents.
“Mud would have formed when the ice melted from heat released from decay of radioactive isotopes, and the resulting water mixed with fine-grained dust,” says Travis.
This meant that embryonic Earth was a giant mud ball. More or less.
The researchers used what’s called the Mars and Asteroids Global Hydrology Numerical Model (MAGHNUM) to carry out simulations based on this hypothesis, adapting the model to simulate the flow of water and minerals in ancient carbonaceous chondrite asteroids of various sizes.
The results line up neatly with the compositions of ancient chondrite meteorites that have been altered by water.
Ancient Earth might have consisted of dust and chondrules – tiny space rocks that have melted and cooled again – settling into a ball where liquid water was gradually squeezed up through muddy layers, dragging fine particles up to the surface as minerals are squeezed into a core in its wake.
For smaller asteroids, this process would have taken just a few million years until the asteroid solidified, meaning as Earth grew, it was peppered with meteors that acted more like mud balls than boulders.
But none of this is meant to explain why our planet is so wet in comparison to our neighbours.
The current best models still suggest icy objects from the outer reaches of the Solar System more than likely contributed most of our supply, and our mild temperatures and magnetic field kept it from being stripped away.
It’s possible our mud ball planet was even wetter once upon a time, until another big object bumped into us and gave us a Moon in compensation. Fair swap.
As we probe various bodies in our Solar System and search for signs of exoplanets around distant stars we’ll no doubt collect more evidence on the evolution of terrestrial objects like ours.
This research was published in Science Advances. | 0.872366 | 3.978464 |
Crescent ♓ Pisces
Moon phase on 13 February 2002 Wednesday is Waxing Crescent, 1 day young Moon is in Pisces.Share this page: twitter facebook linkedin
Previous main lunar phase is the New Moon before 1 day on 12 February 2002 at 07:41.
Moon rises in the morning and sets in the evening. It is visible toward the southwest in early evening.
Moon is passing about ∠8° of ♓ Pisces tropical zodiac sector.
Lunar disc appears visually 9.3% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1770" and ∠1943".
Next Full Moon is the Snow Moon of February 2002 after 13 days on 27 February 2002 at 09:17.
There is medium ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at very acute angle, so their combined tidal force is moderate.
The Moon is 1 day young. Earth's natural satellite is moving from the beginning to the first part of current synodic month. This is lunation 26 of Meeus index or 979 from Brown series.
Length of current 26 lunation is 29 days, 18 hours and 22 minutes. This is the year's longest synodic month of 2002. It is 1 hour and 3 minutes longer than next lunation 27 length.
Length of current synodic month is 5 hours and 38 minutes longer than the mean length of synodic month, but it is still 1 hour and 25 minutes shorter, compared to 21st century longest.
This lunation true anomaly is ∠155.3°. At the beginning of next synodic month true anomaly will be ∠180.3°. The length of upcoming synodic months will keep decreasing since the true anomaly gets closer to the value of New Moon at point of perigee (∠0° or ∠360°).
14 days after point of perigee on 30 January 2002 at 09:02 in ♍ Virgo. The lunar orbit is getting wider, while the Moon is moving outward the Earth. It will keep this direction for the next day, until it get to the point of next apogee on 14 February 2002 at 22:22 in ♓ Pisces.
Moon is 404 959 km (251 630 mi) away from Earth on this date. Moon moves farther next day until apogee, when Earth-Moon distance will reach 406 361 km (252 501 mi).
5 days after its descending node on 7 February 2002 at 15:33 in ♐ Sagittarius, the Moon is following the southern part of its orbit for the next 8 days, until it will cross the ecliptic from South to North in ascending node on 22 February 2002 at 06:26 in ♊ Gemini.
18 days after beginning of current draconic month in ♋ Cancer, the Moon is moving from the second to the final part of it.
4 days after previous South standstill on 8 February 2002 at 20:59 in ♑ Capricorn, when Moon has reached southern declination of ∠-24.309°. Next 9 days the lunar orbit moves northward to face North declination of ∠24.418° in the next northern standstill on 23 February 2002 at 11:48 in ♋ Cancer.
After 13 days on 27 February 2002 at 09:17 in ♍ Virgo, the Moon will be in Full Moon geocentric opposition with the Sun and this alignment forms next Sun-Earth-Moon syzygy. | 0.848363 | 3.263374 |
© Copyright - Karim A. Khaidarov, December 30, 2008
THE ORIGIN AND DYNAMICS OF IMPACT METAMORPHISM
Dedicated to the bright memory of my daughter Anastasia
Abstract. On the base of study of morphology and statistics of impact formation on the Moon and other planets the source of impactial metamorphism is shown. Dynamics of forming the impact structures general for all planets of terrestrial type is shown.
C O N T E N T S
The Myth about Protoplanetary Cloud and its Present Remainder, Oort cloud
Real Sources of celestial bodies mass
The Composition of prestellar stage of accretion of material of galactic disk
Salpeter Mass Function and validation of unceasing accretion theory
The Function of Moon Covering by Impact Craters
Metheoritic Myths and Cometary Reality of Cosmos
Dynamics of Impact Rocks Metamorphism
Categorization of Impact Formations
Volcanic Myths and Impact Origin of Lunar Lavas
The Rate of Accretion on Planets and Stars
Causes of Asymmetry of Moon
Particularities of Impact Metamorphism on Planets with Atmosphere
There are following results of present study.
1. The sources of accretion mass of Moon and planets on more than 99,9% is are comets. Modern "meteoritic theory" of origins of lunar craters is false. Adherents of "volcanic theory" of lunar craters do not understand the cases of magmata eruptions, which have purely impact nature.
2. It is possible to divide lunar impact structures into 8 classes: chalices, circuses, mares, craters, diatremes, end-to-end craters, raws and valleys.
3. Lunar magmatism has purely impact nature, when appearance of magma in one case is due to turning the energy of impact to the heat energy of rocks, and in the other case it is outpouring the material of lunar fluid core on surface through diatreme. There are four types of magmata effusion.
4. Mares have the same cause as circuses but differ from them by size and filling of lava poured out from diatremes. The lava field exist in circuses formed by comets with rocky core overpunching diatreme, through which magma is poured out.
5. In the scale of many billion years accretion goes continuously, but in smaller scale it is a periodic pulsed function of Solar System movement through galactic arms, the main suppliers of cometary mass.
6. On base of discovery of accretion process continuity the author found the way of estimation of age of any area of lunar surfaces on its filling by craters.
7. The real age of lunar craters, circuses and mares much less than accepted in modern astrophysics and it has statistical periodicity of order 73 million years.
8. At collision of comet with planet two termal explosions occur. One of them occurs on surface, when easy melting part of comet bursts. Second occurs at the depth, when refractory comet core consisting of crystalline rocks decays.
9. The impact bodies colliding with Moon and Earth have two main modes of velocity distribution: planetary, up to 72 km/s and galactic, about 200 km/s.
10. At impact of large comets of galactic velocity about 200 km/s on the near lunar side the mares, the huge areas refined from all jaggies with bearing of material from surface for limits of horizon of explosion are forming. Rocky refractory part of comets cans moves through lunar body. For that it is necessary to have diameter of rocky part of comet not less 20 km. The surge stream melt occurs in place of end-to-end exit on thousand kilometres and even it may fall to the Earth. .
11. Salpeter mass function can be continued aside small masses up down to comets and micro comets observed in atmosphere of the Earth in the manner of meteoroids.
12. There is the fundamental function of mass for planetary systems dM/dt = M, similar Salpeter function saving attitude of masses of planets during a long time of evolution of planetary system.
13. The difference of altitude of lunar fare side and near side is defined by double greater accretion to far side of Moon because of gravitational influences of the Earth.
14. Accretion time constant in Solar system is about two trillion years. Then for this time of planet and Sun enlarge its mass in 2.7 times.
15. Diatremes, kimberlite tubes are observed on the terrestrial crust. There are objects of impact metamorphism of terrestrial rocks at influence of refractory core of celestial bodies fallen to the Earth at the speed about 200 km/s. Arising of diamonds is a result of influence impact hyper pressure on terrestrial graphite and coal.
16. The terrestrial hydrosphere is a result of comet accretion containing great mass of water.
17. Mars, other cool planets and their satellites must have powerful hydrosphere in the manner of oceans covered by water ice.
The author expresses its gratitude to
- compilers of SAI - Dubna Catalog "Morphology Catalog of Moon Craters" under general edition of V.V. Shevtschenko, MSI, 1987, without which present work will be impossible,
- creators of Apollo Mission Photo Gallery for given possibility of study of Moon in close distance,
- authors of miraculous computer program "Virtual Moon Atlas" Christian Legrend and Patric Shevalley , using of which has greatly accelerated study of Moon surface,
- Russian planetologist Eugene Dmitriev, the veteran of Design Bureau "Salute" of Khrunichev Cosmic Centre, Moscow), inspirited the author on study of impact events,
- Timur Kryachko (Moscow) for valuable consultations on astronomical equipment and help in its aquisition,
- participant of Bourabai Research forum Boris Andreyev, taken part in active discussing on the problem of present paper.
December 30, 2008
–ыцари теории эфира
|01.10.2019 - 05:20: ¬ќ—ѕ»“јЌ»≈, ѕ–ќ—¬≈ў≈Ќ»≈, ќЅ–ј«ќ¬јЌ»≈ - Upbringing, Inlightening, Education -> ѕросвещение от ¬€чеслава ќсиевского - арим_’айдаров.|
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24.09.2019 - 03:34: “≈ќ–≈“»«»–ќ¬јЌ»≈ » ћј“≈ћј“»„≈— ќ≈ ћќƒ≈Ћ»–ќ¬јЌ»≈ - Theorizing and Mathematical Design -> ‘”“”–ќЋќ√»я - прогнозы на будущее - арим_’айдаров.
24.09.2019 - 03:32: Ќќ¬џ≈ “≈’ЌќЋќ√»» - New Technologies -> "«енит"ы с "ѕротон"ами будут падать - арим_’айдаров. | 0.89275 | 3.600231 |
How was the concept of gravity realized, and how is it measured?
Gravity is defined to be the force by which a planet or other body draws objects towards its center. The same force that allows for planets in our solar system to orbit the sun, or what makes things fall on the ground here on Earth.
How was it discovered?
In the 1600s, the concept of gravity was realized when Isaac Newton witness a falling apple from a tree while he thought about the forces of nature. He developed the theory that defined gravity as a universal force acting on all matter, the farther apart two particles are and the less mass they have, the less gravitational force they posses. The theory was left unchallenged for 3 centuries, until in the 1900s Albert Einsten extended Newton’s theory with his general theory of relativity. He argued that gravity was more than just a force; it was a curve in the fourth dimension of space and time. Given enough mass, an object can cause a straight beam of light to curve, this effect is what astronomers call gravitational lensing, which was one of the methods leading to the discovery of black holes.
Here is a video explaining more about Einsten’s theory of Relativity >>
How can gravity be measured?
It was said that the greater the mass and the closer together, the more stronger the gravitational pull, so with that how exactly were they able to determine the strength of gravity on Earth? It was assumed that the acceleration of a body due to gravity is a constant 9.81 meters per second squared, by every square meter gained toward the planet’s centre, the faster the object goes down. However the assumption would be considered true only if the planet was completely smooth and contains equal amounts of elements and minerals. Earths consists of mountains, caves, difference in terrain, oceans, valleys, etc, all containing different amounts of mass which influences the gravitational pull in different regions.
One of the way to find where on Earth is gravity the strongest or weakest, in 2002 NASA and German Aerospace Centre launch a joint mission names GRACE (short for Gravity Recovery and Climate Experiment), sending 2 satellites into the same orbit around Earth. One about 220 kilometers (137 miles) in front of the other at an altitude of 460 kilometers (286 miles) above the Earth’s surface. As the leading satellite passes over a stronger area of gravity, it would detect the gravitational pull and increase in speed slightly, thus decreasing distance from the tailing satellite, and the opposite happens when the lead satellite passes over a weaker gravitational pull, having distance increase between the satellites. The changes in distance between the satellites are very small– about one-tenth the width of a human hair — that they are undetectable by the human eye. GRACE measures these changes by generating pulses of microwave energy — a highly energetic form of electromagnetic radiation — that bounce back and forth between the two satellites. The distance between the satellites is determined by the time a microwave pulse takes to travel from one satellite to the other and back. Along with this, GRACE maps the entire gravitational field of the planet every 30 days, and with changes in gravity happening over time reveals detail about polar ice, sea level, ocean currents, Earth’s water cycle and the interior structure of the Earth.
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — –
Overall, one of the studies of gravity involves a branch of Quantum Theory, which is known as quantum gravity, in which scientists attempt to generally relate to each other. Quantum Theory refers to how does the universe work in the smallest level (subatomic) and it helps scientists develop standard models for particle physics which details more about the inner workings of the universe. However quantum gravity has one exception – it doesn’t explain much about gravity.
Both theories of Quantum Theory and relativity do explain most about the observable universe (the “horizon” of the universe we are able to see from Earth), and contradict each other like in the study of black holes. Not unexpected, numerous scientist do continuous work toward a unified theory. Whatever theories are adopted, it is difficult to overstate the importance of gravity, it is the glue that holds the cosmos together, even if its leaves unanswered questions about the universe.
Here is a video demonstrating gravity>>
Image – Gravity | 0.839618 | 3.969231 |
I'm trying to work out what the sky looks like on an Earth-like moon, in particular the length of day and apparent size of the other celestial bodies: the gas giant's size, the gas giant's other moon's size, and the relative size of the star). I'm kind of stuck on the numbers here. Maths is my weak point, so I stole Artifexian's formulas and tried a simulation on Universe Sandbox a little while ago, but it wouldn't tell me the length of day on the moons. I was left having to use my brain, but all I got was an internal blue screen. Can anyone help me?
I'm gonna give all my numbers down below, but here's the setting and the result I want: it's a system with two tidally-locked Earth-like moons orbiting a massive Gas Giant.
- How short can Moon A's orbit around its Gas Giant be? I.e., how short can its days be? I'm ideally aiming for 28 hours, but up to a week would be okay-ish (both sound extremely fast to me though. Jupiter's moons can go that fast, but they don't look very hospitable to me).
- How can I have people from Moon A sometimes see Moon B from close enough that you can see its cities lit at night? Is it even possible?
- How big do the gas giant and the star it orbits around look?
So this gas giant (8.3 Jovian masses) orbits a K-type star of 0.8 solar masses. (Though a friend told me that it'd be easier if the gas giant orbited a star hotter than the Sun, maybe a class F of 1.4 solar masses I don't really care either way. I've put in the numbers for both).
At least two of these moons are habitable.
Moon A is tidally locked and fairly close to 1 Earth mass. I don't really care for the mass or situation of Moon B as long as it's habitable. Both are on inclined planes, just because it's more believable. Now, I'd also like our gas giant AND Moon B to be visible to the naked eye from Moon A's sky. The gas giant should appear to be at least the size of Earth's moon, and Moon B's surface should be visible too, because I'd like for people on Moon A to see the cities lit at night on Moon B. Due to the tidal locking, the gas giant would have its different phases during the day and appear full during the night.
(Maybe relevant?) Both moons would have been terraformed to be habitable for humans, though Moon A already had somewhat primitive but intelligent forms of life (most of which were killed during the terraformation process).
If K-type Star (all numbers are relative to our Sun unless indicated otherwise)
- Star mass = 0.8 Sun masses
- Diameter = 0.8477
- Temperature = 0.8934 = 5156.7 Kelvin
- Lifetime = 1.75
- Habitability = 1.7155 AU
- Goldilock zone = between 95% and 137% of 1.7155, so between 0.68 and 0.7 AU = between 10 474 and 541 429 km
If F-type Star
Star mass = 1.4 Sun masses
Star luminosity = 3.8416
Diameter = 1.28
Temperature = 1.185
Lifetime = 0.43
Habitability = 1.96
Goldilock zone = between 95% and 137% of 1.96, so between 1.862 and 2.6852 AU
- Gas Giant mass: 8.3 Jovian masses
- Orbit: 0.68 AU from K-type star or 2.1 AU from F-type star? (I just went through the forum and learnt that tidal locking helps heat a moon, but I don't know how to account for that in the numbers)
- Length of orbit: No idea. Sandbox Sim won't tell me, and whenever I accelerate time in the simulation it sends my planets flying off into deep space...
- Velocity: 48.4 km/s (according to my simulation)
- Mass: 0.8 Earth mass
- Orbit around Gas Giant: 23.8 hours in my simulation (which sounds AWEFULLY fast! Is that even possible?)
- Velocity: 45.1 km/s
- Semimajor axis: 58 007 km (periapsis 24000; apoapsis 92000)
- Eccentricity: 0.59 (Inclination 77.44°; perihelion 178°; node 156°; mean 138°)
- Moon B mass: 1.4 Earth mass
- Orbit around Gas Giant: 2.40 days in my simulation.
- Velocity: 60.5 km/s
- Semimajor axis: 1.05M km
- Eccentricity: 0.061 (Inclination 0.40°; perihelion 305°; node 174°; mean 177°)
How many of these numbers seem off? I could send the Sandbox file if it helps, though I woudn't be surprised if the sim's rubbish too.
Many, many thanks! And sorry for the terribly messy post. (No wonder I kept sending my moons flying in Sandbox Simulator: I can't even keep my sentences in orbit.) | 0.837289 | 3.642111 |
The spacecraft is expected to reach speeds in the region of 430,000 miles per hour
The Parker Solar Probe began its mission to investigate the Sun as it launched from Cape Canaveral, Florida on Saturday.
The Parker probe’s mission is to broaden our understanding of how energy and heat move through the solar corona. A key point is the investigation of what accelerates solar energetic particles and solar winds.
The satellite is named after Dr Eugene Parker, who in the 1950’s proposed that stars give off energy, he named this energy solar wind. This is their first NASA mission to be named after a living person.
The probe was launched using a Delta-IV Heavy rocket and on its path to orbit the sun will become one of the fastest human-made objects ever constructed as it reaches speeds up to 430,000 miles per hour.
The Parker probe will fly directly through the sun’s atmosphere and is expected to pass as close as 3.8 million miles from its surface.
In order to protect the spacecraft and its scientific equipment from the extreme temperatures it will experience in close proximity to our Sun, the craft is fitted with a 4.5 inch thick carbon composite heat shield. The front of the shield is capable of withstanding temperatures 1300 degrees.
The Parker probe contains an array of scientific equipment designed to measure the energy emanating from the sun at close range such as a magnetometer, a low energy plasma instrument and a suite of energetic particle instruments.
One set of scientific equipment on the probe is the Solar Wind Electrons Alphas and Protons (SWEAP). Professor John Belcher of Massachusetts Institute of Technology (MIT) is a co-investigator on the SWEAP project.
Commenting on MIT’s blog Prof Belcher said that SWEAP will: “Directly measure the properties of the plasma in the solar atmosphere during these encounters.”
“A special component of SWEAP is a small instrument that will look around the protective heat shield of the spacecraft directly at the sun, the only instrument on the spacecraft to do so. This will allow SWEAP to sweep up a sample of the atmosphere of the sun, our star, for the first time at these distances.”
“It is only by getting this close to the sun that we have a chance of answering definitely what accelerates the wind. The major question is whether thermal processes or wave acceleration processes are most important, or both,” he notes. | 0.821334 | 3.313562 |
Are you ready to dance with a new discovery? ESA’s Cluster satellites are playing the tune of cosmic particle acceleration – and it’s more efficient than speculated. Now we’re taking a look at the beginnings of universal motion. By embracing a wide variety of astronomical targetry, the images are revealing shock waves where supersonic flows of plasma encounter everything from a slow flow to an irresistible force.
What sets things in motion? When it comes to particle accelerators, something needs to set it off. Here on Earth, the Large Hadron Collider (LHC) located at Cern uses a bank of smaller machines for giving rise to the charged particles before introducing them into the mainstream. In space, cosmic rays act as this “mainstream”, but they aren’t very efficient at setting the particles going initially. Now the ESA Cluster mission has revealed what could be ” natural particle accelerators of space”.
While cruising through a magnetic shock wave, the four Cluster satellites found themselves perfectly lined up with the magnetic field. This perfect chance alignment was a revelation – allowing the mission to sample the event with incredible accuracy on a very short timescale – one of 250 milliseconds or less. What surfaced from the investigation was the realization that the electrons heated rapidly, a state which contributes to acceleration on a greater scale. While this type of action had been speculated before, it hadn’t been observed or proved. No one really knew about the process or the size of the shock layers. With this new data, Steven J. Schwartz of the Imperial College London, and his colleagues were able to estimate the thickness of the shock layer – a significant advancement in understanding, because a thinner layer means faster acceleration.
“With these observations, we found that the shock layer is about as thin as it can possibly be,” says Professor Schwartz.
So just how skinny is this dance partner? Scientists had originally estimated the shock layers above Earth to be no more than 100 km, but the satellite information showed them to be about 17 km… a very fine detail!
This type of knowledge is significant simply because shocks exists universally – originating virtually everywhere a flow encounters an obstacle or another flow. For example, here in the Solar System the Sun generates a speedy, electrically charged stellar wind. When it runs headlong into a magnetic field – such as generated by Earth – it creates a shock wave located in front of the planet. Through the Cluster mission studies, we can apply what we learn here at home and extrapolate it on a grander scale – such as those created by supernovae events, black holes and galaxies. It might even reveal the origin of cosmic rays!
“This new result reveals the size of the proverbial ‘black box’, constraining the possible mechanisms within it involved in accelerating particles,” says Matt Taylor, ESA Cluster project scientist. “Yet again, Cluster has provided us with a clear insight into a physical process that occurs throughout the Universe.”
Come on, baby. Let’s dance…
Original Story Source: ESA News Release. | 0.852419 | 3.907241 |
Dust off your lawn chairs. The most visually stunning meteor shower of the year is about to reach peak activity over the next 2 to 3 days. According to NASA, during peak hours that vary by region, viewers will be able to see up to 100 meteors an hour zooming overhead at 37 miles (about 60 km) per second. In April, NASA said on its Asteroid Watch page that “[i]f you see one meteor shower this year, make it August’s Perseids or December’s Geminids.”
The Perseids borrow their name from the Perseus constellation, first catalogued by Greek astronomer Ptolemy in the 2nd century. The annual meteor shower, which usually takes place during July and August, is the result of falling debris from large comet Swift-Tuttle, which si twice the size of the comet that is believed to have taken out the dinosaurs. The Earth crosses the orbital path of Swift-Tuttle about once a year during the summer, but the bulk of the comet’s debris typically rains down after the first week in August. The meteors will appear to originate from the direction of the constellation, which is meant to resemble the Greek hero Perseus, but in reality they share no connection to the Perseus constellation.
The Perseids boast fast and bright meteors that regularly leave trains, the white tails of light that lag behind meteors in the sky. During this year’s meteor shower there will be no moonlight to detract from their glow, because the shower is happening during a new moon. (During a new moon, the side of the moon that faces Earth is completely dark, causing less light pollution and making it easier to see other objects in the sky.)
The view from less light-intensive areas (as in, places unlike New York’s Times Square) won’t require any fancy tech to appreciate the shower; everything will be viewable with the naked eye. For those in the Northern Hemisphere, experts recommend watching the shower just after midnight on Aug. 12 and 13. | 0.822468 | 3.220697 |
The appropriateness of an underground facility for a particular experiment depends on a number of its characteristics. Typically the most important of these is the effective depth of the laboratory and therefore the degree to which backgrounds associated with cosmic rays are reduced. In addition to the vertical distance from the surface, often referred to as the facility’s “overburden” or “vertical overburden,” the structure, density, and makeup of the earth above the laboratory impact the penetration capability of cosmic rays. A facility’s depth is therefore “normalized” by measuring the actual cosmic ray intensity at that facility and then expressing its depth in terms of meters of water equivalent (m.w.e.), or the equivalent depth of water that would reduce the cosmic ray intensity to the measured amount. Figure 2.1 shows the measured drop-off in cosmic ray muon intensity as a function of m.w.e. Typically, the depth of a facility expressed in m.w.e. is roughly 2.65 times its vertical overburden expressed in meters.
An underground facility’s appropriateness for a given experiment also might be impacted by the absence or availability of active shielding that can be shared by several experiments. This typically is a “shield” outside the inner main detector that is often itself an active detector. By measuring activity at the shield and providing that information to the experiment, the influence of the surrounding environment on the inner main detector can be estimated and accounted for in data analysis.
Still other important characteristics include how the laboratory space is accessed, whether that access is shared, and the nature of the rock surrounding the laboratory. Horizontal shafts that allow the use of vehicles to bring equipment and supplies into and out of the laboratory space typically are preferred to vertical shafts, especially where those shafts, and the lifts in them, are fairly small. Many laboratories coexist with working mines or vehicular tunnels, so access to the laboratory space can at times be limited. The type of rock from which the laboratory was excavated can be of importance, especially for larger experiments. As the size of experiments grows, the density and stability of the surrounding rock and its ability to support the weight of the experimental apparatus could become an issue.
Finally, the comprehensiveness and location of the support facilities for an underground laboratory can be important general characteristics. Most of these facilities are located on the surface and typically include shared items such as electricity, communications, and cold water for the cooling of the experimental apparatus. Further, each underground laboratory needs a support team to care for safety, technical support, transportation between the surface and underground, and the like, which can vary significantly from facility to facility.
Underground research facilities are scattered throughout the world. Figure 2.2 shows the size and effective depth, in m.w.e., of the principal underground laboratories, including the program proposed for DUSEL. The remainder of the chapter discusses the characteristics of the principal laboratories located or planned in North America—DUSEL, Soudan, and SNOLAB—as well as Gran Sasso, the largest underground laboratory in the world; Kamikande, the largest Asian laboratory; and, briefly, CDUSEL/China JinPing Laboratory (CJPL), a laboratory being developed in China that is expected to be large, on the scale of DUSEL. Appendix D contains more detailed information about all of the principal laboratories shown in Figure 2.2. In developing this material, the committee drew from the results of two recent comprehensive surveys of underground laboratories.1
1 A. Bettini. 2011. Underground laboratories. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 626: S64-S68; E. Coccia. 2010. Underground laboratories: Cosmic silence, loud science. Journal of Physics Conference Series 203: 012023.
The proposed DUSEL program was developed by a group of researchers based at the University of California at Berkeley pursuant to an award granted by NSF. The program calls for a multilevel facility at the Homestake mine, an abandoned gold mine in Lead, South Dakota. In addition to surface facilities, the principal underground facilities would be located at the 800-, 4,850-, and the 7,400-ft levels, with the opportunity to place additional small experiments at various other levels, depending upon the demands of the research.
The surface campus, as planned, consisted of approximately 27,000 m2 of research and administrative space, with 1,100 m2 of that for assembly of experiments. Administrative and science support, including shops, offices, and assembly sites, were to be located at this level. It was also envisioned to have a separate maintenance and operations campus and a facility for education and outreach. The size of the facility at 800 ft depended, to a large degree, on whether there would be a liquid argon detector for the neutrino oscillation/proton decay experiments, as discussed in Chapter 3, in the section entitled “Neutrino Physics.”
At 4,850 ft, it was proposed to have 25,000 m2 of total working space, with 6,200 m2 devoted to science. This level would be the principal deep underground laboratory space and the site for the water Cherenkov detector(s), if chosen for the neutrino oscillation and proton decay experiments, as well as the dark matter and nuclear astrophysics experiments. The deepest level, at 7,400 feet, would consist of 7,000 m2 total space, with 1,300 m2 dedicated to research. It would be available for possible dark matter and neutrinoless double-beta decay experiments, as well as ecohydrology, geoscience, and subsurface engineering experiments.
There are currently several small experiments under way at the 4,850 foot level as part of the Sanford Underground Laboratory. This laboratory was established in anticipation of the full-scale implementation of the DUSEL program, but its future is uncertain in light of changes to the DUSEL program. For more information, see http://dusel.org.
Soudan Underground Laboratory (SUL) is the only general research underground laboratory currently located in the United States. This facility was developed in 1980 and installed in an abandoned iron mine in Minnesota. The underground structures include the 1,400 m2 principal laboratory space, which hosts a dark matter experiment and a low-background counting facility; a small, high-purity copper fabrication facility; and the 560 m2 main injector neutrino oscillation search (MINOS) laboratory. The MINOS experiment is the far detector in a neutrino oscillations experiment; its neutrino beam originates at Fermilab. MINOS is expected to run a few years more with a 2-year decommissioning period at the end of that time.
The laboratory is fairly shallow, with a vertical overburden of 700 m of rock, and access is through a small, vertical shaft whose size places some restrictions on installation capability. The laboratory offers some education and outreach to the general public. It coexists with a historic state park that offers mine tours, some of which utilize a visitor’s gallery in the MINOS laboratory. For more information, see http://www.soudan.umn.edu/.
The Sudbury Neutrino Observatory (SNO) was excavated in the 1990s in an operating nickel mine. The original SNO experiment, located in a 200-m2 area, had a very successful set of discoveries and has completed its run. To this original space, new structures have been added to form a new laboratory, the SNOLAB, which consists of a main hall with 270 m2 floor area and ceiling heights from 15 to 19.5 m, a service hall of about 180 m2, and a number of narrow volumes called “ladder labs.” The laboratory space is one of the deepest currently available, with a rock coverage of 2,000 m under a flat surface. A “cryopit,” designed to cope with the safety issues surrounding large volumes of cryogenic fluids, has also been excavated. The total underground laboratory area is 7,215 m2, of which 3,055 m2 is available for experiments.
The access is through a vertical shaft that is shared with the working mine and is available daily. All of the laboratory space will be maintained at Class 1500 cleanliness standards. On the surface a 3,159-m2 building hosts a clean room, laboratories, staging and assembly areas, and administrative space.
The scientific programme includes (1) the Project in Canada to Search for Supersymmetric Objects (PICASSO), which is searching for dark matter (2 kg) using the superheated bubbles technique; (2) the experiment SNO+, which is to be hosted in the former SNO cavity and will use a liquid scintillator in which 150Nd has been dissolved to study low-energy solar neutrinos, geoneutrinos, and double-beta decay; and (3) dark matter searches that include the Dark matter Experiment with Argon and Pulse shape discrimination/Cryogenic Low Energy Astrophysics with Noble gases (DEAP/CLEAN), currently operating with a prototype, and superCDMS, operating with bolometers. For more information, see http://www.snolab.ca/ or http://www.sno.phy.queensu.ca/.
Laboratori Nazionali del Gran Sasso (LNGS) is a national laboratory of Italy’s Istituto Nazionale di Fisica Nucleare (INFN). It is the largest underground laboratory in the world and serves the largest and most international scientific community, about 750 scientists from 26 countries. LNGS arose out of a proposal in 1979 that a large underground laboratory be built close to and in conjunction with the Gran Sasso freeway tunnel then under construction in central Italy (an opportunity that substantially reduced its cost). The Parliament approved the construction in 1982, and construction was completed in 1987.
Access is horizontal, via the freeway. The underground laboratory principally consists of three main halls, each with an area of about 2,000 m2 (100 m × 20 m), 18 m high. There are also ancillary tunnels that provide space for services
and small-scale experiments and two 90-m long tunnels built for two Michelson interferometers for geology studies. The total area is 17,300 m2, and the total volume 180,000 m3. The laboratory is reasonably deep, with a vertical overburden of 1,400 m. Services hosted on the surface campus include a full range of support and administrative facilities, and the laboratory organizes a number of outreach and education activities.
LNGS is operated as an international laboratory with an international scientific committee, appointed by INFN, which advises the director on the suite of experiments for the facility. The scientific program includes these:
• The search for τ neutrino appearance on the μ neutrino beam emitted from the Large Hadron Collider of the European Center for Nuclear Research (CERN), 732 km away. This is the main focus of the OPERA experiment, which uses emulsion techniques and a large (kiloton), sensitive mass, consisting of 150,000 bricks made up of lead sheets interleaved with emulsion layers.
• ICARUS, a general-purpose particle detector in a 600-ton liquid argon time-projection chamber.
• Solar neutrino physics and geoneutrinos with the 1,300-ton liquid scintillator Borexino detector.
• The detection of low-energy neutrinos from the gravitational collapse of galactic objects with the 1,000-ton liquid scintillator Large Volume Detector (LVD) experiment.
• Dark matter searches with LIBRA (250-kg sensitive mass of NaI crystals), CRESST2 (an ultracryogenic CaWO4 detector), XENON (liquid xenon) and WARP (liquid argon)
• Neutrinoless double-beta decay experiments with GERDA (enriched 76Ge), CUORE (TeO2 bolometers), and COBRA (CdZnTe semiconductor detectors).
• Nuclear reaction of astrophysical interest with a 400-kV accelerator with LUNA2.
A special facility is dedicated to low radioactivity measurements, and the laboratory also supports several experiments in geology, biology, and the environment. For more information, see http://www.lngs.infn.it/.
The Kamioka Observatory is operated by the Institute for Cosmic Ray Research, University of Tokyo. It was established in 1983 by M. Koshiba as the Kamioka Underground Observatory. The original purpose of this observatory was
to conduct the Kamioka neutron decay experiment (KamiokaNDE); later, a neutrino observatory, Super-Kamiokande (SuperK), was built, which is currently the largest underground experiment. The Tokai-to-Kamioka long-baseline neutrino oscillation experiment (T2K) recently began operations. It is a third-generation neutrino oscillation experiment on an intense off-axis beam of muon neutrinos (vμ) produced at the J-PARC accelerator facility 295 km from the SuperK detector. The main goal of T2K is to measure the oscillation of vμ to ve and to measure the value of θ13.
The average vertical overburden for the research space is 1,000 m, and access is horizontal by vehicle, with no interference from mining activity. The average number of scientific users is more than 200.
The underground structures comprise the following:
• Hall SK (50-m diameter) hosting Super-Kamiokande;
• Clean room (10 × 5 m2) with XMASS prototype;
• Hall 40 (L-shape, 40 m × 4 m arms) hosting the purification tower for XMASS and the NEWAGE experiment on dark matter;
• Hall 100 (L-shape, 100 m × 4 m arms) with CLIO, a prototype of gravitational antenna (to be terminated in 2013) and a laser displacement detector;
• The new Hall A (15 × 21 m2) hosting XMASS 800 kg; and
• The new Hall B (6 × 11 m2) hosting CANDLE on double-beta decay, to be occupied until 2012.
Small areas are available in the abandoned mine. The underground large cryogenic gravitational antenna (LCGT), which has baseline lengths of 3 km × 3 km, was recently approved. Further enlargements are under development in order to accommodate more experiments. Buildings for offices and computer facilities are available on the surface.
In the same mountain, the Kamioka Liquid Scintillator Antineutrino Detector (KamLAND) experiment is operated by the Neutrino Centre, Tohoku University. KamLAND is designed to detect electron antineutrinos and to provide important results for neutrino oscillation by measuring antineutrinos from the commercial power reactors surrounding the site. For more information, see http://www-sk.icrr.u-tokyo.ac.jp/index_e.html
Recently, the China Deep Underground Science and Engineering Laboratory (CDUSEL) (also known as CJPL), a project for the world’s deepest, and possibly
largest, underground laboratory, was launched in China.2 The facility plans to take advantage of infrastructure being developed by the Ertan Hydropower Development Company (EHDC) in the course of installing a series of 21 hydroelectric power stations on the Yalong River in central China. A system of tunnels 17.5 km long will cut a big U-turn in the river under the 4,193-m-tall JinPing mountain. This system will have a flat area available for development as an underground laboratory that provides at its greatest depths a 2,500 m vertical rock overburden and more than 1,500 m vertical overburden in 70 percent of the directions. The access will be horizontal, from both sides.
Two small experimental halls 5 × 5 × 30 m3 are under construction; their relative size is shown in Figure 2.2. The final size of the laboratory has not been publicly disclosed, although it has been reported that the laboratory will be designed as an international facility, open to the world community. Ventilation, laboratory-grade power supply, and germanium detectors with their shielding will be installed. The muon flux (expected to be very low, on the order of 20 per m2 per year), the neutron flux, and radon concentration in the air will be measured shortly. A working group including scientists and engineers from Chinese institutions and universities as well as EHDC has been established to develop plans for this facility.
2 Qian, Yue. 2010. Status and prospects of China JinPing deep underground laboratory (CJPL) and China dark matter experiment (CDEX). Presentation at the TeV Particle Astrophysics 2010 Conference, Paris, France. | 0.869012 | 3.767078 |
Eta Aquarid Meteor Shower
“Eeeh! I love a good headline, me! But this might be a tad disingenuous to say the least, and there’s certainly no need to panic. Nevertheless, there are some truths within it.
Tonight will indeed coincide with peak of the Eta Aquarid Meteor Shower, and although this particular meteor shower is best viewed in the southern hemisphere, for those who are determined to stay up late (or wake up early perhaps), it will appear low in the eastern sky in the early pre-dawn hours of tomorrow morning (6 May 2020).
One other factor to bear in mind, is that this meteor shower will also clash with a ‘full waxing gibbous’ moon (gibbous meaning hump-backed), and observing conditions will be far from ideal with the bright intensity of the moon interfering for much of the night. But please don’t despair; the Moon is amazing to look at too.
Where will these meteors be coming from? I hear you ask (or maybe not). Well the bit about Halley’s Comet is also true, though we won’t be colliding with the Comet head-on, only with its tail – the stream of lumpy and granular debris that trails behind it as the comet disintegrates. And if you think that’s still too close for comfort, Comet Halley has more than one tail and they each stretch for millions of miles in length!
As the Earth orbits the sun throughout the year, it passes through a number of these comet tails, each one providing the debris material to form meteors. The debris material is mostly dust, the size of peppercorns, and as they pass through the Earth’s ionosphere and vapourise they form the streaks of light, which we see in awe-struck wonder. Tonight, it just happens to be Halley’s Comet, whereas the Perseid Meteor Shower in August is created when we pass through the tail (debris) of Comet Swift-Tuttle, when if you are lucky, you may see between 50 -100 meteors an hour!
The oddly-sounding name’ Eta Aquarid’ is so-called after the constellation that it appears to radiate from in the night sky – in this case, the Aquarius constellation. Specifically, the name comes from one of the stars in this constellation – Eta Aquarii. | 0.812185 | 3.442993 |
The Milky Way is an extremely big place. Measured from end to end, our galaxy in an estimated 100,000 to 180,000 light years (31,000 – 55,000 parsecs) in diameter. And it is extremely well-populated, with an estimated 100 to 400 million stars contained within. And according to recent estimates, it is believed that there are as many as 100 billion planets in the Milky Way. And our galaxy is merely one of trillions within the Universe.
So if we were to break it down, just how much matter would we find out there? Estimating how much there is overall would involve some serious math and incredible figures. But what about a single light year? As the most commonly-used unit for measuring the distances between stars and galaxies, determining how much stuff can be found within a single light year (on average) is a good way to get an idea of how stuff is out there.
Even though the name is a little confusing, you probably already know that a light year is the distance that light travels in the space of a year. Given that the speed of light has been measured to 299,792, 458 m/s (1080 million km/h; 671 million mph), the distance light travels in a single year is quite immense. All told, a single light year works out to 9,460,730,472,580.8 kilometers (5,878,625,373,183.6 mi).
So to determine how much stuff is in a light year, we need to take that distance and turn it into a cube, with each side measuring one light year in length. Imagine that giant volume of space (a little challenging for some of us to get our heads around) and imagine just how much “stuff” would be in there. And not just “stuff”, in the sense of dust, gas, stars or planets, either. How much nothing is in there, as in, the empty vacuum of space?
There is an answer, but it all depends on where you put your giant cube. Measure it at the core of the galaxy, and there are stars buzzing around all over the place. Perhaps in the heart of a globular cluster? In a star forming nebula? Or maybe out in the suburbs of the Milky Way? There’s also great voids that exist between galaxies, where there’s almost nothing.
Density of the Milky Way:
There’s no getting around the math in this one. First, let’s figure out an average density for the Milky Way and then go from there. Its about 100,000 to 180,000 light-years across and 1000 light-years thick. According to my buddy and famed astronomer Phil Plait (of Bad Astronomy), the total volume of the Milky Way is about 8 trillion cubic light-years.
And the total mass of the Milky Way is 6 x 1042 kilograms (that’s 6,000 trillion trillion trillion metric tons or 6,610 trillion trillion trillion US tons). Divide those together and you get 8 x 1029 kilograms (800 trillion trillion metric tons or 881.85 trillion trillion US tons) per light year. That’s an 8 followed by 29 zeros. This sounds like a lot, but its actually the equivalent of 0.4 Solar Masses – 40% of the mass of our Sun.
In other words, on average, across the Milky Way, there’s about 40% the mass of the Sun in every cubic light year. But in an average cubic meter, there’s only about 950 attograms, which is almost one femtogram (a quadrillionth of a gram of matter), which is pretty close to nothing. Compare this to air, which has more than a kilogram of mass per cubic meter.
To be fair, in the densest regions of the Milky Way – like inside globular clusters – you can get densities of stars with 100, or even 1000 times greater than our region of the galaxy. Stars can get as close together as the radius of the Solar System. But out in the vast interstellar gulfs between stars, the density drops significantly. There are only a few hundred individual atoms per cubic meter in interstellar space.
And in the intergalactic voids; the gulfs between galaxies, there are just a handful of atoms per meter. Like it or not, much of the Universe is pretty close to being empty space, with just trace amounts of dust or gas particles to be found between all the stars, galaxies, clusters and super clusters.
So how much stuff is there in a light year? It all depends on where you look, but if you spread all the matter around by shaking the Universe up like a snow globe, the answer is very close to nothing.
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the globular cluster known as Messier 30. Enjoy!
During the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.
One of these objects is Messier 30, a globular cluster located in the southern constellation of Capricornus. Owing to its retrograde orbit through the inner galactic halo, it is believed that this cluster was acquired from a satellite galaxy in the past. Though it is invisible to the naked eye, this cluster can be viewed using little more than binoculars, and is most visible during the summer months.
Messier measures about 93 light years across and lies at a distance of about 26,000 light years from Earth, and approaching us at a speed of about 182 kilometers per second. While it looks harmless enough, its tidal influence covers an enormous 139 light years – far greater than its apparent size.
Half of its mass is so concentrated that literally thousands of stars could be compressed in an area that spans no further than the distance between our solar system and Sirius! However, inside this density only 12 variable stars have been found and very little evidence of any stellar collisions, although a dwarf nova has been recorded!
So what’s so special about this little globular? Try a collapsed core – and one that’s even been resolved by Earth-bound telescopes. According to Bruce Jones Sams III, an astrophysicists at Harvard University:
“The globular cluster NGC 7099 is a prototypical collapsed core cluster. Through a series of instrumental, observational, and theoretical observations, I have resolved its core structure using a ground based telescope. The core has a radius of 2.15 arcsec when imaged with a V band spatial resolution of 0.35 arcsec. Initial attempts at speckle imaging produced images of inadequate signal to noise and resolution. To explain these results, a new, fully general signal-to-noise model has been developed. It properly accounts for all sources of noise in a speckle observation, including aliasing of high spatial frequencies by inadequate sampling of the image plane. The model, called Full Speckle Noise (FSN), can be used to predict the outcome of any speckle imaging experiment. A new high resolution imaging technique called ACT (Atmospheric Correlation with a Template) was developed to create sharper astronomical images. ACT compensates for image motion due to atmospheric turbulence.”
Photography is an important tool for astronomers to work with – both land and space-based. By combining results, we can learn far more than just from the results of one telescope observation alone. As Justin H. Howell wrote in a 1999 study:
“It has long been known that the post-core-collapse globular cluster M30 (NGC 7099) has a bluer-inward color gradient, and recent work suggests that the central deficiency of bright red giant stars does not fully account for this gradient. This study uses Hubble Space Telescope Wide Field Planetary Camera 2 images in the F439W and F555W bands, along with ground-based CCD images with a wider field of view for normalization of the noncluster background contribution. The quoted uncertainty accounts for Poisson fluctuations in the small number of bright evolved stars that dominate the cluster light. We explore various algorithms for artificially redistributing the light of bright red giants and horizontal-branch stars uniformly across the cluster. The traditional method of redistribution in proportion to the cluster brightness profile is shown to be inaccurate. There is no significant residual color gradient in M30 after proper uniform redistribution of all bright evolved stars; thus, the color gradient in M30’s central region appears to be caused entirely by post-main-sequence stars.”
“We report the detection of six discrete, low-luminosity X-ray sources, located within 12” of the center of the collapsed-core globular cluster M30 (NGC 7099), and a total of 13 sources within the half-mass radius, from a 50 ks Chandra ACIS-S exposure. Three sources lie within the very small upper limit of 1.9” on the core radius. The brightest of the three core sources has a blackbody-like soft X-ray spectrum, which is consistent with it being a quiescent low-mass X-ray binary (qLMXB). We have identified optical counterparts to four of the six central sources and a number of the outlying sources, using deep Hubble Space Telescope and ground-based imaging. While the two proposed counterparts that lie within the core may represent chance superpositions, the two identified central sources that lie outside of the core have X-ray and optical properties consistent with being cataclysmic variables (CVs). Two additional sources outside of the core have possible active binary counterparts.”
History of Observation:
When Charles Messier first encountered this globular cluster in 1764, he was unable to resolve individual stars, and mistakenly believed it to be a nebula. As he wrote in his notes at the time:
“In the night of August 3 to 4, 1764, I have discovered a nebula below the great tail of Capricornus, and very near the star of sixth magnitude, the 41st of that constellation, according to Flamsteed: one sees that nebula with difficulty in an ordinary [non-achromatic] refractor of 3 feet; it is round, and I have not seen any star: having examined it with a good Gregorian telescope which magnifies 104 times, it could have a diameter of 2 minutes of arc. I have compared the center with the star Zeta Capricorni, and I have determined its position in right ascension as 321d 46′ 18″, and its declination as 24d 19′ 4″ south. This nebula is marked in the chart of the famous Comet of Halley which I observed at its return in 1759.”
However, we cannot fault Messier, for his job was to hunt comets and we thank him for logging this object for further study. Perhaps the first clue to M30’s underlying potential came from Sir William Herschel, who often studied Messier’s objects, but did not report his findings formally. In his personal notes he wrote:
“A brilliant cluster, the stars of which are gradually more compressed in the middle. It is insulated, that is, none of the stars in the neighborhood are likely to be connected with it. Its diameter is from 2’40” to 3’30”. The figure is irregularly round. The stars about the centre are so much compressed as to appear to run together. Towards the north, are two rows of bright stars 4 or 5 in a line. In this accumulation of stars, we plainly see the exertion of a central clustering power, which may reside in a central mass, or, what is more probable, in the compound energy of the stars about the centre. The lines of bright stars, although by a drawing made at the time of observation, one of them seems to pass through the cluster, are probably not connected with it.”
So, as telescopes progressed and resolution improved, so did our way of thinking about what we were seeing… By Admiral Smyth’s time, things had improved even more and so had the art of understanding more:
“A fine pale white cluster, under the creature’s caudal fin, and about 20 deg west-north-west of Fomalhaut, where it precedes 41 Capricorni, a star of 5th magnitude, within a degree. This object is bright, and from the straggling streams of stars on its northern verge, has an elliptical aspect, with a central blaze; and there are but few other stars, or outliers, in the field.
“When Messier discovered this, in 1764, he remarked that it was easily seen with a 3 1/2-foot telescope, that it was a nebula, unaccompanied by any star, and that its form was circular. But in 1783 it was attacked by WH [William Herschel] with both his 20-foot Newtonians, and forthwith resolved into a brilliant cluster, with two rows pf stars, four or five in a line, which probably belong to it; and therefore he deemed it insulated. Independently of this opinion, it is situated in a blankish space, one of those chasmata which Lalande termed d’espaces vuides, wherein he could not perceive a star of the 9th magnitude in the achromatic telescope of sixty-seven millimetres aperture. By a modification of his very ingenious gauging process, Sir William considered the profundity of this cluster to be of the 344th order.
“Here are materials for thinking! What an immensity of space is indicated! Can such an arrangement be intended, as a bungling spouter of the hour insists, for a mere appendage to the speck of a world on which we dwell, to soften the darkness of its petty midnight? This is impeaching the intelligence of Infinite Wisdom and Power, in adapting such grand means to so disproportionate an end. No imagination can fill up the picture of which the visual organs afford the dim outline; and he who confidently probes the Eternal Design cannot be many removes from lunacy. It was such a consideration that made the inspired writer claim, “How unsearchable are His operations, and His ways past finding out!”
Throughout all historic observing notes, you’ll find notations like “remarkable” and even Dreyer’s famous exclamation points. Even though M30 may not be the easiest to find, nor the brightest of the Messier objects, it is still quite worthy of your time and attention!
Locating Messier 30:
Finding M30 is not an easy task, unless you’re using a GoTo telescope. In any other case, it’s a starhop process, which must begin with identifying the the big grin-shape of the constellation of Capricornus. Once you’ve separated out this constellation, you’ll begin to notice that many of its primary asterism stars are paired – which is a good thing! The northeastern most pair are Gamma and Delta, which is where binocular-users should start.
As you move slowly south and slightly west, you’ll encounter your next wide pair – Chi and Epsilon. The next southwestern set is 36 Cap and Zeta. Now, from here you have two options! You can find Messier 30 a little more than a finger width east(ish) of Zeta (about half a binocular field)… or, you can return to Epsilon and look about one binocular field south (about 3 degrees) for star 41 which will appear just east of Messier 30 in the same field of view.
For the finderscope, star 41 is a critical giveaway to the globular cluster’s position! It won’t be visible to the unaided eye, but even a little magnification will reveal its presence. Using binoculars or a very small telescope, Messier 30 will appear as only a small, faded gray ball of light with a small star beside it. However, with telescope apertures as small as 4″ you’ll begin some resolution on this overlooked globular cluster and larger apertures will resolve it nicely.
And here are the quick facts on Messier 30 to help you get started:
Object Name: Messier 30 Alternative Designations: M30, NGC 7099 Object Type: Class V Globular Cluster Constellation: Capricornus Right Ascension: 21 : 40.4 (h:m) Declination: -23 : 11 (deg:m Distance: 26.1 (kly) Visual Brightness: 7.2 (mag) Apparent Dimension: 12.0 (arc min)
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Globular Cluster known as Messier 28. Enjoy!
Back in the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list would come to include 100 of the most fabulous objects in the night sky.
One of these objects was the globular cluster now known as Messier 28. Located in the direction of the Sagittarius constellation, some 17,900 light-years from Earth, this “nebulous” cluster is easily detectable in the night sky. It is also the third largest known clustering of millisecond pulsars in the known Universe.
Compressed into a sphere measuring about 60 light years in diameter, globular star cluster Messier 28 happily orbits our galactic center about 19,000 light years away from Earth. In all of its thousands upon thousands of stars, M28 contains 18 known RR Lyrae variables and a W Virginis variable star. This very different variable is a Type II, or population II Cepheid that has a precise change rate which occurs every 17 days.
There has also been a second long period variable discovered, which could very well be an RV Tauri type, too. However, one of M28’s biggest claims to fame happened in 1986, when it became the first globular cluster known to contain a millisecond pulsar. This was discovered by the Lovell Telescope at Jodrell Bank Observatory. The work on the pulsar was later picked up by Chandra researchers.
As Martin C. Weisskopf (et al) of the Space Sciences Department put it in a 2002 study of the object:
“We report here the results of the first Chandra X-Ray Observatory observations of the globular cluster M28 (NGC 6626). We detect 46 X-ray sources of which 12 lie within one core radius of the center. We measure the radial distribution of the X-ray sources and fit it to a King profile finding a core radius. We measure for the first time the unconfused phase-averaged X-ray spectrum of the 3.05-ms pulsar B1821–24 and find it is best described by a power law with photon index. We find marginal evidence of an emission line centered at 3.3 keV in the pulsar spectrum, which could be interpreted as cyclotron emission from a corona above the pulsar’s polar cap if the magnetic field is strongly different from a centered dipole. We present a spectral analyses of the brightest unidentified source and suggest that it is a transiently accreting neutron star in a low-mass X-ray binary, in quiescence. In addition to the resolved sources, we detect fainter, unresolved X-ray emission from the central core.”
And the search has far from ended as even more X-ray counterparts have been discovered inside this seemingly quiet globular cluster! As W. Becker and C.Y. Hui of the Max Planck Institute wrote in their 2007 study:
“A recent radio survey of globular clusters has increased the number of millisecond pulsars drastically. M28 is now the globular cluster with the third largest population of known pulsars, after Terzan 5 and 47 Tuc. This prompted us to revisit the archival Chandra data on M28 to evaluate whether the newly discovered millisecond pulsars find a counterpart among the various X-ray sources detected in M28 previously. The radio position of PSR J1824-2452H is found to be in agreement with the position of CXC 182431-245217 while some faint unresolved X-ray emission near to the center of M28 is found to be coincident with the millisecond pulsars PSR J1824-2452G, J1824-2452J, J1824-2452I and J1824-2452E.”
“We have analyzed archival HST/WFPC2 images in both the F555W & F814W bands of the core field of the globular cluster M 28 in an attempt to identify the optical counterpart of the magnetospherically active millisecond pulsar PSR B1821-24. Examination of the radio derived error circle yielded several potential candidates, down to a magnitude of V 24.5 (V0 23.0). Each were further investigated, both in the context of the CMD of M 28, and also with regard to phenomenological models of pulsar magnetospheric emission. The latter was based on both luminosity-spindown correlations and known spectral flux density behaviour in this regime from the small population of optical pulsars observed to date. None of the potential candidates exhibited emission expected from a magnetospherically active pulsar. The fact that the magnetic field & spin coupling for PSR B1821-24 is of a similar magnitude to that of the Crab pulsar in the vicinity of the light cylinder has suggested that the millisecond pulsar may well be an efficient nonthermal emitter. ASCA’s detection of a strong synchrotron-dominated X-ray pulse fraction encourages such a viewpoint. We argue that only future dedicated 2-d high speed photometry observations of the radio error-circle can finally resolve this matter.”
History of Observation:
This globular cluster was an original discovery in July 1764 of Charles Messier who wrote in his notes:
“In the night of the 26th to the 27th of the same month, I have discovered a nebula in the upper part of the bow of Sagittarius, at about 1 degree from the star Lambda of that constellation, and little distant from the beautiful nebula which is between the head and the bow: that new one may be the third of the older one, and doesn’t contain any star, as far as I have been able to judge when examining it with a good Gregorian telescope which magnifies 104 times: it is round, its diameter is about 2 minutes of arc; one sees it with difficulty with an ordinary refractor of 3 feet and a half of length. I have compared the middle with the star Lambda Sagittarii, and I have concluded its right ascension of 272d 29′ 30″, and its declination of 37d 11′ 57″ south.”
As always, Sir William Herschel would often revisit with Messier’s objects for his own private observations and in his notes he states:
“It may be called insulated though situated in a part of the heavens that is very rich in stars. It may have a nucleus, for it is much compressed towards the centre, and the situation is too low for seeing it well. The stars of the cluster are pretty numerous.” It would be his son, John Herschel who would give M28 its New General Catalog Number and describe it as “Not very bright; but very rich, excessively compressed globular cluster; stars of 14th to 15th magnitude; much brighter toward the middle; a fine object.”
Regardless of whether or not you use binoculars or a telescope on M28, part of the joy of this object is understand how very rich the stellar field is in which it appears. As John Herschel once said of M28 in his many observations, “Occurs in the milky way, of which the stars here are barely visible and immensely numerous.”
Locating Messier 28:
Finding M28 is another easy object once you’ve familiarized yourself with the “teapot” asterism of the constellation of Sagittarius. In binoculars, simply center Lambda in the field of view and you will see Messier 28 as a small, faded grey circular area in the 1:00 position away from the marker star.
In the finderscope of telescope, you can start by centering on Lambda and go to the eyepiece and simply shift the telescope to the northwest slowly and Messier 28 will pop into view. While this globular cluster is easily bright enough to be seen in the smallest of optics, it will require at least a 4″ telescope before it begins any resolution of individual stars and telescopes in the 10″ and larger range will fully appreciate all it has to offer.
And here are the quick facts to help you get started:
Object Name: Messier 28 Alternative Designations: M28, NGC 6626 Object Type: Class IV Globular Cluster Constellation: Sagittarius Right Ascension: 18 : 24.5 (h:m) Declination: -24 : 52 (deg:m) Distance: 18.3 (kly) Visual Brightness: 6.8 (mag) Apparent Dimension: 11.2 (arc min)
Not many people have heard of the globular star cluster Terzan 5. It’s a big ball of stars resembling spilled sugar like so many other globular clusters. A very few globulars are bright enough to see with the naked eye; Terzan 5 is faint because it lies far away in the direction of the center of Milky Way galaxy inside its central bulge. Here, the stars that formed at the galaxy’s birth are packed together in great numbers. They are the “old ones” of the Milky Way.
Today, a team of astronomers revealed that Terzan 5 is unlike any globular cluster known. Most Milky Way globulars contain stars of just one age, about 11-12 billion years. They formed around the same time as the Milky Way itself, used up all their available gas early to build stars and then spent the remaining billions of years aging. Most orbit the galaxy’s center in a vast halo like moths whirring around a bright light. Oddball Terzan 5 has two populations aged 12 billion and 4.5 billion years old and it’s located inside the galactic bulge.
The team used the cameras on the Hubble Space Telescope as well as a host of ground-based telescopes to find compelling evidence for the two distinct kinds of stars. Not only do they show a large gap in age, but the differ in the elements they contain. Terzan 5’s dual populations point to a star formation process that wasn’t continuous but dominated by two distinct bursts of star formation.
“This requires the Terzan 5 ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” explains Davide Massari, co-author of the study.
Its unusual properties make Terzan 5 the ideal candidate for the title of “living fossil” from the early days of the Milky Way. Current theories on galaxy formation assume that vast clumps of gas and stars interacted to form the primordial bulge of the Milky Way, merging and dissolving in the process.
While the properties of Terzan 5 are uncommon for a globular cluster, they’re very similar to the stars found in the galactic bulge. Remnants of those gaseous clumps appear to have stuck around intact since the days of our galaxy’s birth, one of them evolving into the present day Terzan 5. That makes it a relic from the Milky Way’s infant days and one of the earliest galactic building blocks. Later, the cluster, which held onto some of its remaining gas, experienced a second burst of star formation.
“Some characteristics of Terzan 5 resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift (galaxies just beginning to form in the remote universe in the far distant past), suggesting that similar assembling processes occurred in the local and in the distant universe at the epoch of galaxy formation,” said Dr. Francesco Ferraro from the University of Bologna, Italy, who headed up the team.
Terzan 5’s chandelier-like presence is helping astronomers understand how our galaxy was assembled. Reconstructing the past is one of the key occupations of astronomy. The present is continually departing with every passing moment. Soon enough, every piece of information slips into the past tense. In the near-past, which records humanity’s comings and goings, details are often forgotten or lost. The deep past is even worse. With no one around and only scattered clues, astronomers continually look for fragmental remains that when woven into the fabric of a theory, reveal patterns and processes before we came to be.
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Sagittarius Cluster (aka. Messier 22). Enjoy!
Back in the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of these objects so that others wouldn’t make the same mistake. Consisting of 100 objects, this “Messier Catalog” would come to be viewed by posterity as a major milestone in the study of Deep Space Objects.
One of these objects is the Sagittarius Cluster, otherwise known as Messier 22 (and NGC 6656). This elliptical globular cluster, is located in the constellation Sagittarius, near the Galactic bulge region. It is one of the brightest globulars visible in the night sky, and was therefore one of the first of its kind to be discovered and later studied.
Located around 10,400 light years from our Solar System, in the direction of Sagittarius, M22 occupied a volume of space that is 200 light years in diameter and is receding away from us at 149 kilometers per second. M22 has a lot in common with many other clusters of its type, which includes being a gravitationally bound sphere of stars, and that most of its stars are all about the same age – about 12 billion years old.
It is part of our galactic halo, and may once have been part of a galaxy that our Milky Way cannibalized. But it’s there that the similarities end. For example, it consists of at least 70,000 individual stars, only 32 of which are variable stars. It also spans an incredible 32 arc minutes in the sky and ranks as the fourth brightness of all the known globular clusters in our galaxy.
And four must be its lucky number, because it is also one of only four globular clusters known to contain a planetary nebula. Recent Hubble Space Telescope investigations of Messier 22 have led to the discovery of an astonishing discovery. For starters, in 1999, astronomers discovered six planet-sized objects floating around inside the cluster that were about 80 times the mass of Earth!
Using a technique known as microlensing, which measures the way gravity bends the light of the background stars, the Hubble Space Telescope was able to determine the existence of the gas giant. Even though the Hubble can’t resolve them because the angle at which the light bends is about 100 times smaller than the telescope’s angular resolution, scientist know they are there because the gravity “powers up” the starlight, making it brighter each time a body passes in front of it.
Because a microlensing event is very rare and totally unpredictable, the Hubble team needed to monitor 83,000 stars every three days for nearly four months. Luckily, a sharp peak in brightness was all the proof they needed that they were on the right track.
Said Kailash Sahu, of the Space Telescope Science Institute, Baltimore, MD, of the discovery in 2007: “Hubble’s excellent sharpness allowed us to make this remarkable new type of observation, successfully demonstrating our ability to see very small objects. This holds tremendous potential for further searches for dark, low-mass objects.”
During their study time, the Hubble team caught six microlensing events that lasted less than 20 hours and one which endured for 18 days. By calculating the times of the eclipses and the spikes in brightness, astronomers could then estimate the mass of the object passing in front of the star. These wandering rogues might be planets torn away from their parent stars by the huge amounts of gravitational influence from so many closely packed suns – or (in the case of the long event) simply a smaller mass star passing in front of another.
They could be brown dwarfs, or even a totally new type of object. As co-investigator Nino Panagia of the European Space Agency and Space Telescope Science Institute said: “Since we know that globular clusters like M22 are very old, this result opens new and exciting opportunities for the discovery and study of planet-like objects that formed in the early universe,”
Two black holes were also discovered in M22 and confirmed by the Chandra X-ray telescope in 2012. The objects have between 10 and 20 solar masses, and their discovery suggests that there may be 5 to 100 black holes within the cluster (and maybe some multiple black holes as well). The presence of black holes and their interaction with the stars of M22 could explain the cluster’s unusually large central region.
Other objects of interesting include two black holes – M22-VLA1 and M22-VLA2 – both of which are part of binary star systems. Each has a companion star and is pulling matter from it. This gas and dust, in turn, forms an accretion disk around each black hole, creating emissions that scientists used to confirm their existence.
Messier 22 is one of only four known globular clusters that contain a planetary nebula. This nebula – catalogued as GJJC1 or IRAS 18333-2357 – is rather small and young, being only 3 arcseconds in diameter and 6,000 years old. It was discovered in 1986 using the infrared satellite IRAS, and identified as a planetary nebula in 1989.
History of Observation:
Chances are, magnificent Messier 22 was probably the first globular cluster to ever be recorded in the history of astronomy, most likely by Abraham Ihle in 1665. Over the years it has been included in many historic observations, including Edmund Halley’s list of 6 objects published 1715, and observed by De Chéseaux (his Number 17) and Le Gentil, as well as by Abbe Nicholas Louis de la Caille, who included it in his catalog of southern objects (as Lacaille I.12).
However, it was Charles Messier who made it famous when he cataloged it as M22 on June 5th, 1764. As he said of the object at the time:
“I have observed a nebula situated a bit below the ecliptic, between the head and the bow of Sagittarius, near the star of seventh magnitude, the twenty-fifth of that constellation, according to the catalog of Flamsteed. That nebula didn’t appear to me to contain any star, although I have examined it with a good Gregorian telescope which magnified 104 times: it is round, and one sees it very well with an ordinary refractor of 3 feet and a half; its diameter is about 6 minutes of arc. I have determined its position by comparing with the star Lambda Sagittarii: its right ascension has been concluded as 275d 28′ 39″, and its declination as 24d 6′ 11”. It was Abraham Ihle, a German, who discovered this nebula in 1665, when observing Saturn. M. le Gentil has examined it also, and he has made an engraving of the configuration in the volume of the Memoirs of the Academy, for the year 1759, page 470. He observed it on August 29, 1747, under good weather, with a refractor of 18 feet length: He also observed it on July 17, and on other days. “It always appeared to me,” he says, “very irregular in its figure, hair and distributing in space of rays of light all over its diameter.”
While Messier’s description is a wonder, let us remember that he was a comet hunter by profession. Once more, it was the observer Admiral Smythto whom we are indebted for the most detailed and vivid description of the cluster:
“A fine globular cluster, outlying that astral stream, the Via Lactea [Milky Way], in the space between the Archer’s head and bow, not far from the point of the winter solstice, and midway between Mu and Sigma Sagittarii. It consists of very minute and thickly condensed particles of light, with a group of small stars preceding by 3m, somewhat in a crucial form. Halley ascribes the discovery of this in 1665, to Abraham Ihle, the German; but it has been thought this name should have been Abraham Hill, who was one of the first council of the Royal Society, and was wont to dabble with astronomy. Hevelius, however, appears to have noticed it previous to 1665, so that neither Ihle nor Hill can be supported.
“In August, 1747, it was carefully drawn by Le Gentil, as seen with an 18-foot telescope, which drawing appears in the Mémoires de l’Académie for 1759. In this figure three stars accompany the cluster, and he remarks that two years afterwards he did not see the preceding and central one: I, however, saw it very plainly in 1835. In the description he says, “Elle m’a toujours parue tres-irrégulière dans sa figure, chevelue, et rependant des espèces de rayons de lumière tout autout de son diamètre.” This passage, I quote, “as in duty bound;” but from familiarity with the object itself, I cannot say that I clearly understand how or why his telescope exhibited these “espèces de rayons.” Messier, who registered it in 1764, says nothing about them, merely observing that it is a nebula without a star, of a round form; and Sir William Herschel, who first resolved it, merely describes it as a circular cluster, with an estimated profundity of the 344th order. Sir John Herschel recommends it as a capital test for trying the space-penetrating power of a telescope.
“This object is a fine specimen of the compression on which the nebula-theory is built. The globular systems of stars appear thicker in the middle than they would do if these stars were all at equal distances from each other; they must, therefore, be condensed toward the centre. That the stars should be accidentally disposed is too improbable a supposition to be admitted; whence Sir William Herschel supposes that they are thus brought together by their mutual attractions, and that the gradual condensation towards the centre must be received as proof of a central power of such kind.”
Locating Messier 22:
From its position almost on the ecliptic plane, bright globular cluster M22 is easy to find in optics of all sizes. The most important clue is simply identifying the Sagittarius “teapot” shape. Once you’ve located it, just choose the “lid” star, Lambda (Kaus Borealis) and look about a fingerwidth (2 degrees) due northeast. In binoculars, if you center on Lambda, M22 will appear in the 10:00 region of your field of view.
In a finderscope, you will need to hop from Lambda northeast to 24 Sagittari and you’ll see it as a faint fuzzy nearby also to the northeast. From a dark sky location, Messier Object 22 can also sometimes be spotted with the unaided eye! No matter what size optics you use, this large, very luminous ball of stars is quite appealing. A joy to binocular users and an exercise in resolution to telescopes.
And here are the quick facts to help you get started:
Object Name: Messier 22 Alternative Designations: M22, NGC 6656 Object Type: Class VII Globular Star Cluster Constellation: Sagittarius Right Ascension: 18 : 36.4 (h:m) Declination: -23 : 54 (deg:m) Distance: 10.4 (kly) Visual Brightness: 5.1 (mag) Apparent Dimension: 32.0 (arc min)
Go on… Magnificent Messier 22 is waiting for you to appreciate it!
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Messier 19 globular star cluster. Enjoy!
In the 18th century, while searching the night sky for comets, French astronomer Charles Messier began noticing a series of “nebulous objects” in the night sky. Hoping to ensure that other astronomers did not make the same mistake, he began compiling a list of these objects,. Known to posterity as the Messier Catalog, this list has come to be one of the most important milestones in the research of Deep Sky objects.
One of these objects is Messier 19, a globular star cluster located in the constellation Ophiuchus. Of all the known globular clusters, M19 appears to be one of the most oblate (i.e. flattest) in the night sky. Discovered by William Herschel, this cluster is relatively difficult to spot with the naked eye, and appears as a fuzzy point of light with the help of magnification.
Speeding away from us at a rate of 146 kilometers per second, this gravitationally bound ball of stars measuring 140 light years in diameter, is one of the Messier globular clusters that has the distinction of being closest to the center of the Milky Way. At a little more than 5000 light-years from the intense gravitation of our own galactic core, it has played havoc on M19’s round shape.
In essence, Milky Way’s gravity has caused M19 to become one of the most oblate of all globular clusters, with twice as many stars along the major axis as along the minor. And, although it is 28,000 light-years from Earth, it’s actually on the opposite side of the galactic core. For all of its rich, dense mass, four RR Lyrae variable stars have been found in M19.
Is Messier 19 unique? It has some stellar branch properties that are difficult to pinpoint. And even its age (though estimated at around 11.9 billion years old) is indeterminate. Says F. Meissner and A. Weiss in their 2006 study, “Global fitting of globular cluster age indicators“:
“The determination of globular cluster (GC) ages rests on the fact that colour-magnitude diagrams (CMDs) of single-age single composition stellar populations exhibit specific time-dependent features. Most importantly, this is the location of the turn-off (TO), which – together with the cluster’s distance – serves as the most straightforward and widely used age indicator. However, there are other parts of the CMD that change their colour or brightness with age, too. Since the sensitivity to time is different for the various parts of the cluster CMD, it is possible to use either the various indicators independently, or the differences in colour and brightness between pairs of them; these latter methods have the advantage of being independent of distance.”
“I show that a possible solution of the puzzle is to assume that a small fraction of the stellar population in the two clusters is strongly helium enriched. The presence of two distinct stellar populations characterized by two different initial He contents can help in explaining the brightness difference between the red portion of the HB and the blue component.”
“Based on a recently updated set of stellar evolution models, we performed an accurate statistical analysis in order to assess whether GGCs show a statistically significant spread in their initial He abundances, and whether there is a correlation with the cluster metallicity. As in previous works on the subject, we do not find any significant dependence of the He abundance on the cluster metallicity; this provides an important constraint for models of Galaxy formation and evolution. Apart from GGCs with the bluest Horizontal Branch morphology, the observed spread in the individual helium abundances is statistically compatible with the individual errors. This means that either there is no intrinsic abundance spread among the GGCs, or that this is masked by the errors. In the latter case we have estimated a firm upper limit of 0.019 to the possible intrinsic spread. In case of the GGCs with the bluest Horizontal Branch morphology we detect a significant spread towards higher abundances inconsistent with the individual errors; this can be fully explained by additional effects not accounted for in our theoretical calibrations, which do not affect the abundances estimated for the clusters with redder Horizontal Branch morphology.”
History of Observation:
M19 was one of Charles Messier’s original discoveries, which he first observed on June 5th, 1764. In his notes, he wrote:
“I have discovered a nebula, situated on the parallel of Antares, between Scorpius and the right foot of Ophiuchus: that nebula is round & doesn’t contain any star; I have examined it with a Gregorian telescope which magnified 104 times, it is about 3 minutes of arc in diameter: one sees it very well with an ordinary refractor of 3 feet and a half. I have observed its passage of the Medirian, and compared it with that of the star Antares; I have determined the right ascension of that nebula of 252d 1′ 45″, and its declination of 25d 54′ 46″ south. The known star closest to that nebula is the 28th of the constellation Ophiuchus, after the catalog of Flamsteed, of sixth magnitude.”
While Charles didn’t resolve it, we must give him due credit for discovery, for its size wouldn’t make it a particularly easy object given his optics. Later, in 1784, William Herschel would become the first to open up its true identity:
“When the 19th of the Connoiss. is viewed with a magnifying power of 120, the stars are visible; the cluster is insulated; some of the small stars scattered in the neighborhood are near it; but they are larger than those belonging to the cluster. With 240 it is better resolved, and is much condensed in the centre. With 300 no nucleus or central body can be seen. The diameter with the 10 feet is 3’16”, and the stars in the centre are too accumulated to be separately seen. It will not be necessary to add that the two last mentioned globular clusters, viewed with more powerful instruments, are of equal beauty with the rest; and from what has been said it is obvious that here the exertion of a clustering power has brought the accumulation and artificial construction of these wonderful celestial objects to the highest degree of mysterious perfection.”
While you may – or may not – resolve Messier 19’s individual stars, even small telescopes can pick up on some of its ellipticity and larger telescopes will make out a definite blue tinge to its coloration. Before you yawn at viewing another globular cluster, remember that you are looking at the other side of our galactic center and think on the words about M19 from Admiral Symth.
“The whole vicinity,” he wrote, “afford a grand conception of the grandeur and richness even of the exterior creation; and indicate the beautious gradation and variety of the heaven of heavens. Truly has it been said, “Stars teach us as well as shine.” This is near the large opening or hole, about 4deg broad, in the Scorpion’s body, which WH [William Herschel] found almost destitute of stars.”
Locating Messier 19:
Finding M19’s location in binoculars is quite easy – it’s less than a fistwidth (8 degrees) east of Antares (Alpha Scorpi). However, ‘seeing’ M19 in binoculars (especially smaller ones) is a little more problematic. The steadier the binoculars are, the better your chances, since it will appear almost stellar at first glance. A good indicator is to have optical double 26 Ophiuchi in the field at the 2:00 position and look for the star that won’t quite come to focus in the 8:00 position.
Star 26 also makes for a great finderscope lead when locating M19 in a telescope as well. Even for aperture sizes as small as 114mm, this globular cluster will show quite easily in a telescope and reveal its oblate nature. When aperture size increase to the 8″ range, it will begin resolution and as it nears 12″ or more, you’ll pick up on blue stars.
And for your convenience, here are the quick facts of M19:
Object Name: Messier 19 Alternative Designations: M19, NGC 6273 Object Type: Class VIII Globular Star Cluster Constellation: Ophiuchus Right Ascension: 17 : 02.6 (h:m) Declination: -26 : 16 (deg:m) Distance: 28.0 (kly) Visual Brightness: 6.8 (mag) Apparent Dimension: 17.0 (arc min)
Welcome back to Messier Monday! Today, in our ongoing tribute to Tammy Plotner, we take a look at the M15 globular cluster, one of the oldest and best known star clusters in the night sky. Enjoy!
In the 18th century, French astronomer Charles Messier began noticing a series of “nebulous objects” in the night sky while looking for comets. Not wanting other astronomers to make the same mistake, he began compiling a list of these objects into a catalog. In time, this list would include 100 objects, and came to be known by future astronomers as the Messier Catalog.
One of these objects is the globular cluster known as M15. Located in the northern constellation Pegasus, it is one of the brightest clusters in the night sky (with a visual brightness that is roughly 360,000 times that of our Sun). It is also one of the finest globular clusters in the northern section of the sky, the best deep-sky object in the constellation of Pegasus, and one of the oldest and best known globular clusters.
Messier 15 is probably the most dense globular cluster in our entire Milky Way galaxy – having already undergone a process of contraction. What does that mean to what you’re seeing? This ball of stars measures about 210 light years across, yet more than half of the stars you see are packed into the central area in a space just slightly more than ten light years in size.
By looking for single stars within globular clusters, the Hubble Space Telescope was either looking for a massive black hole or evidence of a “core collapse” – the intense gravity of so many stars so close together. Although it was peeking nearly 37,000 light-years away, the Hubble was able to resolve hundreds of stars converging on M15’s core. Like magnetism, their gravity would either cause them to attract or repel one another – and a black hole may have formed at some point in the cluster’s 12-billion-year life.
The study which addressed this data – which appeared in the January 1996 issue of the Astronomical Journal, was led by Puragra Guhathakurta of UCO/Lick Observatory, UC Santa Cruz – asked the question of whether or not the speed of the cluster’s stars could tell us if M15’s dense core was caused by a single huge object, or just mutual attraction. As Guhathakurta stated in the study:
“It is very likely that M15’s stars have concentrated because of their mutual gravity. The stars could be under the influence of one giant central object, although a black hole is not necessarily the best explanation for what we see. But if any globular cluster has a black hole at its center, M15 is the most likely candidate.”
John Bahcall and astrophysicist Jeremiah Ostriker of Princeton University were the first to forward the idea that Messier 15 might be hiding a black hole. While it is distinct from many other globular clusters by having such a dense core, it really isn’t that much different than all the rest of the globular clusters we see. Yet, no where else in our galaxy, except at its core, are the stars that dense!
It is estimated that 30,000 distinct stars exist in the inner 22 light-years of the cluster alone. The closer the Hubble telescope looked, the more stars it found. This increase in stellar density continued all the way to within 0.06 light-years of the center – about 100 times the distance between our Sun and Pluto. “Detecting separate stars that close to the core was at the limit of Hubble’s powers,” says Brian Yanny of the Fermi National Accelerator Laboratory.
At this point, even the great Hubble could not distinguish individual stars, or locate the exact position of the core. Guhathakurta and is colleagues theorized that the stars crowd even closer inside the radius, so they plotted the distribution of the stars as a function of distance from the core. When the results came back, they had two answers – either a black hole was responsible, or a gravothermal catastrophe called core collapse was the culprit.
“It’s a catastrophe in the sense that once it starts, this process can run away very quickly,” said Guhathakurta. “But other processes could cause the core to bounce back before it collapses all the way.”
At an estimated 13.2 billion years old, it is one of the oldest known globular clusters, but it isn’t done throwing some surprises at us. M15 was the first globular cluster in which a planetary nebula, Pease 1 or K 648 (“K” for “Kuster”), could be identified – and can be seen with larger aperture amateur telescopes. Even stranger is the fact that Messier 15 contains 112 variable stars, and 9 known pulsars – neutron stars which are the leftovers of ancient supernovae. And one of these is a double neutron star system – M15 C.
History of Observation:
M15 was discovered by Jean-Dominique Maraldi on September 7, 1746 while he was looking for a comet. Says he:
“On September 7 I noticed between the stars Epsilon Pegasi and Beta Equulei, a fairly bright nebulous star, which is composed of many stars, of which I have determined the right ascension of 319d 27′ 6″, and its northern declination of 11d 2′ 22”. About 25 years later, Charles Messier would independently rediscover it to add to his own catalog, describing it as: “In the night of June 3 to 4, 1764, I have discovered a nebula between the head of Pegasus and that of Equuleus it is round, its diameter is about 3 minutes of arc, the center is brilliant, I have not distinguished any star; having examined it with a Gregorian telescope which magnifies 104 times, it had little elevated over the horizon, and maybe that observed at a greater elevation one can perceive stars.”
Sir William Herschel would be the first to resolve some of its stars, but not the core. It would be his son John who would later pick up structure. However, like the dutiful and colorful observer that he was, Admiral Smyth will leave us with this lasting impression:
“Although this noble cluster is rated as globular, it is not exactly round, and under the best circumstances is seen as in the diagram, with stragglers branching from a central blaze. Under a moderate magnifying power, there are many telescopic and several brightish stars in the field; but the accumulated mass is completely insulated, and forcibly strikes the senses as being almost infinitely beyond those apparent comets. Indeed, it may be said to appear evidently aggregated by mutual laws, and part of some stupendous and inscrutable scheme of involution; for there is nothing quiescent throughout the immensity of the vast creation.”
Considering Smyth’s observations were made nearly two centuries before we really began to understand what was going on inside Messier 15, you’ll have to admit he was a very good observer!
Locating Messier 15:
Surprisingly enough, globular cluster M15 is easy to find. Once you’ve located the “Great Square” of Pegasus, simply choose its brightest and southwesternmost star – Alpha. Now identify the small, kite shape of the constellation of Delphinus. Roughly halfway between these two (and slightly south), you’ll spy a slightly reddish star – Epsilon Peg (Enif).
By placing Enif in your binoculars or image correct finderscope at the 7:00 position, you can’t miss this bright, compact beauty. Even the smallest of optics will reveal the round glow and telescopes starting at 4″ will begin resolution – while large telescopes will simply amaze you. However, don’t expect to open this globular up to the core region. As already noted, its pretty dense in there!
And here are the quick facts for Messier 15, for your convenience:
Object Name: Messier 15 Alternative Designations: M15, NGC 7078 Object Type: Class IV Globular Cluster Constellation: Pegasus Right Ascension: 21 : 30.0 (h:m) Declination: +12 : 10 (deg:m) Distance: 33.6 (kly) Visual Brightness: 6.2 (mag) Apparent Dimension: 18.0 (arc min)
Welcome back to Messier Monday! Today, in our ongoing tribute to Tammy Plotner, we take a look at the M14 globular cluster!
In the 18th century, French astronomer Charles Messier began cataloging all the “nebulous objects” he had come to find while searching the night sky. Having originally mistook these for comets, he compiled a list these objects in the hopes of preventing future astronomers from making the same mistake. In time, the list would include 100 objects, and would come to be known as the Messier Catalog to posterity.
One of these objects was the globular cluster which he would designate as M14. Located in the southern constellation Ophiuchus, this slightly elliptically-shaped stellar swarm contains several hundred thousand stars, a surprising number of which are variables. Despite these stars not being densely concentrated in the central region, this object is not hard to spot for amateur astronomers that are dedicated to their craft!
Located some 30,000 light years from Earth and measuring 100 light years in diameter, this globular cluster can be found in the southern Ophiuchus constellation, along with several other Messier Objects. Although it began its life some 13.5 billion years ago, it is far from being done changing. It is still shaking intracluster dust from its shoes.
What this means is that M14, like many globular clusters, contains a good deal of matter that it picked up during its many times orbiting the center of our Galaxy. According to studies done by N. Matsunaga (et al):
“Our goal is to search for emission from the cold dust within clusters. We detect diffuse emissions toward NGC 6402 and 2808, but the IRAS 100-micron maps show the presence of strong background radiation. They are likely emitted from the galactic cirrus, while we cannot rule out the possible association of a bump of emission with the cluster in the case of NGC 6402. Such short lifetime indicates some mechanism(s) are at work to remove the intracluster dust… (and) its impact on the chemical evolution of globular clusters.”
Another thing that makes Messier 14 unusual is the presence of CH stars, such as the one that was discovered in 1997. CH stars are a very specific type of Population II carbon stars that can be identified by CH absorption bands in the spectra. Middle aged and metal poor, these underluminous suns are known to be binaries. Patrick Cote, the chief author of the research team that discovered the star, wrote in their research report to the American Astronomical Society:
“We report the discovery of a probable CH star in the core of the Galactic globular cluster M14 (=NGC 6402 = C1735-032), identified from an integrated-light spectrum of the cluster obtained with the MOS spectrograph on the Canada-France-Hawaii telescope. Both the star’s location near the tip of the red giant branch in the cluster color-magnitude diagram and its radial velocity therefore argue for membership in M14. Since the intermediate-resolution MOS spectrum shows not only enhanced CH absorption but also strong Swan bands of C2, M14 joins Centaurus as the only globular clusters known to contain “classical” CH stars. Although evidence for its duplicity must await additional radial velocity measurements, the CH star in M14 is probably, like all field CH stars, a spectroscopic binary with a degenerate (white dwarf) secondary.”
History of Observation:
The first recorded observations of the cluster were made by Charles Messier, who described it as a nebula without stars and catalogued it on June 1st, 1764. As he noted in his catalog:
“In the same night of June 1 to 2, 1764, I have discovered a new nebula in the garb which dresses the right arm of Ophiuchus; on the charts of Flamsteed it is situated on the parallel of the star Zeta Serpentis: that nebula is not considerable, its light is faint, yet it is seen well with an ordinary [non-achromatic] refractor of 3 feet & a half [FL]; it is round, & its diameter can be 2 minutes of arc; above it & very close to it is a small star of the nineth magnitude. I have employed for seeing this nebula nothing but the ordinary refractor of 3 feet & a half with which I have not noticed any star; maybe with a larger instrumentone could perceive one. I have determined the position of that nebula by its passage of the Meridian, comparing it with Gamma Ophiuchi, it has resulted for its right ascension 261d 18? 29?, & for its declination 3d 5? 45? south. I have marked that nebula on the chart of the apparent path of the Comet which I have observed last year [the comet of 1769].”
In 1783, William Herschel observed the cluster and was the first to resolve it into individual stars. As he noted, “With a power of 200, I see it consists of stars. They are better visible with 300. With 600, they are too obscure to be distinguished, though the appearance of stars is still preserved. This seems to be one of the most difficult objects to be resolved. With me, there is not a doubt remaining; but another person, in order to form a judgement, ought previously to go through all the several gradations of nebulae which I have resolved into stars.“
As always, it was Admiral William Henry Smyth who provided the most lengthy and detailed description, which he did in July of 1835:
“A large globular cluster of compressed minute stars, on the Serpent-bearer’s left arm. This fine object is of a lucid white colour, and very nebulous in aspect; which may be partly owing to its being situated in a splendid field of stars, the lustre of which interferes with it. By diminishing the field under high powers, some of the brightest of these attendants are excluded, but the cluster loses its definition. It was discovered by Messier in 1764, and thus described: “A small nebula, no star; light faint; form round; and may be seen with a telescope 3 1/2 feet long.” The mean apparent place is obtained by differentiation from Gamma Ophiuchi, from which it is south-by-west about 6deg 1/2, being nearly midway between Beta Scorpii and the tail of Aquila, and 16deg due south of Rasalhague [Alpha Ophiuchi]. Sir William Herschel resolved this object in 1783, with his 20-foot reflector, and he thus entered it: “Extremely bright, round, easily resolvable; with [magnification] 300 I can see the stars. The heavens are pretty rich in stars of a certain size [magnitude, brightness], but they are larger [brighter] than those in the cluster, and easily to be distinguished from them. This cluster is considerably behind the scattered stars, as some of them are projected upon it.” He afterwards added: “From the observations with the 20-foot telescope, which in 1791 and 1799 had the power of discering stars 75-80 times as far as the eye, the profundity of this cluster must be of the 900th order.” “It resembles the 10th Connoissance des temps [Messier 10], which probably would put on the same appearance as this, were it removed half its distance farther from us.”
Locating Messier 14:
Messier 14 can be found by first locating Delta Ophiuchi, which M14 is located at about 21 degrees east and 0.4 degrees north from. It can also be found about one-third of the way from Beta to Eta Ophiuchi. If you know where Messier 10 is, take a look 0.8 degrees north and 10 degrees east of it to find M14. The cluster can also be located along the imaginary line from Cebalrai, an orange giant with an apparent magnitude of 2.76 and the fifth brightest star in Ophiuchus, to Antares, the bright red supergiant located in Scorpius.
With an apparent magnitude of +7.6, M14 can be easily observed with binoculars. For those using small telescopes, the bright center and faint halo can be viewed, whereas 8-inch instruments will reveal the cluster’s elliptical shape. To resolve individual stars, you will need a 12-inch telescope or larger. The best time of year to observe the cluster is in the months of May, June and July.
And here are the quick facts for Messier 15, for your convenience:
Object Name: Messier 14 Alternative Designations: M14, NGC 6402 Object Type: Globular Cluster Constellation: Ophiuchus Right Ascension: 17 : 37.6 (h:m) Declination: -03 : 14 (deg: m) Distance: 30.3 (kly) Visual Brightness: 7.6 (mag) Apparent Dimension: 11.0 (arc minutes)
Welcome to another installment of Messier Monday! Today, we continue in our tribute to our dear friend, Tammy Plotner, by taking a look at Messier Object 10.
In the 18th century, French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky while searching for comets. Hoping to ensure that other astronomers did not make the same mistake, he began compiling a list of 1oo of them. This list came to be known as the Messier Catalog, and would have far-reaching consequences.
In addition to being as a major milestone in the history of astronomy and the study of Deep Sky Objects. One of these objects is known as Messier 10 (aka. NGC 6254), a globular cluster that is located in the equatorial constellation of Ophiuchus. Of the many globular clusters that appear in this constellation (seven of which were cataloged by Messier himself) M10 is the brightest, and can be spotted with little more than a pair of binoculars. Continue reading “Messier 10 (M10) – The NGC 6254 Globular Cluster”
In the late 18th century, Charles Messier was busy hunting for comets in the night sky, and noticed several “nebulous” objects. After initially mistaking them for the comets he was seeking, he began to compile a list of these objects so other astronomers would not make the same mistake. Known as the Messier Catalog, this list consists of 100 objects, consisting of distant galaxies, nebulae, and star clusters.
Among the many famous objects in this catalog is the M5 globular star cluster (aka. NGC 5904). Located in the galactic halo within the Serpens Constellation, this cluster of stars is almost as old as the Universe itself (13 billion years)! Though very distant from Earth and hard to spot, it is a favorite amongst amateur astronomers who swear by its beauty. | 0.932606 | 3.89336 |
Astronomers using ESA’s Herschel space observatory to probe the turbulent beginnings of a Sun-like star have found evidence of mighty stellar winds that could solve a puzzling meteorite mystery in our own back yard.
In spite of their tranquil appearance in the night sky, stars are scorching furnaces that spring to life through tumultuous processes – and our 4.5 billion-year-old Sun is no exception. To glimpse its harsh early days, astronomers gather clues not only in the Solar System but also by studying young stars elsewhere in our Galaxy.
Using Herschel to survey the chemical composition of regions where stars are being born today, a team of astronomers has noticed that one object in particular is different.
The unusual source is a prolific stellar nursery called OMC2 FIR4, a clump of new stars embedded in a gaseous and dusty cloud near to the famous Orion Nebula.
“To our great surprise, we found that the proportion of two chemical species, one based on carbon and oxygen and the other on nitrogen, is much smaller in this object than in any other protostar we know,” says Dr Cecilia Ceccarelli, of the Institute de Planétologie et d’Astrophysique de Grenoble, France, who lead the study with Dr Carsten Dominik of the University of Amsterdam in the Netherlands.
In an extremely cold environment, the measured proportion could arise by one of the two compounds freezing onto dust grains and becoming undetectable. However, at the relatively ‘high’ temperature of about –200°C found in star-forming regions like OMC2 FIR4, this should not occur.
“The most likely cause in this environment is a violent wind of very energetic particles, released by at least one of the embryonic stars taking shape in this proto-stellar cocoon,” Dr Ceccarelli adds.
The most abundant molecule in star-forming clouds, hydrogen, can be broken apart by cosmic rays, energetic particles that permeate the entire Galaxy. The hydrogen ions then combine with other elements that are present – albeit only in trace amounts – in these clouds: carbon and oxygen, or nitrogen.
Normally, the nitrogen compound is also quickly destroyed, yielding more hydrogen for the carbon and oxygen compound. As a result, the latter is far more abundant in all known stellar nurseries.
Strangely enough, though, this was not the case for OMC2 FIR4, suggesting that an additional wind of energetic particles is destroying both chemical species, keeping their abundances more similar.
Astronomers think that a similarly violent wind of particles also gusted through the early Solar System, and this discovery might finally point to an explanation for the origin of a particular chemical element seen in meteorites.
Continue reading below
Meteorites are the remains of interplanetary debris that survived the trip through our planet’s atmosphere. These cosmic messengers are one of the few tools we have to directly probe the elements in our Solar System.
“Some elements detected in meteorites reveal that, long ago, these rocks contained a form of beryllium: this is quite puzzling, as we can’t quite understand how it got there,” explains Dr Dominik.
The formation of this isotope – beryllium-10 – in the Universe is an intricate puzzle of its own. Astronomers know that it is not produced in the interior of stars, like some other elements, nor in the supernova explosion that happens at the end of a massive star’s life.
The majority of beryllium-10 was formed in collisions of very energetic particles with heavier elements like oxygen. But since this isotope decays very quickly into other elements, it must have been produced just before it was incorporated in the rocks that would later appear on Earth as meteorites.
In order to trigger these reactions and produce an amount of beryllium matching that recorded in meteorites, our own Sun must have blown a violent wind in its youth.
These new observations of OMC2 FIR4 give a very strong hint that it is possible for a young star to do this.
“Observing star-forming regions with Herschel not only provides us with a view on what happens beyond our cosmic neighbourhood, but it’s also a crucial way to piece together the past of our own Sun and Solar System,” says Göran Pilbratt, ESA’s Herschel project scientist.
“Herschel finds evidence for stellar wind particles in a protostellar envelope: is this what happened to the young Sun?” by C. Ceccarelli et al. is published in The Astrophysical Journal Letters, July 2014.
The study is based on observations performed with the Heterodyne Instrument for the Far-Infrared (HIFI) on Herschel, as part of the Herschel Guaranteed Time Key Programme Chemical HErschel Surveys of Star forming regions (CHESS).
For further information, please contact:
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
Mob: +31 61 594 3 954
Institute de Planétologie et d’Astrophysique de Grenoble
Tel: +33 476 514 201
Astronomical Institute “Anton Pannekoek”, University of Amsterdam
Amsterdam, The Netherlands
Tel: +31 6 43 710 210
Herschel Project Scientist
Tel: +31 71 565 3621 | 0.886899 | 4.04768 |
- Dwarf Planet Discovery Could Help Show Life's Spread Through Solar System
NASA believes there could be lots of space objects (moon and earth size planets) out there (on the fringes of this solar system). NASA has no idea how they got there or what they are or made of or what purpose they might serve (In NASA's defence, they are truly clueless of most of the facts concerning "everything"). NASA postulates several theories in this article about where planets and other strange objects originated from but miss the target by light years and are nowhere near even an inkling to reality. These solar objects "all" came out of the sun (and some of the planets), which has been belching, birthing freakish material into the solar system and beyond for a long long time (as I have been saying for a long time). All these "planets" and other things, regardless of size have life on them (as NASA is starting to realize...with some apprehension). Some of that life came preexisting with no natural biological tags or crosshairs for understanding. The kind of life that most humans would not enjoy making acquaintance with, I might add. Me be pitching a book that has yet to be written, NEVER!
On March 26, researchers announced the discovery of 2012 VP133, an estimated 280-mile wide (450-kilometer) object that lies just beyond the Kuiper Belt of icy objects that swarm outside of Neptune's orbit.
The new object is nicknamed "Biden" after the vice-president of the United States, because both Joe Biden and 2012 VP133 are "VPs." It is one of only two dwarf planets discovered beyond the Kuiper Belt, with Sedna (a decade ago) being the other one. The paper, "A Sedna-like body with a perihelion of 80 astronomical units," was published in the journal Nature.
Mapping tiny worlds at the Solar System's edge could one day show scientists how life arose on Earth. That's because many of these objects could contain organics, carbon-based material that are ingredients for life. [Strangest Places Where Life Is Found On Earth]
As the scientists continue their search, they expect that 2012 VP133 will be the first of a series of discoveries of such objects. Finding such a world has a value of its own, but the team is also thinking of a greater astrobiological question as they study 2012 VP133. Are the possible organics —which show up as ultra-red material in telescopes — a possible source for life on Earth? And could be this be true of other planetary systems as well?"One of the questions I've had is trying to map out what is this ultra-red material in the Kuiper Belt," said Scott Sheppard, a faculty member at the Carnegie Institution for Science, Department of Terrestrial Magnetism (DTM) in Washington, D.C.
Sheppard co-discovered the object along with the Gemini Observatory's Chadwick Trujillo.
Curiously enough, 2012 VP133 has none of this material on it, but Sedna does. It will take more discoveries of such objects to figure out if ultra-red material is common outside of the Kuiper Belt, and how organics could have been transported to Earth early in our Solar System's history.
A treasure trove of possible organics
Most dwarf planets found to date — including Pluto, which was once considered a planet — reside in the Kuiper Belt, a vast collection of frozen objects that orbit our Sun about 30 to 50 astronomical units (AUs) away. One astronomical unit is the distance between the Earth and the Sun, about 150 million kilometers.
There are millions of objects in the Kuiper Belt, but the ones that interest Sheppard and his colleagues are those that have "resonances" with Neptune. An orbital resonance occurs when two bodies — like a planet and a moon, or a planet and an asteroid — exert gravitational influences on each other that put them into closely related orbits.In a 2012 paper in the Astronomical Journal, "The Color Differences of Kuiper Belt Objects in Resonance with Neptune,"Sheppard examined 58 Kuiper Belt objects that have a resonance with the gas giant.
He found that those resonant objects that are embedded in the Kuiper Belt are full of this ultra-red material, indicating likely organics. On the edge of the belt, some of those objects also still have the material, showing that it is somehow leaking into the inner Solar System. Those that are quite far away, however, show none of the material.
Sedna and 2012 VP133 are well beyond the boundaries of the Kuiper Belt. Sheppard's new paper argues that they are part of the edges of the Oort Cloud, a theorized icy collection of objects extending thousands of AUs away from Earth. (The Oort Cloud is perhaps best known for being the supposed source of many comets that fly into the inner solar system.)
It's difficult to envision how dwarf planets such as Sedna and 2012 VP133 could receive ultra-red material from the Kuiper Belt because they are so far away from it. Further, it's unclear why only Sedna (of the two dwarf planets known in that region) has the material. They're too far away for Neptune to have any influence on them. So what happened? [New Dwarf Planet Photos: Images of 2012 VP113]
Determining what resonants have and do not have ultra-red material helps us understand how the ultra-red material has moved around the outer Solar System,” said Sheppard.
A big jolt
Looking at other objects, it becomes clear that something big likely disturbed some of them. For example, Sedna's weird orbit got the attention of researchers because it is so eccentric. The dwarf planet ranges between 80 AU and 940 AU — meaning that one orbit takes about 11,400 years to complete. It's by far the most eccentric orbit in the Solar System.
"It probably formed much further in and somehow got scattered out there and captured into the no-man land area," Sheppard said.
Sheppard and Trujillo then compared Sedna's and 2012 VP133's orbits with 10 representative Kuiper Belt objects that have eccentric orbits. To their surprise, they found that all 12 of them had almost identical "arguments of perihelion." That's an orbital parameter that measures the angle between two points in each object's orbit: the closest approach to the Sun, and the location where the objects cross the plane of the Solar System."They should just have random arguments of perihelion," Sheppard said.
The similarities point to a giant disturbance causing chaos. There are three theories for this. Perhaps a rogue planet (Earth's size or smaller) was ejected out of the Solar System, throwing smaller objects aside as it passed into the outer Solar System.
"That rogue planet could have been ejected or it could be out there today," Sheppard said.
He said it would be too dim to show up in surveys, such as NASA's Wide-field Infrared Survey Explorer (WISE), a spacecraft more suited to finding gas giant planets, which emit their own heat.
Another theory — the leading one — says a passing star about 200 AU from our own caused huge gravitational disturbances. It seems easy to explain a star tugging on the wandering Sedna, but VP113 has a more circular orbit that only goes as far as 266 AU.
"That makes VP113 more tightly bound to the Sun, and it's harder to form that from a stellar encounter," Sheppard said. "It would have to be stronger or a bigger object, so it's less likely to have happened."
The third — Sheppard termed it the "dark horse" theory — suggests the Sun captured extrasolar planets from another star early in the Sun's history, while it was forming in a cloud of gas and young stars.Hundreds of objects waiting for discovery
As Sheppard wrestles with the question of how the ultra-red material moved around, he's also interested in learning more about the nature of the material itself. Researchers suspect it's organics, but what sort of organics is of great interest. Luckily, there's a chance to take a closer look.
NASA's New Horizons probe is currently sailing to the outer Solar System. It's expected to make a pass by Pluto and its moons in 2015 before zooming toward the Kuiper Belt. After the Pluto encounter is finished, perhaps the spacecraft could turn its observations to an ultra-red object. No candidates have been identified yet, but this is a possibility, Sheppard said.
Sheppard's search of the outer Solar System will continue. He and his collaborators have some suspected new objects that need confirmation, and better yet, his research estimates that there could be at least 900 objects in the Oort Cloud's fringes that are at least 621 miles (1,000 km) in diameter — a little less than half of Pluto's size.
"There are for sure some bigger than Pluto, and there might be some bigger than Earth or Mars," Sheppard said. "We think there's a lot of these objects out there." | 0.863663 | 3.104278 |
In the far reaches of the Universe, astronomers have managed to capture a rare interaction. As a supermassive black hole ravenously slurps down matter around it, it’s sending out jets of plasma – pushing into and heating the gas in the galaxy around it.
This is difficult to capture at the best of times, but this case was a particularly impressive feat. The galaxy in question is a whopping 11 billion light-years away – when the Universe was less than 3 billion years old.
It’s called MG J0414+0534, and astronomers managed to capture it in detail because of gravitational lensing. In between us and the galaxy is a different, rather massive galaxy whose gravity distorts the path of the light travelling from behind it, creating four images of MG J0414+0534 around it (see image below).
“This distortion works as a ‘natural telescope’ to enable a detailed view of distant objects,” said astronomer Takeo Minezaki of the University of Tokyo in Japan.
And this can show us how some galaxies evolved in the early Universe.
Black holes – and in particular the supermassive black holes that power galaxies – are extraordinarily complex things. They’re so dense, their gravitational power creates a point of no return around them: a boundary called the event horizon, beyond which not even light speed is sufficient to achieve escape velocity. We can’t, therefore, see into a black hole.
But outside the event horizon – that is, the part we can see – is an incredibly extreme environment. The most extreme example is a quasar, an active galactic nucleus with a supermassive black hole in the centre. These are the early, violent stages of a galaxy’s life, with the black hole actively feasting on the material around it.
This spews out intense light across the electromagnetic spectrum as the accretion disc of material swirling around and into the black hole generates intense light and heat through friction. Quasars are among the brightest objects in the Universe.
But that’s not all. These active black holes also have jets of ionised material that spew forth from their polar regions at relativistic speeds – comparable to the speed of light. These don’t come from inside the black hole; it’s thought that the material is channelled from the inner edge of the accretion disc along the black hole’s magnetic field lines outside the event horizon to the poles, where it’s ejected at high speed.
In turn, those jets can blast into the black hole’s galaxy, blowing away the clouds of dust and gas that would otherwise collapse into stars – effectively turning off star formation, a phenomenon known as quenching.
It’s known that MG J0414+0534 has bipolar jets shooting from its black hole. By combining the four lensed images of the galaxy, and subtracting the gravitational effects of the galaxy in front, the team was able to reconstruct an image of these jets.
Above: Reconstructed images of what MG J0414+0534 would look like if gravitational lensing effects were turned off. The emissions from dust and ionised gas around a quasar are shown in red. The emissions from carbon monoxide gas are shown in green, which have a bipolar structure along the jets.
“Combining this cosmic telescope and ALMA’s high-resolution observations, we obtained exceptionally sharp vision, that is 9,000 times better than human eyesight,” said astronomer Kouichiro Nakanishi of the National Astronomical Observatory of Japan/SOKENDAI.
“With this extremely high resolution, we were able to obtain the distribution and motion of gaseous clouds around jets ejected from a supermassive black hole.”
As the black hole jets slam into the gas of the interstellar medium, the impact creates heat. From this heat map, the researchers were able to calculate that the gas clouds were moving at speeds up to 600 kilometres per second (373 miles per second).
Moreover, both gas clouds and jets were relatively small for a galaxy of this type, indicating that we’re observing a very early stage in jet formation – as early as a few tens of thousands of years. This means it could be very important for understanding how galaxies become quenched.
“MG J0414+0534 is an excellent example because of the youth of the jets,” said astronomer Kaiki Inoue of Kindai University in Japan.
“We found telltale evidence of significant interaction between jets and gaseous clouds even in the very early evolutionary phase of jets. I think that our discovery will pave the way for a better understanding of the evolutionary process of galaxies in the early Universe.”
The research has been published in The Astrophysical Journal Letters. | 0.858132 | 4.158168 |
Hundreds of large flashes have been filmed reflecting off our planet, and they’ve helped NASA solve a mystery that stumped the likes of Carl Sagan more than two decades ago.
These flashes are so large, you can see them from space, and they were originally thought to be caused by sunlight reflecting off the surface of the ocean. But then NASA started spotting them on land, and no one could say why.
“We found quite a few very bright flashes over land as well,” says Alexander Marshak from NASA’s Goddard Space Flight Centre.
“When I first saw it I thought maybe there was some water there, or a lake the sun reflects off of. But the glint is pretty big, so it wasn’t that.”
Back in 1993, astronomer Carl Sagan noticed strange flashes of light showing up in images of Earth taken by the Galileo spacecraft.
The unmanned space probe had been launched four years earlier to study Jupiter and its moons, but Sagan and his team decided to take advantage of one of its flybys past Earth, and scoured the data for signs of life on our own planet.
The idea was that if he could detect signatures of life on Earth from way up in space, any undiscovered extraterrestrial neighbours could too, and know from afar that our planet was inhabited.
In Galileo’s images, they found large glints of light, reflecting like mirrors – but he could only find them in regions of the planet covered in water.
“Large expanses of blue ocean and apparent coastlines are present, and close examination of the images shows a region of specular [mirror-like] reflection in ocean, but not on land,” the team reported at the time.
It came as quite a shock, then, when 24 years later, NASA detected 866 bursts of light between June 2015 and August 2016, and they were all coming from the land.
You can see them in the footage below, which was shot by NASA’s Earth Polychromatic Imaging Camera (EPIC) onboard the NOAA’s Deep Space Climate Observatory (DSCOVR):
When the NASA team dug out the old Galileo photos for comparison, they realised that Sagan and his team had missed a rather crucial detail – those strange reflections had actually appeared on land during that survey too.
Tasked with explaining this bizarre phenomenon, Marshak and his team catalogued all known flashes over land from the Galileo and EPIC images, and mapped out their locations.
They hypothesised that if the glints were caused by reflected sunlight, then only certain parts of the globe could have them – spots where the angle between the Sun and Earth was the same as the angle between the spacecraft and Earth, which would allow the spacecraft to pick up the reflected light.
Sure enough, that pattern emerged, and this helped them discount one potential cause of the glints – lightning.
“Lightning doesn’t care about the Sun and EPIC’s location,” says Marshak.
To figure out what the sunlight was actually reflecting off, the team proposed that water is still the culprit, but up in the atmosphere, rather on the surface.
Using data from EPIC, they were able to map out where exactly the glints were coming from, and narrowed down the source to 5 to 8 km (3 to 5 miles) above the surface, where cirrus clouds full of ice crystals hang.
When they modelled the direction of sunlight reflecting off hypothetical ice crystals that happened to be floating in the air on a horizontal angle, the numbers matched perfectly to what was in the EPIC and Galileo images.
“The source of the flashes is definitely not on the ground. It’s definitely ice, and most likely solar reflection off of horizontally oriented particles,” says Marshak.
The research has yet to be peer-reviewed, so certain aspects of the discovery could change once it’s been independently verified
But the researchers are now looking into how common these horizontal ice crystals actually are, and if they’re having any significant impact on how much sunlight is being reflected through our atmosphere.
And at least we now know one thing for sure – these aren’t the signs of life Carl Sagan was looking for.
You can see all the images from EPIC at NASA’s website.
On – 16 May, 2017 By BEC CREW | 0.83228 | 3.713199 |
Io is the fifth closest in of Jupiter’s many moons and the closest large moon. Io became the first place outside of Earth known to have volcanic eruptions. And Io is the most volcanic and geologically active place known to man. Its molten core is half as wide as the moon itself.
Io is roughly 3,600 kilometers across. It is a little bigger than Earth’s moon. Io orbits Jupiter at an average distance of 422,000 kilometers, though the orbit is very elliptical.
Io orbits Jupiter every 1.76 days. Because it is so close to Jupiter, it is tidally locked. This means that its day is as long as its rotational period, giving Io a “day” of 1.76 Earth days.
History of Io
Galileo Galilei. © NASA
Io is one of the four moons of Jupiter discovered by Galileo in 1610. Io was named for a mythical nymph who worshiped Hera, Jupiter’s wife, before becoming Jupiter’s lover. Io was studied by Ole Romer in 1676. He was studying the eclipses of Jupiter’s moons and used this information to estimate the speed of light. The astronomer de Laplace discovered the 1:2:4 orbital ratios of the orbits of Io, Europa and Ganymede. Io, being the closest moon, is the “1″ in this synchronized dance. Europa may or may not have been larger in its past, since the magnetic field of Jupiter and regular eruptions of its volcanoes cause it to lose about a ton of mass every second. Io continues to suffer regular eruptions. Due to the gravitational pull of the other large moons of Jupiter, it is unlikely to spiral into the Jovian planet like some smaller asteroids and comets have.
Geography of Io
Io is pockmarked with volcanoes. It has at least 400 known volcanoes, giving the surface a spotted appearance. The tug of war between Jupiter and Jupiter’s other moons like Europa literally flex the planet. This keeps the core of Io molten, but the pressure also builds until lava explodes in massive volcanic eruptions. Due to Io’s low gravity, eruptions can rise up to three hundred miles above Io’s surface.
The volcano Loki on Io is the largest active volcano in the solar system. This single volcano on Io may release more material lava than all of Earth’s volcanoes put together. It is larger than the state of Arizona.Geography of Io (surface). © based on NASA images
While Io is primarily composed of iron rock, it is the only moon that we know to also contain large amounts of sulfur and sulfur compounds. This gives Io a yellow color. The volcanic plumes primarily contain sulfur and sulfur dioxide. While Io is volcanically active, the rest of the planet is bitterly cold. Sulfur dioxide frost covers large areas of the planet’s surface.
Io probably receives as many asteroid strikes as Jupiter’s other moons. However, it has few craters because they are filled in periodically by lava and volcanic debris.
Io has mountains that are not the result of volcanic activity. These mountains, many taller than Mount Everest, were formed by the gravitational pull of the moons Europa and Ganymede. Io’s tallest mountain is twice as tall as Mount Everest. Io also has lakes of liquid sulfur.Io’s rotation. © based on NASA images
Possibly due to the constant eruptions and periodic peak temperatures three times as hot as Mercury, there is no water ice evident on Io. In contrast, Ganymede and Europa are thought to have liquid oceans under their frozen exteriors.
The tug of war between Jupiter and the other Jovian moons creates land tides on Io. Io’s surface can rise and fall one hundred meters. In comparison, the greatest known tides on Earth are less than 20 meters. This creates periodic fissures and cracks in Io’s surface that open and close as the moon is literally squeezed and pulled in different directions. This surface of Io essentially shifts over time. Unlike Earth, Io’s volcanoes move. New volcanoes form in new weak points on Io’s surface.
The NASA probe Galileo. © NASA
The Galileo space probe found a hole in Jupiter’s magnetic field. This may or may not be caused by Io’s own magnetic field. The interaction of Io’s liquid core and Jupiter’s magnetic field generates electric currents up to 400,000 volts, causing lightening in Jupiter’s atmosphere.
Atmosphere of Io
Io’s thin atmosphere is comprised of sulfur dioxide. There are no significant traces of hydrocarbons or water vapor. The Galileo spacecraft recorded auroras in Io’s thin atmosphere caused by the interaction of Jupiter’s magnetic field with the moon. Blue areas in the aurora occur where there is dense sulfur vapor left by volcanic eruptions. The rest of the auroras are the familiar reds and greens as would be seen on Earth.
Exploration of Io
Pioneer 10 passed Io in 1973. It was closely followed by 1973. These craft provided data that helped confirm Io’s mass and size. The Pioneer craft did not get good images of Io except for a single polar image.
Voyager 1 passed by Io in 1979. What astronomers originally thought were craters turned out to be volcanoes. Voyager 1 captured the first proof of volcanic activity in the solar system outside of Earth. Voyager 2 also passed by Io and sent back images of volcanic eruptions.
The Galileo probe was sent to Jupiter and arrived in 1995. The NASA probe Galileo measured the temperature of Io’s surface. Active volcanoes had temperatures as host as 1200°C. The hottest active volcanoes were found to be 1700°C. This is hotter than the daytime temperature of the planet Mercury. The Galileo mission ended in 2003.Internal structure of Io, Europa, Ganymede and Callisto. © based on NASA images
The Cassini-Huygens craft sent back images of Io when it passed by in 2000. The New Horizons craft sent back images in 2007.
Io is regularly monitored by telescopes on Earth. The Infrared Telescope Facility observatory caught signs of how rapid Io’s surface changes; the Ra Patera volcano showed changes since the flyby of the Voyager craft. The Hubble space telescope has also periodically been trained on Io.
Future exploration of Io
The Juno mission was launched by NASA in 2011. The craft is expected to reach Jupiter in 2017. Juno was sent to explore Jupiter’s atmosphere. Given how close Io is to Jupiter and how they share an ionosphere, Juno can send back data on how Io affects Jupiter. Juno is expected to last until one year. There is a planned mission to Jupiter’s moons to explore the moons suspected of having underground oceans. However, these exploration craft will not explore Io. | 0.919666 | 3.459775 |
This little chunk of crystalline metal is a tiny slice of a meteorite — a rock that fell from the sky. When one says that, the next natural question is, “how do you know it’s a meteorite?” (We will get to that.) But what is really staggering is not just that we know, but how much we know about it and its history. And what a long history it is.
This specimen is a 68 gram sample cut from a fragment of the Muonionalusta meteorite. According to our best current understanding, the parent body that Muonionalusta came from was one of the earliest bodies to take shape during the formation of our solar system. It began as a protoplanet (or planetisimal) that accreted within the protoplanetary disk that would eventually become our solar system. It accreted over the course of roughly the first million years after the beginning or our solar system. (That is to say, during the first million years after the very first solids condensed from the protoplanetary disk.) The parent body had an iron-nickel “planetary” core, 50–110 km in radius, that was eventually exposed by collisions that stripped away most of its insulating mantle. It cooled very slowly over the next 1-2 million years. It is estimated (with startling precision) by Pb-Pb dating that the body crossed below a temperature of ~300 °C at 4565.3 ± 0.1 million years ago, just 2-3 million years after the solar system began to form. For the next four billion years, it led a largely unremarkable existence as an asteroid (minor planet) until it broke apart (possibly due to a major collision) about 400 million years ago. Then, one fine day roughly one million years ago, a large fragment entered the earth’s atmosphere, breaking into hundreds (perhaps, thousands) of smaller fragments that rained down in a shower of fire upon what is now northern Sweden and Finland. Four ice ages transported the surviving meteorite fragments across the Swedish tundra, until their first discovery (and naming after the nearby Muonio river) in 1906.
But, how do we know all of that?
Continue reading A Fragment of Muonionalusta | 0.826223 | 3.806757 |
Issues in Earth Science
“Eww, There’s Some Geology in my Fiction!”
Issue 13, May 2020
Suggestions for Activities and Discussions to accompany Readings of
Standing in the Shadow of Phobos by Mary Alexandra Agner
Demetrius, the young boy excited by science in this issue's story "Standing in the Shadow of Phobos," describes the transit of the Sun by the moon Phobos this way
"Transits are pretty special because you get to see both of the objects at the same time. And, you get to sort of feel how the entire universe is moving."
How very true. Even before we humans had the ability to measure the distance to stars, we figured out the relative distances of objects in space and something about their motions by watching which objects pass in front of the others. We saw the Moon pass in front of the sun and the planets. We watched planets pass in front of distant stars. Galileo, with his newly-invented telescope, watched the moons of Jupiter pass in front of Jupiter, and then, a while later, watched Jupiter pass in front of the moons. With this observation, he proved that not all objects revolve around the Earth, the beginning of the end for the Earth-centric model for the universe.
As Demetrius points out, watching a transit can be particularly helpful in constructing a mental picture of what is going on in space. In science, we call that mental picture a model. Constructing models is particularly important in doing science, and is one of the important practices of science promoted by the Next Generation Science Standards (2013). For our classroom resources this issue, we are going to consider how various models for the movement of objects in our solar system can be supported or disproven by observations of the motions of bodies in space.
Consider the possible solar system models below. Which of these models does Demetrius' observation of the transit disprove (select all that apply)?
The answer, of course, is it disproves models 1 and 4. In those two models, Phobos would never come between Mars and the Sun, and Demetrius could never observe a transit of the Sun by Phobos.
Now, if you have already talked about the model for our solar system with your class, some of your students may have identified ALL of the models as being wrong. We do think they are all wrong! But they are not all proven wrong by Demetrius' observation of the transit.
Often in the classroom, instead of teaching students to identify evidence and construct models, we ask them to learn, explain, and apply the models that we have given them. They then just "know" which model is correct and don't always think about evidence. Sometimes, we even make the model the evidence for itself—An example of this type of circular reasoning is when a student offers an argument like "We know that model 2 is wrong because we know that the Earth orbits the Sun, not the other way around."
What one additional observation of Phobos would Demetrius have almost certainly made, living on Mars, that would disprove both models 2 and 3?
If you need a hint, think about watching the sky at night. What would Demetrius see in the night sky, when the Sun is on the complete opposite side of Mars? What would this observation imply?
He would have observed Phobos in the sky at night. Meaning that Phobos sometimes appears between Mars and the Sun (the transit) and Mars sometimes appears between the Sun and Phobos (when he sees Phobos in the night sky). From this, he can figure out that Phobos must orbit Mars, not only the Sun or the Earth.
As mentioned above, the observation that not everything in our solar system orbits the Earth was a key argument that Galileo offered against a geocentric model for our solar system. Of course, Galileo could not watch the moons of Jupiter from the surface of Jupiter, like Demetrius watches Phobos from Mars. He had to figure out that the moons orbit Jupiter by watching from Earth. Below is an illustration of the positions of the moons of Jupiter on nine sequential nights (With thanks to an unknown source for this image).
Can you follow the orbits of each moon? Can you figure out how long it takes each moon to orbit Jupiter?
Note: the distances from Jupiter are in millions of miles.
The modern orbital periods for the Galilean moons (in Earth days) are: Io= 1.77, Europa = 3.55, Ganymede = 7.15, and Callisto = 16.69
The following puzzle in celestial mechanics comes from Learning to Read the Earth and Sky (2016) by Russ and Mary Colson, published by NSTA Press.
Often people imagine that the geocentric model of Ptolemy was like that shown below. But this is not true. Even without telescopes, ancient people knew this model was not correct. Consider this model, and think about what it predicts that one could see in the night sky. What observation that ancient people could easily make disproves this model?
Need a hint? Think about the time of day and locations in the sky that Venus could appear.
This model implies that Venus should sometimes be seen on the complete opposite side of the Earth from the Sun. For example, we should be able to see Venus high in the sky at midnight during times when Venus has orbited to the opposite side of Earth from the Sun. In fact, Venus—the morning and evening star—is never seen at midnight, nor is it ever seen high in the sky at night. Thus, ancient people knew this model was wrong. A better illustration of Ptolemy's model, also from Learning the Read the Earth and Sky (2016) is shown below. In this model, Venus and the Sun both orbit the Earth in lock-step. Notice that this model does not allow Venus to be on the opposite side of the Earth from the Sun.
Galileo disproved this model by observing the phases of Venus through a telescope, that is, he observed how much of the lit side of Venus can be seen from Earth at different times. Only a tiny sliver of the lit side of Venus could ever be seen if Ptolemy's model were right. Yet Galileo observed a nearly fully-lit Venus, proving that Venus must orbit the Sun. Try sketching models for orbits to show that this is so. Explain your reasoning!
More on this investigative problem is found in Learning to Read the Earth and Sky (2016).
Think about the model for the solar system shown below, showing Phobos orbiting Mars and Mars and Earth orbiting the Sun. What might the phases of Earth look like as seen from Mars? How much of the Earth would appear to be "lit" as viewed from Mars at each of the stages of Earth shown?
Your students might model the appearance of phases with reference to the illustration below.
You students might make a prediction of phases like that shown below.
You might encourage your students to also draw what the phases would look like if Earth and the Sun both orbited Mars (a Mars-centric solar system, much like the geocentric model of Ptolemy, except putting Mars in the center—Use the Ptolemaic geocentric model illustration above for reference in predicting the phases, but imagine Mars for the Earth and Earth for Venus). The phases in this case will look quite different—never being more than a crescent Earth. Thus, a Martian could watch the phases of Earth and see that there are gibbous and full-Earth phases—proving that the Sun, and not Mars, is the center of Earth's orbit.
How long do you think it would take the Earth to go through its set of phases if you viewed Earth from a fixed point out in space, at about the distance of Mars? Yes, you can figure this out!
Since it takes Earth 1 year to orbit the Sun, it will take one year to go through its set of phases.
What about the duration of the cycle of phases as seen from Mars? Would it be the same or different?
Since Mars is also moving as it orbits the sun, the duration of the cycle of phases of Earth as seen from Mars would be longer than 1 Earth year. Convince yourself by sketching out what the Earth phases would look like as Mars also orbits the Sun but not as fast as the Earth.
What would the phases of Mars look like as viewed from the Earth? Would they go through the same cycle of phases as shown above for the phases of Earth as seen from Mars, or would they be different? Sketch out what these phases would look like.
A little bit of thought reveals that since Mars' orbit is outside Earth's orbit, Mars will never appear less than half lit. There will be no "new" or "crescent" Mars! That is one way that we can confirm that Mars' orbit is outside of Earth's orbit.
What is another way that someone living on Mars could confirm this?
Think about transits!
Only planets closer than you to the Sun will be seen to transit the Sun. From Earth, it only happens with Mercury and Venus. From Mars, you could also see the Earth transit the Sun. Imagine living on Mars and watching your own home world cross the face of your sun!
Kepler described the motion of the planets with empirical laws. Later Newton's laws of gravity provided a deeper theoretical understanding of why planetary motions are as they are and expanded the relationships to include moons and other satellites.
If one body orbits another, and if one body is much, much larger than the other, then Kepler's third law*, with Newton's modifications, can be expressed as the following:
Where P = the period of orbit, G = the gravitational constant, a = the distance of orbit, and M1 = the mass of the larger object (or, more exactly, the sum of the mass of both objects).
From the story, Phobos was 9300 km from Mars. The mass of Mars is about 6.39 x 1023 kg. G = 6.674 × 10-11 m3 kg-1 s-2. Based on this, how long will it take Phobos to orbit Mars once (in Earth days)? This will be within a few seconds of the time it takes for Phobos to go through all of its phases.
Remember, you have to get units correct.
(did you convert kilometers to meters to match the units in G? Did you convert seconds to days to match the question request?)
Period (in seconds) = sqrt(4*3.14159*3.14159*9300000*9300000*9300000)/(6.674E-11 * 6.39E23))
Period (in days) = (Period (in seconds) /(60*60*24)
You should get about 0.316 days. Pretty fast, huh!? That little moon is really zipping around. That transit didn't last long, that's for sure!
The actual time for Phobos to go through its cycle of phases (called the synodic period) is 0.3191 days. That compares to Earth's moon at 29.5 days, nearly 100 times longer.
* Note: Kepler's three empirical laws describe the motions of the planets of our solar system. Kepler's third law relates the distance of a planet from the sun to the time it takes for the planet to orbit the sun, according to the relationship P2 ∝ a3.
In the story, small Phobos does not cover the entire Sun, making it very clear that Phobos must be smaller than the Sun. That is not so obvious on Earth where the Moon can completely cover the Sun during an eclipse. Which must be larger?
Over 2000 years ago, Aristarchus measured the distances to the Sun and Moon, and measured their relative sizes compared to the size of the Earth. It was quite astonishing, at the time, to discover that the Earth was really a tiny little place in a very vast universe.
Let's reproduce one part of Aristarchus' calculation—how big is the Sun?
Aristarchus started with the observation that the Sun and the Moon appear to be about the same size in the sky (thus, the Moon just covers the Sun during an eclipse of the Sun). He first figured out the size and distance to the Moon and then the distance to the Sun (which we aren't going to do here),. With this information, he calculated the size of the Sun using similar triangles.
Here is his concept based on the Moon and Sun appearing to be the same size in the sky:
Notice that triangles A-B-C and A-D-E are similar, meaning the ratios of their sides will be equal. Knowing the size of the Moon (radius is about 0.135 Earth Diameters), the distance to the Moon (about 30.1 Earth Diameters), and the distance to the Sun (about 11679 Earth diameters). How much bigger is the Sun than the Earth (don't forget to go from radius to diameter!)
Using similar triangles, we have:
0.135/30.1 = X/11679 where X = the radius of the Sun.
X ~ 52.4 so the Sun is about 105 times bigger than the Earth! This was big news at the time of Aristarchus, when many people thought not only that the Earth was the center of the universe, but that it took up most of the space in the universe. (Artistarchus estimate was a bit smaller than this, and today it is thought that the Sun is about 109 times bigger that Earth).
Connecting to the Next Generation Science Standards.
Students can exercise skills in the practices of science including:
1) Developing and Using Models in conjunction with Arguing from Evidence—in Puzzles 1, 2, 3, 4 and 5, students test various models against observational evidence. In Puzzles 6 and 7, students use their model of motion in the solar system to make predictions.
2) Using Mathematics—in Puzzle 8, students use Kepler’s 3rd Law and Newton’s work on gravity to calculate the orbital period of Phobos. In Puzzle 9, students use similar triangles to find the distance to the Sun.
Students use the crosscutting concepts of
1) Patterns — Students describe patterns of change in celestial objects as predicted by various models of motion in the solar system (geocentric, heliocentric)
2) Scale, proportion and quantity— Students use similar triangles and the unit of ‘earth diameter’ to calculate the distance to the sun.
The investigative activities above support the following NGSS performance expectations:
MS-ESS1-1 Develop and use a model of the Earth-sun-moon system to describe the cyclic patterns of lunar phases, eclipses of the sun and moon, and seasons.
MS-ESS1-2 Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system.
HS-ESS1-4 Use mathematical or computational representations to predict the motion of orbiting objects in the solar system.
The Teacher Resources for Standing in the Shadow of Phobos are written by Russ and Mary Colson, authors of .
Return to by Mary Alexandra Agner
Return to “.”
Find more essays, games, and stories at
©2020 Issues in Earth Science | 0.897053 | 3.202248 |
There may be many Earth-like planets scattered around the universe, a study has suggested, raising the possibility that other habitable worlds are out there—and that life may have evolved on it.
The first exoplanets—a planet beyond our solar system—were discovered in the 1990s. Since then, thousands have been revealed, with over 4,000 confirmed and a further 4,495 candidate exoplanets, according to NASA.
Whether or not any of these host alien life is unknown, and scientists are currently trying to narrow down the exoplanets that may have properties similar to Earth, therefore having conditions suitable to life. These include being a rocky planet that is not too hot or cold, so liquid water can exist.
In a study published in Science, a team of researchers has now found geochemical evidence to suggest there may be more Earth-like planets across the universe than previously thought. Led by Alexandra Doyle, from the University of California, Los Angeles, the team looked at the rocks of solar systems surrounding white dwarfs. These are dead stars—and what the sun will turn into in about five billion years when it runs out of fuel.
“White dwarfs are unique when it comes to studying exoplanets,” Doyle told Newsweek. “White dwarf stars are the last known phase of stellar evolution for sun-like stars. When a star like a sun dies, it evolves into a white dwarf. This evolution can be very chaotic for the planetary system surrounding the star, and as the star expands and contracts the smaller bodies orbiting the star will change trajectories, which can send some of them towards the star, thus causing eventual trapping of the rocky material by the white dwarf.”
She said most studies of the geochemistry of exoplanets are done by looking at the mass/radius relationship, or by looking at the chemistry of the star it orbits. With white dwarfs, however, you can be more direct, as the elements measured come directly from rocks falling onto the star.
In the study, the team looked at six white dwarfs and rocks from the planets that once orbited it. “The geochemistry and geophysics of interiors of exoplanets are crucial because they can determine important parameters for the habitability of a planet, such as, whether or not it has a magnetic field, what the atmosphere will look like and the existence of plate tectonics,” Doyle said.
They evaluated the elemental remains that had been left in the atmospheres of white dwarfs after the planets had crashed into them. Their findings showed the former planets would have had interiors similar to those of Earth or Mars. “The more rocks around other stars look like the rocks that made the Earth, the more likely it is that there are habitable planets like the Earth out there,” Doyle said.
“For rocky exoplanets in general, we are finding that rocks forming around other stars are geochemically similar to most of the rocky bodies in the Solar System. We are seeing that rocks are rocks, even when they form around other stars.”
The team now hopes to make more measurements of other white dwarfs in order to build on their findings. If even more white dwarfs are found to have had planets with Earth-like interiors, the statistical significance is greater, Doyle explained.
In a statement, Edward Young, a co-author of the study, said their findings had “raised the probability that many rocky planets are like the Earth—and there’s a very large number of rocky planets in the universe.” | 0.81426 | 3.698884 |
- Open Access
Anisotropy evolution of magnetic field fluctuation through the bow shock
Earth, Planets and Space volume 62, pagese1–e4(2010)
Measurement of energy distributions in the wave vector domain reveals how anisotropy of turbulent magnetic field fluctuations evolves as the solar wind encounters the terrestrial bow shock and the magnetosphere. While fluctuations in the solar wind, the magnetosheath, and the magnetospheric cusp regions are characterized by the perpendicular wave vector geometry to the mean magnetic field direction, that in the foreshock region is characterized by the parallel wave vector geometry. Linear and nonlinear plasma processes are discussed for the anisotropy evolution.
Many in-situ spacecraft observations suggest that shock waves in the interplanetary space such as planetary bow shocks and traveling shocks in the co-rotating interaction regions are often accompanied by turbulent fluctuations, and furthermore, there are indications that interstellar shocks or supernova remnants may be associated with turbulence (Hester et al., 1994; Spitler and Spangler, 2005). How turbulence evolves as it encounters the shock wave in a collisionless plasma is an interesting problem and of particular importance in space physics and astrophysics. Earth’s bow shock, a standing shock wave located at about 20 Earth radii in front of the Earth, serves as an ideal, natural laboratory for studying turbulence evolution across the shock. Many spacecraft visited the Earth’s bow shock and observed various kinds of electrostatic and electromagnetic fluctuations near the shock, e.g., Shin et al. (2007). Spatial properties of waves or turbulence in the surroundings of the bow shock can be extensively studied by the Cluster mission (Escoubet et al., 2001), as it provides four-point measurements in the near-Earth space.
Here we present a measurement of energy distributions of magnetic field fluctuations in the wave vector domain using the Cluster fluxgate magnetometer data (Balogh et al., 2001). We use the concept of two distinct fluctuation geometries to study anisotropy: parallel and perpendicular wave vector geometries (Fig. 1). The idea of the two fluctuation geometries is motivated by long-standing questions about the nature of symmetries of plasma turbulence, viz., whether wave vectors in plasma turbulence prefer parallel or perpendicular directions to the mean magnetic field (Matthaeus et al., 1990; Carbone et al., 1995).
We investigate the magnetic field data for two Cluster orbits of bow shock crossings during the mission phase with about 100 km mean spacecraft separation. The orbit of the first crossing (orbit A) encountered (1) the solar wind, (2) the foreshock, and (3) the magnetosheath. The orbit for the second crossing (orbit B) encountered (4) the solar wind, (5) the magnetosheath, and (6) the magnetospheric cusp region. While the first orbit represents a crossing of the quasiparallel shock (angle between the shock normal and the upstream magnetic field 30.5 deg), the second one represents a crossing of the quasi-perpendicular shock (angle 75.7 deg). Figure 2 displays the observed magnetic field magnitude for the two shock crossings. The orbit A is inbound and encountered the shock crossing at about 1600 UT and the magnetopause crossing at about 2130 UT. We use the interval (1) Feb. 11, 2002, 1730–2030 UT for the solar wind, (2) Feb. 12, 2002, 0630–1230 UT for the foreshock, and (3) 1615–2100 UT for the magnetosheath. The orbit B is outbound. After exiting the nightside magnetosphere just before 0900 UT, the spacecraft re-entered the magnetosphere on the dayside at about 1000 UT and encountered the dayside magnetopause and the shock at about 1015 UT and 1350 UT, respectively. We use the intervals (4) Mar. 4, 2002, 1415–1615 UT for the solar wind, (5) 1015–1330 UT for the magnetosheath, and (6) 0900–0945 UT for the cusp. The cusp region is an extended part of the magnetosheath where the flow becomes trapped and stagnant, and is known to be in a turbulent state, e.g., Pilipenko et al. (2008). Therefore it is an interesting question how the wave vector anisotropy develops when the solar wind enters the magnetosheath and further encounters the cusp region.
With Cluster data it is possible to measure the cross spectral density matrix of magnetic field fluctuations directly in the three-dimensional wave vector domain without using Taylor’s hypothesis. From this matrix we obtain the magnetic energy distribution in the wave vector domain. The distribution is measured up to the Nyquist wave number kmax = 3.0 × 10−2 rad/km that is determined by the spacecraft separation distance (cf. wave numbers of the ion inertial length are about 0.008, 0.009, 0.017, 0.013, 0.026, and 0.014 rad/km for the region 1 to 6, respectively). The wave telescope technique (or k-filtering technique) is used to determine the fluctuation energy in the frequency and wave vector domain. This technique was developed particularly for analyzing multi-spacecraft data (Pinçon and Lefeuvre, 1991; Motschmann et al., 1996; Glassmeier et al., 2001). The distribution is then integrated over spacecraft-frequency up to the Doppler limit kmaxVflow, where the flow speed Vflow is obtained by the measurement of the ion bulk flow using electrostatic analyzer CIS-HIA on board Cluster (Rème et al., 2001). Figure 3 displays the energy distributions averaged over the directions around the mean magnetic field for the six analyzed regions. The distributions are furthermore reduced to one-dimensional energy spectra for the two fluctuation geometries by summing over the parallel or the perpendicular wave numbers, respectively, and then the spectra are compared at the same wave numbers by setting k‖= k⊥ to measure the wave vector anisotropy. Figure 4 displays the ratios of the energy for the parallel to the perpendicular wave vector geometry. A positive trend of the ratio in the wave number domain represents the dominance of the parallel wave vector geometry, and vice versa. Figure 4 also exhibits an error estimate for the determined energy. The error in the energy determination comes primarily from the motion of the spacecraft and the change of spacecraft distance during the observations, which is on average about 15% to the determined energy.
In the solar wind (region 1 and 4) the fluctuation energy is the smallest for the both shock crossings. In region 1 the distribution is extended in the perpendicular direction to the mean magnetic field and is elliptically shaped on an intermediate scale (about 0.010 rad/km), while it is moderately rectangular with dominant extension in the perpendicular direction at larger wave numbers (about 0.020 rad/km). In region 4 the distribution is also extended in the perpendicular direction. The ratio of the two reduced spectra exhibits a negative trend down to values 0.8–0.9 toward larger wave numbers in the both cases, reflecting the dominance of the perpendicular wave vector geometry. These results justify the picture of two-dimensional turbulence in the solar wind (Matthaeus et al., 1990; Carbone et al., 1995). In the foreshock region (region 2) the fluctuation energy becomes larger than that of the solar wind by factor about 10. In contrast to the solar wind, the energy distribution is extended in the parallel direction to the mean magnetic field and represents the dominance of the parallel wave vector geometry, which is reflected in the anisotropy ratio as a positive trend up to the ratio 1.5.
In the magnetosheath (region 3 and 5) the fluctuation energy is further enhanced from the foreshock by factor about 10 (region 3) and from the solar wind by factor about 50 (region 5). The distribution in region 3 exhibits an asymmetric feature between the parallel and the anti-parallel directions as well as anisotropy between the parallel and the perpendicular directions. The ratio of the two reduced spectra exhibits a negative trend down to 0.6 and suggests the dominance of the perpendicular wave vector geometry. Anisotropy preferring the perpendicular wave vector geometry is stronger than that of the solar wind (region 1). In region 5 the fluctuation energy is enhanced from the solar wind across the shock while the distribution maintains the extended structure in the perpendicular direction. Also, there is a moderate asymmetry between the parallel and the anti-parallel directions. The ratio of the reduced spectra exhibits a negative trend, preferring the perpendicular wave vector geometry, and the anisotropy ratio curve is very similar to that of the solar wind (region 4).
In the cusp region (region 6) the fluctuation energy is enhanced from the magnetosheath and the energy distribution is further extended in the perpendicular direction. The anisotropy ratio curve exhibits a negative trend 0.5, which may suggest that cusp turbulence inherits the properties of the magnetosheath fluctuations.
There are both new results and confirmation of previous results in our analysis. The anisotropies between parallel and perpendicular directions to the mean magnetic field support the results obtained by earlier spacecraft measurements. The measurements before Cluster were limited to one or at most two-point measurements (Le and Russell, 1990; Matthaeus et al., 1990; Carbone et al., 1995) and it was not known about how general those results are in the 3-D space. Our measurements with Cluster data not only justify the earlier results of the anisotropic features but also provide the quantitative estimate of the anisotropies in the 3-D space, which is new. With Cluster data the anisotropies and the asymmetries of the energy distribution are visualized for the first time. Here, it should be noted that our analysis is performed in the spacecraft frame and the results are subject to the Doppler shift due to the presence of the mean flow. Doppler shift correction will be needed to verify our results.
One of likely sources for the anisotropies of turbulent fluctuations is plasma instabilities. In the foreshock, electron-beam and ion-beam modes are the most likely instabilities, because the bow shock is a source of heated electrons and reflected ions. In the frequency range of concern to us (up to about ion gyro-frequency), the most likely mode to grow is the electromagnetic ion/ion righthand resonant instability. This has been confirmed observationally by Watanabe and Terasawa (1984) and Fuselier et al. (1986) using single spacecraft methods and recently by multi-spacecraft methods of Cluster (Narita et al., 2003; Narita and Glassmeier, 2005). Linear kinetic theory (Gary, 1993) shows that the instability has maximum growth in the parallel and anti-parallel directions to the mean magnetic field, so that enhanced fluctuations from this instability should have properties of the parallel wave vector geometry. Magnetosheath plasma shows the consequences of magnetic compression and heating at the shock, so that the primary characteristic of proton distributions in this regime is a strong temperature anisotropy. This anisotropy leads to the growth of both electromagnetic ion cyclotron and mirror-mode fluctuations with the mirror instability often dominating the high-β plasmas near and downstream of the shock. The mirror instability has maximum growth at directions strongly oblique to the mean magnetic field, so that enhanced fluctuations from this growing mode should have properties of the perpendicular wave vector geometry. Anisotropy in the cusp region can also be qualitatively explained by the mirror mode fluctuations. Luhmann et al. (1986) argued that one of the major sources of fluctuations downstream of the quasi-parallel shock is the foreshock activity, but our result suggests that the property of the foreshock fluctuations is lost across the shock. Our result is consistent with the statistical analysis of Cluster data that the foreshock fluctuation property is lost in the magnetosheath (Narita et al., 2006). It is also worthwhile to note that the perpendicular wave vector geometry may be interpreted not only as the mirror mode but also as quasi-two-dimensional turbulence. Distinguishing these two fluctuation types will require polarization or helicity analysis combined with the wave telescope technique.
It was also discovered in our results that the fluctuation energy is on the whole evenly distributed between parallel and anti-parallel directions to the mean magnetic field. In particular, the energy distribution in the foreshock region is almost symmetric between these two directions, while the analysis of dispersion relations gives a preferred direction for wave propagation (Narita et al., 2003; Narita and Glassmeier, 2005). The symmetric distribution may be a sign that nonlinear wave-wave interactions, such as decay instability, are operating so that the fluctuation energy becomes distributed in both parallel and anti-parallel directions. But strictly speaking, the energy distributions exhibit asymmetries and distortions, particularly in the two magnetosheath regions. Possible causes of the asymmetries would be: waves propagating in a preferred direction; Doppler effect; and spatial aliasing (Sahraoui et al., 2003; Narita and Glassmeier, 2009). We also note that even though we observe fluctuations downstream of the bow shock with a particular magnetic field geometry (or shock angle), the plasma may be also affected by other portions of the shock (having different shock angles) which are magnetically connected to the spacecraft positions, as discussed by Feldman et al. (1983).
Another process which may be relevant is wave amplification across the shock. Fluctuations in the solar wind may be amplified at the bow shock independently of any instabilities. The interaction of the magnetohydrodynamic waves with the shock wave was analytically studied by McKenzie and Westphal (1969, 1970) and McKenzie (1970). Their analysis suggests that the magnetic field amplitude of an Alfvén wave incident in the shock-upstream region is enhanced by a factor of unity or three, depending on the sense of wave propagation in the upstream and downstream region with respect to the shock normal direction and that the amplification of a fast magnetosonic wave is about a factor of four. Therefore a naive estimate gives the jump of the spectral power by factors 10–20 across the shock, as energy is proportional to the squared amplitude of fluctuation. We obtain in our measurement the jump of the energy by factor about 10 from the foreshock to the magnetosheath across the quasi-parallel shock, and about 50 across the quasi-perpendicular shock. Probably there are a variety of mechanisms that contribute to the amplification across the shock such as wave mode conversion and wave reflection at the shock or at the magnetopause. In this analysis it is difficult to distinguish between plasma instabilities and shock amplification effects because only the total energy is used in the analysis. The polarization or helicity analysis will verify our results and help us to distinguish these two effects, as such an analysis can determine energy spectra for different fluctuation components and for different wave vectors.
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This work was financially supported by Bundesministerium für Wirtschaft und Technologie and Deutsches Zentrum für Luft- und Raumfahrt, Germany, under contract 50 OC 0901. We thank H. Rème and I. Dandouras for providing the ion data of Cluster, and S. P. Gary for discussion.
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Cite this article
Narita, Y., Glassmeier, K. Anisotropy evolution of magnetic field fluctuation through the bow shock. Earth Planet Sp 62, e1–e4 (2010). https://doi.org/10.5047/eps.2010.02.001
- Wave-vector spectra
- magnetic field
- bow shock
- multi-point measurements | 0.871697 | 3.834295 |
Astronomy is one of those rare scientific fields that seems to capture everyone's interest. It's innately human to gaze up at the heavens at night in wonder and awe, and we've sought since ancient times to understand the universe and our place in it. From the days of Nicolaus Copernicus, Johannes Kepler, and Galileo Galilei, the revolutions of modern astronomy have rocked the very foundations of science and society. In the 21st century, the advent of large astronomical surveys like the Sloan Digital Sky Surveys, the launch of space-based observatories like NASA's Kepler and the European Space Agency's Gaia, and the dawning of multimessenger and gravitational-wave astronomy have enabled some of the most remarkable discoveries of our lifetime. In this age of big data, astronomy has found an unlikely hero—statistics.
"We've entered into an era when the data have become too big to look at," says Penn State astronomer Eric Feigelson. "We can't just plot a few points on a graph and begin to understand the phenomenon; there are too many variables, too many points, too much complexity. In order to extract scientific knowledge from astronomical data and test our astrophysical theories, we need to learn to do better analysis—so the need for statistics has greatly increased."
It was out of his own need for statistical insight that Feigelson—primarily an X-ray astronomer—first reached out to Penn State statistician Jogesh Babu more than 30 years ago, sparking a lasting friendship and longstanding collaboration that would eventually lead them to foundPenn State's groundbreaking Center for Astrostatistics in 2003. Together, they have organized a highly successful series of international astrostatistics conferences, authored a number of books—including one that received the Association of American Publishers' Award for Professional and Scholarly Excellence (PROSE) in cosmology and astronomy in 2012—and launched a succession of summer school programs that has taught advanced statistical methods for astronomy to thousands of graduate students from around the world. As a result, today Penn State is widely recognized as both a founder of and leader in astrostatistics. At the outset, though, success didn't come quite so easily.
"In the beginning, it was a bit of a struggle," Babu recalls."Even though we both speak English, we didn't understand each other, because what astronomers call certain statistical terms is different than what statisticians use those terms for. But by listening to each other patiently for some time—a couple of years—we came to understand each other well."
One could say that Babu's and Feigelson's story mirrors that of statistics and astronomy, and after years of talking and listening, the two fields have begun to understand each other well enough to yield fruit in the form of tangible research results. Now, at the leading edge of astronomy, statistics is key to the search for potentially habitable worlds beyond our own solar system and to our understanding of how the universe is evolving.
Astrostatistics in action
Penn State astronomer Eric Ford studies the formation and evolution of planetary systems. Using data from the Kepler and Gaia missions as well as various ground-based surveys, he combines advanced statistical and computational algorithms in complex models that could help to inform the design and planning of future exoplanet-hunting missions searching for potentially habitable planets orbiting sunlike stars.
"We're trying to apply fundamental physics to predict what's going on in the universe," Ford says, "Statistics allows us to go from qualitative inspection to quantifying 'How good are our predictions?'Are they acceptable? Is this model sufficiently accurate and precise to accomplish our science goals?"
Feigelson, too, is applying statistics to studying exoplanets, specifically focusing on data from the Kepler mission's observations. With its highly sensitive photometer, Kepler was capable of detecting infinitesimal dips in stars' brightness as orbiting planets transited those stars, passing in front of them along its line of sight. But Kepler's sensitivity also brought an unexpected problem to light: Most stars exhibit intrinsic variations in brightness that can obscure the signs of planetary transits.To address this challenge, Feigelson adapted—of all things—a modeling method more commonly used by economists to predict the stock market.
"Removing the complicated variations of these stars ends up being a statistical problem," he says. "Astronomers were developing methods to remove them in various ways, but they missed the most common approach used by statisticians and econometricians for this kind of problem since the 1970s, a form of regression known as autoregressive modeling. So I wondered if this would work on stars. My graduate student Gabriel Caceres tried it out and found it was very successful. We basically rewrote part of the NASA pipeline using methods that a time-series statistician would find totally normal but were largely unused in astronomy. With this procedure, we ended up uncovering several dozen new candidate planets orbiting Kepler stars."
Penn State's newest astrostatistician, Hyungsuk Tak, has developed a novel statistical model to refine the Hubble constant—scientists' estimate of the universe's rate of expansion—one of the most important parameters in cosmology, the study of the origin and evolution of the universe. Differing estimates and methods of calculating the Hubble constant are a source of constant debate within the astronomical research community, and Tak hopes to alleviate some of that by using his own independent methods.
"No one knows the exact answer," he says. "There are so many Hubble constant estimates, and there are tensions between some important physical properties of the data. In analyzing the data, what statisticians are interested in is whether we can also develop a new method, practically motivated by the science, to confirm whether these estimates are consistent with the observed data. Probably I'm not the person who finally solves this; but if more and more people contribute, then there maybe consensus in the future, and I hope to contribute in that direction."
Babu, on the other hand, is applying his statistical expertise to gravitational-wave astronomy, in a collaboration that is using methods much different from those employed by the LIGO (Laser Interferometer Gravitational-Wave Observatory) Scientific Collaboration, which made the first-ever observation of gravitational waves in 2015. The North American Nanohertz Observatory for Gravitational Waves—known colloquially as NANOGrav—is a National Science Foundation Physics Frontier Center that aims to use radio telescopes to detect low-frequency, nanohertz, gravitational waves by measuring the waves' effects on the timing of light pulses from rotating neutron stars known as pulsars.
"Rapidly rotating pulsars keep precise time periods," Babu explains, "and if a gravitational wave passes between us and the pulsar, there is a delay in the signal coming to us. We are developing statistical methods that will help us use that information to detect nanohertz gravitational waves—a complimentary effort to LIGO, covering an entirely different region of the gravitational-wave spectrum."
What lies ahead
All of this knowledge is crucial to better understanding our universe, and while its scope may be largely confined to astronomy and other, closely related fields, the impact of the underlying research ripples outward across the whole of science.
"Questions about how our solar system formed, how Earth fits in, whether life in the universe is common or rare are intrinsically interesting in themselves," Ford says. "But to me, the process of how we're learning those things, the techniques we're developing, and the students we're training, those are equally important and potentially even a bigger legacy in terms of our impact on society. This knowledge can be applied to a wide range of issues beyond astronomy."
In truth, we all benefit from better statistics. Brought to bear on all manner of data, its methods and mindsets are crucial to science advancing society toward a better and sustainable future. Its insights are furthering far-reaching initiatives in personalized medicine and public health, green energy and global economics, meteorology and climate change mitigation—the list goes on. Data are everywhere. Rapidly evolving technology is enabling us to collect them at an ever-increasing rate. And now the grand challenge is to elicit the greatest meaning from those data. Succeeding, statistics may yet be rightly counted among the heroes of 21st-century science.
Jogesh Babu, Distinguished Professor of Statistics and of Astronomy and Astrostatistics, is the director of the Center for Astrostatistics.
Eric Feigelson, Distinguished Senior Scholar and professor of astronomy and astrostatistics and of statistics, is an associate director of the Center for Astrostatistics.
Eric Ford, professor of astronomy and astrophysics, is a co-hire with the Institute for Computational and Data Sciences, the director of Penn State's Center for Exoplanets and Habitable Worlds, and an associate director of the Center for Astrostatistics.
Hyungsuk Tak, assistant professor of statistics and of astronomy and astrophysics, is a co-hire with the Institute for Computational and Data Sciences and a member of the Center for Astrostatistics. | 0.889533 | 3.742122 |
The European Space Agency has officially announced that it will launch a new space telescope tasked with the primary objective of finding Earth-like planets in our neighboring cosmic backyard. Though the mission’s budget is rather small, there’s nothing modest about its goals.
Dubbed CHEOPS or CHaracterising ExOPlanets Satellite, at the end of its 3.5 year-long scheduled mission the space telescope should offer a list of Earth-like planets or exoplanets of close proximity. To do this, CHEOPS will function much in the same way as Kepler, the most famous planet-hunter space telescope, by studying a star’s brightness and looking for blips that hint of an object orbiting. By measuring the wobbling effect of a star’s brightness, scientists can tell its radius and mass. With this at hand, they can further establish a planet’s density, which helps describe its composition.
Kepler has retrieved some exciting finds during its mission, as it currently confirmed 77 planets and discovered thousands of candidates. The main problem with Kepler, though, is that its aimed at points in the skyline extremely far away from Earth. Thus, the planets found thus far by the space telescope can’t be followed-up with subsequent research using ground telescopes simply because they’re so far away. CHEOPS seeks to address this issue by peering through closer stars, as it surveys dense starfields in the Milky Way.
The 50 million euro CHEOPS will be able to detect planets down to the mass of the Earth and will have the sensitivity to show which planets have dense atmospheres; valuable information that might hint the fabled discovery of a potentially life harboring alien planet. And it’s not only CHEOPS scientific goals that are exciting, but the prospects it holds for future space exploration as well – the space telescope will be the first of a series of small missions, each one rapidly developed at low cost to investigate new scientific ideas quickly.
“I think it is realistic to expect to be able to infer within a few decades whether a planet like Earth has oxygen/ozone in its atmosphere, and if it is covered with vegetation,” Martin Rees, Britain’s Astronomer Royal. | 0.829497 | 3.497317 |
- Describe the mechanism for circular orbits
- Find the orbital periods and speeds of satellites
- Determine whether objects are gravitationally bound
The Moon orbits Earth. In turn, Earth and the other planets orbit the Sun. The space directly above our atmosphere is filled with artificial satellites in orbit. We examine the simplest of these orbits, the circular orbit, to understand the relationship between the speed and period of planets and satellites in relation to their positions and the bodies that they orbit.
As noted at the beginning of this chapter, Nicolaus Copernicus first suggested that Earth and all other planets orbit the Sun in circles. He further noted that orbital periods increased with distance from the Sun. Later analysis by Kepler showed that these orbits are actually ellipses, but the orbits of most planets in the solar system are nearly circular. Earth’s orbital distance from the Sun varies a mere 2%. The exception is the eccentric orbit of Mercury, whose orbital distance varies nearly 40%.
Determining the orbital speed and orbital period of a satellite is much easier for circular orbits, so we make that assumption in the derivation that follows. As we described in the previous section, an object with negative total energy is gravitationally bound and therefore is in orbit. Our computation for the special case of circular orbits will confirm this. We focus on objects orbiting Earth, but our results can be generalized for other cases.
Consider a satellite of mass m in a circular orbit about Earth at distance r from the center of Earth (Figure 13.12). It has centripetal acceleration directed toward the center of Earth. Earth’s gravity is the only force acting, so Newton’s second law gives
We solve for the speed of the orbit, noting that m cancels, to get the orbital speed
Consistent with what we saw in Equation 13.2 and Equation 13.6, m does not appear in Equation 13.7. The value of g, the escape velocity, and orbital velocity depend only upon the distance from the center of the planet, and not upon the mass of the object being acted upon. Notice the similarity in the equations for and . The escape velocity is exactly times greater, about 40%, than the orbital velocity. This comparison was noted in Example 13.7, and it is true for a satellite at any radius.
To find the period of a circular orbit, we note that the satellite travels the circumference of the orbit in one period T. Using the definition of speed, we have . We substitute this into Equation 13.7 and rearrange to get
We see in the next section that this represents Kepler’s third law for the case of circular orbits. It also confirms Copernicus’s observation that the period of a planet increases with increasing distance from the Sun. We need only replace with in Equation 13.8.
We conclude this section by returning to our earlier discussion about astronauts in orbit appearing to be weightless, as if they were free-falling towards Earth. In fact, they are in free fall. Consider the trajectories shown in Figure 13.13. (This figure is based on a drawing by Newton in his Principia and also appeared earlier in Motion in Two and Three Dimensions.) All the trajectories shown that hit the surface of Earth have less than orbital velocity. The astronauts would accelerate toward Earth along the noncircular paths shown and feel weightless. (Astronauts actually train for life in orbit by riding in airplanes that free fall for 30 seconds at a time.) But with the correct orbital velocity, Earth’s surface curves away from them at exactly the same rate as they fall toward Earth. Of course, staying the same distance from the surface is the point of a circular orbit.
We can summarize our discussion of orbiting satellites in the following Problem-Solving Strategy.
Orbits and Conservation of Energy
- Determine whether the equations for speed, energy, or period are valid for the problem at hand. If not, start with the first principles we used to derive those equations.
- To start from first principles, draw a free-body diagram and apply Newton’s law of gravitation and Newton’s second law.
- Along with the definitions for speed and energy, apply Newton’s second law of motion to the bodies of interest.
The International Space Station Determine the orbital speed and period for the International Space Station (ISS).
Solution Using Equation 13.7, the orbital velocity is
which is about 17,000 mph. Using Equation 13.8, the period is
which is just over 90 minutes.
Significance The ISS is considered to be in low Earth orbit (LEO). Nearly all satellites are in LEO, including most weather satellites. GPS satellites, at about 20,000 km, are considered medium Earth orbit. The higher the orbit, the more energy is required to put it there and the more energy is needed to reach it for repairs. Of particular interest are the satellites in geosynchronous orbit. All fixed satellite dishes on the ground pointing toward the sky, such as TV reception dishes, are pointed toward geosynchronous satellites. These satellites are placed at the exact distance, and just above the equator, such that their period of orbit is 1 day. They remain in a fixed position relative to Earth’s surface.
By what factor must the radius change to reduce the orbital velocity of a satellite by one-half? By what factor would this change the period?
Determining the Mass of Earth Determine the mass of Earth from the orbit of the Moon.
Strategy We use Equation 13.8, solve for , and substitute for the period and radius of the orbit. The radius and period of the Moon’s orbit was measured with reasonable accuracy thousands of years ago. From the astronomical data in Appendix D, the period of the Moon is 27.3 days , and the average distance between the centers of Earth and the Moon is 384,000 km.
Solution Solving for ,
Significance Compare this to the value of that we obtained in Example 13.5, using the value of g at the surface of Earth. Although these values are very close (~0.8%), both calculations use average values. The value of g varies from the equator to the poles by approximately 0.5%. But the Moon has an elliptical orbit in which the value of r varies just over 10%. (The apparent size of the full Moon actually varies by about this amount, but it is difficult to notice through casual observation as the time from one extreme to the other is many months.)
There is another consideration to this last calculation of . We derived Equation 13.8 assuming that the satellite orbits around the center of the astronomical body at the same radius used in the expression for the gravitational force between them. What assumption is made to justify this? Earth is about 81 times more massive than the Moon. Does the Moon orbit about the exact center of Earth?
Galactic Speed and Period Let’s revisit Example 13.2. Assume that the Milky Way and Andromeda galaxies are in a circular orbit about each other. What would be the velocity of each and how long would their orbital period be? Assume the mass of each is 800 billion solar masses and their centers are separated by 2.5 million light years.
Strategy We cannot use Equation 13.7 and Equation 13.8 directly because they were derived assuming that the object of mass m orbited about the center of a much larger planet of mass M. We determined the gravitational force in Example 13.2 using Newton’s law of universal gravitation. We can use Newton’s second law, applied to the centripetal acceleration of either galaxy, to determine their tangential speed. From that result we can determine the period of the orbit.
Solution In Example 13.2, we found the force between the galaxies to be
and that the acceleration of each galaxy is
Since the galaxies are in a circular orbit, they have centripetal acceleration. If we ignore the effect of other galaxies, then, as we learned in Linear Momentum and Collisions and Fixed-Axis Rotation, the centers of mass of the two galaxies remain fixed. Hence, the galaxies must orbit about this common center of mass. For equal masses, the center of mass is exactly half way between them. So the radius of the orbit, , is not the same as the distance between the galaxies, but one-half that value, or 1.25 million light-years. These two different values are shown in Figure 13.14.
Using the expression for centripetal acceleration, we have
Solving for the orbit velocity, we have . Finally, we can determine the period of the orbit directly from , to find that the period is , about 50 billion years.
Significance The orbital speed of 47 km/s might seem high at first. But this speed is comparable to the escape speed from the Sun, which we calculated in an earlier example. To give even more perspective, this period is nearly four times longer than the time that the Universe has been in existence.
In fact, the present relative motion of these two galaxies is such that they are expected to collide in about 4 billion years. Although the density of stars in each galaxy makes a direct collision of any two stars unlikely, such a collision will have a dramatic effect on the shape of the galaxies. Examples of such collisions are well known in astronomy.
Galaxies are not single objects. How does the gravitational force of one galaxy exerted on the “closer” stars of the other galaxy compare to those farther away? What effect would this have on the shape of the galaxies themselves?
See the Sloan Digital Sky Survey page for more information on colliding galaxies.
Use this interactive simulation to move the Sun, Earth, Moon, and space station to see the effects on their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it.
Energy in Circular Orbits
In Gravitational Potential Energy and Total Energy, we argued that objects are gravitationally bound if their total energy is negative. The argument was based on the simple case where the velocity was directly away or toward the planet. We now examine the total energy for a circular orbit and show that indeed, the total energy is negative. As we did earlier, we start with Newton’s second law applied to a circular orbit,
In the last step, we multiplied by r on each side. The right side is just twice the kinetic energy, so we have
The total energy is the sum of the kinetic and potential energies, so our final result is
We can see that the total energy is negative, with the same magnitude as the kinetic energy. For circular orbits, the magnitude of the kinetic energy is exactly one-half the magnitude of the potential energy. Remarkably, this result applies to any two masses in circular orbits about their common center of mass, at a distance r from each other. The proof of this is left as an exercise. We will see in the next section that a very similar expression applies in the case of elliptical orbits.
Energy Required to Orbit In Example 13.8, we calculated the energy required to simply lift the 9000-kg Soyuz vehicle from Earth’s surface to the height of the ISS, 400 km above the surface. In other words, we found its change in potential energy. We now ask, what total energy change in the Soyuz vehicle is required to take it from Earth’s surface and put it in orbit with the ISS for a rendezvous (Figure 13.15)? How much of that total energy is kinetic energy?
Strategy The energy required is the difference in the Soyuz’s total energy in orbit and that at Earth’s surface. We can use Equation 13.9 to find the total energy of the Soyuz at the ISS orbit. But the total energy at the surface is simply the potential energy, since it starts from rest. [Note that we do not use Equation 13.9 at the surface, since we are not in orbit at the surface.] The kinetic energy can then be found from the difference in the total energy change and the change in potential energy found in Example 13.8. Alternatively, we can use Equation 13.7 to find and calculate the kinetic energy directly from that. The total energy required is then the kinetic energy plus the change in potential energy found in Example 13.8.
Solution From Equation 13.9, the total energy of the Soyuz in the same orbit as the ISS is
The total energy at Earth’s surface is
The change in energy is . To get the kinetic energy, we subtract the change in potential energy from Example 13.6, . That gives us . As stated earlier, the kinetic energy of a circular orbit is always one-half the magnitude of the potential energy, and the same as the magnitude of the total energy. Our result confirms this.
So the kinetic energy of the Soyuz in orbit is
the same as in the previous method. The total energy is just
Significance The kinetic energy of the Soyuz is nearly eight times the change in its potential energy, or 90% of the total energy needed for the rendezvous with the ISS. And it is important to remember that this energy represents only the energy that must be given to the Soyuz. With our present rocket technology, the mass of the propulsion system (the rocket fuel, its container and combustion system) far exceeds that of the payload, and a tremendous amount of kinetic energy must be given to that mass. So the actual cost in energy is many times that of the change in energy of the payload itself. | 0.830884 | 4.088115 |
Astronomers have discovered the closest candidate black holes stellar mass, which is a triple system of stars visible to the naked eye in the southern hemisphere of the Earth. The lower limit on the mass of this black hole is estimated at $ 4.2 solar masses and the distance to the system is one thousand light-years. Article published in the journal Astronomy&Astrophysics, briefly about work it is told on the website of the European southern Observatory.
The existence of black holes as regions of space-time, which is due to the strong gravitation can not leave even a photon was predicted over a hundred years ago in the framework of General relativity. For a long time astronomers had only indirect evidence of their existence, such as a strong gravitational influence on other bodies, the detection of relativistic jets in distant galaxies or observation for a bright accretion disks in binary systems. Only recently, with the development of methods of observations and processing of data, scientists were able to obtain direct evidence of the reality of such bodies in the Universe in the form of the shadow a black hole in the center of the active galaxy M87, and has recorded gravitational waves from mergers of black holes and confirmed for the first time predicted by the theory of relativity features of the motion of stars in a strong gravitational field near the supermassive black hole at the center of the milky Way.
Until recently, the closest to the Earth known black hole was considered to be one of the components of x-ray binaries A0620-00, located at a distance of three thousand light years away in the constellation of the Unicorn. Now a team of astronomers led by Thomas Rivinius (Thomas Rivinius) of the European southern Observatory reported the discovery of an even closer black hole in the triple star system of HR 6819, which is distant from the Sun a thousand light years. The system visible to the naked eye in the southern constellation of the Telescope in a clear moonless night.
The discovery was made in the course of the study system with spectrograph FEROS (Fibre Extended Range Optical Spectrograph) mounted at the 2.2 m MPG telescope at the Observatory of La Silla in Chile. HR 6819 consists of Ve stars, which is in a wide orbit around a close pair of stars of type B3 III and invisible companion in a circular orbit. The orbital period of a close binary is 40 earth days. Palampiddi radial velocity in the interior of the star is equal 61,3 kilometers per second, together with the estimation of its minimum mass 6.3 mass of the Sun gives the lower limit of the mass of invisible bodies 4.2 the mass of the Sun. This means that we face a black hole of stellar mass, which does not absorb in the moment stuff.
Scientists believe that this discovery will provide an impetus to search for other “quiet” black holes. If we consider that about twenty percent of all the stars of earlier type are triple systems, and 0.01 percent of them have the structure of the system, similar to HR 6819, then the discrepancy between the expected and observed number of black holes in the galaxy may be reduced by several orders of magnitude, if these black holes are found in such systems. In addition, in systems with a configuration that is similar to the HR 6819, may occur of the merger of two black holes, which will cause a burst of gravitational waves that can be registered.
To see the “shadow” of a black hole and look into the bowels of quasars, astronomers were helped by the method of radiointerferometry with an extra-long wheelbase, one of the founders of which is an astrophysicist Nikolai Semenovich Kardashev, the discoveries which you can find from our material, “Creator “Radioastron””. | 0.930164 | 3.955183 |
In Greg Bear’s novel Queen of Angels (Gollancz, 1990), a robotic probe called AXIS (Automated eXplorer of Interstellar Space) has used antimatter propulsion to make a fifteen-year crossing to Alpha Centauri. The world’s various networks of the future begin to feast on reports of what it finds, like this one:
“In the past few weeks, AXIS has returned images of three planets circling Alpha Centauri B. As yet these worlds have not been named, and are called only B-1, B-2, and B-3. B-3 was already known to moonbased astronomers; it is a huge gas giant some ten times larger than Jupiter in our own solar system. Like Saturn, it is surrounded by a thin rugged ring of icy moonlets. B-1 is a barren rock hugging close to Alpha Centauri B, similar to Mercury. But the focus of our attention is now on B-2, a justright world slightly smaller than Earth. B-2 possesses an atmosphere closely approximating Earth’s, as well as continents and oceans of liquid water. It is orbited by two moons each about a thousand kilometers in diameter.”
It’s a tale that is only partially devoted to interstellar matters, but those with an interest in artificial intelligence of a high order indeed and its possibilities in future probes will want to become familiar with it. As you can see, Bear’s guess about Centauri Bb is about right, at least based on what little we know about the candidate world located in a scorching inner orbit. We can rule out the gas giant based on subsequent work which has whittled down the possibilities for large worlds, but we do have the region within 2 AU in which to hope for a stable orbit for another planet (outside of that, planetary orbits according to our simulations are quickly disrupted).
Are we likely to find another Alpha Centauri planet, a hypothetical Centauri Bc? We can certainly hope so, but while we await the lengthy period of data acquisition and analysis that may tell us, we can look at recent work from Elliott Horch (Southern Connecticut State) and team, which has shown, using Kepler data, that 40% to 50% of host stars for exoplanets are binary stars. Says Horch: “It’s interesting and exciting that exoplanet systems with stellar companions turn out to be much more common than was believed even just a few years ago.”
Image: The Kepler field of view, located between two bright stars in the summer triangle, rising over the WIYN telescope in southern Arizona. Credit: NOAO.
Indeed, there was a time not all that long ago when the idea of planets around multiple star systems was considered unlikely because of the gravitational disruptions such systems — at least relatively close binaries — would experience. But a number of studies since the 1990s have demonstrated stable orbits even in systems as close as Alpha Centauri, where the separation between Centauri A and B closes from 40 AU down to a tight 11 AU. That 2 AU of breathing room I mentioned above re Centauri B gives us a planet possibility perhaps as far out as the asteroid belt in our own system if we throw in a fudge factor, but not much further.
As to the work of Horch and company, the researchers used speckle imaging using data from the WIYN telescope located on Kitt Peak in southern Arizona and the Gemini North telescope (Mauna Kea) to look at targets at a rate of 15 to 25 times per second. The resolution achieved through this method, combining the images with suitable algorithms, can detect companion stars that are as much as 125 times as faint as the target star and only 0.05 arcseconds away. The occurrence rate of binaries in this work yields the high percentage of exoplanet host stars that turn out to be binaries, or at least appear to be. From the paper:
After a distance-limited subsample of these objects is constructed, the known statistics concerning binarity among stars near the Sun is added. The simulations predict that the very large majority of sub-arcsecond companions will be physically bound to the Kepler star.
The needed simulations are there to rule out objects that may only be in line of sight with the Kepler Object of Interest star being studied. As this National Optical Astronomy Observatory news release explains, the simulation relies on known statistical properties of binary star systems and line of sight ‘companions.’ Continuing from the paper:
This result suggests that, over the separation range to which we are sensitive, exoplanet host stars have a binary fraction consistent with that of field stars. Our speckle imaging program has identified a sample of candidate binary-star exoplanet systems in which only a modest number of false positives are likely to exist.
Thus the large majority of stellar companions revealed around KOI stars turn out to be actual companion stars rather than line of sight stars not connected with the system. And because we are talking about companion stars with separations between several AU out to no more than 100 AU, we may not always be sure around which star a given planet orbits. Now that binaries are thought to account for about half of known stars, these results suggest that the presence of the companion star does not not adversely affect the formation of planets.
The paper is Horch et al., “Most Sub-Arcsecond Companions of Kepler Exoplanet Candidate Host Stars are Gravitationally Bound,” accepted at The Astrophysical Journal (preprint). | 0.931906 | 3.966015 |
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The astonishing science of black holes, and their role in understanding the history and future of our universe.
Black holes are the most extreme objects in the universe, yet every galaxy harbours a black hole at its centre. In Einstein’s Monsters, Chris Impey builds on this profound discovery to explore questions at the cutting edge of cosmology, such as what happens if you travel into a black hole and whether the galaxy or its black hole came first.
Impey chronicles the role black holes have played in theoretical physics. He then describes the phenomena that scientists have witnessed while observing black holes: dozens of stars swarming around the dark object at the centre of our galaxy; black holes performing gravitational waltzes with normal stars; the cymbal clash of two black holes colliding, releasing ripples in spacetime. Einstein’s Monsters is the incredible story of one of the most enigmatic entities in nature.
“Black holes were originally flights of theoretical fancy, difficult for even professional physicists to wrap their brains around. In Einstein's Monsters, Chris Impey shows how modern astronomy has brought them into vivid focus, and conveys how much more we're learning about these extreme beasts with every passing year.” — Sean Carroll, author of The Big Picture: On the Origins of Life, Meaning, and the Universe Itself
“In Einstein's Monsters, Impey provides a history of black holes and an overview of investigations into their supremely counter-intuitive behaviour...[he] addresses the seeming absurdities of [the] subject with authority and wit.” — Nature
“Impey does an admirable job describing multiple facets of the often contradictory field of black hole astrophysics... Einstein's Monsters will be sure to capture the imagination of most who pick it up, simultaneously convincing the reader that these monsters, while in fact quite certainly real, should be loved and not feared.” — Science
“Astronomer Impey's accessible approach breaks down complex scientific concepts with ease and flair, name-checking everyone from Edgar Allen Poe to Pink Floyd as he lays out what we think we know about black holes—and what remains mysterious.” — Discover
“Impey skilfully weaves a fascinating tale out of the work and ideas of the scientists who... pieced together the history of black holes by understanding the evolution of stars and how they can, depending on their mass, end up as white dwarfs, ultra-dense neutronstars, rapidly spinning pulsars or as an exploding supernova.” — Financial Times
“Einstein's Monsters cuts through the "fiendishly complex" mathematics to set out the evidence for black holes, and how they are born and die.” — Times Higher Education
“The book gives an awe-inspiring account of the complexity and beauty of black holes that were there before our Galaxy formed and will probably be there after everything else has been shredded apart by the forces of an ever-expanding Universe.” — Nature
Related to this Book
Sky at Night
Tim and Simon learn about black holes. | 0.827395 | 3.706268 |
Advancing Basic Science for Humanity
12/20/2019 - The Highest-Energy Light Ever Recorded: Astrophysics Highlights
By Adam Hadhazy
Gamma-Ray bursts are the most luminous explosions in the universe. Within a few seconds they radiate more energy than the sun in billions of years. Understanding the physical processes at work in these monstrous explosions are an important goal of modern astrophysics. Artist’s view of a GRB and the formation of extremely fast jets (Credit: ESO/A. Roquette)
The terms "science" and "technology" are often paired, and for good reason. For either to advance, you ultimately can't have one without the other. Astrophysics is an example of this inextricability par excellence. Take the case of gamma-ray bursts. The most powerful explosions in the universe, they come to us here on Earth as mere flashes of the highest-energy form of light, gamma rays. But to reach us from across billions of light years with such relative oomph, the events underlying these bursts somehow must unleash more energy in a few seconds than our Sun will pump out over its 10-or-so eons of radiance. Potent stuff, indeed.
For decades, the sources of these GRBs, as they're called for short, have perplexed astronomers—all the more so because the bursts occur over two distinct lengths, simply designated as short and long. Space telescopes, which can catch high-energy gamma rays that cannot penetrate Earth's atmosphere, have vastly expanded our knowledge about GRBs. But it took a key collaboration with two ground telescopes, sensitive to the most powerful gamma rays that do manage to punch through to the Earth's surface, to solidify at last the mechanism behind long GRBs.
One array, called the High Energy Stereoscopic System (H.E.S.S.), started up in the early 2000s, featuring a special 28-meter gamma-ray telescope as its centerpiece in Namibia. The second set of instruments, called the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes, has operated in La Palma in the Canary Islands for a decade. Tipped off by the space-based telescopes just seconds after they captured the start of a GRB, these telescopes swung into action and soaked up rare, valuable photons of powerful light streaming from a cataclysm half a universe way. The observations of two GRBs—one by H.E.S.S. in July 2018, the other by MAGIC in January 2019—marked the first-ever ground-based detections of these cosmic blasts. Astonishingly, MAGIC caught photons with a trillion times the energy of those emitted by our Sun—the most powerful on record. Altogether, the data demonstrates that GRBs occur when massive stars go supernova and collapse into black holes. Material is hurled out by this explosion at tremendous, near-light speed, slamming into other material spewed out by the star, generating a shock wave and, in the process, gamma rays with exquisitely high energy. This full illustration of the anatomy of a GRB will surely not be the last astrophysical fruit borne of science and technology's union.
- Record-setting strong gamma rays reveal physics of colossal explosions
For the first time, researchers have captured very-high-energy gamma rays from a cataclysmic cosmic explosion called, appropriately enough, a gamma-ray burst (GRBs). Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) scientists were involved in the effort, which all but settles the mystery of how freshly formed black holes power long-lasting GRBs.
- A doppelganger dozen: Distant galaxy's visage repeats due to gravitational lensing
A new study has examined the Sunburst Arc, an extraordinary example of a distant galaxy that appears at least 12 times in the sky as stretched-out arcs around a closer-by galaxy cluster. That cluster's powerful gravity acts like a lens for the light from the distant galaxy, magnifying, warping, and duplicating the galaxy's appearance. Researchers from the Kavli Institute for Cosmological Physics (KICP) at the University of Chicago and the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MKI) are study coauthors.
span class="smallerText">Astronomers using the NASA/ESA Hubble Space Telescope have observed a galaxy in the distant regions of the Universe which appears duplicated at least 12 times on the night sky. This unique sight, created by strong gravitational lensing, helps astronomers get a better understanding of the cosmic era known as the epoch of reionisation.
- Galaxies undergoing stellar manufacturing slowdowns
A study, led by a member of the Kavli Institute for Cosmology, Cambridge (KICC), shows that as galaxies slow their starmaking, it's not only the amount of star-forming gas fuel that has gotten depleted—the galaxies also form stars at a slower rate with this leftover gas. In a novel analysis, the study made this assessment on a huge batch of local galaxies, 62,000 in all, demonstrating how to obtain this information without having to resort to long, deep, expensive observations.
- Sputtering supermassive black hole lets new stars form
It's a Kavli twofer. Researchers from the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MKI) and the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University have discovered why the Phoenix galaxy cluster sports a collection of young, blue stars, while most clusters' core regions are full of old, red stars. The supermassive black hole in the core of the cluster's central galaxy is going through a poorly understood, less-energetic phase, allowing gas to cool and form new stars.
- Seeing supernovae from the past
A story in Symmetry magazine explores how Mark Vagins, an experimental physicist at Kavli IPMU, had the idea to add gadolinium to the ultrapure water inside Japan's Super-K neutrino detector. Gadolinium uniquely soaks up neutrons released by water's interactions with a type of antineutrino, produced in prodigious amounts when stars explode. The gadolinium-doped detector should now be able to detect antineutrinos, via the neutron signal, from distant, ancient supernovae, allowing researchers to study these explosions in unprecedented detail. | 0.881187 | 3.831259 |
At 150 years old, the periodic table of chemical elements is still growing. In 2016, four new elements with atomic numbers 113, 115, 117 and 118 were added to it: nihonium, moscovium, tennessine, and oganesson. It took a decade and worldwide effort to confirm these elements, and now scientists wonder: how far can the periodic table go? Some answers can be found in a paper published in the journal Nature Physics by Michigan State University’s Professor Witek Nazarewicz.
All elements with more than 104 protons are labeled as ‘superheavy,’ and are part of a vast, totally unknown land that chemists as well as nuclear and atomic physicists are trying to uncover.
It is predicted that atoms with up to 172 protons can physically form a nucleus that is bound together by the nuclear force. That force is what prevents its disintegration, but only for a few fractions of a second.
These lab-made nuclei are very unstable, and spontaneously decay soon after they are formed.
For the ones heavier than oganesson, this might be so quick that it prevents them from having enough time to attract and capture an electron to form an atom. They will spend their entire lifetime as congregations of protons and neutrons.
If that is the case, this would challenge the way scientists today define and understand ‘atoms.’
They can no longer be described as a central nucleus with electrons orbiting it much like planets orbit the Sun. And as to whether these nuclei can form at all, it is still a mystery.
Researchers are slowly but surely crawling into that region, synthesizing element by element, not knowing what they will look like, or where the end is going to be.
The search for element 119 continues at several institutions.
“Nuclear theory lacks the ability to reliably predict the optimal conditions needed to synthesize them, so you have to make guesses and run fusion experiments until you find something. In this way, you could run for years,” Professor Nazarewicz said.
If element 119 is confirmed, it will add an eighth period to the periodic table.
“The discovery might not be too far off. Soon. Could be now, or in two to three years. We don’t know. Experiments are ongoing,” the scientist said.
Another exciting question remains: can superheavy nuclei be produced in space?
It is thought that these can be made in neutron star mergers, a stellar collision so powerful that it literally shakes the very fabric of the Universe.
In stellar environments like this where neutrons are abundant, a nucleus can fuse with more and more neutrons to form a heavier isotope. It would have the same proton number, and therefore is the same element, but heavier.
The challenge here is that heavy nuclei are so unstable that they break down long before adding more neutrons and forming these superheavy nuclei. This hinders their production in stars.
The hope is that through advanced simulations, researchers will be able to see these elusive nuclei through the observed patterns of the synthesized elements.
As experimental capabilities progress, they will pursue these heavier elements to add to the remodeled table.
In the meantime, they can only wonder what fascinating applications these exotic systems will have.
“We don’t know what they look like, and that’s the challenge. But what we have learned so far could possibly mean the end of the periodic table as we know it,” Professor Nazarewicz said.
Witold Nazarewicz et al. 2018. The limits of nuclear mass and charge. Nature Physics 14: 537-541; doi: 10.1038/s41567-018-0163-3 | 0.814537 | 3.65632 |
Braneworld challenges Einstein’s general relativity. Image credit: NASA. Click to enlarge
Scientists have been intrigued for years about the possibility that there are additional dimensions beyond the three we humans can understand. Now researchers from Duke and Rutgers universities think there’s a way to test for five-dimensional theory (4 spatial dimensions plus time) of gravity that competes with Einstein’s General Theory of Relativity. This extra dimension should have effects in the cosmos which are detectable by satellites scheduled to launch in the next few years.
Scientists at Duke and Rutgers universities have developed a mathematical framework they say will enable astronomers to test a new five-dimensional theory of gravity that competes with Einstein’s General Theory of Relativity.
Charles R. Keeton of Rutgers and Arlie O. Petters of Duke base their work on a recent theory called the type II Randall-Sundrum braneworld gravity model. The theory holds that the visible universe is a membrane (hence “braneworld”) embedded within a larger universe, much like a strand of filmy seaweed floating in the ocean. The “braneworld universe” has five dimensions — four spatial dimensions plus time — compared with the four dimensions — three spatial, plus time — laid out in the General Theory of Relativity.
The framework Keeton and Petters developed predicts certain cosmological effects that, if observed, should help scientists validate the braneworld theory. The observations, they said, should be possible with satellites scheduled to launch in the next few years.
If the braneworld theory proves to be true, “this would upset the applecart,” Petters said. “It would confirm that there is a 4th dimension to space, which would create a philosophical shift in our understanding of the natural world.”
The scientists’ findings appeared May 24, 2006, in the online edition of the journal Physical Review D. Keeton is an astronomy and physics professor at Rutgers, and Petters is a mathematics and physics professor at Duke. Their research is funded by the National Science Foundation.
The Randall-Sundrum braneworld model — named for its originators, physicists Lisa Randall of Harvard University and Raman Sundrum of Johns Hopkins University — provides a mathematical description of how gravity shapes the universe that differs from the description offered by the General Theory of Relativity.
Keeton and Petters focused on one particular gravitational consequence of the braneworld theory that distinguishes it from Einstein’s theory.
The braneworld theory predicts that relatively small “black holes” created in the early universe have survived to the present. The black holes, with mass similar to a tiny asteroid, would be part of the “dark matter” in the universe. As the name suggests, dark matter does not emit or reflect light, but does exert a gravitational force.
The General Theory of Relativity, on the other hand, predicts that such primordial black holes no longer exist, as they would have evaporated by now.
“When we estimated how far braneworld black holes might be from Earth, we were surprised to find that the nearest ones would lie well inside Pluto’s orbit,” Keeton said.
Petters added, “If braneworld black holes form even 1 percent of the dark matter in our part of the galaxy — a cautious assumption — there should be several thousand braneworld black holes in our solar system.”
But do braneworld black holes really exist — and therefore stand as evidence for the 5-D braneworld theory?
The scientists showed that it should be possible to answer this question by observing the effects that braneworld black holes would exert on electromagnetic radiation traveling to Earth from other galaxies. Any such radiation passing near a black hole will be acted upon by the object’s tremendous gravitational forces — an effect called “gravitational lensing.”
“A good place to look for gravitational lensing by braneworld black holes is in bursts of gamma rays coming to Earth,” Keeton said. These gamma-ray bursts are thought to be produced by enormous explosions throughout the universe. Such bursts from outer space were discovered inadvertently by the U.S. Air Force in the 1960s.
Keeton and Petters calculated that braneworld black holes would impede the gamma rays in the same way a rock in a pond obstructs passing ripples. The rock produces an “interference pattern” in its wake in which some ripple peaks are higher, some troughs are deeper, and some peaks and troughs cancel each other out. The interference pattern bears the signature of the characteristics of both the rock and the water.
Similarly, a braneworld black hole would produce an interference pattern in a passing burst of gamma rays as they travel to Earth, said Keeton and Petters. The scientists predicted the resulting bright and dark “fringes” in the interference pattern, which they said provides a means of inferring characteristics of braneworld black holes and, in turn, of space and time.
“We discovered that the signature of a fourth dimension of space appears in the interference patterns,” Petters said. “This extra spatial dimension creates a contraction between the fringes compared to what you’d get in General Relativity.”
Petters and Keeton said it should be possible to measure the predicted gamma-ray fringe patterns using the Gamma-ray Large Area Space Telescope, which is scheduled to be launched on a spacecraft in August 2007. The telescope is a joint effort between NASA, the U.S. Department of Energy, and institutions in France, Germany, Japan, Italy and Sweden.
The scientists said their prediction would apply to all braneworld black holes, whether in our solar system or beyond.
“If the braneworld theory is correct,” they said, “there should be many, many more braneworld black holes throughout the universe, each carrying the signature of a fourth dimension of space.”
Original Source: Duke University | 0.881629 | 3.778597 |
Did an Astronomical Body Cause the Global Floods of Ancient Myths with Its Gravitational Tidal Floods? - Part 2
This is the concluding part of a two-part article that offers a unifying scientific hypothesis that connects diverse ancient flood myths with mainstream scientific fact.
Part 1 offered scientific facts which seem to tally with the many flood stories that exist around the world. Having established the likelihood of a massive global event, it suggested the possibility that an event of this kind could be caused by a close encounter by an astronomical object.
This section will consider whether the science allows this theory to be viable.
The Path of Destruction
Here, I have plotted all the flood myth locations as per Graham Hancock’s research and overlaid a possible ground track (see definition below) where the body’s gravitational pull would have generated the highest levels of tidal flood. In the Pacific Ocean this tidal wave would have spread out wide to hit the whole west coast of the Americas.
Flood Myth Locations (Circled) with suggested ground Track-Tidal Wave Path. (Author provided)
A ground track is the path on the surface of the Earth directly below a satellite. It is the projection of the satellite's orbit onto the surface of the Earth (or whatever body the satellite is orbiting).
A satellite ground track may be thought of as a path along the Earth's surface which traces the movement of an imaginary line between the satellite and the center of the Earth. In other words, the ground track is the set of points at which the satellite will pass directly overhead, or cross the zenith, in the frame of reference of a ground observer.
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Example of a ground track. (Author provided)
A gravitational cataclysm would not only cause immense tidal floods but also earthquakes, volcanic eruptions, and it would be followed by the associated volcanic winter, a freeze causing plants to die and species’ habitat destruction.
So, how large would such a space body need to be and would it not affect Earth’s orbit?
In order to calculate the gravitational force between two objects with masses of m1 and m2 , the equation is: where G is the gravitational constant (6.67E-11 m3 s-2 kg-1), r is the distance between the two objects, and F is the magnitude of the force between the objects.
Some Facts, Numbers and Assumptions
Earth’s mass: 5.97237×10 24 kg
Moon’s mass: 7.342×10 22 kg
Earth’s mean radius – 6371 km (3958.75 miles)
The Moon's average orbital distance at the present time: 384,40 km (238.86 miles)
Astronomical bodies larger than 400km (248.55 miles) have enough gravitational pull to assume a spherical shape.
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The average height (amplitude) of oceanic tides caused by the moon is about 0.54 meters (1.77 ft.) As 80% of humanity lives near a coastline, or in lowland plains, a catastrophic supertide/tsunami that could devastate coastal valleys and flatlands needn’t be more than 50-100 meters (164.04-328.08 ft.) in height.
The Flood (Die Sintflut, Suendflut) by Lesser Ury. ( The Commons )
This means that the gravitational pull needed to create it needs to be a near 50-100 times stronger than the Earth currently experiences from the moon. This however doesn’t require an object 50-100 times larger than the moon, the gravity equation above allows us to have a much smaller body that flies much closer to the earth. This is because gravity is inversely proportional to the square of the distance. But not the mass. To illustrate this, imagine we halved the moon’s mass and at the same time brought it halfway closer to the earth, then the gravitational force would be doubled!
We can divide both these values by 50 to get a distance of around 8000 km (4970.97 miles) and a volume of around 400 k m3, which translates to approximately 900 km (559.23 miles) diameter. This will give us a gravitational pull of 50 times the moon.
If my calculations and assumptions are correct, an object of around 900 km in diameter passing the earth at an altitude of less than 1000 kilometers (621.37 miles) (of average, rocky density) would be large and heavy enough to create a strong localized tidal uplift in the oceans beneath its flight path (approximately 50 times the current tidal amplitude). That is large enough to destroy most of humankind, and a large portion of the fauna, but small enough to not cause a major extinction event or to disturb earth’s orbital path and rotation.
A huge meteor flew over the Urals in Russia early in the morning of 02/15/2013. The fireball exploded above Chelyabinsk city that caused damages of buildings and hundreds of people were injured. (Alex Alishevskikh/ CC BY SA 2.0 )
Top image: Meteor strike. ( Public Domain )
By Kirk Kirchev
Hancock, Graham. Fingerprints of the Gods 1996 p.202-214
John Bierhorst. The Mythology of South America 1988, p 165
Edwards, L. Humans were Once an Endangered Species 2010. Phys.org https://phys.org/news/2010-01-humans-endangered-species.html
Smithsonian. What Really Killed Off the Woolly Mammoth? Smithsonian https://www.smithsonianmag.com/videos/category/science/what-really-killed-off-the-woolly-mammoth/ | 0.825446 | 3.457554 |
“Does the Solar System contain undiscovered massive planets or a distant stellar companion of the Sun?” asks Lorenzo Iorio at the Istituto Nazionale di Fisica Nucleare in Pisa, Italy.
If it does, then the orbital period of such a body would be so long that any gravitational influence on the known planets can be thought of as a constant, tiny perturbation.
Iorio has looked at a the perihelion precessions of Venus, Earth and Mars in the last century and asked whether there is any indication of such a force in action.
Apparently not, he says, but that doesn’t rule out its presence. Instead, it has allowed Iorio to place limits on how far away such a planet might be.
His conclusion is that if Planet X is out there and about the size of Earth, it must more than 130 AU away. If it is the size of Jupiter, it cannot be closer than 886 AU and if it were a brown dwarf with a mass around 80 times that of Jupiter, it would have to be more than 3800 AU away.
Let’s get looking!
Ref: arxiv.org/abs/0904.1562: Constraints on Planet X and Nemesis from Solar System’s Inner Dynamics | 0.806496 | 3.166146 |
Authors: Brent Miszalski, P. A. Woudt, S. P. Littlefair et al.
First author’s institution: South African Astronomical Observatory
Status: Accepted for publication in MNRAS
On the 16th of November in 483 CE, astronomers in China recorded the appearance of “a guest star east of Shen, as large as a peck measure, and like a fuzzy star”. The new celestial light shone brightly for just under a month, then faded to nothing. Over 1500 years later, the authors of today’s paper may have found the source.
The suspect is a nebula known as Te 11, a cloud of expanding, glowing gas around half a light-year across at its widest point. Te 11 was originally thought to be a planetary nebula. These are, confusingly, nothing to do with planets, but are instead made out of material thrown off a red giant star as it shrinks into a white dwarf.
But although visually Te 11 looks like a planetary nebula, many of its characteristics don’t quite fit. It’s moving too slowly, and has much less mass than other, confirmed examples.
To search for alternative ways in which the nebula could have formed, the authors obtained a light curve, shown in the figure below, and spectroscopy of the object lurking in Te 11’s centre. They found a white dwarf, just as the planetary nebula hypotheses predicted. But it wasn’t alone.
The white dwarf is accompanied by an M dwarf star, so close together that they orbit around their centre of mass in less than three hours. At such close proximity, the gravity of the white dwarf draws material off its companion, forming a ring of gas known as an accretion disc. The material in the disc then gradually spirals down onto the white dwarf.
In a number of these systems, the disc becomes unstable every few years, probably due to a change in the viscosity of the gas caused by a rise in temperature (no one is exactly sure how it works). The material falling onto the white dwarf briefly turns from a gentle trickle into a raging torrent, releasing huge amounts of gravitational energy as light. The regular mini-explosions give the systems their name: Dwarf novae, after the larger cosmic explosions called novae and supernovae.
The authors’ observations of Te 11 had been prompted by five novae-like events in the last ten years, spotted by the Catalina Real-Time Transit Survey. The new observations both confirmed that the system was a dwarf nova, and provided exact measurements of some of the characteristics of the two stars, such as their masses and radii.
Te11 hosts an was unusually massive white dwarf, 1.18 times the mass of the Sun (a typical white dwarf is around 0.6). This meant that, as well as dwarf novae, bigger classical novae could also occur. Classical novae take place when the mass building up on the white dwarf becomes so dense that the hydrogen begins to fuse, releasing huge amounts of energy and blowing apart the (newly added) outer layers of the star.
Such a high mass white dwarf means that a novae could reasonably have occurred recently, within a time scale of hundreds of years. The material from the novae would have slammed into the unusually dense interstellar medium in the area, creating the Te 11 nebula. The authors postulate that this huge explosion was the source of the “fuzzy star” spotted in 483 CE.
Miszalski et al. finish by suggesting that more novae could have occurred since then, and high resolution imagining might reveal shells of material nestled inside the nebula. Observing these would give unprecedented insight into the physics of novae and the structures they leave behind. | 0.865808 | 4.002296 |
NGC 6334 - A Mini Starburst Region
(From an NOAO Press Release)
Stars are known to form in dense clouds of gas and dust, but why do some regions show prodigious rates of star formation, while others barely produce any young stars at all? Many of the richest sites are found in distant galaxies: the name “starburst” is applied to them. Now, a team has identified a region in our own galaxy that may deserve this title, and help explain what leads to the furious production of new stars in a starburst region.
This region, NGC 6334 or informally named the Cat’s Paw Nebula, is rich in gas and dust. Long known to contain very massive young stars, NGC 6334 lies in the constellation Scorpius, toward the galactic center at a distance of about 5,500 light years, and practically in the plane of the Milky Way. It is the massive, hottest stars, classified by astronomers as type O, that cause the gas surrounding them to glow in the optical spectrum.
Imaging done at the NOAO Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, Chile, combined with data from the Spitzer Space Telescope, have enabled the team, led by Sarah Willis (Iowa State University), to catalog much fainter young stars in NGC 6334 than has been done before. The image shows combined images from space and ground-based telescopes. In this false color composite, blue is assigned to a ground-based image, green to a longer-wavelength image from †he Spitzer Space Telescope, and red to an even longer-wavelength image from the Herschel Space Telescope. The ground-based data were taken with the NOAO Extremely Wide-Field Infrared Imager, or NEWFIRM. (Figure 2).
“The study of NGC 6334 is a major component of Sarah Willis’ PhD thesis which is aimed to bridge the gap between the distant starburst galaxies and their relatively modest counterparts in our own galaxy.” says Massimo Marengo (Iowa State) who is Willis’ thesis advisor.
Starting from the brightest and most massive stars in the region, the team has identified and catalogued all the stars down to those with the brightness of the sun - approximately a million times fainter. Then, based on previous knowledge of the number of stars that form as a function of stellar mass, they can extrapolate to identify how many lower mass stars exist in the region. This is analogous to saying that if we observe the adult population in a town, we can estimate how many children live in the town, even if we can’t see them. In this way, the team can derive an estimate of the total number of stars in the region, and the efficiency with which stars are forming.
As team member Lori Allen (NOAO) says, “The observations acquired with NEWFIRM allowed us to identify and separate out the large number of contaminating sources, including background galaxies and cool stellar giants in the Galactic plane to obtain a more complete census of the newly-formed stars”. The team finds that the star formation rate in this region is equivalent to 3600 solar masses of gas becoming stars every million years – a tremendous rate even by astronomical standards.
National Optical Astronomy Observatory (NOAO) is operated by the Association of Universities for Research in Astronomy Inc. (AURA) under a cooperative agreement with the National Science Foundation. | 0.906489 | 3.872689 |
Uranus stinks. And we're not joking.
The enigmatic outer solar system planet has long had a credibility problem, what with it being the butt of countless immature jokes. Now, astronomers have just discovered a gas in Uranus' clouds that does nothing to curtail the giggles. At all.
The new study, published in the journal Nature Astronomy, has discovered the chemical signature of hydrogen sulfide, a compound that gives rotten eggs their distinctive stench, in the planet's clouds. Besides launching a thousand new smelly planet puns, this finding could transform our understanding of how our solar system evolved. It also may help us to understand the atmospheres of massive planets orbiting other stars.
First, a bit of background: Uranus has only been visited by a spacecraft once, when NASA's Voyager 2 zipped past the planet in 1986. The flyby produced many beautiful and iconic views of the almost featureless, light-blue world. Astronomers have made countless ground-based observations of Uranus, too, in the hopes of better understanding the composition of its atmosphere. Despite these efforts, however, we know surprisingly little about this enigmatic planet. But the discovery of hydrogen sulfide is a big step forward, and it could only be done using one of the planet's most powerful observatories.
Using the Near-Infrared Integral Field Spectrometer (NIFS) that is attached to the Gemini North telescope in Hawaii, astronomers were able to detect the very slight spectroscopic signature of hydrogen sulfide in the uppermost layers of Uranus' clouds. This whiff of hydrogen sulfide is only the tip of the odoriferous iceberg, however; the presence of this gas is indicative of a huge reservoir below the obscuring cloud deck.
"Only a tiny amount [of hydrogen sulfide] remains above the clouds as a saturated vapour," said co-investigator Leigh Fletcher, of the University of Leicester, U.K., in a Gemini North statement. "And this is why it is so challenging to capture the signatures of ammonia and hydrogen sulfide above cloud decks of Uranus. The superior capabilities of Gemini finally gave us that lucky break."
Astronomers have long argued over whether hydrogen sulfide or ammonia dominate Uranus' clouds. It is well-known that the inner massive planets, Jupiter and Saturn, have atmospheres dominated by ammonia ice, whereas Uranus (and presumably Neptune) do not. It's those very differences in atmospheric compositions that place Jupiter and Saturn in the "gas giant" category and Uranus and Neptune in the "ice giant" category, and these differences reveal an insight as to where the planets formed.
"During our Solar System's formation the balance between nitrogen and sulphur (and hence ammonia and Uranus's newly-detected hydrogen sulfide) was determined by the temperature and location of planet's formation," said Fletcher.
The thought is that early in our solar system's history, the massive planets migrated from where they initially formed, eventually settling into the stable orbits we see them in today. Through the analysis of the chemicals in their clouds, astronomers can now formulate theories as to how far away from the sun these giant worlds formed and where they migrated from. With this information in mind, astronomers can then look to other stars and gain an insight as to how and where giant exoplanets formed.
This is all very interesting, but the biggest question scientists are likely answering right now is: If we could smell Uranus' atmosphere, would it kill us?
"If an unfortunate human were ever to descend through Uranus's clouds, they would be met with very unpleasant and odiferous conditions," said lead author Patrick Irwin, of the University of Oxford, U.K., also in the accompanying release. But it's not the stench that will kill you.
"Suffocation and exposure in the negative 200 degrees Celsius atmosphere made of mostly hydrogen, helium, and methane would take its toll long before the smell," he concluded. | 0.855946 | 3.889246 |
There’s a new paper doing the rounds of the blogosphere, called Varying planetary heat sink led to global-warming slowdown and acceleration. Judith Curry has a post about it. The basic result of the paper is that the “missing heat” is going into the deep parts of the Atlantic because a salinity variation is allowing warm water to sink rapidly. That sounds plausible, but I don’t really know enough to judge. The reason it’s generated some interest seems to be because it suggests that the “hiatus” will last another decade or so, and because it suggests (although this appears to only be in the press release) that only half the warming between 1970-2000 was anthropogenic (or due to global warming).
The paper concludes with
The next El Niño, when it occurs in a year or so, may temporarily interrupt the hiatus, but, because the planetary heat sinks in the Atlantic and the Southern Oceans remain intact, the hiatus should continue on a decadal time scale. When the internal variability that is responsible for the current hiatus switches sign, as it inevitably will, another episode of accelerated global warming should ensue.
Many seem to ignore the very end of that sentence and focus only on the part that says the hiatus should continue on a decadal time scale. Now, the paper seems to have gone through the historical records (including the Central England record) and found some kind of 60-70 year pattern of warm and cool phases, and is then arguing that we’re in some kind of cool phase now and that it will last another decade or so, since it has existed for about 15 years already.
One issue I have is that it is very likely that none of the cool phases in the past were coincident with the planet being significantly out of energy balance – as we are now. Even though we are in this supposed cool phase, we are still warming at something like 0.1 degrees per decade (which is something else the paper rather failed to point out). It’s possible that we could sustain this slowdown for another decade or so, but if we continue increasing our emissions, that would imply that we could remain in a cool phase with slow surface warming even when the energy imbalance is > 1 Wm-2. I find that somewhat implausible, but I may well turn out to be wrong.
Although I find the possibility that the “hiatus” could continue for more than another decade, or longer, a little unlikely, there is a claim in the press release that I find rather strange. It says
Rapid warming in the last two and a half decades of the 20th century, they proposed in an earlier study, was roughly half due to global warming and half to the natural Atlantic Ocean cycle that kept more heat near the surface.
When people say things like this, it makes me think that they don’t really understand anthropogenic global warming (AGW). AGW is simply the fact that we are increasing atmospheric greenhouse gas concentrations (GHGs) which then act to trap outgoing radiation, producing an energy imbalance, and increasing the energy in the climate system. There isn’t really some special anthropogenic mechanism that simply heats the surface. The surface warms because some of this extra energy heats the surface, increasing the surface temperature, which then reduces the energy imbalance.
On the other hand, its very likely that variability means that sometimes the surface will warm faster than at other times. Therefore one could define the anthropogenic (global warming) contribution as the mean long-term trend, and the natural contribution as being variations from this mean. If we consider the period 1970-2000, the Skeptical Science Trend Calculator suggests that we were warming at 0.16 degrees per decade. If half of this is global warming and half is natural, that would suggest that the global warming contribution was 0.08 degrees per decade. If so, that would suggest that over about a 60 year period, the trend should be 0.08 degrees per decade. However, this would imply that the trend since 2000 would have to be about 0 degrees per decade, which it isn’t. In fact, if you go back to the Skeptical Science Trend Calculator, the trend from 1970-2014 is also about 0.16 degrees per decade. So, if half the warming between 1970 and 2000 was natural, and we’ve been in a cooling phase since 2000, how can the 1970-2014 trend be the same as the 1970-2000 trend. It doesn’t really make sense.
So, as far as I can tell, the press release has a claim that isn’t in the paper and that doesn’t really make much sense, and the conclusion about the hiatus continuing for another decade or so is really just based on identifying some kind of 60-70 year cycle in the historical records – none of which contain periods really comparable to what we’re going through today. If I remember correctly, there was a massive outcry when the press release for the Marcott et al. Holocene temperature reconstruction paper rather overplayed the significance of part of their reconstruction. I wonder if the same people will be similarly shocked by the, apparently, unsupported claims in this press release? Don’t bother answering that question. I suspect we all know the answer. And, to be honest, I don’t really care. I do wish people wouldn’t overplay the significance of their papers in press releases, but they do and it’s really a systemic problem, rather than just a few individuals. | 0.814006 | 3.30863 |
"This site is called Moon 2," says Gian Gabriele Ori of the International Research School of Planetary Sciences (IRSPS). He pauses, looks around, and then says with a laugh, "I don’t remember the reason why."
In fact, the wide plain where Ori is standing resembles the planet Mars much more than the dusty grey moon. This valley east of Morocco’s Atlas Mountains has a profusion of red, black and tan rocks scattered about as far as the eye can see.
The distant mountains on the horizon call to mind the walls of an ancient impact crater as photographed by the Mars rovers Spirit and Opportunity. Even the volcanic origin of many of the rocks here is similar to the geological history of Mars.
Ori and his colleagues recently brought a group of scientists to this remote region near the Algerian border, where many of the instruments being developed for the upcoming ExoMars missions will be put through their paces. The missions, joint ventures of NASA and the European Space Agency (ESA), will study the Martian atmosphere, geology, and water cycle, and also search for signs of past and present life on Mars.
One Red Planet, Two Probes
For the first ExoMars mission, slated for launch in 2016, an orbiter will analyze the gases that make up the thin atmosphere of Mars.
The orbiting satellite will be keeping a keen eye out for methane – a gas that, on Earth, is often a sign of microbial life but also can be produced by volcanic activity. Previous detections of methanein the Martian atmosphere have generated a great deal of speculation about the possibility for life on Mars.
The ExoMars missions could help answer the question of whether microbes are living in protected regions underground on Mars today, and expelling methane gas as a waste product just as some microbes do on Earth.
In addition to the orbiter, the 2016 ExoMars mission will send a stationary weather platform to the planet’s surface. This meteorological station will only operate between four to eight days on a battery, but the main point is to have ESA successfully land a mission on Mars for the first time.
The capsule will detach from the orbiter, parachute through the atmosphere, and use retrorockets to decelerate before plopping down on the surface. The underside of the capsule will be made of a crushable material that will hopefully protect the contents of the capsule if it lands on large rocks.
This landing system is not the same planned for the 2018 ExoMars mission – that will use the same entry, descent and landing system as the upcoming Mars Science Laboratory – but if successful it could be used for later missions.
The 2016 ExoMars mission will help the 2018 mission in other ways: The orbiter’s measurements of trace gases in the atmosphere will help scientists select a landing site for the 2018 rovers. Spotting a location where methane periodically appears, for instance, would pinpoint a key place to send the rovers so they could search for the elusive signs of life on Mars.
The orbiter also will act as a relay satellite for the dual rovers to send data back to Earth.
The ESA-designed 2018 ExoMars rover will be larger then the Spirit and Opportunity rovers currently on Mars, and it will be built to last for at least 218 Martian days. The six-wheeled ESA rover will have a suite of tools at its disposal: ground-penetrating radar, an X-ray deffractometer, infrared instruments, cameras, spectrometers, and a drill to dig beneath the Martian surface.
The main goal of the second proposed rover, a NASA design called the Mars Astrobiology Explorer Cacher (MAX-C), will be to collect and analyze samples of Martian soil.
The rover would then store these samples so they could be picked up at a later time and brought back to Earth for additional analysis. (MAX-C was recently called out by the National Research Council as the highest priority large planetary science mission for the United States in the next decade.) The follow-up sample-return mission, which would bring home the soil samples MAX-C puts into storage, is currently projected to take place sometime in the 2020s.
But before any of this complicated coordination can be played out on Mars, every component of the missions must be tested on Earth, over and over again.
Martian analogs, here on Earth
The arid and varied Morocco landscape provides plenty of opportunities for scientists to test the limits of their instruments.
IRSPS’s Ibn Battuta Centre is in charge of the test sites, in cooperation with the Université Cadi Ayyad of Marrakech. One of the first tests scheduled this year will be for the laser altimeter for the ExoMars 2016 entry, descent and landing demonstrator module (EDM).
"The experiment will consist of a platform with a sort of radar to measure the reflectance of the surface," Ori said. "The instrument will be keptat about 20 to 30 meters from the ground with some balloons, but anchored to the ground."
The scientists are planning to perform these tests for several types of surfaces that have close similarities to the Martian landscape. To aid these tests, the scientists will create super-resolution Digital Elevation Models of five or six different areas, using stereo images shot from an unmanned helicopter.
The images will be quite detailed, with a resolution of 3 to 30 centimeters per pixel – slightly better than the 25 to 50 centimeters per pixel resolution of the HiRISE camera now on the Mars Reconnaissance Orbiter.
The unmanned helicopter also will be used to simulate landing a spacecraft on the surface of Mars, flying at 3,000 meters and descending at several tens of meters per second.
In addition, the 2018 ExoMars rover drill will be brought to the different field sites.
"We will test the equipment in the field and also the science that can be investigated," says Ori. "The driller will collect samples up to 2 meters of depth and will be the first samples from the Martian subsurface."
One planned drill test site, near the town of Ouarzazate, once was an ancient lagoon. Evidence of the lagoon is provided by 600-million-year old stromatolite fossils, free-standing pillars of rock that had been constructed by microbes in their watery environment.
Similar stromatolitescan be found being made today at Shark Bay in Australia and other estuaries and ponds around the globe, and the microbes that build them are thought to represent some of the most ancient life on Earth. Although stromatolites have not been found on Mars, evidence suggests ancient Mars was covered by oceans and had all the conditions thought to be necessary for such microbial life to thrive.
Rock samples from a variety of other regions in this part of Morocco – volcanic, hydrothermal, mountain, and desert – will be collected so the ExoMars drill can be tested under the controlled conditions of a laboratory. Of course, since life is abundant in even the most seemingly barren deserts on Earth, the samples will not be perfect stand-ins for the rocks of Mars.
Neither is the Morocco desert exactly like Mars – there are no Martian versions of Nomadic tents, dromedaries, snakes or scorpions in evidence from Mars rover photos. But the two worlds are not so far apart, either. For instance, one day the 4-wheel drive vehicles that shuttled the scientists to the different test sites became mired in fine desert sand. This scenario was similar to the struggles of the Spirit rover, which often became stuck in sand traps during its travels.
Just as NASA operators tried various strategies to set Spirit free, our drivers deliberated on different methods to escape the sand: rocking the vehicle back and forth, pushing from behind, pulling with front tow lines tied to other vehicles, setting metal braces under the front tires.
As scientists prepare the ExoMars rovers for Mars, such experiences must sink in deeply. It’s an ironic fact that of all the alien dangers and challenges that Mars poses for future explorers, something as basic as sand can bring even the most high-tech missions to a halt.
The Spirit rover is now stuck forever, unable to break free of its final sand trap – a rover no more, but instead a "stationary science platform."
Hopefully, by providing real-world challenges for the future ExoMars rovers and other mission components, test sites like the ones in Morocco increase the chance these missions will succeed in the most unforgiving proving ground of all – Mars itself.
This story was provided to SPACE.com by Astrobiology Magazine. | 0.839655 | 3.772999 |
Stephanie LaMassa did a double take. She was staring at two images on her computer screen, both of the same object — except they looked nothing alike.
The quasar seemed to have vanished, leaving just another galaxy.
That had to be impossible, she thought. Although quasars turn off, transitioning into mere galaxies, the process should take 10,000 years or more. This quasar appeared to have shut down in less than 10 years — a cosmic eyeblink.
LaMassa , an astronomer now at the Space Telescope Science Institute, was mystified. Until that moment in 2014, she, like so many others, had expected quasars to be relatively stagnant. “Then you see these drastic changes within a human lifetime, and it’s pretty cool,” she said.
Confusion turned into excitement, and a hunt began to find more of these oddities. Although less luminous examples had already been seen, astronomers wanted to know if changes as dramatic as the one LaMassa discovered were common. It was no straightforward task, given that surveys tend not to go back and look at objects they have previously observed. But astronomers searched through archived data and discovered 50 to 100 more of what became known as “changing-look quasars.” Some of these have dimmed substantially more than LaMassa’s first example. Others have transitioned in the space of a month or two. And others, after disappearing, have reappeared again.
“It’s clear that the reason we weren’t finding these objects before is that we weren’t looking for them,” said Eric Morganson , an astronomer at the University of Illinois.
But how could such massive objects — superluminous beacons generated by solar-system-scale vortexes of gas and dust swirling into black holes with the mass of millions of suns — shut down so quickly? At first, astronomers refused to believe that they could, instead suggesting that these weren’t quasars at all, but rather supernovas and flaring stars masquerading as such. Or perhaps dust clouds were temporarily blocking our view.
But those ideas have largely failed to match what astronomers see. Within the past year a number of observations have peered more closely at these systems, providing details that suggest the accretion disk — that swirl of hot matter that encircles the black hole and gives these objects their dazzling luminosity — appears to flicker on and off. In parallel, theoretical astrophysicists have brainstormed how this change might happen. “It’s a little crazy that this whole system, which is just so enormous, is changing that quickly,” Morganson said.
Black Hole Doppelgängers
For the last four years, astronomers have attempted to understand changing-look quasars using the simplest theories possible. At first, that meant finding scenarios that did not require sweeping changes in the accretion disk.
To understand why, it helps to consider the size of these systems. If you could plop a quasar on top of the solar system, the supermassive black hole would swallow the sun, while the accretion disk would stretch out tens of thousands of times farther than Earth. To turn the quasar off, all of that material would have to swirl inward and fall onto the black hole — a process that calculations and even observations suggest should take tens to hundreds of thousands of years.
“There’s no way that the accretion should be able to shut down as quickly as we’ve seen it do,” said Paul Green , an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. “The physics just doesn’t really make sense.”
So astronomers considered other possibilities. When LaMassa first made her startling discovery in 2014, she postulated that a massive dust cloud passed in front of the quasar’s bright beacon and momentarily blocked its light. But when she and her colleagues tried to model that scenario, they found that only an overly complex situation with multiple clouds could reproduce the observations. It seemed far too unlikely. To boot, any change would have taken much longer than a few years.
Others considered whether these objects weren’t quasars at all. In 2015, Andrea Merloni at the Max Planck Institute for Extraterrestrial Physics in Germany suggested that perhaps LaMassa’s object was actually a star that passed too close to the black hole and was torn apart, creating a bright flare. Similarly, others have argued that the purported quasars were actually powerful supernovas.
Both possibilities would outshine their host galaxies, much like quasars, and might even emit similar wavelengths of light. Then the light from these events would fade over the course of a few months to years — thus matching the timescale behind changing-look quasars. But the problem was that the light would also fade with a particular signature, one that astronomers didn’t see.
So researchers have recently turned back toward quasars. They’ve been helped by several new studies that have explored the swirling disk of matter itself.
In 2017, Zhenfeng Sheng, an astronomer at the University of Science and Technology of China, and his colleagues examined multiple changing-look quasars in both visible and infrared light. Those wavelengths allowed the team to view not only each quasar’s accretion disk, but also its torus — the doughnut-shape ring of dust clouds that wraps around the accretion disk.
That’s important because the glowing accretion disk sends visible light toward the dark torus, where it is absorbed and re-emitted as infrared light. Because of this, any change in the accretion disk will later be echoed within the torus. Sheng and his colleagues saw just such an echo (as did other studies), allowing them to conclude that it must be a sign of a change in the amount of material flowing through the accretion disk.
Just how this sweeping change occurs is still a matter of debate — but many hypotheses have recently emerged.
Half-Eaten Buffets and Shape-Shifters
It could be that a quasar does not have to clear its plate completely in order to shut down. One way to understand this is to break up the accretion disk into separate parts: a bright inner region that illuminates an outer dull region. Then if the black hole consumes the inner region (a process that could occur in mere months), the inner disk will disappear, and without its bright beacon, the outer disk will grow dark — much like the death of the sun would cause the moon to lose its shine.
“We kind of thought these were just hungry guys at a buffet,” Morganson said. “If there is just an infinite amount of food in front of them, they were just going to keep eating as fast as they could, and then they would remain relatively stable. But instead we find that they’re just taking breaks when the food is still there.”
Or it could be that the accretion disk changes its shape. It sounds wild, but this year studies of two different quasars found evidence to support this theory based on another echo. In each, the ultraviolet and blue colors fell away first, followed by the green and finally the red. That sequence flows from highest-energy colors to lowest-energy colors. It therefore resembles changes that ripple from the inner disk to the outer disk. “Something is causing the accretion disk to dim from the inside-out,” said Barry McKernan , an astrophysicist at the American Museum of Natural History.
Because the colors don’t completely disappear, the researchers don’t suspect that the inner accretion disk was completely swallowed by the black hole. Instead, they think that a cooling front swept out from the supermassive black hole at an incredible clip. The red colors, for example, dropped merely a year after the green colors.
That speed is important, McKernan noted, because it can reveal hints about the structure of the disk. If the disk is viscous and turbulent, then it’s fairly easy to send information through it. (Just think about the fact that sound travels faster in water than in air.) So McKernan argues that the disk must be viscous and therefore fairly puffed up — a doughnut, not a DVD — before collapsing into a thin disk once the cool front passes through.
But a second hypothesis suggests just the opposite: The accretion disk starts thin before puffing up. This is precisely what astronomers think occurs when stellar mass black holes — supermassive black holes’ lower-mass doppelgängers — turn inactive. When they’re accreting a lot of mass onto the black hole, their accretion disk is quite thin and luminous. But when that accretion rate drops, the disk puffs up into a quasi-spherical structure that struggles to emit light.
Hirofumi Noda from Tohoku University in Japan and Chris Done from Durham University in England wanted to see if such a puffing-up could also be responsible for changing-look quasars. So this year, they applied their models for the accretion disks around stellar mass black holes to those around supermassive black holes. They found that this change could happen in a quasar’s accretion disk, and fast (though not as fast as decades).
Astronomers can’t yet say if the supermassive black hole has been starved, if the disk itself has shape-shifted — either puffing up or caving in — or if an entirely different mechanism is responsible. It’s still unclear how gas in the accretion disk flows from an orbit at a large radius to one near the black hole and how it finally falls onto the black hole. And other factors — magnetic fields, for example — likely play a crucial role that astronomers don’t yet understand. “It’s a failure of our imagination,” said Meg Urry , an astrophysicist at Yale University.
A Murder-Suicide Pact
While the details remain hazy, a better understanding of how gas and dust flow onto a black hole will do more than answer our sheer curiosity; it will help explain how galaxies evolve.
Nearly 20 years ago, astronomers discovered that the mass of a supermassive black hole is tightly correlated with the mass of the entire galaxy. In fact, the black hole actually truncates a galaxy’s growth, causing it to be 10 to 100 times smaller than simulations predict. “The gravitational sphere of influence of a black hole is tiny in comparison to an entire galaxy,” said John Ruan , an astrophysicist at McGill University. “So why is there such a close relation between the two?”
When the correlation was first discovered, the answer to that question was a mystery, but astronomers now suspect that quasars can wreak havoc on their host galaxy — and the effects are surprisingly far-reaching. A quasar’s extreme wind drives dust and gas outside of the galaxy. Its extreme luminosity heats any leftover gas to such high temperatures that new stars can’t form. It effectively starves both itself and its host galaxy of the stars required to stay alive in “a murder-suicide pact,” said Gordon Richards , a physicist at Drexel University.
At least that’s the current thinking. It has been extremely hard to pin down the details because astronomers can’t observe a distant quasar and its galaxy simultaneously — the quasar is simply too bright. If astronomers could set up cosmic experiments, however, they would study a quasar and then turn off the switch, causing it to grow dark. Changing-look quasars are precisely this experiment, Ruan said, offering an unprecedented opportunity to better understand a quasar’s far-reaching effects.
But to truly grasp this relationship, astronomers will need a large sample of changing-look quasars. And to find them, they will have to return time and again to the same quasars and galaxies to spot any changes. Already, the Zwicky Transient Facility in California has been mapping the sky since 2017, returning to the same objects nearly 300 times per year. And many more facilities are soon to come online. The Large Synoptic Survey Telescope , for example, planned for 2022, will map the entire sky in five colors every night. “We’ll have a color movie of the whole sky that will just discover millions of fascinating oddball objects like this,” Green said.
McKernan is on the fence about how lucky we’ll be in the future. In optimistic moments, he imagines those surveys might help astronomers catch a break. “If we’re in the right place at the right time such that we can catch one of these things as it’s happening and follow it with several instruments, we might get a breakthrough,” he said. “That might be our Rosetta stone.” Though it would still require a stroke of luck, such an observation might even help describe our Milky Way down the road.
In roughly five billion years, after all, our galaxy and the Andromeda galaxy will collide — likely sparking yet another quasar and throwing our night sky into disarray. But a clearer foresight into those details could come from better understanding this mysterious disappearing act.
Original story reprinted with permission from Quanta Magazine , an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.
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Prof. Dr. Mario Trieloff explains why geoscience is so important for exploration of the universe. In the interview, he also discusses questions surrounding the origins of the solar system, the Earth, and life itself, pondering on the future devel-opment of space exploration and the challenges this will pose for his Steinbeis Enterprise.
Professor Trieloff, space travel often brings eye-opening missions to mind, things like the recent New Horizons discoveries and those amazing images from space. You work in an area that, for any layperson, is probably a completely unknown in space – extraterrestrial materials and geomaterials. What topics and areas does this involve?
People often think that investigating far-flung heavenly bodies belongs to physics. Classic astronomical obser-vation uses telescopes to examine electromagnetic radiation coming from extraterrestrial bodies, typically from huge distances. The strategy at the core of space missions is different. They involve transporting a relatively small load of scientific instruments to a target object somewhere in the solar system to study it at close quarters. This mainly involves engineers – to deal with flight capability and robotics – and physicists and chemists – to carry out experiments.
But when it’s a planet with a solid surface, like Mars or the Earth’s moon, or a small planetary body like an asteroid or comet, it’s all about investigating rocks and minerals. This is where the right geoscientific expertise is needed, to interpret the re-sults, and before that, to make the right instruments, to tackle the sorts of issues that are relevant to geoscience, or to test laboratory-type scientific instruments on suitable rocks and minerals – by which I mean extraterrestrial materials or geomaterials.
What happens specifically with the insights gained from researching extraterrestrial geomateri-als? And what services does your Steinbeis Transfer Center for AstroGeomaterials offer in this area?
To judge the kinds of rocks and materials we can – theoretically – expect to find on asteroids, comets, Mars or the Moon, and to analyze these from a space probe, we’ve already gained some astonishingly good information by analyzing meteorites. Meteorites are typically a couple of centimeters or several meters in diameter – big chunks of rock that fell to earth at an extremely high velocity at around 10km per second. The collection of meteorites on Earth keeps growing; we currently have around 50,000 samples, most of which come from asteroids, and there are also minute dust particles from comets and about 100 meteorites from the Moon, plus a similar number from planet Mars. This allows us to “probe” many more planetary bodies then we would actually get from mission sample returns like the Apollo missions, Stardust or Hayabusa.
One obvious idea is to simply use samples from these meteorites as experimental material or calibration materials for experiments. But because these are extremely complex rocks or multi-mineral materials, it’s better initially to carry out tests with the individual minerals that make up the rocks. Often the problem with this is that to separate off the minerals properly, you need large volumes of rocks or, for example, you need large volumes of materials to calibrate space ex-periments. But extraterrestrial samples are extremely rare and sometimes they’re also extremely expensive; often curators won’t even make them available for such purposes, so you have to fall back on analogous terrestrial materials, which are available in sufficient quantities. The Steinbeis Transfer Center for AstroGeomaterials provides specific advice on selecting such rocks to ensure that the analogous material that is taken is suitable for gauging certain types of space experiments.
Your research at the University of Heidelberg also involves questions regarding the origins of the solar system. What secrets have emerged from interstellar dust about primeval materials and the solar system? What impact do you believe such insights could have on further developments in space travel?
With lots of space missions, like the current Rosetta project, the aim is to gain a better understanding of the origins of our solar system, the Earth, and life itself. We also look into these issues by studying meteorites. We now know that all bodies in our solar system originated from an interstellar cloud of gas and dust 4.6 billion years ago. There was a primeval nebular formation, a protoplanetary disk around our sun, which was just developing, with phases of heat lasting just a short time resulting in the first solid objects – only millimeters or centimeters in size. After a period lasting several million years, there were swarms of small planets whose descendants are today’s asteroids. It then took another several tens of millions of years for the forerunners of today’s terrestrial planets to take shape. We still find the remnants of these first solid objects in meteorites in our solar system, and we even find rare grains of stardust, micrometers in size, that developed in the wind of all stars even before our solar system existed. Without meteorites, we wouldn’t know the exact age of the Earth and we wouldn’t have so much detail of its constituent materials. Meteorites contain amazingly complex prebiotic materials such as amino acids, and these could have played an important role in the origins of life on Earth.
The meteorites that come down to earth are only meters in size. Much more rare, but also much more dangerous, are the ones that measure kilometers in diameter, like the ones that came down in the past and had such a significant effect on the geosphere and biosphere. They were linked to mass mortality between the Cretaceous and Paleogene periods – and the end of the di-nosaurs – after a meteorite came down in Mexico 66 million years ago. Future space mission concepts are also looking at different ways to divert menacing asteroids early enough, or different ways to use asteroids to build a space industry.
Can you estimate from today’s standpoint what challenges future space travel developments will pose for your Steinbeis Enterprise and how this might affect your portfolio of services?
During the pioneering time, the priority was flight capabilities. That won’t be the case anymore, just getting a probe properly underway and maneuvering it away from Earth to the target object to land it on the surface. Such missions are only justifiable if more scientific insights are gained than from previous missions. What’s needed in this respect is more professional and interdisciplinary collaboration between physicists and geoscientists. This will increasingly become the case if the missions are about sample returns – for example when it comes to selecting the right landing area. If the Earth were an unknown planet and we were explor-ing it, the geoscientists would tell you how incredibly important it is to collect the first samples from specific places in order to find out something about the planet.
Prof. Dr. Mario Trieloff is director of the Steinbeis Transfer Center for AstroGeomaterials at the University of Heidelberg. His Steinbeis Enterprises offers clients astromineralogical and geoscientific expertise needed to participate in the planning and conducting of space experiments, as well as advice on the acquisition and analysis of extraterrestrial geomaterials.
Prof. Dr. Mario Trieloff
Steinbeis Transfer Center AstroGeomaterials (Heidelberg) | 0.862234 | 3.662855 |
A team of astronomers at the University of Warwick think they’ve finally explained what caused the bizarre transient object SCP 06F6. By comparing the optical spectrum of SCP 06F6 to that of carbon-rich stars in our own galaxy, the team concludes the sudden outburst was not a low-energy local event but a supernova-like explosion within a cool carbon-rich atmosphere some 2 billion light years away. If they’re right, it means the collapse of carbon-rich stars may lead to supernovae unlike any yet seen.
First observed in 2006 by U.S. researchers on images from the Hubble Space Telescope, SCP 06F6 flashed suddenly then faded from view over some 120 days. The U.S. team published their findings in September 2008. But they had no idea what might cause this outburst. The event was so unusual, if fact, that astronomers had didn’t know whether SCP 06F6 was located in our own galaxy or at the other end of the universe. Talk about experimental uncertainty!
The Warwick team noticed the optical spectrum of SCP 06F6 looked a lot like light from cool stars with molecular carbon in their atmosphere. But to get a close spectral match with SCP 06F6, the team had to apply a redshift to the spectra of the carbon stars to correspond to a rapidly receding object some 2 billion light years away. The large distance and the sudden appearance of SCP 06F6 suggest the object may be related to the sudden collapse of a carbon-rich star. If so, it’s a brand new type of supernova.
But questions remain. SCP 06F6 seems to be alone in space… it has no known visible host galaxy. And the 120-day time scale of the object’s rise and fall in brightness is four times longer than most Type-II supernovae (the kind caused by the core-collapse of a massive star).
What’s more, X-ray observations by the European satellite XMM-Newton show the object blasts out up to 100 times more X-rays energy than expected from a typical Type-II supernova.
The strong X-ray emission may suggest the star was ripped apart by a black hole rather than exploding on its own. But according to Boris Gansicke, the lead researcher of Warwick team, “The lack of any obvious host galaxy for SCP 06F6 would imply either a very low black hole mass (if black holes do exist at the centres of dwarf irregular galaxies) or that the black hole has somehow been ejected from its host galaxy. While neither is impossible, this does make the case for disruption by a black hole somewhat contrived.”
The findings were published in the June 1, 2009 issue of Astrophysical Journal Letters.
Source: University of Warwick | 0.853993 | 3.99723 |
The Dogon, an African tribe, were said to have astronomical knowledge that should have been beyond them, specifically relating to the star Sirius. The Dogon were reported to have carried that information with them down through their long history, which is remarkable in itself - but the claims of ancient contact with aliens who may have been the Dogon's ancestors are what really pushed this story into the limelight.
The Dogon are an ethnic group located mainly in the Bandiagara and Douentza districts of Mali, West Africa. They live mainly along a 125-mile stretch of escarpment called the Cliffs of Bandiagara which runs from south-west to north-east, roughly parallel to the river Niger. The Dogon typically live in villages of less than 500 people, which used to be built very close to the cliffs but, with time and the decreasing fertility of the nearby land, they have started to move away. The Dogon are an ancient people - one account describing their origins says that they lived originally in what became Egypt, but migrated away to Libya and then to Mauritania before settling in Mali. It is difficult to be sure of this because the Dogon still have a oral tradition of record-keeping and the story varies from clan to clan and area to area.
If you want to find Sirius1, look at the night sky and locate the constellation Orion. Then look south and east from the line of Orion's belt. The brightest star in that part of the sky is Sirius. It's twice as large as our Sun and 23 times as luminous - so despite it being over 8.6 light years2 away it still seems very bright. Bright enough, in fact, to completely obscure its neighbour star. Sirius B is a smaller, denser star known as a white dwarf. The two orbit each other, elliptically, about once every 50 years. Dwarf stars are made of incredibly dense material, with Sirius B weighing in at about a metric ton per cubic centimetre3. Sirius B wasn't discovered until 1926.
In 1931, two French anthropologists called Marcel Griaule and Germaine Dieterlen contacted the Dogon and began a thirty-year relationship with them. This resulted in a detailed study undertaken between 1946 and 1950, a study which included an examination of Dogon religious beliefs4.
It was claimed that, during this study, the two anthropologists had access to the Dogon people's innermost religious secrets, much of this being naturally of an obscure and complex nature. Some of those secrets were rather startlingly less obscure than the two had been expecting. It appeared that the Dogon - a people without much in the way of telescopes - knew a great deal about Sirius and, more surprisingly still, claimed it had a companion star.
This information remained relatively obscure until 1976, which saw the publication of The Sirius Mystery by Robert Temple. Temple had seized upon a number of Dogon religious beliefs and realised that here, in the tribe's history and traditions, might lie evidence of contact with ancient extraterrestrials.
Firstly, Temple argued, it was impossible for the Dogon to have any knowledge of the companion star; it's too small to be seen with the naked eye. The Dogon also identified Sirius B as being very heavy, which is true - but again is something they couldn't know without observing the star or understanding its action on Sirius A. Additionally, this Dogon knowledge predated the Western discovery of Sirius B by centuries, possibly millennia. The clincher for Temple was a Dogon myth which told of their contact with the Nommo.
According to the Dogon, an 'ark' descended from the sky amid a great wind. This brought the Nommo to Earth. The Nommo, who supposedly came to Earth to set up a civilisation, were a group of amphibious beings. The Nommo were apparently from Sirius, or at least a planet orbiting Sirius, and passed on much information to the Dogon.
Robert Temple was also eager to connect the Dogon to the peoples of the Mediterranean, particularly Egypt, who he contended also had special reverence for Sirius.
Since the publication of the book there have been those eager to follow Robert Temple's reasoning and there have been those who have wanted to debunk it.
In his book, Temple offered a prediction. He said:
What if this is proven by our detecting on our radio telescopes actual traces of local radio communications?In April 1977, Paul Feldman and Robert S Dixon (of the Algonquin radio observatory and Ohio State University respectively) were asked to listen to Sirius. They didn't find anything unusual. There were no signs of artificial radio sources.
There are some good reasons for this. Stellar evolutionary theory says that the brighter and larger a star is, the faster it burns out. At some time in the distant past, Sirius B was brighter and more massive than Sirius A. What happened to it? Firstly, Sirius B became a Red Giant; it increased its size dramatically and also increased its output of energy as the nuclear reactions that power a star ran out of control. This increase in heat and radiation output would have baked and scoured worlds anywhere near Sirius B. As Sirius B burned its fuel source out, it became smaller again. At this time, it is believed that it may have shared some of its mass with Sirius A in the form of a gale of solar material lasting up to one hundred thousand years. Sirius A and Sirius B also moved apart slightly, leading to the destablisiation of the orbits of any nearby worlds. And finally, around 30 million years ago, Sirius B became a White Dwarf star and began emitting soft X-Rays, bathing the local area in very unfriendly radiation. This is why astronomers don't feel that Sirius is a good candidate as a potential life-supporting planet.
Then we come to Robert Temple himself.
In 1965, Robert Temple was handed the Griaule and Dieterlen study by his mentor, Arthur M Young. A year later, Temple became the Secretary of Young's Foundation for the Study Of Consciousness. A year after that, Temple began work on the thesis that would become The Sirius Mystery - a thesis he would have to submit to Young for evaluation. This doesn't sound like much of an issue until you know a little more about Arthur M Young.
Arthur Young was a believer in a group of channelled entities5 called 'The Council of Nine'. These entities claim to be the nine creator gods of ancient Egypt, something that Young was well aware of having been present at the first 'meeting' of the council, an event made possible by Andrija Puharich6.
Tellingly, 'The Nine' also claimed to be extraterrestrial entities from the star Sirius.
Temple's close association with Young has lead some researchers7 to suggest that The Sirius Mystery contained conclusions that would please Young. Critics have contended that much of the book is based on deliberate misrepresentations of Egyptian mythology and occasional errors made in understanding source material.
In Temple's defence, although his conclusions may have been spurious or ill-founded, at the core of them lay The Pale Fox, an original work by Griaule and Dieterlen. The strongest challenge to that study did not come until 1991, when Walter Van Beek led a team of anthropologists to Mali8. He declared that, in the decade he spent with the Dogon, he found no trace of detailed knowledge about Sirius. Griaule claimed that 15% of the tribe possessed such knowledge. Van Beek was fortunate enough to speak to some of the same Dogon as Griaule, but he reports:
'though they do speak about sigu tolo9 they disagree completely with each other as to which star is meant; for some it is an invisible star that should rise to announce the sigu [festival], for another it is Venus that, through a different position, appears as sigu tolo. All agree, however, that they learned about the star from Griaule'
This takes us a step closer to the heart of the mystery, and we discover that although he was an anthropologist, Griaule was an amateur astronomer. He studied the subject in Paris and apparently took star maps with him on his trips to prompt the locals to talk about stars10. If this is the case, is it possible that the Dogon merely answered Griaule's questions in a way that they believed he would like? Were the Dogon treating Griaule the same way Temple treated Young, telling them what they wanted to hear?
If this is true, the mystery of the Dogon link with Sirius does stem from contact with aliens, not the amphibious Nommo, but the very terrestrial French anthropologists who sought to study them. | 0.866271 | 3.375094 |
Crescent ♈ Aries
Moon phase on 3 February 2082 Tuesday is Waxing Crescent, 5 days young Moon is in Aries.Share this page: twitter facebook linkedin
Previous main lunar phase is the New Moon before 5 days on 28 January 2082 at 20:46.
Moon rises in the morning and sets in the evening. It is visible toward the southwest in early evening.
Moon is passing about ∠17° of ♈ Aries tropical zodiac sector.
Lunar disc appears visually 9.5% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1770" and ∠1946".
Next Full Moon is the Snow Moon of February 2082 after 9 days on 13 February 2082 at 06:16.
There is medium ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at very acute angle, so their combined tidal force is moderate.
The Moon is 5 days young. Earth's natural satellite is moving from the beginning to the first part of current synodic month. This is lunation 1015 of Meeus index or 1968 from Brown series.
Length of current 1015 lunation is 29 days, 18 hours and 2 minutes. It is 14 minutes shorter than next lunation 1016 length.
Length of current synodic month is 5 hours and 18 minutes longer than the mean length of synodic month, but it is still 1 hour and 45 minutes shorter, compared to 21st century longest.
This New Moon true anomaly is ∠122.6°. At beginning of next synodic month true anomaly will be ∠154.1°. The length of upcoming synodic months will keep increasing since the true anomaly gets closer to the value of New Moon at point of apogee (∠180°).
1 day after point of apogee on 2 February 2082 at 18:11 in ♈ Aries. The lunar orbit is getting closer, while the Moon is moving inward the Earth. It will keep this direction for the next 11 days, until it get to the point of next perigee on 14 February 2082 at 17:46 in ♍ Virgo.
Moon is 404 931 km (251 612 mi) away from Earth on this date. Moon moves closer next 11 days until perigee, when Earth-Moon distance will reach 360 321 km (223 893 mi).
3 days after its ascending node on 31 January 2082 at 01:22 in ♓ Pisces, the Moon is following the northern part of its orbit for the next 10 days, until it will cross the ecliptic from North to South in descending node on 14 February 2082 at 00:16 in ♍ Virgo.
3 days after beginning of current draconic month in ♓ Pisces, the Moon is moving from the beginning to the first part of it.
8 days after previous South standstill on 25 January 2082 at 12:10 in ♐ Sagittarius, when Moon has reached southern declination of ∠-28.230°. Next 5 days the lunar orbit moves northward to face North declination of ∠28.278° in the next northern standstill on 9 February 2082 at 02:32 in ♊ Gemini.
After 9 days on 13 February 2082 at 06:16 in ♌ Leo, the Moon will be in Full Moon geocentric opposition with the Sun and this alignment forms next Sun-Earth-Moon syzygy. | 0.848363 | 3.217948 |
Bakersfield Night Sky - October 7, 2018
by Nick Strobel
The William M Thomas Planetarium will be upgrading its all-dome Spitz SciDome system over the next two to three weeks. The new system will have sixteen times the number of pixels on the dome for much sharper images. I’m looking forward to seeing what the ever-popular “Black Holes” show looks like with the new projection system. We’ll still have the Goto Chronos star projector to display a gorgeous night sky.
Last week the Japanese Aerospace Exploration Agency’s (JAXA) Hayabusa2 mission to the small asteroid Ryugu had its first of hopefully several successful ways of exploring Ryugu with the deployment of two small “rovers” onto the surface. I put “rovers” in quotes because the two small craft will not roll across the surface on wheels but instead will hop about. The surface gravity of Ryugu is much too weak for wheeled transport to work. The hoppers are called MINERVA II-1ab for second "Micro-Nano Experimental Robot Vehicle for the Asteroid” project. (With a name that begins with “micro-nano”, you know that the scientists were stretching a bit to make the acronym work.) The first MINERVA rovers were part of the first Hayabusa mission that explored the asteroid Itokawa thirteen years ago. Those rovers never made it to the surface of Itokawa and were lost to space due to an error in measuring how far it was from the asteroid when it deployed the MINERVA rovers.
No such problem this time! The MINERVA hoppers are cylindrical in shape and just 7 inches wide by 3 inches high with a mass of 2.4 pounds. A larger version of the MINERVA hoppers will be deployed next year. (It still carries the MINERVA label even though it is probably a “micro-micro” instead of a “micro-nano” because “mimerva” just doesn’t quite have a nice ring to it.) Later in October, a lander built by Germany and France will land on the surface. Also later in October will be Hayabusa’s primary mission: descent of the main craft to the surface to collect samples from the surface and return them to Earth. Later in 2019, Hayabusa will shoot a two-kilogram copper lump into Ruygu’s surface to make a crater and then collect samples from the inside of the new crater. The two sets of samples will be returned to Earth in 2020. For more exploration of the mission go to http://global.jaxa.jp/projects/sat/hayabusa2/ .
A few weeks ago I received a call from a reporter to comment about a paper by Philip Metzger making the rounds in the popular media that said Pluto should be reclassified as a planet because one of the metrics for distinguishing planets from “dwarf planets” is not historically valid. The invalid metric says that the body must be the largest gravitational force in its orbit, so that it has “cleared” out its orbit in order to be called a “planet”. That metric is what got Pluto re-classified (not demoted, mind you) as a “dwarf planet”.
Well, I’m not sure what is so newsworthy about the historical research on how the word “planet” has been used. We already knew that the orbit clearing metric was a late add-on to the definition of planet and that the metric had not been used in the past. Of course, the story is really about our emotional attachment to Pluto. Many feel Pluto was unfairly kicked out of the “planet club” by some underhanded shenanigans at the 2006 IAU meeting when the orbit clearing metric was added late in the process. I’m surprised Dan Brown (of “da Vinci Code” fame) hasn’t written a book about it.
The orbit clearing metric is problematic for three reasons: 1) how much clearing of the orbit a true planet does is not defined; 2) it takes A LOT of observations over many years to see if the orbit has been truly cleared out; and 3) the metric cannot be used for exoplanets. What is more practical to use is an object’s diameter or its mass. A body above a certain size will have enough internal gravity to make itself round and also initiate active geology. Pluto certainly fits the bill—it has the second-most geologically diverse terrain in the solar system after Earth.
Metzger and his co-authors, one of whom is Alan Stern (the head of the New Horizons mission to Pluto), are intellectually honest in accepting what a proper definition of “planet” would mean: over a hundred objects in our solar system would become a planet, including the large moons. I would hate to be the one who tells our school teachers and parents that their kids will now need to learn the names of not just eight planets but over a hundred.
Venus has now disappeared from our evening sky and bright Jupiter is getting low in the west in the evening. Saturn is high in the south when twilight ends and Mars in the southeast is now dimmer than Jupiter. Saturn still offers a great view of its rings. Check it out at the KAS public star party on Saturday, October 20 at Barnes & Noble. Before then look for the beautiful crescent moon as it moves by the planets over this week. | 0.859565 | 3.076317 |
Advances in Understanding Celestial Mechanics
Advances in Understanding Celestial Mechanics
Modern celestial mechanics began with the application of Isaac Newton's laws of motion to the observations of astronomy. Mathematicians of the eighteenth and nineteenth centuries worked to understand the workings of the solar system in terms of all its gravitational forces. While the gravitational pull of the Sun keeps the planets in their orbits, each planet's path is slightly disturbed by the presence of the others.
Early astronomy was primarily concerned with celestial mechanics in a broad sense; that is, understanding the apparent motion of the stars and planets. Without telescopes, the Moon was the only celestial body upon which details could be observed. Everything else was too distant, except for the Sun, which was too bright. So theories could be devised about the nature of the other bodies, but the only property that could actually be measured was their motion.
The word planet comes from the Greek word for wanderer. As seen from Earth, the stars all march across the sky at the same steady pace, but the planets move at a variable rate, sometimes even changing direction. We now know that we see the planets in this way because they, like Earth, are moving in their separate orbits around the Sun. The apparent regular motion of the distant stars arises from our changing point of view as Earth rotates on its axis and revolves around the Sun.
Of course, none of this was obvious to the ancients, who assumed that the entire cosmos revolved around Earth. The most influential ancient astronomer, Ptolemy, lived in Alexandria around 150 A.D.. He explained the variable motion of the planets by assuming that they revolved in small orbits called epicycles, on a larger circle called a deferent that orbited Earth. Ptolemy adjusted the speeds and distances in his system until he was able to make accurate predictions of planetary positions. His system, preserved in a work his successors called the Almagest, or the "Greatest," was used until the Renaissance.
The Polish astronomer Nicolaus Copernicus (1473-1543) is generally considered the father of modern-day astronomy. He realized that Earth orbits the Sun like the other planets and that our view of the sky is affected by Earth's motion. He put forth his heliocentric, or sun-centered, view of the cosmos in his great work Concerning the Revolutions of the Celestial Sphere (1543). Since he still assumed, incorrectly, that the orbits of the planets were circular, he had to retain some of Ptolemy's epicycles to accurately match their positions.
Johannes Kepler (1571-1630), using twenty years of precise measurements made by his mentor Tycho Brahe (1546-1601), developed his famous laws of planetary motion, the first of which states that the orbits are elliptical. Kepler's laws were accurate, but empirical; that is, they accounted for the observed data, but had no explanation for why the orbits should be shaped as they are. It was Isaac Newton (1642-1727) who provided that explanation. Newton derived three general laws of motion, and concluded that the gravitational force between two bodies was proportional to the product of their masses and the inverse square of the distance between them.
With the new understanding of gravity and the laws of motion, it was now possible to consider the planets as an n-body problem; that is, a theoretical problem of predicting the behavior of a fixed number of masses interacting by means of their gravitational fields. Such problems are complex because every object affects every other. So, for example, in our Solar System, the main determinant of the planetary orbits is the gravitational field of the Sun. However, each planet experiences perturbations in its own orbit because of all the others. Once the basic mechanism of orbits was understood, the discipline of celestial mechanics began to concentrate on understanding the perturbations.
Planetary motion is described in terms of differential equations. Differential equations involve derivatives, mathematical expressions for the rate of change of one quantity with respect to another. For example, the derivative, or rate of change, of distance with respect to time is velocity. The rate of change of velocity with respect to time is acceleration, and acceleration is determined by the gravitational or other force on an object. The equations describing position, velocity, and force necessarily involve derivatives.
Differential equations are themselves an important field of study in mathematics. Many are extremely difficult to solve. While some have exact solutions, the solutions to others must be approximated, and many techniques have been developed to do so. Today differential equations are sometimes solved using numerical computing techniques.
In celestial mechanics, a "two-body problem" such as the rotation of a single planet around the Sun without taking any other masses into account is described by a relatively simple differential equation. It can be solved exactly, and the solution reproduces Kepler's laws. Add in the masses of the other planets, however, and the situation becomes much more complicated. Even the great Newton essentially threw up his hands and attributed the stability of the Solar System to occasional divine intervention in which everything was nudged back into place.
The stability problem was taken up by the French astronomer Pierre-Simon Laplace (1749-1827). Observations seemed to indicate that the orbit of Jupiter was continuously shrinking while that of Saturn was expanding. In 1786 Laplace showed that the eccentricities of the planetary orbits and the angles at which they are inclined with respect to one another will remain small and self-correcting. Because the perturbations in the motion are periodic, they do not accumulate and disrupt the stability of the solar system. In the case of Jupiter and Saturn, the effect being observed had a period of 929 years.
Between 1798 and 1827 Laplace's five-volume work on planetary motion, Traité de mecanique céleste ("Treatise on Celestial Mechanics"), was published. In it he provided a complete method for calculating the movements of the planets and their moons, including gravitational perturbations and the tidal disturbances of the bodies' shapes. The book quickly became a classic. It was updated and enlarged by both the American mathematician Nathaniel Bowditch (1773-1838) and the French astronomer Félix Tisserand (1845-1896). Tisserand's version, four volumes published between 1889 and 1896, remains an important reference in the field.
For any given planet, it is generally convenient to consider the sum of the forces from all the others as a net perturbation of the orbital ellipse. The French-Italian mathematician Joseph-Louis Lagrange (1736-1813) expressed this in a set of differential equations sometimes called the Lagrange planetary equations. They must be solved numerically or by means of successive approximations using a series of mathematical terms to increase the range over which a solution is a good fit to the actual motion. Lagrange used his equations to explain the libration of the Moon; that is, the oscillations seen as a slight change in the position of the visible lunar features. The techniques also resulted in the discovery of the planet Neptune in 1846, after its position was predicted from perturbations of the orbit of Uranus.
In 1889 the French savant Henri Poincaré (1854-1912) won a prize offered by King Oscar II of Sweden for a contribution to the n-body problem. Poincaré applied to the problem several of the advances in mathematical analysis that had been developed since the time of Laplace and Lagrange and added a few important techniques of his own invention. His work was published between 1892 and 1899 as Les méthodes nouvelles de la méchanique céleste ("The New Methods of Celestial Mechanics").
Poincaré was more concerned with the mathematics of celestial mechanics than with obtaining precisely accurate predictions of planetary motion. He studied the series approximations used with the differential equations of motion, to understand when they would converge to a useful solution. In cases where they did not converge to a general solution, he showed under what conditions they could be used to approximate the motion for a significant period of time.
The advances made by nineteenth-century mathematicians and astronomers with respect to celestial mechanics set the stage for further developments in the twentieth century. Poincaré's work, for instance, anticipated the modern idea of chaotic motion—or chaos theory—in which for some initial conditions the future state of a system becomes unpredictable within an allowable range.
SHERRI CHASIN CALVO
Arnold, V. I., ed. Mathematical Aspects of Classical and Celestial Mechanics. New York: Springer-Verlag, 1993.
Collins, George W., II. The Foundations of Celestial Mechanics. Tucson, AZ: Pachart Pub. House, 1989.
Poincaré, Henri. New Methods of Celestial Mechanics. Edited and introduced by Daniel L. Goroff. Woodbury, NY: American Institute of Physics, 1993.
Roy, Archie E. and Bonnie A. Steves, eds. From Newton to Chaos: Modern Techniques for Understanding and Coping with Chaos in n-body Dynamical Systems. New York: Plenum Press, 1995.
Sternberg, Shlomo. Celestial Mechanics. New York: W. A. Benjamin, 1969. | 0.887684 | 4.009496 |
Japan asteroid probe makes ‘tantalizing’ solar system discoveries
An unmanned Japanese spacecraft orbiting an asteroid has made surprising discoveries that scientists say will improve understanding about the origin’s of the Earth’s water and help search for life in other solar systems.
Scientists working on Japan’s Hayabusa 2 space mission said that by using a wide range of cameras and instruments to collect images and data about the near-Earth asteroid Ryugu, they had made some “tantalizing discoveries.”
“The primary one being the amount of water, or lack of it, Ryugu seems to possess,” said Seiji Sugita of the University of Tokyo’s Department of Earth and Planetary Science in a press statement as the mission released its initial findings.
“It’s far dryer than we expected, and given Ryugu is quite young (by asteroid standards) at around 100 million years old, this suggests its parent body was much largely devoid of water too,” Sugita added.
The finding is significant, he said, because of all of Earth’s water is thought to have come came from local asteroids, distant comets and the nebula or dust cloud that became our sun.
“The presence of dry asteroids in the asteroid belt would change models used to describe the chemical composition of the early solar system,” he added.
The discovery also has implication for finding extraterrestrial life. “There are uncountably many solar systems out there and the search for life beyond ours needs direction,” Sugita said. “Our findings can refine models that could help limit which kinds of solar systems the search for life should target.”
The mission’s three initial papers published in the journal Science on Tuesday described the mass, size, shape, density, spin and geological properties of the asteroid, a porous “pile of rubble” shaped like a spinning top.
The Japanese space agency, JAXA, research has also benefited from cooperation with NASA, which has its own probe, OSIRIS-REx, exploring a different asteroid known as Bennu.
NASA and JAXA share data from their respective missions and this cooperation has thrown up a further surprise.
Both Bennu and Ryugu are extremely dark, spinning-top shaped asteroids that are covered in large boulders, but the latest findings show that Ryugu is a lot drier.
Researchers had expected the two asteroids to have similar levels of water, but the discrepancy has opened up new avenues for future research.
“Thanks to the parallel missions of Hayabusa2 and OSIRIS-REx, we can finally address the question of how these two asteroids came to be,” Sugita said. “That Bennu and Ryugu may be siblings yet exhibit some strikingly different traits implies there must be many exciting and mysterious astronomical processes we have yet to explore.”
Other scientists shared Sugita’s optimism. “It seems that the asteroid formed as a spinning rubble pile from a previous generation of asteroidal parent bodies, and that those parent bodies had undergone thermal or shock metamorphism,” said John Bridges from the space research center at UK’s University of Leicester.
“This is far from the old stereotype of a potato-shaped, inert and perhaps rather dull, gray asteroid,” he added. “Ryugu shows that asteroids have recorded an incredibly rich history.”
Some scientists echoed Sugita’s initial reaction to the discovery of the asteroid’s lack of water, which he surmised by saying, “what felt limiting is now enlightening.”
Matthew Genge, an earth and planetary scientist from Imperial College London, said Hayabusa 2 had aimed to be the first to sample a C-type asteroid rich in water and carbon-rich objects because they are thought to preserve the best record of the earliest stages of the solar system.
He added that Ryugu appeared to be a type of asteroid that had had its history of the early solar system “overwritten” by a heating experience.
“It’s like mounting an expedition to find the world’s largest elephant, and instead finding the world’s smallest,” he said. “Not what you expected, but perhaps just as valuable. How did that elephant become so small?”
“Understanding how and why asteroids lose water is… a very important question in understanding how rocky planets become habitable,” he added.
In February, Hayabusa 2 touched down on the surface of the asteroid and fired a “bullet” into its surface in order to disturb material which was then collected by a “sample horn” on the underside of the probe.
These samples will be analyzed when the craft returns to Earth by the end of 2020.
“When we bring back the samples to Earth, we will know the answer. The greatest news is that we have already obtained the samples in the spacecraft. We are very excited about this,” Sugita said. | 0.848755 | 3.358545 |
Allright, to start off with, I absolutely love this asteroid. She’s nuts, in the best kind of way. And I can’t think of a better guide for us right now.
The Astronomy– 3753 Cruithne is a Q-type, Aten asteroid in orbit around the Sun in 1:1 orbital resonance with Earth, making it a co-orbital object. It is an asteroid that, relative to Earth, orbits in a bean-shaped orbit that ultimately effectively describes a horseshoe, and that can transition into a quasi-satellite orbit. It has been incorrectly called “Earth’s second moon”. Cruithne does not orbit Earth and at times it is on the other side of the Sun. Its orbit takes it inside the orbit of Mercury and outside the orbit of Mars. Cruithne orbits the Sun in about 1 year but it takes 770 years for the series to complete a horseshoe-shaped movement around the Earth.
The Myth(?)– The Cruthin were a people of early Ireland, who occupied parts of the present day Counties of Antrim, Laois, Galway, Londonderry and Down in the early medieval period.
The Cruthin comprised a number of túatha, including the Dál nAraidi in southern Antrim and the Uí Echach Cobo in western Down. Early sources preserve a distinction between the Cruthin and the Ulaid, who gave their name to the province of Ulster, although the Dál nAraide claimed in their genealogies to be na fir Ulaid, “the true Ulaid”. The Loígis, who gave their name to County Laois in Leinster, and the Sogain of Connacht are also claimed as Cruthin in early Irish genealogies.
By the late 8th century, the Dál nAraidi had secured their over-kingship of the Cruthin and their name replaced that of the Cruthin. Early Irish writers used the name Cruthin to refer to both the north-eastern Irish group and to the Picts of Scotland. Likewise, the Scottish Gaelic word for a Pict is Cruithenor Cruithneach, and for Pictland is Cruithentúath. It has thus been suggested that the Cruthin and Picts were the same people or were in some way linked. Professor T. F. O’Rahilly proposed that the Qritani/Pritani were the first Celts to inhabit Great Britain and Ireland and describes them as “the earliest inhabitants of these islands to whom a name can be assigned”. It has also been suggested that Cruthin was a name used to refer to all the Britons who were not conquered by the Romans – those who lived outside Roman Britain, north of Hadrian’s Wall. Other scholars disagree, pointing out that althoughCruthin was used to translate Picti into Irish, Picti was never used to translate Cruthin into Latin. Professor Dáibhí Ó Cróinín believes that the “notion that the Cruthin were ‘Irish Picts’ and were closely connected with the Picts of Scotland is quite mistaken” while Professor Kenneth H. Jackson has said that the Cruthin “were not Picts, had no connection with the Picts, linguistic or otherwise, and are never called Picti by Irish writers”. The Cruthin cannot be distinguished from their neighbors by archaeology. The records show that the Cruthin bore Irish names, spoke Irish and followed the Irish derbfine system of inheritance rather than the matrilineal system sometimes attributed to the Picts. It is suggested that Cruthin was not what the people called themselves, but was what their neighbors called them.
Why She Matters– Okay, so… Even though the grand high source of wisdom that is Wikipedia seems to shatter the connection to the Picts and the matriarchal influence, almost all sources on the astrology of this really fascinating asteroid seem to work on that assumption. Yes, I know this opens up the door to the criticisms (sometimes extremely valid) of the field as a whole, but one of the great secrets of Astrology (and Religion. Oh, Quantum Physics too. Well, at least our understanding of them) is that the more you believe something, and the more you expect it to be or act a certain way, the more it does; right up until the moment it doesn’t. Belief is power. And that is an interesting point to make on this particular one, as from a heliocentric perspective, it has a very boring orbit, with medium eccentricity, but when veiwed from our perspective on Earth, the picture changes significantly, becoming a crazy, potato-shaped orbit, and coming close enough to be considered a “second moon”. So I would posit that this one deals with perception and perspective, specifically the view from the outside, not particularly one that is from the self. I have also found that this asteroid has quite a lot to do with matters of where one feels truly at home, somewhere where one can find a community that understands the native. Mark Andrew Holmes expounds, saying that Cruithne indicates sense of connectedness to ethnic, regional or racial roots or to the land or earth; ethnic or racial pride; environmentalism; clinging to core identity; stigma.. Australian astrologer Heather Cameron links it to putting effort into being alluring; acting too good for someone. Others link it to brands, tattoos or piercing. There may also be something to do with a connection to Druidry, natural energies and mysticism of that type.
To find out where she shows up in your chart, go to astro.com, put in your birth details and in the extended options, all the way at the bottom, there will be a menu of additional objects. Under that is a blank space where you can enter the number 3753, for Cruithne. Once you have it entered, generate the chart! Where does Cruithne affect your life? Post it below in the comments! | 0.824247 | 3.212886 |
Planets Could Be Orbiting Black Holes, Calculations Show Possibility of Bizarre Worlds
Theoreticians in two fields defied the received wisdom that planets only orbit stars like the sun. They proposed the possibility of thousands of planets around a supermassive black hole.
“With the right conditions, planets could be formed even in harsh environments, such as around a black hole,” says Keiichi Wada, a professor at Kagoshima University researching active galactic nuclei, luminous objects energized by black holes.
According to the latest theories, planets are formed from fluffy dust aggregates in a protoplanetary disk around a young star. But young stars are not the only objects that possess dust disks. In a novel approach, the researchers focused on heavy disks around supermassive black holes in the nuclei of galaxies.
“Our calculations show that tens of thousands of planets with 10 times the mass of the Earth could be formed around 10 light-years from a black hole,” says Eiichiro Kokubo, a professor at the National Astronomical Observatory of Japan who studies planet formation. “Around black holes, there might exist planetary systems of astonishing scale.”
Some supermassive black holes have large amounts of matter around them in the form of a heavy, dense disk. A disk can contain as much dust as 100,000 times the mass of the sun. This is 1 billion times the dust mass of a protoplanetary disk.
In a low temperature region of a protoplanetary disk, dust grains with ice mantles stick together and evolve into fluffy aggregates. A dust disk around a black hole is so dense that the intense radiation from the central region is blocked and low temperature regions are formed. The researchers applied the planet formation theory to circumnuclear disks and found that planets could form over several hundred million years.
Currently, there are no techniques to detect these planets around black holes. However, the researchers expect this study to open a new field of astronomy.
More information: Keiichi Wada, et al. Planet Formation around Super Massive Black Holes in the Active Galactic Nuclei. Astrophysical Journal. arxiv.org/abs/1909.06748
Journal information: Astrophysical Journal | 0.901263 | 3.653772 |
One of the best things about Cassini is that its on-board science instruments can be fine-tuned. The Cosmic Dust Analyzer's (CDA) science team, in Germany, decided to adjust the instrument's settings this week. Based on their experience during the previous "proximal" passages between Saturn's rings and atmosphere, they created a string of 39 commands that would set the instrument to make the best possible observations during the next proximal plunge, coming up on June 29. Details about this direct-sensing instrument may be found here: https://go.nasa.gov/29COVlu.
The commands were designed to accomplish several things. First, they would adjust voltages on the instrument's internal grids, so the instrument could focus on making spectral measurements of the particles it ingests. Also, the instrument would articulate its aperture to the necessary angle. Test pulses would confirm that the instrument's amplifiers were in the necessary ranges of sensitivity. The commands would also set the instrument's data-collection rate to 4 kilobits per second, thus making sure all ring-particle impacts would be sensed.
Wednesday, June 21 (DOY 172)
Writers, vloggers, photographers, educators, students, artists and others who use social media to engage specific audiences are encouraged to apply for special access to Cassini's Grand Finale event in mid-September. Details are available here: /news/13075/witness-cassinis-finale-at-saturn-live-from-jpl.
Thursday, June 22 (DOY 173)
The Composite Infrared Spectrometer (CIRS) turned and looked at Saturn's large icy moon Dione for 3.5 hours today. The Imaging Science Subsystem (ISS), the Visible and Infrared Mapping Spectrometer (VIMS), and the Ultraviolet Imaging Spectrograph (UVIS) – all the other Optical Remote-Sensing (ORS) instruments – rode along to make observations as well. CIRS's goal was to measure Dione's surface emissivity at thermal-infrared wavelengths, which hold clues to the composition and structure of that moon's regolith.
A summertime view of Saturn’s largest moon Titan was selected as today's Astronomy Picture of the Day: https://apod.nasa.gov/apod/ap170622.html.
Friday, June 23 (DOY 174)
Beginning late today, the spacecraft trained its High-Gain Antenna dish on the distant Earth. It then accurately tracked our planet for a total of 28 hours. Accordingly, the Radio Science Subsystem (RSS) team had Cassini power on its S-band (2 GHz) and Ka-band (32 GHz) radio transmitters, which directed their beams of energy out the HGA along with the main communications beam at X-band (8 GHz). The result was a high-precision measurement of Saturn's gravitation, which will be analyzed to reveal deviations from spherical symmetry. This in turn will show how the atmosphere's density varies with depth, and how surface winds influence lower layers in Saturn. The mass of the ring system can also be determined. Cassini must be very close to Saturn to feel the weakest gravity perturbations, and this is one reason why the current “Grand Finale” orbits are unique and important. While keeping the HGA pointed to Earth, prior to periapsis passage the spacecraft rolled to an attitude that also placed the Cosmic Dust Analyzer (CDA) in a favorable position to sample any stray ring particles.
As if gravity measurement and CDA observations weren't enough surrounding today's periapsis passage, the continuous radio signals from Cassini also probed Saturn's rings twice: once looking from inside the rings outward towards Earth (occultations with this geometry have never been attempted before), and then a few hours later from farther behind the planet (this is the "standard" RSS occultation geometry, which is also highly valuable).
These observations provided for characterization of ring asymmetry due to waves that are known to permeate the A and B rings, caused by phenomena such as resonant interaction with satellites and Saturn’s interior structure. Measurements of the rings by RSS and CDA, along with data from the optical instruments, also provide data for scientists to more accurately determine the rings' age.
Saturday, June 24 (DOY 175)
CIRS observed the dark side of Saturn's A ring at far-infrared wavelengths for five hours today, with the other ORS instruments riding along. In addition to studying ring-particle compositions, the observation was part of a campaign to compare the spectral properties of ices among different regions of Saturn’s rings and icy moons.
Cassini and Titan happened to come close to one another today, to a distance about the same as that from Earth to our own Moon. Starting today, ISS performed a total of 13.6 hours of high priority observations to study Titan’s clouds, which are of particular interest as northern summer sets in there; CIRS and VIMS rode along. Next, ISS and VIMS rode along while CIRS took control for 4.4 hours and scanned Titan’s northern hemisphere, mapping its temperature, and the atmosphere's gas concentrations.
In between Titan observations, UVIS turned towards Saturn and observed two stellar occultations, totaling 5.2 hours. Epsilon Orionis and then Zeta Orionis went behind Saturn’s atmosphere and then re-emerged. These occultation observations mapped the temperature and chemical constituents in Saturn's upper atmosphere and thermosphere.
Sunday, June 25 (DOY 176)
This week’s Titan observing wrapped up today with its final 4.3 hours devoted to observing clouds on the planet-like moon; VIMS rode along.
Monday, June 26 (DOY 177)
ISS turned and spent 7.7 hours observing Saturn's irregular moon Bebhionn, an object of about six kilometers diameter, which orbits Saturn in an inclined ellipse that reaches as far as 25.1 million km from the planet. It might have a binary or contact-binary nature. Bebhionn was named after the goddess of birth in early Irish mythology.
UVIS spent 4.7 hours observing the occultation of the blue star Kappa Orionis as it drifted behind Saturn's rings. This occultation was of particular interest because the point where the star appeared to reverse direction occurred in the B-Ring. This made for an ultra-fine-resolution observation that has not typically been possible until now (during the proximal orbits). Next, CIRS observed the far-infrared spectra of Saturn’s A and B rings, to learn about ring-particle composition.
The flight team held a Command Approval Meeting today for the file of CDA's fine-tuning commands. Representatives from each of the affected spacecraft subsystems and instruments voiced and signed their okays, and the file was approved for radiation to the spacecraft.
An image featured today shows Dawn on Saturn: /resources/17692.
Tuesday, June 27 (DOY 178)
UVIS observed the egress occultation of the bright blue star Beta Canis Majoris, as it rose out of Saturn’s atmosphere. This 1.1-hour stellar occultation mapped temperatures and chemical species in Saturn's thermosphere. Next, VIMS, UVIS, ISS and CIRS observed another stellar occultation by Saturn's rings. This one lasted 10.7 hours while the bright star Alpha Canis Majoris, also known as Sirius, probed the rings' radial structure and further constrained particle-size distributions.
Ten minutes after the Deep Space Network (DSN) station in Australia acquired Cassini's downlink, its 18-kilowatt transmitter was turned on, and the Realtime Operations team sent the approved CDA fine-tuning commands on their way. After a round-trip of 2 hours 31 minutes, telemetry confirmed that the commands had been received and were ready to take effect right before Cassini's eleventh proximal plunge on June 29.
The DSN communicated with and tracked Cassini on 11 occasions this week, using stations in California and Australia. The European Space Agency contributed ground antenna support three times from Australia and Argentina. A total of 58 individual commands were uplinked, and about 1,625 megabytes of science and engineering telemetry data were downlinked and captured at rates as high as 142,201 bits per second.
Cassini is executing its set of 22 Grand Finale Proximal orbits, which have a period of 6.5 days, in a plane inclined 61.9 degrees from the planet's equatorial plane. Each orbit stretches out to an apoapsis altitude of about 1,272,000 km from Saturn, where the spacecraft's planet-relative speed is around 6,000 km/hr. At periapsis, the distance shrinks to about 2,500 km above Saturn's visible atmosphere (by comparison, Saturn is about 120,660 km in diameter), and the speed is around 123,000 km/hr.
The most recent spacecraft tracking and telemetry data were obtained on June 28 using the 70-meter diameter DSN station in Australia. The spacecraft continues to be in an excellent state of health with all of its subsystems operating normally except for the instrument issues described at http://saturn.jpl.nasa.gov/anomalies.
This illustration shows Cassini's path up to mid-day June 27: https://go.nasa.gov/2qCHH5s.
The countdown clock in Mission Control shows 79 days until the end of the Mission.
This page offers all the details of the Mission's ending: <https://saturn.jpl.nasa.gov/mission/grand-finale/overview/>
Milestones spanning the whole orbital tour are listed here:
Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
To unsubscribe from Cassini Spacecraft Updates or to subscribe with a different email address, visit:
For comments and questions, please contact Cassini Public Engagement at: | 0.813324 | 3.118026 |
Mysterious Slab May Be Ancient Sun/Moondial Oct 17, 2014 22:35:10 GMT -5
Post by Joanna on Oct 17, 2014 22:35:10 GMT -5
Ancient Slab May Be Sundial/Moondial
A strange slab of rock discovered in Russia more than 20 years ago appears to be a combination sundial and moondial from the Bronze Age, a new study finds. The slab is marked with round divots arranged in a circle, and an astronomical analysis suggests that these markings coincide with heavenly events, including sunrises and moonrises. The sundial might be "evidence of attempts of ancient researchers to understand patterns of apparent motion of luminaries and the nature of time," study researcher Larisa Vodolazhskaya of the Archaeoastronomical Research Center at Southern Federal University in Russia told Live Science in an email.
Ancient instrument. Last year, Vodolazhskaya and her colleagues analyzed a different Bronze Age sundial, this one found in Ukraine, and discovered it to be a sophisticated instrument for measuring the hours. The work caught the eye of archaeologists in Rostov, Russia, who knew of a similar-looking artifact found in that area in 1991. That slab had been lying in a museum in Rostov ever since its discovery and had never been thoroughly studied. The Rostov slab was found over the grave of a man of about 50 and dates back to the 12th century BC, similar in age to the one found in Ukraine. Sundials from this era have also been discovered in ancient Egypt, including in the tomb of the Pharaoh Seti I.
By studying the geometry of the Rostov slab, Vodolazhskaya and her colleagues discovered the carved circles, which are arranged in a pattern spanning about 9 inches in diameter, correspond with the sunrises at equinoxes (days of the year when night and day are equal in length) and solstices (days of the year when day or night are at their longest).
The Bronze Age people who created the sundial weren't interested in only the sun. The circles that didn't correspond to solar movements were linked to lunar wanderings. Because of the angle of the moon's orbit, our lone satellite goes through an 18.6-year cycle. During this cycle, when the moon rises, its position shifts from southerly to northerly and its movements across the sky are relatively high and low. The Rostov slab tracks these movements with circular carvings indicating the southernmost and northernmost moonrises of these "low" and "high" moons.
Savvy civilization. The slab was found at a Bronze Age Srubna or Srubnaya site, a culture which flourished on the steppes between the Ural Mountains and Ukraine's Dneiper River. The Srubna people may have used the sun/moondial to time their annual rituals or to organize their work. Or, Vodolazhskaya said, the artifact may be the work of Bronze Age scientists. "One cannot exclude a purely research appointment of such instruments. … In ancient times, people were just as inquisitive as modern physicists and astronomers," Vodolazhskaya said.
In combination with the Ukraine sundial and other Bronze Age artifacts, the find suggests the people in the Northern Black Sea region were astronomically savvy, Vodolazhskaya said, with technology on par with what was seen in ancient Egypt around the same time. The new study has not yet been peer-reviewed
Source: Stephanie Pappas, LiveScience, October 15, 2014. | 0.814437 | 3.112962 |
An important historical question related to Hubble's momentous 1929 discovery concerns its relationship to contemporary work in the general theory of relativity. That the invention of cosmological solutions based on general relativity occurred at precisely the same time that Slipher and Humason were beginning to detect large systematic nebular red shifts was simply a coincidence. The two developments were largely independent. The advances in telescopic instrumentation that made the nebular research possible followed from improvements in technology and the increased financial support for astronomy in America from government and philanthropic foundations. General relativity, by contrast, developed within a central European scientific culture, with a strong emphasis on advanced mathematics and pure theory. In retrospect, it seems that Hubble's relation would have been detected inevitably with improvements in the size, quality, and location of observing facilities; it could well have been discovered earlier or later. It is nonetheless a fact that throughout the decade leading up to the 1929 breakthrough, speculation about the red shifts was often tied in with theorizing in relativistic cosmology. Hubble was aware of de Sitter's writings and explicitly cited the de Sitter effect in the 1929 paper. It was also the case that general relativists such as Eddington were among the first to explore the implications of Hubble's discovery in terms of dynamical world solutions.
Although the observational discoveries of the period were independent of theoretical work in relativistic cosmology, the converse cannot be said to be true. At the time he wrote his 1917 paper de Sitter was aware of Slipher's findings through a report on them published by Eddington in the Monthly Notices of the Royal Astronomical Society. A more detailed description of these findings was presented by Eddington in his 1920 book Space, Time and Gravitation, where he wrote, "The motions in the line-of-sight of a number of nebulae have been determined, chiefly by Professor Slipher. The data are not so ample as we should like; but there is no doubt that large receding motions greatly preponderate" (161) It is significant that Friedmann, in his 1922 paper, cited both de Sitter's paper and the French translation of Eddington's book. The very high red shifts reported in these sources certainly would have raised doubts about Einstein's assumption of a static universe and suggested the possibility of dynamical cosmological solutions of the field equations. It is also known that Slipher's findings were reported in 1923 in a widely read Russian scientific magazine published in Petrograd, Friedmann's home city. The case of Friedmann is interesting because he, more than Lemaitre, is often seen as someone who was uninfluenced by observation and whose geometric solutions represented a prescient achievement of pure theory. It should be noted that one of the key assumptions of his relativistic solution, the dependence of the scale function only on the time, was later found to hold for the universe as a whole. The relativists were not working in complete isolation from observational work, although it is nonetheless the case that the emergence of dynamic theoretical solutions at precisely this time was a highly unusual event of which there are few parallels in the history of science.
In the work during the 1920s on relativistic cosmology, no one, with the possible exception of Carl Wirtz and Howard Robertson, had predicted a linear red shift-distance relation or made an attempt to configure the spectroscopic data to what was then known about distances to nebulae. The very status of the nebulae, much less their distances, was only being clarified during this period. To understand why an expansionist interpretation of the universe was not generally considered before 1930, it is also important to understand the intellectual atmosphere of the 1920s. What most struck scientists of the period about the spectroscopic data was the fact that it might well consist of a verification of Einstein's radical new theory of gravity. It was this theory and its revolutionary implications that excited scientists. The nebular spectral shifts seemed to offer clear and unequivocal evidence for general relativity, much clearer than the fine discriminations involved in interpreting eclipse observations. The focus of scientific attention was on the meaning of the observational data for general relativity and not on the possible fact of universal expansion.
After 1929, when expansion seemed to be the most probable interpretation of Hubble's law, the general relativists were able to turn to the until then neglected dynamical solutions of Friedmann and Lemaitre. It is worth noting that Hubble regarded the concept of an expanding universe as a notion rooted in the general theory of relativity. In retrospect, it seems clear that if one accepts the red shifts as due to real velocities—and this is the most obvious explanation—then it follows that the universe is expanding, a conclusion that requires for its warrant no particular theory of gravity, much less the formidable machinery of general relativity. In 1933 Eddington wrote that the theorists had for the past 15 years been expecting something "sensational" along the lines of Hubble's discovery (and there could be no finding more sensational than Hubble's) and seemed almost to be taking some credit on behalf of the theorists for the discoveries coming from the great American observatories.
There seems little doubt that Hubble was concerned with emphasizing the purely phenomenological character of his result: its independence from contemporary theorizing in mathematical cosmology. To concede that the red shifts were recessional velocities was in Hubble's view to accept an underlying theoretical approach to cosmology and possibly to suppose that an achievement of skilled observation owed something to the "invented universe" of the theorist. As Hubble (1936, vii-viii) emphasized, "the conquest of the Realm of the Nebulae is an achievement of great telescopes."
Was this article helpful? | 0.817342 | 4.010758 |
For millennia, scientists have pondered the mystery of life – namely, what goes into making it? According to most ancient cultures, life and all existence was made up of the basic elements of nature – i.e. Earth, Air, Wind, Water, and Fire. However, in time, many philosophers began to put forth the notion that all things were composed of tiny, indivisible things that could neither be created nor destroyed (i.e. particles).
However, this was a largely philosophical notion, and it was not until the emergence of atomic theory and modern chemistry that scientists began to postulate that particles, when taken in combination, produced the basic building blocks of all things. Molecules, they called them, taken from the Latin “moles” (which means “mass” or “barrier”). But used in the context of modern particle theory, the term refers to small units of mass.
By its classical definition, a molecule is the smallest particle of a substance that retains the chemical and physical properties of that substance. They are composed of two or more atoms, a group of like or different atoms held together by chemical forces.
It may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). As components of matter, molecules are common in organic substances (and therefore biochemistry) and are what allow for life-giving elements, like liquid water and breathable atmospheres.
Types of Bonds:
Molecules are held together by one of two types of bonds – covalent bonds or ionic bonds. A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. And the bond they form, which is the result of a stable balance of attractive and repulsive forces between atoms, is known as covalent bonding.
Ionic bonding, by contrast, is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions. The ions involved in this kind of bond are atoms that have lost one or more electrons (called cations), and those that have gained one or more electrons (called anions). In contrast to covalence, this transfer is termed electrovalance.
In the simplest of forms, covelant bonds take place between a metal atom (as the cation) and a nonmetal atom (the anion), leading to compounds like Sodium Chloride (NaCl) or Iron Oxide (Fe²O³) – aka. salt and rust. However, more complex arrangements can be made too, such as ammonium (NH4+) or hydrocarbons like methane (CH4) and ethane (H³CCH³).
History of Study
Historically, molecular theory and atomic theory are intertwined. The first recorded mention of matter being made up of “discreet units” began in ancient India where practitioners of Jainism espoused the notion that all things were composed of small indivisible elements that combined to form more complex objects.
In ancient Greece, philosophers Leucippus and Democritus coined the term “atomos” when referring to the “smallest indivisible parts of matter”, from which we derive the modern term atom.
Then in 1661, naturalist Robert Boyle argued in a treatise on chemistry – titled “The Sceptical Chymist“- that matter was composed of various combinations of “corpuscules”, rather than earth, air, wind, water and fire. However. these observations were confined to the field of philosophy.
It was not until the late 18th and early 19th century when Antoine Lavoisier’s Law of Conservation of Mass and Dalton’s Law of Multiple Proportions brought atoms and molecules into the field of hard science. The former proposed that elements are basic substances that cannot be broken down further while the latter proposed that each element consists of a single, unique type, of atom and that these can join together to form chemical compounds.
A further boon came in 1865 when Johann Josef Loschmidt measured the size of the molecules that make up air, thus giving a sense of scale to molecules. The invention of the Scanning Tunneling Microscope (STM) in 1981 allowed for atoms and molecules to be observed directly for the first time as well.
Today, our concept of molecules is being refined further thanks to ongoing research in the fields of quantum physics, organic chemistry and biochemistry. And when it comes to the search for life on other worlds, an understanding of what organic molecules need in order to emerge from the combination of chemical building blocks, is essential.
We have written many interesting articles about molecules for Universe Today. Here’s Molecules From Space May Have Affected Life On Earth, Prebiotic Molecules May Form in Exoplanet Atmospheres, Organic Molecules Found Outside our Solar System, ‘Ultimate’ Prebiotic Molecules Found in Interstellar Space.
For more information, check out Encyclopaedia Britannica‘s page on molecules.
We’ve also recorded an entire episode of Astronomy Cast all about Molecules in Space. Listen here, Episode 116: Molecules in Space. | 0.86997 | 3.385165 |
Authors: Jade Checlair, Kristen Menou, Dorian S. Abbot
First Author’s Institution: Department of the Geophysical Sciences, University of Chicago
Status: Accepted at ApJ, open access
Like most of the main sequence stars, the Sun brightened as it aged due to the gravitational contrast from hydrogen fusion. About 4 billion years ago, the Sun shined only about 70 percent as bright as today. Astronomers Carl Sagan and George Mullen raised the issue that according to the irradiation from the fainter young Sun, Earth should have been in a fully frozen state about 4 billion years ago, the so-called snowball Earth. However, if the Earth was truly in a snowball state, it would have been very difficult to escape the global glaciation, as we will discuss later in the article. The geological evidence, such as sedimentary rocks, also tells us that the Earth had liquid oceans over its evolution history. Carl Sagan and George Mullen proposed that a different atmospheric composition with more greenhouse gases, like ammonia or carbon-dioxide, would help to warm up the early Earth, preventing it from being locked in a global glaciation state.
An interesting complication is that the climate is not always the only stable state. Keeping all the conditions unchanged, a close to current climate can be tipped into a snowball state when the solar insolation slightly decreases. This may be easily understood by simply considering the albedo (reflectivity) of the ice. Ice has a much higher albedo (about 0.6) than seawater (about 0.2), so a snowball Earth is able to reflect much more radiation and maintain the temperature below the freezing point. There is a tipping point as the solar insolation decreases, the climate suddenly transitions to global glaciation, referred as the snowball bifurcation. In today’s paper, the authors investigate the snowball bifurcation on habitable tidally-locked planets compared to Earth.
The authors first apply a simple 1D energy balance model, which allows us to derive analytical solutions and understand the underlying mechanisms. The model describes the balance between solar insolation, outgoing radiation, and the heat transport. One can obtain the relation for the solar insolation as a function of the ice latitude (the latitude where water begins to freeze), as shown in Figure 1. The y-axis is the sine of the ice latitude, so 1 means ice-free and 0 means fully covered by ice. The solid line shows the stable solution and the dashed line represents the unstable solution. Depending on the direction of the external perturbation (heating or cooling), the unstable point will jump to the ice-free state (top line) or the snowball state (bottom line). For example, for any point on the dashed line, when insolation drops a little, the ice latitude correspondingly moves toward the equator, but it has to move all the way down to the bottom line to reach a steady state. This is due to the positive feedback of ice-ocean albedo contrast: Due to the higher albedo of ice, once in the unstable region, decreasing insolation leads to more ice built up and reflects more sunlight, and hence in turn forming more ice. The joint of the stable and unstable solution marks the beginning of this bifurcation. In the bifurcation region, which steady state the climate will end up is determined by the initial condition.
Many habitable planets, like Proxima Centauri b and TRAPPIST-1 e, f, are found around M-dwarf stars since they are the most common stellar types. The potential climate state on these worlds is naturally of great interest. Working out the same exercise to the tidally locked planets, the authors find that due to the geometry of insolation (the position of the star is fixed), it is somehow more difficult to have a snowball bifurcation than Earth. Figure 2 shows the same solution from the energy balance model but for a tidally-locked planet. The ice latitude change is smooth and there is no bifurcation. Only when the heat transport is very strong, there will be snowball bifurcation (not shown).
The authors testify this analysis by running simulations including the thermodynamics of sea ice and clouds. The results confirm the energy balance model. One can see that opposed to Earth, the steady state on a tidally-locked planet almost does not depend on the initial condition (the small deviation in the purple shaded area in Figure 3. is found due to artifact). In addition, clouds tend to form near the sub-stellar point (Figure 4). Because clouds have a higher albedo than seawater, it reduces the ice-sea albedo contrast, making the system more stable and less plausible to have snowball bifurcation.
This work implies that we have a higher chance of finding “actual habitable worlds” planets for tidally locked exoplanets, since they are unlikely to be locked into a snowball state. An interesting future work would be including silicate weathering and investigating the case of planets with larger orbits and not being fully tidally locked. | 0.805843 | 3.957001 |
On a day when NASA, Roscosmos and the rest of the world breathed a collective sigh of relief as a Soyuz MS-10 spacecraft and its crew returned safely to Earth after an aborted launch, news emerges of a leading Russian astronomer who believes we are not alone in the universe. How soon can one of these civilizations get here with a replacement?
“I admit the existence of extraterrestrial intelligent civilizations.”
Dmitry Bisikalo is the director of the Astronomy Institute at the Russian Academy of Sciences in Moscow and a specialist in the gas dynamics of interacting binary stars and accretion disks. How does this qualify him to proclaim that aliens exist? It doesn’t, but his research includes studying the components of a star’s gases and those of any exoplanets around them. As he told Sputnik News, those gases – especially oxygen, ozone and methane – are biological markers that can be indicators of civilizations making things and polluting their atmospheres just like we do.
“It is important to note that many biomarkers appear in the ultraviolet region of the spectrum, which will be studied by the Spektr-UF space observatory, which will be launched into orbit in 2024.”
Spoken like a true bureaucratic astronomer making sure he has a job in a few years by plugging the Spektr-UV or World Space Observatory-Ultraviolet (WSO-UV) — a proposed joint (Russia, Spain, Germany, Ukraine and Kazakhstan) space telescope that has been planned since 2007 and needed well before 2024 with the gyroscope problems currently being experienced by the Hubble space telescope. While waiting for the launch, Bisikalo is also generating interest in both astronomy and space travel with comments like his recent one.
“After all, if our civilization exists, by analogy there may be others, and probably many of them.”
Bisikalo is channeling American astronomer Frank Drake and his famous equation putting the probability of the existence of alien civilizations at ‘high’. Unfortunately, like Drake, Bisikalo is dealing in possibilities, not proofs, and he brings in his own theory as to why we haven’t seen any extraterrestrials yet.
“[They] do not want to contact.”
Of course they don’t. We’re big polluters just like themselves and are on our way to destroying our planet, just as they may have. All they need to do is sit quietly and wait.
“For example, until the beginning of the twentieth century, our civilization did not radiate anything. Now the Earth is full of electronic signals at different intervals, but the general tendency is to reduce losses and consequently decrease signal level.”
“Decrease signal level.” In other words, die off. That may be what happens (spoiler alert) to all civilizations before they can change their ways or develop the technology to go somewhere else.
Based on the Soyuz incident today and the previous and still unsolved manmade hole found in the Soyuz capsule currently docked at the International Space Station, our signal level may be decreasing before we can leave too.
Bisikalo is still confident he and the rest of us will be around for the launch and usage of the Spektr-UV space telescope.
“Probably with the help of this infrared space telescope we will see something really interesting.”
Let’s hope it’s a starship delivering reliable space vehicles. | 0.845159 | 3.014082 |
NASA’s successful test flight of Orion on Dec. 5th heralds a renewed capability to send astronauts into deep space. A paper just published in the journal Space Weather, however, points out a growing peril to future deep space explorers: cosmic rays. The title of the article, penned by Nathan Schwadron of the University of New Hampshire and colleagues from seven other institutions, asks the provocative question, “Does the worsening galactic cosmic ray environment preclude manned deep space exploration?” Using data from a cosmic ray telescope onboard NASA’s Lunar Reconnaissance Orbiter, they conclude that while increasing fluxes of cosmic rays “are not a show stopper for long duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic radiation remains a significant and worsening factor that limits mission durations.” This figure from their paper shows the number of days a 30 year old astronaut can spend in interplanetary space before they reach their career limit in radiation exposure:
According to the plot, in the year 2014, a 30 year old male flying in a spaceship with 10 g/cm2 of aluminum shielding could spend approximately 700 days in deep space before they reach their radiation dose limit. The same astronaut in the early 1990s could have spent 1000 days in space.
What’s going on? Cosmic rays are intensifying. Galactic cosmic rays are a mixture of high-energy photons and subatomic particles accelerated to near-light speed by violent events such as supernova explosions. Astronauts are protected from cosmic rays in part by the sun: solar magnetic fields and the solar wind combine to create a porous ‘shield’ that fends off energetic particles from outside the solar system. The problem is, as the authors note, “The sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the Space Age. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of cosmic rays in the Space Age.”
The shielding action of the sun is strongest during solar maximum and weakest during solar minimum–hence the 11-year rhythm of the mission duration plot. At the moment we are experiencing Solar Max, which should be a good time for astronauts to fly–but it’s not a good time. The solar maximum of 2011-2014 is the weakest in a century, allowing unusual numbers of cosmic rays to penetrate the solar system.
This situation could become even worse if, as some researchers suspect, the sun is entering a long-term phase of the solar cycle characterized by relatively weak maxima and deep, extended minima. In such a future, feeble solar magnetic fields would do an extra-poor job keeping cosmic rays at bay, further reducing the number of days astronauts can travel far from Earth.
To learn more about this interesting research, read the complete article in the online edition of Space Weather. | 0.874228 | 3.96143 |
Gamma rays are the most energetic type of light, packing a punch strong enough to pierce through metal or concrete barriers. More energetic than X-rays, they are born in the chaos of exploding stars, the annihilation of electrons and the decay of radioactive atoms. And today, medical scientists have a fine enough control of them to use them for surgery. Here are seven amazing facts about these powerful photons. [Read the rest at Symmetry Magazine…]
Granulation on the surface of the Sun, created by rising bubbles of hot plasma. Fluctuations in these bubbles can be measured on distant stars, which provides a way to calculate the stars’ surface gravity. [Credit: Hinode JAXA/NASA/PPARC]
I’ve been remiss in blogging at Bowler Hat Science, largely because…well, I’ve been writing too much elsewhere. So, I’m going to try something different: instead of blogging each new article I write in a separate entry, I’ll write a single post summarizing everything in one go.
How I learned to stop worrying and love tolerate the multiverse (Galileo’s Pendulum): My explanation of cosmology involving parallel universes is a response to a piece placing the multiverse in the same category as telepathy. While I’m not a fan of the multiverse concept, I reluctantly accept that it could be a correct description of reality.
An Arguably Unreal Particle Powers All of Your Electronics (Nautilus): Electrons in solids behave differently than their wild cousins. In some materials, the electronic and magnetic properties act as though they arise from particles that are lighter or heavier than electrons, or multiple types of particles with strange spins or electric charges. Are these quasiparticles real?
Kepler finds stars’ flickers reveal the gravity at their surface (Ars Technica): The Kepler observatory’s primary mission was to hunt for exoplanets, but arguably it’s been equally valuable for studying stars. A new study revealed a way to measure a star’s surface gravity by timing short-duration fluctuations — the rippling of hot plasma bubbles on the surface known as granulation (see above image).
Destruction and beauty in a distant galaxy (Galileo’s Pendulum): The giant galaxy M87 has a correspondingly huge black hole at its heart. That black hole in turn generates an enormous jet of matter extending 5,000 light-years, which fluctuates in a way we can see with telescopes. In that way, an engine of destruction shapes its environment and produces a thing of beauty.
The Freaky Celestial Events We See—and the Ones We Don’t (Nautilus): In another faraway galaxy, a black hole destroyed a star, producing a burst of gamma rays that lingered for months. This event is the only one of its kind we’ve yet seen, prompting the question: how do we evaluate events that are unique? How can we estimate how likely they truly are, especially if we’re seeing them from a privileged angle?
This isn’t writing, but after listing two black hole articles in a row, it seems a good time to advertise my Introduction to Black Holes online class in October! Sign up to learn all* about black holes. *All = what I can cover in four hours of class time.
Warp Speed? Not So Fast (Slate): Many articles have appeared over the last year or so profiling a NASA researcher, whose research supposedly could lead to a faster-than-light propulsion system. The problem: very little actual information about his work is known, and what he’s said publicly contradicts what we understand about general relativity and quantum physics.
Any core-collapse supernova—the explosion of a massive star—is by nature powerful, destructive, and rare. The really dramatic supernovas have the extra effect of exploding in a non-spherical way, beaming a lot of their matter and energy along an axis. When Earth is aligned with those beams, we see the supernova as a gamma ray burst (GRB), the brightest of which can be seen from billions of light-years away. (As the name suggests, these events are exceptionally bright in gamma ray light. In fact, they were first discovered by spy satellites monitoring for illicit nuclear tests—which are also marked by heavy gamma ray emission.) Observations of a supernova remnant in our galaxy strongly hint both that it was a GRB, and that it harbors a black hole at its center. That would mean the supernova is the only known GRB in our galaxy, and its black hole is the youngest known—a wonderful double discovery.
While stars like our Sun go gently into that good night, stars more than 25 times more massive explode in violent supernovae. Since stars that big are rare, their explosions are too, so astronomers typically have to do forensic work on supernova remnants in our galaxy. One particular remnant is one the brightest X- and gamma-ray sources around, marking it as a relatively recent explosion. By studying the remnant, astronomers have determined it likely harbors the youngest black hole in the Milky Way, and the original explosion may have been extremely energetic. [Read more…] | 0.836334 | 3.595506 |
NASA’s TESS, or the Transiting Exoplanet Survey Satellite, will launch on Monday aboard a SpaceX Falcon 9 rocket from Cape Canaveral, Florida, if everything goes to plan. People are excited.
The first confirmed planets outside of our own solar system were only discovered around 25 years ago. Since then, missions including Kepler and K2 have found thousands of exoplanets and exoplanet candidates. But many of these were too far away to detail, and the Kepler/K2 mission is slated to end in the next few months, as the Kepler spacecraft will soon run out of fuel. The TESS telescope will be able to pick up where Kepler left off, cataloguing lots of planets around closer stars for followup study.
“Once the TESS survey is done, we’ll have a catalog of some (but not all) of the nearest worlds beyond our solar system,” Harvard astrophysicist Jonathan McDowell said in a tweet. “Later telescopes such as James Webb can then study them in detail.”
The telescope is small, as NASA scientist Jessie Christiansen points out—roughly the size of a little sports car with its solar panels extended, but only a third the weight. It will sweep the sky with its four cameras, looking for planets around the 200,000 stars in the closest 300 light-years around Earth. Like Kepler, it will watch for planets passing in front of the stars they orbit, producing a telltale dimming and brightening effect.
Additionally, astronomers are especially interested in looking for planets around a kind of star you’ve probably heard a lot about recently: red dwarfs. Our dim neighbor Proxima Centauri is such a star, and potentially has a planet in its habitable zone, the place where conditions are ripe for liquid water to exist. So is TRAPPIST-1, which may host two potentially habitable worlds.
Ultimately, the question everyone has is, “Is there an Earth 2.0 out there?” TESS won’t answer that question. Instead, it will give scientists a list of candidates to look more closely at with the James Webb Space Telescope, a long-delayed project currently slated to launch in 2020. Future telescopes like proposed LUVOIR or HabEx might be required to actually spot signatures of life, such as how alien life forms change the composition of their planet’s atmosphere.
Everything appears to be ready for Monday’s launch, and SpaceX reported that the rocket has successfully performed its static fire test.
We’ll be keeping our eyes on the launch and keeping you updated on how things go. | 0.891187 | 3.579909 |
Our brains are wired to seek patterns. We see castles in the clouds, butterflies in inkblots, and faces or even rabbits on the Moon. Amateur astronomers experience this pareidolia when gazing at the vast dot-to-dot tableau of the night sky. We imaginatively sketch figures among the stars, spawning a wealth of cosmic doodles that we call asterisms.
Let’s take a look at some of the asterisms that populate the sky at this time of the year, sticking to those that are noteworthy for the images they’ve evoked.
You’ll find the star-figure known as Jaws in the constellation Virgo, near the border it shares with Corvus. Jaws is one of my favorite asterisms. It’s just beautiful in the field of view with the Sombrero Galaxy (M104) through my 130-mm refractor at 48×. My pencil sketch shows the two as seen through the scope and also outlines the asterism. Jaws represents a skeletal shark whose most prominent feature is a toothy mouth of four stars, the brightest one gold. Its six-star spine curves northeast and is all you can see of the shark’s body, while a solitary star to the west marks the tip of its dorsal fin. Mouth to tail, our finny friend spans 27′. Well-known author Phil Harrington gave Jaws its popular name in his book The Deep Sky: An Introduction.
French amateur Laurent Ferrero keeps an internet list of interesting star groups that he’s noticed during more than 20 years of deep-sky observing. His catalog currently consists of 53 objects, some of which proved to be true open clusters. Among his asterisms, the Eiffel Tower (Ferrero 6) is thus named because its tapered form is reminiscent of this famous cultural icon. In the 130-mm scope at 37×, it’s composed of 16 stars, magnitude 8.2 and fainter, the brightest one deep yellow. The tower is 28′ tall, with its tip pointing south-southwest. The Eiffel Tower is easy to locate by picturing the right triangle that it makes with Zeta (ζ) and Epsilon (ε) Ursae Majoris in the Big Dipper’s handle. Our asterism’s discoverer is also the author of a French-language, five-volume observing guide called Splendeurs du Ciel Profond.
Just 40′ south-southwest of Arcturus in Boötes, we find Napoleon’s Hat (Picot 1). Fulbert Picot, the French amateur astronomer for whom the group is named, also bestowed its apt nickname. Through the 130-mm refractor at 23×, the emperor’s chapeau consists of seven stars ranging from magnitude 9.4 to 10.7, distributed along a bell curve. The brim of the hat is 20′ long and runs northeast to southwest. My 18×50 image-stabilized binoculars capture six of the seven stars, missing only the one at the top of the hat. Ken Hewitt-White, a contributing editor for Sky & Telescope, fittingly thinks this asterism “suggests a caterpillar humped-up in mid crawl.” Ken is probably referring to the caterpillars commonly called inchworms, since most other caterpillars don’t have the inchworm’s looping gait.
Now commonly called the Zigzag, our next asterism was introduced by Phil Harrington in Touring the Universe through Binoculars, a book affectionately known as TUB. Look for the Zigzag about 2° west-southwest of Omega (ω) Herculis. The asterism’s name describes the view through large binoculars, but it’s a wonderful area for dot-to-dot games through any telescope that offers a field of view of at least 1½°. My 105-mm refractor at 28× shows a score of 8th- to 10th-magnitude stars in a switchback, 1.3° chain. It reminds me of the beautiful Chinese dragons carried in parades, its head at the south-southeastern end. Since the tail’s brightest star gleams gold, I think of this as the Golden Dragon. At a similar magnification, the 130-mm scope plucks out more stars and turns the asterism into a flower, as outlined on my pencil sketch. On one occasion, I even fashioned a balloon animal with its stars.
Webb’s Wreath also resides in Hercules, 2.7° south-southwest of Omicron (ο) Herculis. The wreath was first mentioned in the fourth edition (1881) of Thomas William Webb’s observing guide, Celestial Objects for Common Telescopes. Its brightest star, 7th-magnitude HD 164922 (SAO 85678), adorns the wreath’s eastern side. My 130-mm scope at 63× discloses 16 additional stars, magnitudes 10.7 and fainter, outlining an 11′ × 7′ oval that leans northeast and is dented inward at the bright star. Although some skygazers call this asterism the Ruby Ring, I see the ring’s bright gem sparkling with a deep-yellow hue.
In far northeastern Hercules we find an asterism that comes from the fertile imagination of John A. Chiravalle, author of Pattern Asterisms: A New Way to Chart the Stars. Known as the Candle and Holder, Chiravalle thinks of it as the flame that lights Hercules’ way though the dark. This cute asterism sits 4.2° east-northeast of Iota (ι) Herculis, and it’s brightest star is 6th-magnitude HD 165358 (SAO 47173) in the base of the holder. The pattern’s stars are bright enough to see in my 18×50 binoculars, with the candle dangling upside-down in the sky. The sketch shows my interpretation of the Candle and Holder as seen through these binoculars, which is slightly different than Chiravalle’s. Base to flame, the asterism is 1.1° tall, and the star that marks the flame flickers with an appropriately yellow-orange hue.
We’ll find another of Chiravalle’s unique star patterns in Draco, the Dog and Stick, which Chiravalle calls “absolutely remarkable.” Its brightest star is Omega Draconis, the dog’s nose, and the next brightest is yellow-orange 27 Draconis on the back of his head. The asterism shows quite well in the 18×50 binoculars, displaying 24 stars within 1.5°, magnitudes 4.8 to 9.2. Once again, the interpretation on my sketch is a bit different that Chiravalle’s, so feel free to let your own fancy rule.
In 1961, William L. Dutton reported an asterism that he called the Engagement Ring (S&T: Jan. 1961, p. 41). Polaris, the North Star, is the ring’s brilliant diamond, and through my 18×50 binoculars, nine 6th- to 9th-magnitude stars form the band. One has to wonder if the engagement was broken, because the dented band looks as if it was vehemently thrown and damaged in some lovers’ spat. Even the diamond is chipped, as you’ll see if you look at Polaris with a telescope at 50× or more. This little diamond chip is a 9th-magnitude companion star, separated from the diamond by 18″. Overall, the Engagement Ring is about 48′ across.
Our final target is the Ring of the Nibelung (Ferrero 27) in Draco. Ferrero says its name is a “reference to Norse mythology, which says that the dragon Fafnir was the guardian of the cursed ring forged by the Nibelung, the ring that brought misfortune to the knight Siegfried.” Unfortunately, this compact asterism is not a good target for small telescopes. One of the stars looks very faint even in my 10-inch reflector. Nevertheless, this tiny ring is adorable. It’s made up of six stars and appears to be tipped away from us so that we see it as a 1.4′ × 0.6′ oval. The ring’s colorful stars make it an especially tempting target for imagers. Give it a try!
This article originally appeared in print in the June 2017 issue of Sky & Telescope. | 0.888567 | 3.690374 |
Astronomersnow have their best-ever view of the most extreme energy in the cosmos with anew map combining three month's worth of data, a team of scientists said today.
The map isbased on data collected by NASA's Fermi Gamma-ray Space Telescope, which hasscopes and cameras that peer out into the universe ? from within our solarsystem to galaxies billionsof light-years away ? in search of the sources of the highest energyradiation, called gamma rays.
Gamma rayssit on the far left of the electromagnetic, or light, spectrum, with shorterwavelengths and higher energy than ultraviolet light and even X-rays.
The all-skyimage produced by the Fermi team shows us how the cosmos would look if our eyescould detect radiation 150 million times more energetic than visible light. Theview merges observations from Fermi's LargeArea Telescope (LAT) spanning 87 days, from August 4, 2008, to October 30,2008.
"Fermihas given us a deeper and better-resolved view of the gamma-ray sky than anyprevious space mission," said Peter Michelson, the lead scientist for theLAT at Stanford University. "We're watching flares from supermassive blackholes in distant galaxies and seeing pulsars, high-mass binary systems, andeven a globular cluster in our own."
The mapincludes one object familiar to everyone: the sun. "Because the sunappears to move against the background sky, it produces a faint arc across theupper right of the map," Michelson explained.
During thenext few years, as solar activity increases, scientists expect the sun toproduce growing numbers of high-energy flares. "No other instrument willbe able to observe solar flares in the LAT's energy range," Michelsonsaid.
From themap, the Fermi team created a "top 10" list of five sources withinthe Milky Way and five beyond our galaxy.
The topsources within our galaxy include the sun; a star system known as LSI +61 303,which pairs a massive normal star with a super-dense neutron star; PSRJ1836+5925, which is one of many new pulsars, a type of spinning neutron starthat emits gamma-ray beams; and the globular cluster 47Tucanae, a sphere of ancient stars 15,000 light-years away.
Topextragalactic sources include NGC1275, a galaxy that lies 225 million light years away and is known forintense radio emissions; the dramatically flaring active galaxies 3C 454.3 andPKS 1502+106, both more than 6 billion light years away; and PKS 0727-115,which is thought to be a type of active galaxy called a quasar.
The Fermitop 10 also includes two sources ? one within the Milky Way plane and onebeyond it ? that researchers have yet to identify.
A paperdescribing the 205 brightest sources the LAT sees has been submitted to TheAstrophysical Journal Supplement.
"Thisis the mission's first major science product, and it's a big step towardproducing our first source catalog later this year," said David Thompson,a Fermi deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
- Video ? The GLAST Cast Part 1, Part 2
- New Gamma-Ray Energy Source Spotted By Astronomers
- Vote: The Strangest Things in Space | 0.866863 | 3.847124 |
This picture of the asteroid Ceres was made by the Hubble Space Telescope in December 2003 and January 2004. Ceres was declared a "dwarf planet", along with Pluto and Eris, in 2006.
Click on image for full size
Image courtesy of NASA, ESA, J. Parker (Southwest Research Institute), P. Thomas (Cornell University), L. McFadden (University of Maryland, College Park), and M. Mutchler and Z. Levay (STScI).
Ceres: Asteroid and Dwarf Planet
Ceres is the largest asteroid in the main asteroid belt. It was classified as a "dwarf planet" in 2006, along with Pluto and Eris. Ceres was discovered on January 1, 1801 by the Italian astronomer and monk Giuseppe Piazzi.
Ceres has a diameter of about 975 km (605 miles). It is by far the largest and most massive body in the main asteroid belt, and contains about a third of the belt's total mass. Ceres orbits the Sun once every 4.6 years. Its orbit lies between the orbits of Mars and Jupiter. The asteroid turns on its axis once every 9 hours, so that's how long a day is on Ceres.
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DEBORAH NETBURN | May 19, 2014, 11:00 AM
A star born from the same cloud of gas as our sun 4.5 billion years ago has been found at last, astronomers say.
This solar sibling is a little bigger than our sun, and a little hotter at its surface. But an international team of researchers says it has the same chemical fingerprint as the star at the center of our solar system, leading them to conclude both stars were born in the same stellar nursery, at the same time.
“Stars that were born in different clusters have different compositions,” said Ivan Ramirez, an astronomer at the University of Texas at Austin. “If a star has the exact same chemical composition as our sun, that establishes that they were born in the same place.”
Ramirez is the lead author of a paper about the discovery that will be published June 1 in the Astrophysical Journal.
Like most stars, our sun emerged from an immense cloud of gas and space dust that gave rise to 1,000 to 10,000 stars. Those baby stars stayed clustered together for hundreds of millions of years — a relatively short time on the astronomical scale.
But as they grew up, their cluster broke up and the individual stars began to drift apart. Billions of years later, these stellar siblings are now scattered across the Milky Way galaxy.
Our sun’s newly discovered solar brother from the same gas-cloud mother is known as HD 162826. It is just 110 light years away from our sun, which Ramirez said is remarkably close.
“It is almost certain that if there is another star like this one this close to us, we would have found it already,” he said, “so the next siblings we find are going to be further away.”
Ramirez wasn’t expecting to find a solar sibling even this close to our own sun. In an interview with the Los Angeles Times, he explained that the original intent of his research was to determine efficient ways of identifying our sun’s closest relatives in the future when surveys like space-based telescope Gaia’s provide astronomers with a flood of new data. | 0.824004 | 3.401123 |
Gibbous ♊ Gemini
Moon phase on 8 February 2052 Thursday is First Quarter, 8 days young Moon is in Taurus.Share this page: twitter facebook linkedin
First Quarter is the lunar phase on . Seen from Earth, illuminated fraction of the Moon surface is 59% and growing larger. The 8 days young Moon is in ♉ Taurus.
* The exact date and time of this First Quarter phase is on 7 February 2052 at 17:35 UTC.
Moon rises at noon and sets at midnight. It is visible high in the southern sky in early evening.
Lunar disc appears visually 1.2% wider than solar disc. Moon and Sun apparent angular diameters are ∠1969" and ∠1945".
Next Full Moon is the Snow Moon of February 2052 after 6 days on 14 February 2052 at 18:21.
There is medium ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at very acute angle, so their combined tidal force is moderate.
The Moon is 8 days young. Earth's natural satellite is moving through the first part of current synodic month. This is lunation 644 of Meeus index or 1597 from Brown series.
Length of current 644 lunation is 29 days, 13 hours and 6 minutes. It is 2 hours and 15 minutes longer than next lunation 645 length.
Length of current synodic month is 22 minutes longer than the mean length of synodic month, but it is still 6 hours and 41 minutes shorter, compared to 21st century longest.
This lunation true anomaly is ∠285.5°. At the beginning of next synodic month true anomaly will be ∠314.8°. The length of upcoming synodic months will keep decreasing since the true anomaly gets closer to the value of New Moon at point of perigee (∠0° or ∠360°).
1 day after point of perigee on 6 February 2052 at 18:01 in ♈ Aries. The lunar orbit is getting wider, while the Moon is moving outward the Earth. It will keep this direction for the next 12 days, until it get to the point of next apogee on 21 February 2052 at 10:01 in ♏ Scorpio.
Moon is 364 032 km (226 199 mi) away from Earth on this date. Moon moves farther next 12 days until apogee, when Earth-Moon distance will reach 404 402 km (251 284 mi).
3 days after its descending node on 5 February 2052 at 10:04 in ♈ Aries, the Moon is following the southern part of its orbit for the next 10 days, until it will cross the ecliptic from South to North in ascending node on 18 February 2052 at 16:11 in ♎ Libra.
16 days after beginning of current draconic month in ♎ Libra, the Moon is moving from the second to the final part of it.
11 days after previous South standstill on 28 January 2052 at 05:17 in ♐ Sagittarius, when Moon has reached southern declination of ∠-18.646°. Next day the lunar orbit moves northward to face North declination of ∠18.554° in the next northern standstill on 10 February 2052 at 09:08 in ♊ Gemini.
After 6 days on 14 February 2052 at 18:21 in ♌ Leo, the Moon will be in Full Moon geocentric opposition with the Sun and this alignment forms next Sun-Earth-Moon syzygy. | 0.83659 | 3.334435 |
eso1413 — Photo Release
A Study in Scarlet
16 April 2014
This new image from ESO’s La Silla Observatory in Chile reveals a cloud of hydrogen called Gum 41. In the middle of this little-known nebula, brilliant hot young stars are giving off energetic radiation that causes the surrounding hydrogen to glow with a characteristic red hue.
This area of the southern sky, in the constellation of Centaurus (The Centaur), is home to many bright nebulae, each associated with hot newborn stars that formed out of the clouds of hydrogen gas. The intense radiation from the stellar newborns excites the remaining hydrogen around them, making the gas glow in the distinctive shade of red typical of star-forming regions. Another famous example of this phenomenon is the Lagoon Nebula (eso0936), a vast cloud that glows in similar bright shades of scarlet.
The nebula in this picture is located some 7300 light-years from Earth. Australian astronomer Colin Gum discovered it on photographs taken at the Mount Stromlo Observatory near Canberra, and included it in his catalogue of 84 emission nebulae, published in 1955. Gum 41 is actually one small part of a bigger structure called the Lambda Centauri Nebula, also known by the more exotic name of the Running Chicken Nebula (another part of which was the topic of eso1135). Gum died at a tragically early age in a skiing accident in Switzerland in 1960.
In this picture of Gum 41, the clouds appear to be quite thick and bright, but this is actually misleading. If a hypothetical human space traveller could pass through this nebula, it is likely that they would not notice it as — even at close quarters — it would be too faint for the human eye to see. This helps to explain why this large object had to wait until the mid-twentieth century to be discovered — its light is spread very thinly and the red glow cannot be well seen visually.
This new portrait of Gum 41 — likely one of the best so far of this elusive object — has been created using data from the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. It is a combination of images taken through blue, green, and red filters, along with an image using a special filter designed to pick out the red glow from hydrogen.
ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
- Photos of the MPG/ESO 2.2-metre telescope
- Photos from the MPG/ESO 2.2-metre telescope
- Photos of La Silla
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591 | 0.841218 | 3.781812 |
Thought-Experiments in Honor of John Wheeler
About 20 years ago I ran into John Wheeler at a Baltimore hotel. “Tell me,” he asked, “how do you hold up half the ghost of a photon?” His question was a typically Wheelerish: intriguing, enigmatic, pithy, and provocative. I soon discovered it referred to an outlandish thought-experiment designed to probe the conceptual foundations of quantum mechanics.
Imagine, Wheeler mused, a photon source on a distant quasar, billions of light years away. Suppose the quasar were gravitationally lensed by an intervening massive galaxy, producing a double image when viewed from Earth (several such cases are known to astronomers). Then this arrangement will constitute a sort of cosmic interferometer. A given photon is presented with two possible paths to Earth, and in accordance with the weird requirements of quantum mechanics, it may in some sense take both routes, even though an observer on Earth would detect only a single photon. Wheeler expressed this by saying that the photon is a sort of ghost during its transit from quasar to Earth (in another famous metaphor, he described this indeterminate phase as “a great smoky dragon”). Hence “half a ghost” takes each path. Wheeler envisaged doing an interferometry experiment, but realized that the path lengths might differ, so the “ghosts” would reach Earth at different times. How might one of them be stored to allow the other one time to arrive? Would an optical fiber do the trick?
Like many of Wheeler’s thought experiments, he had taken the germ of an idea and carried to the ultimate extreme, in order to present the conceptual issue as starkly as possible. “Science advances more by the clash of ideas than the steady accumulation of facts,” I once heard him pronounce. In this case the germ of the idea was what became known as the delayed choice experiment. Niels Bohr had long before made explicit that quantum nonlocality and the theory of relativity were uneasy bedfellows, although technically compatible. Physicists had become used to the idea that a measurement made at spatial location A has instantaneous physical implications for the situation at a different location B, in spite of the fact that no direct physical influence could pass between A and B in the time available. Events that are simultaneous in space have ambiguous time order, and Wheeler seized this point to devise a nonlocality thought experiment that would appear to reach not only across space, but back in time too.
He conceived of an adaptation of the normal Young’s two-slit interference experiment in which the observer may choose, for any given photon, whether to sneak a look at the path the photon was taking, or whether to not look. The consequences of such a choice had been debated by Bohr and Einstein in the 1930’s. Today, the agreed position is that when the observer decides to not look, the photons create an interference pattern on the image screen. If the observer looks at “which path” the photon takes, then the interference pattern is destroyed. Wheeler’s refinement was to point out that a decision on “to look or not to look” can be delayed until after the photon has transited the slit system, and just before it arrives at the image screen. In effect, the observer could, at the last minute, decide to “look back” and see from which slit the photon had come. Wheeler proposed a simple way to do this.
The delayed choice experiment does not allow us to change the past or send signals backward in time. However, it startlingly demonstrates how the actions of an observer now can help determine the nature of reality that was—in the past. Since the photon has already transited the slit system when the decision is made, the photon cannot itself have decided whether to follow one path, the other path, or both paths. Which state of affairs was in fact the case (in the past) is determined by the observer (in the future). By casting this weird set-up in terms of quasars, Wheeler emphasized the fact that quantum observations made today can have a hand in determining the nature of reality that was—billions of years ago. Such ideas led to his famous notion of the “participatory universe” in which observers—minds, if you like—are inextricably tied to the concretization of the physical universe emerging from quantum fuzziness over cosmological durations. I should also point out that within a few years the delayed choice experiment was carried out (on a laboratory, not a cosmic, scale) by Carroll Alley, and was further developed by Marlan Scully and other into the famous “quantum eraser” experiments in which the choice is not only delayed, but the observer can change his or her mind afterward!
The following paper by Freeman Dyson of the Institute for Advanced Study in Princeton briefly introduces new quantum thought experiments. One of these is a simple attempt to beat Heisenberg’s uncertainty principle by seeking to acquire simultaneous information about both the position and momentum of a quantum particle. The set-up is a pair of posts placed a known distance apart, and the proposal is to time how long a particle takes to pass between them. This can be used to compute the speed, hence momentum, of the particle. However, because the location of the posts may be known with arbitrary precision, position information is also available. Dyson then concludes that a quantum description cannot be applied to past events.
Dirac considered a similar situation when discussing why the eigenvalues of the velocity operator for an electron are +c or -c. If we try to pin down the electron at one post, we know its position precisely. Hence, according to Heisenberg’s uncertainty principle, its momentum is infinitely uncertain. In nonrelativistic physics this would imply infinite speed, but Dirac’s relativistic wave equation replaced that with the speed of light, c, corresponding to infinite momentum. So when we time the electron between two posts, it seems to travel at the speed of light.
However, that was not the last word on the subject. In the 1980s attention was given to the whole problem of how to measure time and time intervals in quantum mechanics. The difficulty here is that time is not an operator, but a parameter. Analyzing the measurement of time in quantum mechanics ought, for consistency, to involve the use of quantum clocks, themselves subject to uncertainty. If a simple model quantum clock is used to measure the time of flight of a quantum particle between two posts, it turns out that so long as attention is restricted to the time difference, sensible values for the speed are obtained. That is, the expectation values can lie anywhere in the range from +c to -c, depending on the momentum eigenstate chosen. However, this thought experiment cannot tell us anything about the absolute time of passage of the particle. Attempts to acquire that information would return us to Dirac’s scenario.
The new thought experiment of Dyson neatly links back to Wheeler’s delayed choice experiment, the participatory universe, and the way in which quantum potentiality becomes transformed into physical actuality.
The subject of this lecture is a set of four thought-experiments that are intended to set limits to the scope of quantum mechanics. Each of the experiments explores a situation where the hypothesis that quantum mechanics can describe everything that happens leads to an absurdity. The conclusion that I draw from these examples is that quantum mechanics cannot be a complete description of nature.
Two of the thought-experiments, the cat in a cage proposed by Schrodinger, and the evaporating black hole proposed by Hawking, are well known. The other two, so far as I know, are novel. The novel experiments are very simple. One consists of an electron traveling through two counters separated by an accurately known distance. The velocity of the electron is measured using a time-of-flight technique, and its position is measured as it passes through the counters. The measurements can be so accurate that the Heisenberg uncertainly relation between position and momentum is violated. The other novel experiment is a variant form of the old Einstein clock-in-a-box experiment, in which the energy of a photon emitted from the box is measured by weighing the box before and after the emission, while the time of emission is measured by the clock. The experiment is changed by putting the clock outside the box instead of inside, so that the time of emission of the photon is measured after it leaves the box. With this new arrangement, the measurements can be so accurate that the uncertainty relation between time and energy is violated.
Bohr would not have been disturbed for a moment by these thought-experiments. They only violate the uncertainty principle by violating the rules that Bohr laid down for a legitimate use of quantum mechanics. Bohr’s rules say that the quantum-mechanical description can only be used to predict probabilities of different outcomes of an experiment, not to describe what happened after the experiment is finished. The thought-experiments merely confirm that this restriction of the use of quantum mechanics is necessary. Although Bohr would say that the two experiments confirm the correctness of his interpretation of quantum mechanics, Einstein might also claim that they justify his distrust. They prove in a simple and convincing fashion the contention of Einstein that quantum mechanics is not a complete description of nature. Perhaps Einstein would be happy to learn that his box is still alive and well after seventy years, and still making trouble for believers in quantum mechanics.
I deduce two general conclusions from these thought-experiments. First, statements about the past cannot in general be made in quantum-mechanical language. We can describe a uranium nucleus by a wave-function including an outgoing alpha-particle wave which determines the probability that the nucleus will decay tomorrow. But we cannot describe by means of a wave-function the statement, “This nucleus decayed yesterday at 9 a.m. Greenwich time.” As a general rule, knowledge about the past can only be expressed in classical terms. My second general conclusion is that the “role of the observer” in quantum mechanics is solely to make the distinction between past and future. The role of the observer is not to cause an abrupt “reduction of the wave-packet,” with the state of the system jumping discontinuously at the instant when it is observed. This picture of the observer interrupting the course of natural events is unnecessary and misleading. What really happens is that the quantum-mechanical description of an event ceases to be meaningful as the observer changes the point of reference from before the event to after it. We do not need a human observer to make quantum mechanics work. All we need is a point of reference, to separate past from future, to separate what has happened from what may happen, to separate facts from probabilities. | 0.812448 | 3.969623 |
In 1964, Gary Flandro stated that the outer planets – Jupiter, Saturn, Uranus, and Neptune – would align in a rare pattern in the late 1970s. And NASA scientists really wanted to catch hold of such event that occurred only once in two centuries. 176 years to be very precise. But how? By launching a mission that would take a road trip towards these giant marbles. In less time. With less cost.
Determined to not let go of this opportunity, they approached the then President of The United States, Richard Nixon, and apprised him of their plan. To their utter surprise, they received the green signal for the mission but with limits. A limit that would restrict them to visit just two planets at a time. That, too, for a short period of time. But NASA had other plans. The long-game plan.
Finally, in 1977, their eagerness came into existence.
One-by-one, two space probes were launched. Voyager 2 followed by Voyager 1 after 16 days. The former was intended to visit all four planets while the latter would follow a different trajectory covering Jupiter and Saturn.
Initially, these twins were commissioned for planetary exploration. But later on, their missions were extended. To explore the outer limits of the solar system. To find the traces of extraterrestrial life deep into the interstellar space. Space where no man-made object, in the history of mankind, had stepped in. NASA’s long-game plan had planned a mission within a mission.
It’s been 41 years now. Under the influence of ungrateful radiations and insane temperatures, they’re invading the deep space like never before. Beating the Sun’s gravitational pull, a lovely small space probe is still going strong at a speed of 15km/s in a lovely big universe. By the time you scroll down to read further, it’ll complete a full marathon.
But how did NASA’s long-game plan help? Well, what the mission has uncovered so far was unknown to humans for the past many centuries. It’s the long-game plan that reported the presence of an active 350-years old giant cyclone on Jupiter. It’s the long-game plan that showed Saturn’s polar regions to the world. It’s the long-game plan that solved the unsolved mysteries that baffled even the great astronomers Galileo and Copernicus.
Now, let me talk about its relevance in the field of investing.
When we start SIP (Systematic Investment Plan), the initial contributions will never create something enormous instantly. In fact, nothing changes drastically during the initial few weeks, months, or even years. Rather, it turns out to be extremely boring. And who loves staying monotonous throughout the journey? Well, no one.
And that’s why we love playing short games. The games that produce immediate results. Going through a summary instead of reading ‘The Intelligent Investor’. Tweeting rather than writing a blog post. Munching a Bournville instead of running on a treadmill. Short games are extremely addictive. Believing that just Rs 5,000 a month is not going to make us rich tomorrow, we convert it into something that makes us really happy on-the-spot. We tend to overlook the potential of a paltry amount of money ribboned with a long-game plan.
“The problem with the short game is that the costs are small and never seem to matter much on any given day. Saving $5 today won’t make you a millionaire. Going to the gym won’t make you fit. Reading a book won’t make you smart. Since the results are not immediate, we revert back to the short game.”
– Shane Parish, Farnam Street
For instance, when we increase our monthly SIP amount by 5 percent, 10 percent, or even 12 percent every year, the end result will cease to change during the initial years of compounding. The difference in the end result between an increment of 5 percent and 12 percent seems irrelevant. In fact, it stays neck-to-neck for the first 7-10 years.
But as the game gets elongated further, this difference starts exploding. The end results start taking the shape of a snowball. The variance that looks minimal in the first place, starts growing bigger and bigger. In a long-game plan of 40 years, an annual step-up of 12 percent instead of 5 percent in a SIP of Rs 5,000 a month makes your corpus bigger by Rs 10 crore. A huge disparity.
On the contrary, this variation reduces to just Rs 4 lakh with a short-game plan of 10 years. And much less if planned even shorter.
When days are turned into months, months into years, and years into decades, the compounding treadmill starts accomplishing higher speed. The little and tiny contributions that look unbelievably small initially, become enormous after decades of compounding. What looks extremely meaningless in a short game, becomes something that is difficult to avoid in a long-game plan.
James Clear, the author of The Atomic Habits, has written on a broad scale about forming habits with a long-game plan. As per the book, we grossly miscalculate the importance of small and little efforts that contribute towards achieving our goals. If we swim for 40 minutes for a week, we still don’t get lean. If we cook for a week, we still don’t become a skilled chef. If we write for a week, we still don’t become a prolific writer. But when continued for months and years, the results turn out to be worthy. Certainly, the long-game plan works in forming a habit too.
If we wrap our mentality of getting better with just 1 percent every day, we’ll end up getting 37-times better at the end of the year. And this keeps compounding year after year. The below equation by James proves that following a system with a long-game plan does benefit us immensely. Unquestionably!!!
1 percent better every day for 1-year: (1.01)365 = 37.78
1 percent worse every day for 1-year: (o.99)365 = 00.03
– James Clear, The Atomic Habits
* * *
Kathleen Magowan, despite being a teacher for 35 long years, amassed a fortune of $6 million. Throughout her life, she never attracted anyone’s attention. Neither she married. Nor she had any grandchild. Lived frugally in the same inherited house. Sweet. Compassionate. She always preferred to maintain a low-key profile. Surprisingly, after her death in 2011, it was revealed that even her Quaker Oats boxes were worth $183K as they contained the savings bonds of the 1940s and 50s. Yes, she invested with a long-game plan.
Same goes for Anne Scheiber, who built a massive corpus of $22 million despite living on a pension of $3,100. Yes, she invested with a long-game plan. And just like Voyager 2, Warren Buffett is still going strong even at the age of 88. Yes, he has been investing with a long-game plan since the age of 11. | 0.892135 | 3.291888 |
The 'Wow!' signal has perplexed scientists for decades - but an explanation could be close
The so-called ‘Wow!’ signal is the name given to a powerful blast of radio waves which was recorded by astronomer Jerry R. Ehman in August 1977.
While monitoring data from Ohio State University’s ‘Big Ear’ radio telescope, Ehman came across an exceptionally strong radio signal, which lasted solidly for 72 seconds.
Drawing attention to the mysterious transmission on a printout, Ehman circled the signal and jotted down ‘Wow!’ next to it. Since then, it’s become one of the most well-know space signals ever received.
The ‘Wow!’ signal has never been heard since, and its origins are still unknown. It appears to have come from an area near the M55 star cluster in the Sagittarius constellation, and some alien enthusiasts believe its strength and clarity mean it came from another intelligent species.
However, this kind of theory is exactly what Professor Antonio Paris, from Florida’s St. Petersburg College, is trying to disprove.
In a previous job, Paris was an analyst for the US Department of Defence, and he’s hoping to use this investigative background to dig into the true origins of the signal.
Speaking to The Guardian, he said: “I approached the ‘Wow!’ signal as if I’m going back to the crime scene.”
“It’s a cold case, so I went to various [astronomical] databases to find culprits or suspects that were at this crime scene at the time.”
Rather than being an attempt at contact by an alien civilisation, Paris believes the signal comes from two recently-discovered comets, which were near the signal’s suspected place of origin when it was picked up.
According to the theory, the giant clouds of hydrogen which surround the comets are responsible for the signal. It’s a compelling explanation, especially since the radio frequency hydrogen naturally emits is 1420 MHz, the same frequency as the ‘Wow!’ signal.
The two comets will pass by the vicinity of the signal once again in the near future, and Paris wants to monitor them to see if they produce it again. In order to prove his theory, he’ll need a radio telescope, and has set up a GoFundMe page in order to raise the money.
His target is $16,000 and he’s already raised almost $14,000 in a month, so an explanation is looking promising.
One of the comets will pass through the system in January 2017, while the other will arrive a year later – so we may not have to wait for long to see if the ‘Wow!’ signal is just a cosmic anomaly, rather than a deliberate transmission. | 0.878541 | 3.0787 |
Can non-intelligent life forms evolve to leave their home planet and travel in interplanetary space, for instance, grow on atmosphereless icy moons and transfere spores over interplanetary space?
Yes, via panspermia.
Panspermia is the idea that extremophiles "hitch a lift", as it were, on ejecta from collisions between celestial bodies. There are a few obstacles, because the microbes would have to survive all three phases of travel:
- Launch (as well as the impact event)
- Travel in the harsh environment of space
- Atmospheric entry and landing, with high temperatures
Extremophiles are really the only types of organisms that could survive such a journey. More complicated organisms (with more needs) would surely die en route.
On Earth, here have been some discoveries of materials related to organic matter that might be evidence of panspermia; see Bell et al. (2015) for one example.
Image courtesy of Wikipedia user Beao under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Yes it can be done but I would list a few caveats.
Odds are the natural selection process is not going to select for surviving in space...why would it. Natural selection selects the individuals most fit in their respective environments. This simply means that if an organism makes it to space accidentally survival will also be random/accidental.
The more complicated the creature the less likely they are to pull this off. The more biologically complicated you become the more you are tied to your environment, mainly because you need more quantity and variety of resources.
The most likely scenario in my mind is a single celled organism. The organism would be launched into space via natural phenomenon, to be trendy lets go with the ejection of water from a nice little moon called Enceladus. If there are single celled organisms in the theoretical oceans on the moon, the plumes of water vapor could contain little critters.
Over time some could randomly have the ability to survive in space by essentially being dormant while they travel. Say they land on an asteroid or another moon that has the simple resources they need to survive...a particular mineral maybe and viola, you have your space faring critters.
If there was a low gravity moon with an atmosphere but in which its tallest mountains were so high that their tips were to stick out above the atmosphere then that could potentially lead to some life evolving to survive in the vacuum of space. Because the transition from atmosphere to vacuum on the mountains could be very gradual individuals that don't travel very far from where they started life might live with basically the same amount of atmospheric pressure as their parents.
Over many generations populations could migrate however from regions with normal pressure on the ground to the peaks of the mountains that would be in a vacuum. As populations migrate up the mountains their skin and the openings to their bodily holes could become more and more pressurized to hold in their bodily fluids. Plants could also evolve to become more and more and more pressurized as they migrate up the mountains. Animals that fly would at first evolve more and more powerful wings as they migrate up the mountains but would eventually evolve to have smaller and smaller wings as wings become useless in a vacuum. Animals and plants living at higher and higher elevations might start to evolve to extract more and more energy from chemicals in the ground as it would be inefficient to extract energy from the air.
Animals and plants on the peaks of the mountains would tend to evolve skin that protects their insides from deadly radiation considering that they would have no atmosphere to protect them. If there was ice at the peaks of the mountains life on the peaks of the mountains could use that as a source of hydration considering that water could not exist as a liquid in a vacuum.
If some animals that live on the peaks of mountains use chemical defenses that involve chemical reactions that could end up getting modified into a means of locomotion as they could eject fuel out of their backsides in order to move. Animals that evolve this means of locomotion could diversify the fastest out of the animals living in a vacuum as they would tend to be able to travel the furthest the fastest. If the planet had multiple mountains that stick out above the atmosphere then animals that can move by ejecting fuel out of their back sides that evolve on the peak of one mountain could migrate to the peak of another mountain.
If some of the animals were able to move fast enough using chemical propulsion they could escape their moons gravity and travel to other moons including ones that have no atmosphere as they would have evolved to live without atmosphere. Some of them could carry the seeds of plants as well as having smaller animals that can't use chemical propulsion hitch a ride on them so that they spread other animals and plants with them meaning that they moon hop in the same way that some animals and plants island hop on Earth. These types of animals would be the most diverse as they would be able to spread to moons that have no atmosphere where life could never have started.
Some could perhaps evolve to eat parts of their gas giants rings so that they could get nutrients on journeys between moons. Some species could perhaps even evolve to subsist entirely on space junk and they could perhaps live entirely in space between moons and eventually between planets. Species that live between moons and planets could get very large as they wouldn't have to fight against gravity in the same way as animals on the surface of a planet and being very big could allow them to go longer without eating. Being very large would also allow for larger eyes that would be better at detecting food from large distances as in distances potentially larger than the radius of a moon.
There is no known reason to believe there is any limitation on what can evolve, simply because we do not understand the process to assign limits, so the answer almost has to be a default "yes."
Escaping a gravity well is very tricky, requiring a lot of energy, but if there was a reason, there might be a species that figures out how to use things like winds, solar energy, and possibly a small packet of chemical energy to try to escape. I don't think it's likely (as in it'd be a miracle if it happened), but there's nothing in the laws of physics that forbids it.
Waterbears are known to be able to survive the rigors of a deep vacuum, so we know its possible for organics to function in extremely inhospitable worlds.
That all being said, when it comes to world building, we must always remember Sanderson's First Rule of Magic:
An author's ability to resolve conflict using magic is directly proportional to the reader's ability to understand it.
This rule goes not only for high-fantasy magic, but science fiction magics as well. This species is highly "exotic," as in a real scientist would scoff at the possibility (but "can" is such a great open-ended word in a question!). You would have to make sure you don't resolve to much conflict with it unless you fleshed out why such an astonishingly unique species came into being.
There are three main routes to natural evolution into space-going life:
Panspermia is covered in other answers. I think that this is cheating though, as panspermia is planet-based life that travels through space in an inert form and then resumes life on a new planet. I don't consider it to be life in space, as it's not really alive in space.
Life could develop on planets and then evolve into something that can live in space. Note that this works best if there is a lot of life somewhere that is becoming progressively more like space. It needs to be a lot of life because space kills life optimized for planets. We need enough base material to leave room for natural selection. It needs to happen over a long period of time so that new generations can build life for the new circumstances. Note that panspermia may be a stage in this.
It is conceivable that life might find moments on comets or in a sufficiently soupy region of a nebula to develop in space. Maybe when we explore enough we'll find some. Note that there is Earth-based life in extreme conditions like volcanoes. Perhaps an environment like Saturn's rings could hold life. It seems like it would take a really long time to develop though. Realize that we think that what we now call one-celled life developed from even smaller life (e.g. we think that mitochondria might have started outside cells). Given how vast space is, it might be difficult for the life to encounter enough additional life to even get as far as one-celled life. It might still be stuck at the prokaryote stage or even the protocell stage. Realize that it took something like 3.5 billion years for the first animal life to develop on Earth. This route may be slower than that.
I'm assuming that what you want is to eventually get to a form of life that can reproduce in space. Perhaps you even want a form of life that can travel in space willfully. So a space plant that floats through a nebula collecting materials may not count.
It seems at least potentially possible. We really haven't traveled far enough to disprove the existence of such life. Is there life on Mercury? Or the sun? We don't know. We haven't found life on Mars, but that merely suggests that it is difficult.
I think that a form of life that travels via a solar sail, collecting material as it goes would be possible. I think that an intelligent race could create some. Since the universe is a big place, it should be possible for randomness to duplicate that feat -- somewhere.
some bacteria survives in space: http://www.panspermia.org/bacteria.htm
They could be launched into space when their planet is smashed into fragments by an astroid.
You can't get much more unintelligent than that.
Well, you said 'non-intelligent' but if we loosen the definition a bit I see an interesting option.
How about custom made 'Pets' modified to live in space by an intelligent species. Think something like flying cats or dogs with large solar energy gathering 'wings', GMed to thrive in vacuum and naturally extract organics from rocks and space debris. 'Built' to aid in asteroid mining but then abandoned or escaped and gone wild. Perhaps very long lived and with 'natural' solar sails or other propulsion systems. Migrating back and forth from comets and small moons.
Perhaps with enough time, they might evolve into a complex biome with multiple competing species. | 0.887893 | 3.282814 |
MIGHTY oaks from little acorns grow. In the 1840s an astronomer called Urbain Le Verrier noticed there was something wrong with the orbit of Mercury. The main axis of the planet's orbital ellipse shifts each time it goes round the sun. That was well known, and is caused by the gravitational pull of Venus. Le Verrier, however, realised that the orbit was shifting too fast. The excess was a tiny fraction of a degree. But it was a disturbing departure from the purity of Newton's majestic clockwork—a departure that was explained only 70 years later, when Einstein's general theory of relativity swept Newton away by showing that gravity operates by distorting space itself.
Even Einstein, however, may not have got it right. Modern instruments have shown a departure from his predictions, too. In 1990 mission controllers at the Jet Propulsion Laboratory (JPL) in Pasadena, California, which operates America's unmanned interplanetary space probes, noticed something odd happen to a Jupiter-bound craft, called Galileo. As it was flung around the Earth in what is known as a slingshot manoeuvre (designed to speed it on its way to the outer solar system), Galileo picked up more velocity than expected. Not much. Four millimetres a second, to be precise. But well within the range that can reliably be detected.
Once might be happenstance. But this strange extra acceleration was seen subsequently with two other craft. That, as Goldfinger would have put it, looks like enemy action. So a team from JPL has got together to analyse all of the slingshot manoeuvres that have been carried out over the years, to see if they really do involve a small but systematic extra boost. The answer is that they do.
Altogether, John Anderson and his colleagues analysed six slingshots involving five different spacecraft. Their paper on the matter is about to be published in Physical Review Letters. Crucially for the idea that there really is a systematic flaw in the laws of physics as they are understood today, their data can be described by a simple formula. It is therefore possible to predict what should happen on future occasions.
That is what Dr Anderson and his team have now done. They have worked out the exact amount of extra speed that should be observed when they analyse the data from a slingshot last November, which involved a craft called Rosetta. If their prediction is correct, it will confirm that the phenomenon is real and that their formula is capturing its essence. Although the cause would remain unknown, a likely explanation is that something in the laws of gravity needs radical revision.
Dr Anderson and his team have, of course, gone through painstaking efforts to rule out conventional physical explanations and systematic errors. Their model takes into account both general relativity and all known gravitational effects of the sun, the moon, the planets and large asteroids. Effects stemming from the Earth's atmosphere, from ocean tides and from the solar wind of charged particles were all found to be too small to explain the spacecrafts' extra velocity. And to rule out computer bugs, independent groups verified the calculations using several different versions of the modelling software.
Furthermore, because the effect is present in data from five vehicles—Galileo, the Cassini mission to Saturn, the MESSENGER craft sent to Mercury, and the NEAR and Rosetta missions to study asteroids and comets—the team thinks it is unlikely to be caused by the spacecraft themselves. Each has a unique design, so a systematic machine-related error is unlikely.
Dr Anderson is no stranger to anomalous behaviour by spacecraft. In the early 1970s Pioneer 10 and Pioneer 11 were sent to fly past Jupiter and Saturn. Once their missions were accomplished, they carried on into the outer reaches of the solar system. He and his colleagues noticed soon afterwards that the sibling crafts' trajectories were deviating from those predicted by Einstein. Both Pioneers act as though an extra force beyond mere gravity is tugging at them from the direction of the sun.
Thirty years later, no explanation for this has been found. Each year the Pioneers fall a further 5,000km behind their projected paths. Hundreds of scientific papers have been written on the Pioneer anomalies, many of them trying to find explanations beyond the current laws of gravity.
Dr Anderson himself points out that several features of the Pioneer anomalies and the slingshot anomalies suggest they may have a common explanation. Both, for example, involve small objects. By contrast, the data on which Newton and Einstein built their theories were from stars, planets and moons. In addition, the spacecraft in question are all travelling in types of orbit not usually seen in natural systems. Not for them the closed ellipses of Mercury and the other planets; at the whim of their masters in Pasadena they are following much more unusual hyperbolic curves.
What it all means is not yet clear. Perhaps there is some overlooked explanation within the laws of physics. But Le Verrier thought that must be so for his discovery, too. He and later astronomers spent decades looking for the missing planet within the orbit of Mercury which, they were convinced, explained what was going on. They even gave it a name: Vulcan. But it wasn't there.
There is a good chance that modern physics is in a similar situation. It would be nice, therefore, to believe that somewhere, the contemporary equivalent of a bored patent clerk is thinking about the problem, and that when he has thought hard enough, a new reality will emerge.
This article appeared in the Science & technology section of the print edition under the headline "Wanted: Einstein Jr" | 0.873575 | 3.915776 |
UCLan academic in team that discovers regular rhythms among pulsating stars
By listening to the beating hearts of stars, international astronomers have for the first time identified a rhythm of life for a class of stellar objects that had until now puzzled scientists.
Dr Daniel Holdsworth, from the University of Central Lancashire (UCLan), is part of the global team whose new findings have been published today, 13 May, in the prestigious Nature journal.
Lead author Professor Tim Bedding, from the University of Sydney, said: “Previously we were finding too many jumbled up notes to understand these pulsating stars properly. It was a mess, like listening to a cat walking on a piano.”
The international team used data from NASA’s Transiting Exoplanet Survey Satellite (TESS), a space telescope mainly used to detect planets around some of the nearest stars to Earth. It provided the team with brightness measurements of thousands of stars, allowing them to find 60 whose pulsations made sense.
“The incredibly precise data from NASA’s TESS mission have allowed us to cut through the noise. Now we can detect structure, more like listening to nice chords being played on the piano,” Professor Bedding said.
The findings are an important contribution to our overall understanding of the processes that occur inside the billions of stars in the Milky Way.
The intermediate-sized stars in question – about 1.5 to 2.5 times the mass of our Sun – are known as delta Scuti stars, named after a variable star in the constellation Scutum. When studying the pulsations of this class of stars, astronomers had previously detected many pulsations, but had been unable to determine any clear patterns.
The Australian-led team of astronomers has reported the detection of remarkably regular high-frequency pulsation modes in 60 delta Scuti stars, ranging from 60 to 1,400 light years away.
“This definitive identification of pulsation modes opens up a new way by which we can determine the masses, ages and internal structures of these stars,” Professor Bedding said.
Dr Holdsworth, Research Associate in Asteroseismology at UCLan, was one of four UK based academics to work on the research. His research was funded by the Science and Technology Facilities Council (STFC).
He commented: “These findings have opened a new window on the analysis, and so understanding, of the delta Scuti stars. Previously it has been hard to identify patterns in the pulsation modes in these stars, and it is the regular patters which hold the key to understanding the physics at play in the stellar interiors. Although the 60 stars studied in the paper represent just a small fraction of the total delta Scuti population, these results will have implications for future studies.
“For example, we have shown that these stars are young, they are just starting the main part of their life, so we can use the information about regular spacings in other delta Scuti stars as an age diagnostic. The age of a star, or groups of stars, can be hard to determine with results differing by a factor of two. However, asteroseismology has the power to provide very precise ages thus providing the opportunity to expand our understanding of the Galaxy around us.”
Daniel Hey, a PhD student at the University of Sydney and co-author on the paper, designed the software that allowed the team to process the TESS data.
He said: “We needed to process all 92,000 light curves, which measure a star’s brightness over time. From here we had to cut through the noise, leaving us with the clear patterns of the 60 stars identified in the study. Using the open-source Python library, Lightkurve, we managed to process all of the light curve data on my university desktop computer in a just few days.”
The insides of stars were once a mystery to science. But in the past few decades, astronomers have been able to detect the internal oscillations of stars, revealing their structure. They do this by studying stellar pulsations using precise measurements of changes in light output.
Over periods of time, variations in the data reveal intricate – and often regular – patterns, allowing us to stare into the very heart of the massive nuclear furnaces that power the universe.
This branch of science, known as asteroseismology, allows us to not only understand the workings of distant stars, but to fathom how our own Sun produces sunspots, flares and deep structural movement. Applied to the Sun, it gives highly accurate information about its temperature, chemical make-up and even production of neutrinos, which could prove important in our hunt for dark matter.
Professor Bedding added: “Asteroseismology is a powerful tool by which we can understand a broad range of stars. This has been done with great success for many classes of pulsators including low-mass Sun-like stars, red giants, high-mass stars and white dwarfs. The delta Scuti stars had perplexed us until now.”
Isabel Colman, a co-author and PhD student at the University of Sydney, said: “I think it’s incredible that we can use techniques like this to look at the insides of stars.
“Some of the stars in our sample host planets, including beta Pictoris, just 60 light years from Earth. The more we know about stars, the more we learn about their potential effects on their planets.”
The identification of regular patterns in these intermediate-mass stars will expand the reach of asteroseismology to new frontiers, Professor Bedding said. For example, it will allow us to determine the ages of young moving groups, clusters and stellar streams.
“Our results show that this class of stars is very young and some tend to hang around in loose associations. They haven’t got the idea of ‘social distancing’ rules yet,” Professor Bedding said.
Dr George Ricker, from the MIT Kavli Institute for Astrophysics and Space Research is Principal Investigator for NASA’s Transiting Exoplanet Sky Survey, added: “We are thrilled that TESS data is being used by astronomers throughout the world to deepen our knowledge of stellar processes. The findings in this exciting new paper led by Tim Bedding have opened up entirely new horizons for better understanding a whole class of stars.” | 0.862161 | 3.566884 |
A massive fireball exploded from the planet’s atmosphere in December, based on Nasa.
The explosion has been the second biggest of its kind in 30 years, and also the largest since the fireball more than Chelyabinsk in Russia six decades back.
However, it went mostly unnoticed until today since it warms up across the Bering Seaoff Russia’s Kamchatka Peninsula.
Lindley Johnson, planetary defence officer at Nasa, told BBC News that a fireball this large is just expected about a couple of times every 100 decades.
What is the significance?
Space stones of the size are so-called”problems without passports” since they’re anticipated to affect whole areas should they collide with Earth. But scientists estimate it’ll take them the next 30 years to match this specific congressional directive.
After an incoming object is recognized, Nasa has had a notable achievement at calculating where on Earth the effect will happen, dependent on an exact determination of its orbit.
Back in June 2018, the tiny 3m asteroid 2018 LA was detected by a ground-based observatory at Arizona eight hours prior to impact. The middle for Near-Earth Object Research at Nasa’s Jet Propulsion Laboratory (JPL) subsequently made a precision determination of its own orbit, which has been utilized to compute a likely effect place. This revealed the rock was supposed to strike southern Africa.
As the calculation indicated, a fireball was listed over Botswana by safety camera footage onto a farm. Fragments of the thing were later discovered in the region.
What exactly do we understand?
“That was 40 percent the energy release of Chelyabinsk, but it had been over the Bering Sea therefore it did not possess exactly the exact same sort of impact or appear in the information,” explained Kelly Quick, near-Earth objects observations programme director at Nasa.
“That is just another thing we’ve got in our defence, there is lots of water around Earth.”
Allied satellites picked up the burst this past season; Nasa was informed of this episode by the US Air Force.
Dr Johnson said the fireball came in within a place not too far from paths employed by commercial airplanes flying between North America and Asia. So researchers were assessing with airlines to find out whether there were any documented sightings of this occasion.
How can monitoring be made better?
The most recent occasion within the Bering Sea demonstrates that bigger objects can collide with us without warning, underlining the need for improved monitoring.
A stronger network could be dependent not just on floor telescopes, but space-based observatories also.
A mission concept in evolution would observe a telescope named NeoCam launched to some gravitational balance point in space, in which it’d detect and characterise potentially hazardous asteroids bigger than 140m.
Dr Amy Mainzer, chief scientist on NeoCam in JPL, said:”The concept would be to have as near as possible to attaining that 90 percent purpose of locating the 140m and bigger near-Earth asteroids awarded to Nasa by Congress.
She explained that in case the assignment didn’t establish, projections indicated it would”take us several decades to arrive using the present package of ground-based polls”.
Dr Mainzer added:”However, in case you’ve got an IR-based (infrared) telescope, then it goes much quicker.” | 0.909091 | 3.257633 |
On this page I will explain the mathematical models devised by Greek astronomers and mathematicians to account for (and ultimately to be able to predict) the motions of the celestial bodies (the stars, sun, moon and five visible planets). As you will see, these models are all based on combinations of uniform circular motion. Remember that the Greeks believed that the heavens were perfect and orderly, and that the sphere was the most perfect and harmonious shape. They further believed that uniform circular motion, which has no beginning and no end, was the most perfect kind of motion. So, the perfect and orderly heavens were spherical, and they were composed of numerous spheres. And all the observed motions of heavenly bodies were uniform and circular, or were combinations of uniform circular motions.
Unless you have prodigious mental visualization skills (which I certainly do not!), these models are nearly impossible to grasp without diagrams. And an even better aid to understanding is animated diagrams. Fortunately, some very clever people have produced animated diagrams of Greek astronomical models and put them on the web. I have included links to these resources. These links are part of your required reading, so go over them carefully.
The biggest challenge for the ancient Greeks was figuring out how the order and pattern underlying the seemingly irregular motions of the planets (recall the phenomenon of retrograde motion). Eudoxus of Cnidus (408 – 355 B.C.), a philosopher and mathematician who studied with Plato, devised the first important model of the cosmos that accounted for the complexities of planetary motion. He devised a mathematical model of the universe that accounted for the motions of the sun, moon, and planets by means of concentric spheres. Here is a diagram of his model for one planet.
The planet’s motion is the combined motion of four concentric and interlocking spheres all centered on the earth. The outermost sphere rotates east to west once every twenty-four hours. This gives you the planet’s daily rising and setting. The second sphere rotates west to east on an axis tilted somewhat from that of the outermost sphere. This accounts for the planet’s movement through the zodiac. The inner two spheres rotate on different axes and at different speeds and they account for the planet’s retrograde motion. Each sphere conveys it motion to the sphere underneath it. The planet is fixed on the innermost sphere, so its motion is the combined motion of all four spheres. Watch this video clip to see how this works:
Eudoxus appears to have used this system of concentric spheres only as a computational device. That is, he did not argue that the heavens were actually made up of solid concentric spheres with planets embedded in these spheres. Eudoxus’ system was enormously influential because Aristotle adopted it. Aristotle changed the system in a fundamental way – he argued that it represented the real physical structure of the cosmos. So Aristotle’s celestial realm is more complicated than I described in my discussion of Aristotelian physics. Each planet has multiple concentric spheres (made of ether) associated with it. Aristotle’s heavens are actually made up of 56 concentric spheres. These spheres are all nested inside each other with no “space” in between them. I like to think of Aristotle’s universe as a giant cosmic onion, with layer after layer of spheres made of ether.
However, as the video explains, the Eudoxian model is not completely accurate for the outer planets. Aristotle never worked out the mathematics of this system, and it was not used to make predictions about where celestial bodies would be at particular times.
Let me turn back to mathematical models of the cosmos, that it, models that allowed the ancient Greeks to accurately calculate where a planet or the moon or sun would be at any given time. Greek astronomers after Aristotle developed two powerful models to account for celestial motions. Unlike Aristotle, they did not argue that these models were physically real. These were computational devices.
The first mathematical device was the eccentric. In the eccentric model, the planet moves with uniform circular motion, but this motion is not centered on the earth. Instead, the earth is offset from the center of the circle by some distance – called the eccentricity. In the diagram on the left, C is the center of the circle and E is the earth. The distance between C and the center of E is the eccentricity. Although the planet is moving with uniform circular motion, because the earth is not at the center of this rotation, to an observer on earth the planet appears to move with varying speed. This was an important model because no celestial body (except the stars) was observed to move around the earth uniformly. The sun, moon and planets all appeared to move faster at some times and slower at others.
The second mathematical device was the epicycle on deferent. In this model, the planet is carried on a small circle (the epicycle) that rotates with constant speed. The center of this small circle in turn rotates around a large circle (the deferent). This model can account for retrograde motion, because the combination of these two uniform circular motions can produce backward loops.
In the second century A.D., Claudius Ptolemy of Alexandria (ca. 100 – ca. 170) produced a work of mathematical astronomy that synthesized and advanced the work of his predecessors. Ptolemy produced the most comprehensive and accurate models of the motions of celestial bodies, and his work was read and used for centuries. In Greek, this work was titled the Mathematical Compilation or Syntaxis. It was translated into Arabic, and then into Latin, and medieval and early modern Europeans knew it by its Arabic title, the Almagest. In the Almagest, Ptolemy used combinations of eccentric circles and epicycles to work out accurate mathematical models for the motions of each planet, the moon, sun and stars. In addition, Ptolemy devised another mathematical model, the equant, which he incorporated into his models for the motions of celestial bodies. In the equant model, the planet moves around a circle, and it sweeps out equal angles in equal times as measured from an equant point (Q in the diagram on the left), which is different than the center of the circle (C in the diagram). (If the planet swept out equal areas in equal times as measured from the center of the circle, it would be moving with uniform circular motion. As in the eccentric model, an observer on the earth (E) will see the planet moving with non-uniform speed.
To see animated versions of these three models, look at the website Models of Planetary Motion from Antiquity to the Renaissance, put together by Craig Sean McConnell. Another excellent resource, although this is OPTIONAL, is Dennis Duke’s Ancient Planetary Model Animations. | 0.810054 | 3.622926 |
The image composite is just one of hundreds that the infrared observatory produced during its 16 years in space.
Five days before NASA's Spitzer Space Telescope ended its mission on Jan. 30, 2020, scientists used the spacecraft's infrared camera to take multiple images of a region known as the California Nebula - a fitting target considering the mission's management and science operations were both based in Southern California at NASA's Jet Propulsion Laboratory and Caltech. This mosaic is made from those images. It is the final mosaic image taken by Spitzer and one of hundreds the spacecraft captured throughout its lifetime.
Located about 1,000 light-years from Earth, the nebula looks more than a little like the Golden State when viewed by visible-light telescopes: It is long and narrow, bending to the right near the bottom. The visible light comes from gas in the nebula being heated by a nearby, extremely massive star known as Xi Persei, or Menkib. Spitzer's infrared view reveals a different feature: warm dust, with a consistency similar to soot, that is mixed in with the gas. The dust absorbs visible and ultraviolet light from nearby stars and then re-emits the absorbed energy as infrared light.
The mosaic displays Spitzer's observations much the way that astronomers would view them: From 2009 to 2020, Spitzer operated two detectors that simultaneously imaged adjacent areas of the sky. The detectors captured different wavelengths of infrared light (referred to by their physical wavelength): 3.6 micrometers (shown in cyan) and 4.5 micrometers (shown in red). Different wavelengths of light can reveal different objects or features. Spitzer would scan the sky, taking multiple pictures in a grid pattern, so that both detectors would image the region at the center of the grid. By combining those images into a mosaic, it was possible to see what a given region looked like in multiple wavelengths, such as in the gray-hued part of the image above.
In the final week of operations, the mission science team chose from a list of potential targets that would be within Spitzer's field of view. The California Nebula, which hadn't been studied by Spitzer before, stood out due to the likelihood that it would contain prominent infrared features and have the potential for high science return.
"Sometime in the future, some scientist will be able to use that data to do a really interesting analysis," said Sean Carey, manager of the Spitzer Science Center at Caltech in Pasadena, who helped select the nebula for observation. "The entire Spitzer data archive is available to the scientific community to use. This is another piece of the sky that we're putting out there for everyone to study."
The Spitzer team made additional science observations through Jan. 29, the day before the mission ended, though none was quite so visually stunning as the California Nebula. Those observations included measuring the light from dust sprinkled throughout our own solar system, called zodiacal dust. This tenuous dust cloud arises from the evaporation of comets and collisions between asteroids. Comets and asteroids are like fossils that retain the chemical composition of the material that formed the planets, so the dust provides a look back in time.
Observatories close to Earth typically have trouble observing the overall zodiacal dust glow because blobs of dust tend to collect around our planet. But Spitzer's orbit eventually carried it 158 million miles (254 million kilometers) from Earth, or more than 600 times the distance between Earth and the Moon. From that distance, Spitzer had a unique vantage point away from the dust blobs.
The mission team also closed the shutter on Spitzer's camera for the first time in the mission's 16-year lifetime. This exercise allowed scientists to observe and then subtract subtle effects that Spitzer's instruments may have on the measurement of light from distant sources, enabling them to produce more accurate measurements of their cosmic targets.
To learn more about Spitzer and some of its biggest discoveries, check out NASA's Exoplanet Excursions, a free VR application for HTC Vive and Oculus Rift. This VR experience features a new activity that lets users interactively control a simulation of Spitzer. The application is available from the Spitzer website. Two non-interactive VR activities can be viewed as immersive YouTube 360 videos on the Spitzer YouTube page.
Spitzer science data continues to be analyzed by the science community via the Spitzer data archive located at the Infrared Science Archive housed at IPAC at Caltech in Pasadena. JPL managed Spitzer mission operations for NASA's Science Mission Directorate in Washington. Science operations were conducted at the Spitzer Science Center at IPAC at Caltech. Spacecraft operations were based at Lockheed Martin Space in Littleton, Colorado. Caltech manages JPL for NASA.
For more information about Spitzer, visit:
News Media ContactCalla Cofield
Jet Propulsion Laboratory, Pasadena, Calif. | 0.879526 | 3.882559 |
Earth's "Magnetosphere" COLLAPSED in space TODAY for two+ hours! Trouble ahead for all of us
A stunning and terrifying event has taken place in space surrounding our planet; for two hours today, earth's "Magnetosphere" COLLAPSED around the entire planet! The magnetosphere is what protects earth from solar winds and some radiation.
Deep within the Earth, a fierce molten core is generating a magnetic field capable of defending our planet against devastating solar winds. The protective field, called the "magnetosphere" extends thousands of miles into space and its magnetism affects everything from global communication to animal migration and weather patterns. The magnetosphere is the region of space surrounding Earth where the dominant magnetic field is the magnetic field of Earth, rather than the magnetic field of interplanetary space. The magnetosphere is formed by the interaction of the solar wind with Earth’s magnetic field. This figure illustrates the shape and size of Earth’s magnetic field that is continually changing as it is buffeted by the solar wind.
It has been several thousand years since the Chinese discovered that certain magnetic minerals, called lodestones, would align in roughly the north-south direction. The reason for this effect wasn’t understood, though, until 1600, when William Gilbert published De Magnete and demonstrated that our Earth behaved like a giant magnet and loadstones were aligning with Earth’s magnetic field.
After several more centuries of investigation, it is now known that Earth’s magnetic field is quite complex, but still, to a great extent, can be viewed as a dipole, with north and south poles like a simple bar magnet. Earth’s magnetic axis, the dipole, is inclined at about 11 degrees to Earth’s spin axis. If space were a vacuum, Earth’s magnetic field would extend to infinity, getting weaker with distance, but in 1951, while studying why comet tails always point away from the sun, Ludwig Biermann discovered that the sun emits what we now call the solar wind. This continuous flow of plasma, comprised of mostly electrons and protons, with an embedded magnetic field, interacts with Earth and other objects in the solar system.
Would you be able to sustain your loved ones when all hell brakes loose?In this video, I will unearth a long-forgotten secret that helped our ancestors survive famines, wars, economic crises, diseases, droughts, and anything else life threw at them… a secret that will help you do the same for your loved ones when America crumbles into the ground.I’m also going to share with you three old lessons that will ensure your children will be well fed when others are rummaging through garbage bins. Click here to learn all about the 3 skills that will help you thrive in any crises situation.
The pressure of the solar wind on Earth’s magnetic field compresses the field on the dayside of Earth and stretches the field into a long tail on the nightside. The shape of the resulting distorted field has been compared to the appearance of water flowing around a rock in a stream. On the dayside of Earth, rather than extending to infinity, the magnetic field is confined to within about 10 Earth radii from the center of Earth and on the nightside, the field is stretched out to hundreds of Earth radii, well beyond the orbit of the moon at 60 Earth radii.
FIELD WEAKENING DETECTED IN 2014
This magnetic field, so important to life on Earth, has weakened by 15 per cent over the last 200 years. And this, scientists think, could be a sign that the Earth’s poles are about to flip.
Experts believe we're currently overdue a flip, but they're unsure when this could occur.
If a switch happens, we would be exposed to solar winds capable of punching holes into the ozone layer.
The impact could be devastating for mankind, knocking out power grids, radically changing Earth’s climate and driving up rates of cancer.
‘This is serious business’, Richard Holme, Professor of Earth, Ocean and Ecological Sciences at Liverpool University said. ‘Imagine for a moment your electrical power supply was knocked outfor a few months – very little works without electricity these days.’
The Earth's climate would change drastically. In fact, a January, 2014 Danish study suggested global warming is directly related to the magnetic field rather than CO2 emissions.
The study claimed that the planet is experiencing a natural period of low cloud cover due to fewer cosmic rays entering the atmosphere.
TODAY: COMPLETE COLLAPSE FOR TWO+ HOURS!
This morning at 01:37:05 eastern US Time, which is 05:37:05 UTC, satellites from the NASA Space Weather Prediction Center detected a complete collapse of earth's magnetosphere! It simply vanished for just over two hours, resuming as normal around 03:39:51 eastern US time, which is 07:39:51 UTC.
Here is how NASA Space Weather Satellites recorded the event:
BEFORE the collapse:
DURING the collapse:
Notice the Black colored area, the MagnetoPAUSE is the only thing remaining. The boundary between the solar wind and Earth’s magnetic field is called the magnetopause. The boundary is constantly in motion as Earth is buffeted by the ever-changing solar wind. While the magnetopause shields us to some extent from the solar wind, it is far from impenetrable, and energy, mass, and momentum are transferred from the solar wind to regions inside Earth’s magnetosphere. The interaction between the solar wind and Earth’s magnetic field, and the influence of the underlying atmosphere and ionosphere, creates various regions of fields, plasmas, and currents inside the magnetosphere such as the plasmasphere, the ring current, and radiation belts. The consequence is that conditions inside the magnetosphere are highly dynamic and create what we call “space weather” that can affect technological systems and human activities. For example, the radiation belts can have impacts on the operations of satellites, and particles and currents from the magnetosphere can heat the upper atmosphere and result in satellite drag that can affect the orbits of low-altitude Earth orbiting satellites. Influences from the magnetosphere on the ionosphere can also affect communication and navigation systems.
Even worse, during this outage of the magnetosphere, the arrows on the image below show complete reversal of Interstellar magnetic flows around earth; the arrows show all the magnetic energy from interstellar space is moving back toward the Sun!
AFTER the collapse:
Just over two hours later, the Magnetosphere was back and all the Solar wind magnetic energy is once again flowing away from the sun.
This magnetic juggling act can have devastating effects upon Earth. This is not a small magnetic situation; it is HUGE . . . planetary HUGE. When something this large happens to earth's magnetic fields, it can trigger massive earthquakes, volcanic eruptions, unpredictable ocean currents and tides. The blast of heat energy that managed to get through the magnetoPAUSE during this time on the dayside of the planet, will have sent a large surge of heat energy into the exposed ocean areas, increasing water temperatures enough to cause severe storms.
Hang-on, folks. We could be in for quite a ride over the next few days as this strange occurrence plays out in earth's weather and seismic events.
SOURCE : superstation95.com | 0.819218 | 3.126 |
The scientific phenomenon is not a new one: Einstein himself predicted that any spinning body drags the fabric of spacetime in his general theory of relativity, and coined the process “frame-dragging.” Scientists have even hypothesized the effect that the Earth has on the spacetime around it, estimating that the area around the globe rotates one degree every 100,000 years or so.
However, researchers were able to finally see the theory proven after scientists searched for an example with a greater gravitational pull, and found one in a white dwarf and neutron star pair.
White dwarfs are the dead remnants of a star and are hundreds of thousands of times more massive than Earth. Moreover, they spin quickly, completing one cycle every 60-120 seconds vs. every 24 hours.
That means that the frame-dragging caused by a white dwarf would be close to 100 million times more powerful than Earth’s.
A neutron star is also the remnant of a dead star, but even denser. It spins an incredible 150 times per minute, emitting a light beam that astronomers used to help calculate their predictions.
The specific pulsar — and white dwarf — targeted by astronomers was PSR J1141-6545, which includes a young pulsar about 1.27 times the mass of the sun, at an eye-watering 10,000 to 25,0000 light years away from Earth.
Scientists measured when the light flashes of the pulsars would arrive on Earth for a period of over 20 years, using the Parkes and UTMOST radio telescopes in Australia. Over the two decades, they noticed that there were slight changes in their calculations, meaning the object had “drifted” from its original location.
Since there were no other explanations for the movement, astronomers realized that the gravitational force of the pairing had caused the pulsar’s orbit to change its orientation over time by altering spacetime around it.
The new study “confirms a long-standing hypothesis of how this binary system came to be, something that was proposed over two decades ago,” said lead author Vivek Venkatraman Krishnan, an astrophysicist at the Max Planck Institute for Radio Astronomy in Bonn, Germany (via Space).
Venkatraman Krishnan added that he hoped he could use the method to investigate double neutron star systems.
“The density of matter inside a neutron star far exceeds what can be achieved in a lab, so there is a wealth of new physics to be learnt by using this technique to double neutron-star systems,” he continued.
In other space news, scientists have discovered that the black hole in the center of our galaxy is creating a new type of star not seen before, as was previously reported by The Inquisitr. | 0.822601 | 4.092871 |
New images of the dwarf planet Ceres, the largest body in the asteroid belt, reveal a world that's even stranger than scientists expected.
The 590-mile-wide (950 kilometers) icy world is pockmarked by craters, photos released Tuesday show, and has curiously rugged terrain at its south pole and several enigmatic bright spots dotting its surface.
It's those bright spots—perhaps expanses of ice, but for now scientists can't say—that are attracting the bulk of speculation. At least one of them has been glimpsed before in blurrier pictures taken with the Hubble Space Telescope.
"Our sharper view reveals some [spots] that Hubble could not discern," says Dawn chief engineer and mission director Marc Rayman of NASA's Jet Propulsion Laboratory. "As Dawn gets closer and gathers more data on their appearance and their composition, we surely will get insight into what they are. I can't wait!"
Shot February 12, the latest images were taken when the Dawn spacecraft was 53,500 miles (86,000 kilometers) from Ceres. Dawn is scheduled to slip into orbit around Ceres on March 6 and spend the next year looking for clues about what the world is made of, what lies beneath its surface, and the unexpected tufts of water vapor reported in 2014.
Why It Matters
Watery and relatively huge, Ceres is wildly out of place in the asteroid belt, a stretch of space between Mars and Jupiter that's mostly populated by smaller, dustier space rocks.
Some scientists think that's because Ceres was born somewhere else, while others suggest it might have grown up at a slightly different time. Dawn will help unravel the mystery of Ceres by comparing it with another relative giant in the asteroid belt: dry and dusty Vesta, which Dawn orbited from mid-2011 through late 2012.
The Big Picture
Ceres and its neighbors are relics from the dawn of the solar system, when the sun was young and the planets grew from a swirling disk of gas and dust. Reading the ancient records stored in bodies like Ceres helps reconstruct those early years.
These worlds contain clues not only about the solar system's birth 4.5 billion years ago, but also about a tumultuous reorganization that took place hundreds of millions of years later.
The Dawn spacecraft will spend the next year studying Ceres, and when it runs out of fuel, it'll shut down and stay in orbit around the dwarf planet. | 0.891088 | 3.644249 |
Comets may not have played as big of a part in the moon’s early surface as once thought. A new study out in Nature Communications today says that 80 percent of the moon’s inner water may actually come from asteroids.
After hydrogen atoms were found in samples of the moon’s interior six years ago, an international group of researchers set out to find the water’s origin. By studying hydrogen isotopes, carbon to nitrogen ratios, and other elements, they were able to compare moon samples to lists of asteroid and comet components. They matched most of the moon’s interior water to asteroids and a smaller percentage, less than 20 percent, to comets.
The researchers were also able to tell that the brunt of lunar water, which measures at around 100 parts per million, was delivered about 4.5 billion years ago, before the Late Heavy Bombardment, a time when the moon, Earth and other inner planets were hit by an astounding number of asteroids.
While the scientists speculate that most of the water came from asteroids, they also propose an alternative theory where up to 25 percent of lunar water came from the creation of the moon from the Earth 4.5 billion years ago. But some scientists think it is unlikely any water from Earth would have made it through a time in the moon’s early history when the surface was molten and water easily evaporated.
Nicely enough, these findings support the idea that not only the moon and Earth but all of the inner solar system’s water came from asteroids from about 4.5 to 3.9 billion years ago.
Asteroids, and some comets, may have been the beginnings of water in our solar system, and therefore, the beginnings of life.
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- On the Moon, Astronaut Pee Will Be a Hot Commodity - May 24, 2020 | 0.827066 | 3.475316 |
Astronomers reveal top 20 planets with aliens, most similar to Earth
• Second Earth’ found orbiting sun’s stellar neighbour could have oceans of liquid water
• NASA’s Kepler has discovered over 4,000 exoplanets in three years
• Theory says life could have evolved on Venus with ‘nudge’ in conditions
The United States Aeronautic Space Agency (NASA’s) Kepler telescope has been busy in the hunt for alien life, finding over 4,000 new planets outside Earth’s solar system over the past three years.
Now a team of astronomers has narrowed down this list to those with the most potential to have liquid water, or even life.They pinpointed 20 out of the 4,000 that are most likely to be like our own, and are starting to look more closely at these candidates.The ‘habitable zone’ is an area around a star in which an orbiting planet’s surface could hold liquid water.
The boundaries of the habitable zone are critical. If a planet is too close to its star, it will experience a runaway greenhouse gas effect, like Venus. But if it’s too far, any water will freeze, as is seen on Mars.A group led by San Francisco State University physicists searched through the list Kepler had returned to find those most likely to support life like our own.
They found 216 Kepler planets are located within the ‘habitable zone’ – an area around a star in which an orbiting planet’s surface could hold liquid water.Of those, they list 20 that are the best candidates to be habitable rocky planets like Earth.These include Kepler-186 f, Kepler-62 f, Kepler-283 c and Kepler-296 f.
Meanwhile, if reports of a new discovery are to be believed, of all the 100 billion stars in our universe, the one closest to us might just be one that supports alien life.According to reports, a newly-spotted planet in our galactic neighbourhood might have the right conditions for life.
Scientists spotted the planet, which is believed to be ‘Earth-like’, orbiting the star Proxima Centauri, the nearest stellar neighbour to our sun.The researchers are due to unveil the discovery later this month and apparently believe it orbits its star at a distance that could favour life – the so-called habitable zone, claims German weekly Der Spiegel.
Proxima Centauri is part of the Alpha Centauri star system just 4.2 light years from our own solar system.According to Der Spiegel, the European Southern Observatory (ESO) will announce the finding at the end of August.ESO spokesman Richard Hook said he is aware of the report, but refused to confirm or deny it. “We are not making any comment,” he said.
Proxima Centauri is the closest star to our own. A planet orbiting the star would be the closest exoplanet to Earth.Discovered in 1915, Proxima Centauri is one of three stars in the Alpha Centauri system, a constellation mainly visible from the southern hemisphere.The planet is thought to be in the star’s ‘habitable zone’ – an area around a star in which an orbiting planet’s surface could hold liquid water.
Meanwhile, a new theory has claimed if conditions had been just a little different, life could exist on a lush, green Venus and Earth would be a dead planet.Researchers say that minor evolutionary changes could have altered the fates of both Earth and Venus – and hope to soon be able to model them.
This could make the search for alien life far more fruitful, and rewrite the theory of ‘goldilocks zones’ where life can exist. The hypothesis by Rice University scientists and their colleagues is published in Astrobiology this month.
The Goldilocks zone has long been defined as the band of space around a star that is not too warm, not too cold, rocky and with the right conditions for maintaining surface water and a breathable atmosphere.
But that description, which to date scientists have only been able to calibrate using observations from our own solar system, may be too limiting, Rice Earth scientist Adrian Lenardic said.Lenardic and his colleagues suggested that habitable planets may lie outside the ‘Goldilocks zone’ in extra-solar systems, and that planets farther from or closer to their suns than Earth may harbor the conditions necessary for life.
“For a long time we’ve been living, effectively, in one experiment, our solar system,” he said.Lead author of the first study, Prof. Stephen Kane, said: “This is the complete catalogue of all of the Kepler discoveries that are in the habitable zone of their host stars.
“That means we can focus in on the planets in this paper and perform follow-up studies to learn more about them, including if they are indeed habitable.“This study is a really big milestone toward answering the key questions of how common is life in the universe and how common are planets like the Earth.”
The research also confirms the distribution of Kepler planets within the habitable zone is the same as the distribution of those outside of it.This means the universe is teeming with planets and moons where life could potentially exist.
The researchers further sorted them by planet size: smaller, rocky planets versus larger gas giants.The 20 planets in the most restrictive category, rocky surface and a conservative habitable zone, are the most likely to be similar to Earth.
Kane has already started to gather more data on these planets, as well as those in the other categories.“It’s exciting to see the sheer amount of planets that are out there, which makes you think that there is zero chance of there not being another place where life could be found,” said Michelle Hill, undergraduate student.The four categories are aimed at helping astronomers focus their research.
Those looking for moons that could potentially hold life can study exoplanets in the gas giant categories, for example.“There are a lot of planetary candidates out there, and there is a limited amount of telescope time in which we can study them,” Kane said.
“This study is a really big milestone toward answering the key questions of how common is life in the universe and how common are planets like the Earth.”An international team of astronomers has discovered a treasure trove of new worlds.Both Kepler and its K2 mission discover new planets by measuring the subtle dip in a star’s brightness caused by a planet passing in front of its star.
As early as 2012, Kepler scientists found that all five planets orbit in an area about 150 times smaller than the Earth’s orbit around the Sun, with ‘years’ of about one, three, four, seven and nine days.So far they have reported finding 197 planet candidates, with 104 planets confirmed by scientists.The planets, which are all between 20 and 50 per cent larger than Earth by diameter, are orbiting the M dwarf star K2-72, found 181 light years away.
The scientists, led by the University of Arizona, said the possibility of life on the new planets around such a star could not be ruled out.Four of the planets discovered have been found to be rocky, and could host alien life. They are thought to be between 20 and 50 per cent more massive than Earth, and they orbit a star smaller than our sun.
Two of the worlds could have radiation levels that are similar to Earth. The huge finding of planets was found by combining data with follow-up observations by earth-based telescopes including the North Gemini telescope and the WM Keck Observatory in Hawaii.
A crop of more than 100 planets, discovered by NASA’s Kepler Space Telescope, includes four in Earths size-range orbiting a single dwarf star. Two of these planets are too hot to support life as we know it, but two are in the stars ‘habitable’ zone, where liquid water could exist on the surface. These small, rocky worlds are far closer to their star than Mercury is to our sun. | 0.911002 | 3.330796 |
Skywatchers this week get a chance to track down an elusive frozen planet in the outer reaches of the solar system and glimpse the only moon known to have clouds and a dense atmosphere.
Moon meets with Uranus. On Monday and Tuesday, June 3 and 4, early bird skywatchers around the world get to see a waning crescent moon pass near the green giant Uranus before dawn. The cosmic odd-couple will appear about three degrees apart in the sky—equal to six full moons side-by-side on Monday. On Tuesday the pair will be about 12 degrees apart – a little more than the width of your fist at arm’s length.
The seventh planet from the sun has four times the width of Earth. But since Uranus lies nearly 1.9 billion miles (3.1 billion kilometers) away from Earth, it’s barely visible to the naked eye—and only in very dark, pristine skies.
With the glare from the nearby moon, binoculars will be your best bet in spotting Uranus easily. Just look for a tiny greenish-blue disk in the field of view. By the way, the absorption of red light by methane in the atmosphere is what gives Uranus it’s cool cyan coloring.
Planetary row. About a half hour after sunset on Monday Mercury, Venus, and Jupiter form a near straight ten degree line, with Mercury farthest from the horizon and Jupiter closest, and Venus nearly right in the middle.
Over the course of the rest of the week watch the lineup lengthen as Mercury climbs higher the evening sky and Jupiter continues to sink closer to the horizon.
Saturn’s moon Titan. The ringed planet Saturn is on prime display this season, riding high in southern skies in the early evenings (high in the east in southern hemisphere skies). The bright star next door is Spica—lead member of the constellation Virgo.
On Wednesday, June 5, with a small telescope trained on Saturn you can glimpse its brightest and biggest moon, Titan. It will appear as a bright star-like object about four ring-widths to the east of the planet (south of the planet in the southern hemisphere).Cassini spacecraft’s view of Saturn’s rings—edge-on—and the planet’s moon Titan. This week backyard telescope users get to glimpse the giant moon for themselves. Credit: Nasa, CICLOPS
Big Dipper dips. On Friday, June 7, with exactly two weeks to go until summer officially begins in the northern hemisphere, the iconic Big Dipper within the Ursa Major (Great Bear) constellation hangs high in the northwest at nightfall. The distinctive seven-star pattern hangs straight down with its handle high in the northwest after dark.
Venus points to young moon. Look towards the very low northwest sky about 30 minutes after sunset on Sunday, June 9, for an observing challenge. Venus will act as a guidepost to a razor-thin crescent moon directly below. The pair will be separated by about six degrees—a little more than the width of three fingers at arm’s length. For skywatchers in the southern hemisphere, the moon will be paired with Jupiter to its lower right.
Tell us—what amazing sky phenomena have you seen lately? | 0.923329 | 3.501175 |
Discover these astounding space colonies designed by NASA in the 1970s and the Mars colony they're plotting now.
NASA’s innocently named “summer studies” were anything but. Over the course of ten weeks in the summer of 1975, the project had one goal: to craft a future that would send humanity beyond its home planet.
Scientists, engineers, and academics teamed up to envision three different types of space colonies, some holding as many as a million people. If NASA’s audacious dreams had come true, handfuls of these colonies would be orbiting the Earth right now.
Here’s a look at the variety of space colonies NASA has dreamed up in the past–and the ones they’re planning for our future:
Space Colonies Of The Past: The Stanford Torus
The Stanford Torus was—comparatively speaking—the most feasible of all the space colonies proposed during the summer studies. It would have held 10,000 people in a one-mile long donut-shaped ring.
The Torus would have paired an overhead mirror with mirrors on the colony’s inner ring to pull sunlight into the inhabited outer ring. And by rotating constantly, the colony would create artificial gravity for those inside it.
According to the concept art, the Torus would also have contained a colony-wide monorail as well as trees, grass, and a water reservoir--nothing says ambitious like a lake in space.
Thanks to budget cuts from Congress, the Stanford Torus never came to be. However, the ideas behind the structure are still relevant as proven by artist Dan Roam’s sleeker, more efficient 2006 take on the basic design, presented above.
The Bernal Sphere
The Bernal Sphere was the second space colony proposed by NASA in 1975. It follows design principles similar to the Stanford Torus, but with a cylinder rather than a donut shape. Once again, a series of adjustable mirrors would provide sunlight to roughly 10,000 inhabitants.
According to an exuberantly optimistic 1977 prediction, the Bernal Spheres would perhaps be functional by the 1990s, when the space-centric workforce was estimated to be large enough to churn out a new Bernal Sphere every two years.
Needless to say, the money wasn’t there and the dream didn’t come true, but, first, NASA produced a fascinating array of concept art. How would NASA have supported their multi-billion-dollar projects? Through a number of lucrative industries they predicted would result from space colonization: space tourism, asteroid mining, zero-gravity manufacturing, and solar power, which would be transmitted to Earth via microwaves.
The O’Neill Cylinder
Princeton physicist Gerard K. O’Neill was the visionary behind the most ambitious of NASA's space colonies: the O’Neill Cylinder. The 20-mile-wide structure would house a million people in Earth’s orbit. 1970s NASA scientists referred to it as “Island 3,” meaning that it would be a third generation space colony not operable until far into the 21st century.
In NASA’s vision, entire generations of people would live on the colony. For them, curved landscapes leading to an entire land directly above their heads would appear normal. They might even be able to vote on what weather they would prefer.
Different modules would be tailored for the growth of different foods, and each cylinder would be paired with another one in order to cancel out the gyroscopic forces that might otherwise keep the space colonies spinning away from the sun.
Space Colonies Of The Future: Mars
In addition to creating viable space colonies, 1970s-era NASA sought to develop interplanetary travel. Coming off of their big 1969 moon-landing win, NASA set its sights on the natural next target: Mars.
The Apollo Extensions Program explored possible plans: a manned lunar colony, Earth-orbiting space station, and space probe fly-bys for the entire outer solar system. A spin-off of that program, the Apollo Applications Program, was NASA’s push for a manned fly-by of Mars in 1978.
Sadly, Congress was more interested in defense spending and the budget for any 1970s plans was cut short by half a billion dollars in 1967. NASA still managed to send unmanned probes past Venus, Jupiter, and Mercury, but no space stations got off the ground.
Still, the future looks bright for NASA: They’re working on the manned Mars mission once more, with a landing planned for the 2030s.
This time, they’re looking beyond their 1970s plans to orbit the Earth with space stations, with the lofty goal of starting a colony on the surface of the Red Planet. A planned 2035 Mars landing could establish a small greenhouse, a prerequisite for future colonization.
To prep for a Mars mission, the agency will complete a series of tough missions in the next two decades, including an “asteroid mission” that will capture an asteroid, redirect its orbit around the moon, and land astronauts on it. NASA’s chief scientist Dr. Ellen Stofan has even speculated on NASA’s goals after reaching Mars, saying that a trip to the Jupiter moon Europa is “clearly our next step.”
NASA’s dreams for a multi-billion-dollar industry in Earth's orbit might have fallen though, but the agency’s ambition and optimism clearly can’t be killed. | 0.857155 | 3.02562 |
A new study provides the first conclusive proof of the existence of a space wind first proposed theoretically over 20 years ago.
By analysing data from the European Space Agency’s Cluster spacecraft, researcher Iannis Dandouras detected this plasmaspheric wind, so-called because it contributes to the loss of material from the plasmasphere, a donut-shaped region extending above the Earth’s atmosphere. The results are published today in Annales Geophysicae, a journal of the European Geosciences Union (EGU).
“After long scrutiny of the data, there it was, a slow but steady wind, releasing about 1 kg of plasma every second into the outer magnetosphere: this corresponds to almost 90 tonnes every day. It was definitely one of the nicest surprises I’ve ever had!” said Dandouras of the Research Institute in Astrophysics and Planetology in Toulouse, France.
The plasmasphere is a region filled with charged particles that takes up the inner part of the Earth’s magnetosphere, which is dominated by the planet’s magnetic field.
To detect the wind, Dandouras analysed the properties of these charged particles, using information collected in the plasmasphere by ESA’s Cluster spacecraft. Further, he developed a filtering technique to eliminate noise sources and to look for plasma motion along the radial direction, either directed at the Earth or outer space.
As detailed in the new Annales Geophysicae study, the data showed a steady and persistent wind carrying about a kilo of the plasmasphere’s material outwards each second at a speed of over 5,000 km/h. This plasma motion was present at all times, even when the Earth’s magnetic field was not being disturbed by energetic particles coming from the Sun.
Researchers predicted a space wind with these properties over 20 years ago: it is the result of an imbalance between the various forces that govern plasma motion. But direct detection eluded observation until now.
“The plasmaspheric wind is a weak phenomenon, requiring for its detection sensitive instrumentation and detailed measurements of the particles in the plasmasphere and the way they move,” explains Dandouras, who is also the vice-president of the EGU Planetary and Solar System Sciences Division.
The wind contributes to the loss of material from the Earth’s top atmospheric layer and, at the same time, is a source of plasma for the outer magnetosphere above it. Dandouras explains: “The plasmaspheric wind is an important element in the mass budget of the plasmasphere, and has implications on how long it takes to refill this region after it is eroded following a disturbance of the planet’s magnetic field. Due to the plasmaspheric wind, supplying plasma – from the upper atmosphere below it – to refill the plasmasphere is like pouring matter into a leaky container.”
The plasmasphere, the most important plasma reservoir inside the magnetosphere, plays a crucial role in governing the dynamics of the Earth’s radiation belts. These present a radiation hazard to satellites and to astronauts travelling through them. The plasmasphere’s material is also responsible for introducing a delay in the propagation of GPS signals passing through it.
“Understanding the various source and loss mechanisms of plasmaspheric material, and their dependence on the geomagnetic activity conditions, is thus essential for understanding the dynamics of the magnetosphere, and also for understanding the underlying physical mechanisms of some space weather phenomena,” says Dandouras.
Michael Pinnock, Editor-in-Chief of Annales Geophysicae recognises the importance of the new result. “It is a very nice proof of the existence of the plasmaspheric wind. It’s a significant step forward in validating the theory. Models of the plasmasphere, whether for research purposes or space weather applications (e.g. GPS signal propagation) should now take this phenomenon into account,” he wrote in an email.
Similar winds could exist around other planets, providing a way for them to lose atmospheric material into space. Atmospheric escape plays a role in shaping a planet’s atmosphere and, hence, its habitability.
This research is presented in the paper ‘Detection of a plasmaspheric wind in the Earth’s magnetosphere by the Cluster spacecraft’ to appear in the EGU open access journal Annales Geophysicae on 2 July 2013. Please mention the publication if reporting on this story and, if reporting online, include a link to the paper or to the journal website.
The scientific article is available online, free of charge at: http://www.ann-geophys.net/31/1143/2013/angeo-31-1143-2013.html
The paper is authored by Iannis Dandouras of the Research Institute in Astrophysics and Planetology (IRAP), a joint institute of the French National Centre for Scientific Research (CNRS) and the Paul Sabatier University in Toulouse, France. The data was acquired by the CIS, Cluster Ion Spectrometry, experiment onboard ESA’s Cluster, a constellation of four spacecraft flying in formation around Earth.
The European Geosciences Union (EGU) is Europe’s premier geosciences union, dedicated to the pursuit of excellence in the Earth, planetary and space sciences for the benefit of humanity, worldwide. It is a non-profit interdisciplinary learned association of scientists founded in 2002. The EGU has a current portfolio of 15 diverse scientific journals, which use an innovative open access format, and organises a number of topical meetings, and education and outreach activities. Its annual General Assembly is the largest and most prominent European geosciences event, attracting over 11,000 scientists from all over the world. The meeting’s sessions cover a wide range of topics, including volcanology, planetary exploration, the Earth’s internal structure and atmosphere, climate, energy, and resources. The 2014 EGU General Assembly is taking place is Vienna, Austria from 27 April to 2 May 2014. For information regarding the press centre at the meeting and media registration, please check http://media.egu.eu closer to the time of the conference.
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(THIS ARTICLE IS COURTESY OF THE ST. GEORGE NEWS)
ST. GEORGE — Earth’s ancient relative, the Smith-Tuttle comet, is set to be the headliner for three nights in August, producing a brilliant light show as fragments of the 4-billion-year-old snowy dirtball streak across the skies during one of the most active meteor showers of the year.
The Perseid meteor shower will make its peak three-night appearance from Aug. 11-13, and is known to be a rich, steady meteor shower that sends 60-70 meteors slamming into the Earth’s atmosphere at more than 130,000 mph every hour. This year’s meteor shower event will be make even more spectacular by the “slender waxing crescent moon,” according to EarthSky’s 2018 Meteor Shower Guide.
Meteors are small fragments of cosmic debris entering the earth’s atmosphere at extremely high speed. They are caused by the copious amounts of particles produced each time a comet swings around the sun and eventually spread out along the entire orbit of the comet to form a meteoroid stream.
If the Earth’s orbit intersects with the comet’s orbit, as it does with the Swift-Tuttle Comet, then it passes through that stream, which produces a meteor shower. If that intersection occurs at roughly the same time each year, then it becomes an annual shower, according to the American Meteor Society.
Swift-Tuttle has an eccentric, oblong orbit around the sun that takes 133 years. The comet’s orbit takes it outside the orbit of Pluto when farthest from the sun, and inside the Earth’s orbit when closest to the sun, releasing particles of ice and dust that become part of the Perseid meteor shower.
Perseid showers last for weeks instead of days and have been streaking across the sky since July 17, and while they are heaviest during the three-day period beginning Saturday, they will continue for at least 10 days after.
The fast, bright meteors appear in all parts of the sky, roughly 50 to 75 miles above the earth’s surface and leave continual trains, which is the persistent glow caused by the luminous interplanetary rock and dust left in the wake of the meteoroid, and often remain long after the light trail has dissipated.
These meteors, which can reach temperatures of more than 3,000 degrees Fahrenheit, start from northerly latitudes during mid-to-late evening and tend to strengthen in number as the night continues, typically producing the greatest number of showers in the hours just before dawn, which is also moonless and makes them easier to see against the black backdrop.
Because meteor shower particles are all traveling in parallel paths at the same velocity, they appear to radiate from a single point in the sky, similar to railroad tracks converging to a single point as they vanish beyond the horizon. The Perseid shower originates from a point in front of the constellation Perseus, which ranks 24 on the list of largest constellations and is visible from August to March in the Northern Hemisphere.
Here are Perseid meteor shower viewing tips:
- An open sky is essential as these meteors streak across the sky in many different directions and in front of a number of constellations.
- Getting as far away from city lights will provide the best view, and the best time to watch the showers is between midnight and dawn.
- Provide at least an hour to sky watch, as it can take the eyes up to 20 minutes to adapt to the darkness of night.
- Put away the telescope or binoculars, as using either one reduces the amount of sky you can see at one time, and lowers the odds that you’ll see a meteor.
- Let your eyes relax and don’t look in any one specific spot. Relaxed eyes will quickly catch any movement in the sky and you’ll be able to spot more meteors.
- Be sure to dress appropriately – wear clothing appropriate for cold overnight temperatures.
- Bring something comfortable on which to sit or lie. A reclining chair or pad will make it far more comfortable to keep your gaze on the night sky.
- Avoid looking at your cell phone or any other light, as both destroy night vision.
To mix things up a bit, the Delta Aquariids meteor shower, which peaked July 27, the same night as the century’s longest lunar eclipse, is still showering icy space dust across the sky and is running simultaneously with the Perseid’s.
Email: [email protected]
Copyright St. George News, SaintGeorgeUtah.com LLC, 2018, all rights reserved. | 0.865732 | 3.51748 |
The The Infrared Astronomical Satellite (IRAS) orbits the Earth in this illustration.
Two defunct satellites will zip past each other at 32,800 mph (14.7 kilometers per second) in the sky over Pittsburgh on Thursday evening (Jan. 29). If the two satellites were to collide, the debris could endanger spacecraft around the planet.
It will be a near miss: LeoLabs, the satellite-tracking company that made the prediction, said they should pass between 50 feet and 100 feet apart (15 to 30 meters) at 6:39:35 p.m. local time.
One is called the Infrared Astronomical Satellite (IRAS). Launched in 1983, it was the first infrared space telescope and operated for less than a year, according to the Jet Propulsion Laboratory. The other is called the Gravity Gradient Stabilization Experiment (GGSE-4), and was a U.S. Air Force experiment launched in 1967 to test spacecraft design principles, according to NASA. The two satellites are unlikely to actually slam into each other, said LeoLabs CEO Dan Ceperley. But predictions of the precise movements of fairly small, fast objects over vast distances is a challenge, Ceperley told Live Science. (LeoLabs’ business model is selling improvements on those predictions.)
If they did collide, “there would be thousands of pieces of new debris that would stay in orbit for decades. Those new clouds of debris would threaten any satellites operating near the collision altitude and any spacecraft transiting through on its way to other destinations. The new debris [would] spread out and form a debris belt around the Earth,” Ceperley said.
LeoLabs uses its own network of ground-based radar to track orbiting objects. Still, Jonathan McDowell, a Harvard-Smithsonian Center for Astrophysics astronomer who tracks satellites using public data, said the near-miss prediction was plausible.
“I confirm there is a close approach of these two satellites around 2339 UTC Jan 29. How close isn’t clear from the data I have, but it’s reasonable that LEOLabs data is better,” McDowell told Live Science.
(When it’s 23:39 UTC it’s 6:39 p.m. Eastern time, which is the time zone in Pittsburgh.)
“What’s different here is that this isn’t debris-on-payload but payload-on-payload,” McDowell said. In other words, in this case two satellites, rather than debris and a satellite, are coming close to one another.
It’s pretty common for bits of orbital debris to have near misses in orbit, Ceperley said, which usually go untracked. It’s more unusual, though, for two full-size satellites to come this close in space. IRAS in particular is the size of a truck, at 11.8 feet by 10.6 feet by 6.7 feet (3.6 by 3.2 by 2.1 m).
“Events like this highlight the need for responsible, timely deorbiting of satellites for space sustainability moving forward. We will continue to monitor this event through the coming days and provide updates as available,” LeoLabs said on Twitter. | 0.805175 | 3.28664 |
SPRING EQUINOX: A TIME OF BALANCE AND REBIRTH
The Vernal or Spring Equinox, which occurred, March 20, 2019, is easily the most important astronomical event of the year. It was a time of almost equal hours of sunlight and darkness in a day. It signaled a new beginning: a time of balance, change, rebirth, resurrection and fertility. It was a time to clean up the fields and sow new seeds after the cold barren winter. Indeed, it was used to mark the beginning of the astronomical year. (January 1 became the new year in 46 BC as decreed by Julius Caesar).
The spring equinox’s lures were so profound that it has been celebrated, incarnated, reincarnated and deified with myths and legends abounding in almost all major civilizations, since antiquity. Indeed, it is the common thread in many major religions and cultures since Mesopotamia and was based on the position of the sun in the sky.
On a philosophical note, the spring equinox is a time of balance as there is an equal amount of sunlight (good) and darkness (bad). It is the beginning of a time when the light (good) conquers darkness (bad) for 6 months as the hours of daylight per day begin to lengthen until it reaches its longest on June 22, beginning of summer. It is a time to clear out the negatives and to start new projects and relationships. It’s a time to resurrect the positive energy that flows within but has been dormant.
Undoubtedly, the magic of spring has had such a cocaine hallucinating addictive type effect on mankind since creation that its deification and worship is almost surreptitious.
WHAT’S MAGICAL ABOUT THE VERNAL (SPRING) EQUINOX
In the Northern Hemisphere, the Spring Equinox can take place on March 19, 20 or 21. The Vernal or Spring equinox is also called “the first day of spring“, with vernal meaning spring or “fresh” and equinox meaning equal nights. On March 20, the sun moves from south of the celestial equator to north of the equator. The hours of day lights, which have been getting longer since the winter solstice, Dec. 20 – 23, now equals the nights in length.
From March 20, until the summer solstice on June 20 – 21, the sunlight will gradually get longer because the sun will be higher in the sky, giving more hours of sunlight. (If you were noticing, night fall comes much earlier in December than say in June).
Also, if you live in North America you will understand and feel the magic that early man was experiencing when spring came. It was life anew: the birds that flew south were returning; the trees were putting out leaves as if resurrected; the snow was gone and long lonely days of winter were gone. More hours of sun means warmer, I mean hotter, days. Warmer days mean more farming, more food supplies and more fun and frolic. It was magic happening.
It begs the question, who are what was causing this magic and rebirth of life. Naturally, it would not only be important to know but also prudent to help encourage these entities to act favourable to man through worship and praise. Since the creator, to whom all praise is due, is a spirit and cannot be seen, man created god (s) in his own image and likeness based on astrological designs. The spring equinox was one of the first deity created to give recognition to nature.
EASTER (ISHTAR): MAGIC MEETS MYSTICISM
According to popular myths and legends , Inanna, was the first name for the Spring Equinox deity as coined by the ancient Sumerian who called her goddess of love, beauty, sex, desire, fertility, war, combat, justice, and political power. She was also known as the Queen of Heaven. Later on, Inanna was worshiped by the Babylonians and Assyrians under the name Ishtar or Ashtoreth or (goddess of fertility).In Greek Mythology she was called Aphrodite and her husband was Adonis or Dumuzid the Shepherd (later known as Tammuz). Ancient Egypt had her as Isis and her husband Osiris. German (Eostre) and Anglo Saxons (Easter) were similar. She was associated with the planet Venus, the morning star, the brightest object in the sky.
EASTER AND SEMIRAMIS, WIFE OF NIMROD
Some Easter legends and myths also include Nimrod of the tower of babel fame, and his wife, Semiramis. After his death, Nimrod became the sun god and used his rays of light to impregnate his wife, now a widow.
The child was called Tammuz , son of the sun god and was responsible for bringing light into the world and to fight darkness.
After, Semiramis’s death, Nimrod sent her back to earth as the Spring fertility goddess, Ashtoreth or Easter. She emerged from a giant egg that landed in the Euphrates River in Mesopotamia on the Spring Equinox. To prove her divine authority, Semiramis, changed a bird into an egg laying rabbit. (Easter eggs and rabbits?)
The tragedy continued with Tammuz being killed by a boar (hog) at age 40. In order to bring him back to life, the idea of 40 days of abstinence from wantonness and red meat was instituted. One day for each year of his life. His death celebrations (now Lent) are tied to Easter, with the beginning (called Ash Wednesday) being 40 days counting backward, from Easter, without the Sundays. Sundays are “Holy days”. Ham or pig was eaten at Easter in remembrance of Tammuz’s death.
KEEPING TRACK OF THE SPRING EQUINOX AND EASTER
To keep track of the beginning of spring in order to worship Easter was no easy feat despite the use of calendars. Today, we are used to a solar calendar with New Years Day falling on January 1; a “year” of 12 months (365 1/4 days) which was based on the earth’s rotation around the sun.
However, the early Romans, had a lunar calendar with 10 months of 304 days, much less than the solar 365 1/4 days. The year begun in March. Romulus, the legendary first ruler of Rome, is accredited with this calendar in 753 B.C.E.
The Roman ruler Numa Pompilius , 713 BCE, was credited in adding January at the beginning and February at the end of the calendar to create the 12-month year This made the Roman year 355 days long but still shorter than the solar 365 1/4 as it was still lunar.
Julius Caesar, corrected this in 46 B.C. by making that year 445 days long by imperial decree, bringing the calendar back in step with the seasons. He made the solar year (with the value of 365 days and 6 hours) the new basis for the calendar. The months were 30 or 31 days in length, and to take care of the 6 hours, every fourth year was made a 366-day year. Moreover, Caesar decreed the year began with the first of January, not with the traditional vernal equinox in late March.
However, despite this correction, the Julian calendar was still 111/2 minutes longer than the actual solar year, and after a number of centuries, even 111/2 minutes adds up.
The Church became concerned with this problem, as it was affecting the actual date of the spring equinox, and in the 1582 Pope Gregory XIII introduced a new calendar. The Gregorian calendar omitted 10 days for that year and established the new rule that only one of every four centennial years should be a leap year. In short, the new formula for calculating leap years required the year to be evenly divisible by 4; that the year cannot be evenly divided by 100, unless it is also evenly divisible by 400.
FACTS, FICTION AND FALLACY OF EASTER AND THE SPRING EQUINOX
Let’s recall that a fact is a thing done or known to be true or existent; in reality. On the other hand a fiction is ” invented statement or narrative; conventionally accepted false hood. Fallacy is ” mistaken belief; faulty reasoning or misleading argument. Some prevailing facts, fiction and fallacy surrounding the Spring Equinox and Easter are outlined below.
Spring equinox is an astronomical event that was once used to note the beginning of the year. This is a fact and it still does. It occurs between March 19 – 21, when the sun moves from south of the celestial equator to north of the equator and the day light equaled the dark night in length, or “equinox” — Latin for “equal nights.”
The spring equinox was deified and worshiped. Fact. Since the spring equinox promised balance, the beginning of fertility and rebirth, it was made into “goddess of fertility” and the “queen of heaven” since antiquity. Fact. She went under different names such as Inanna, Ishtar, Easter and Ashtoreth, before Abraham, Moses, Jeremiah or even Jesus Christ was born..
Easter, as the deification of the spring equinox was calculated using the full moon after the spring equinox. Fact, It is now held on the Sunday after the full moon after the spring equinox as decreed by Constantine at the Nicea council in AD 326. Since, it is dependent on the full moon after the spring equinox, it can be as early as March 22 or as late as April 25. Recall last year 2018, Easter was fittingly on April 1 or All’ Fools’ Day. This year it is April 21. It will be on April 12, 2020.
Easter was not originally in recognition of Christ’s death and resurrection. It is a fact that Easter is now being taught as the “death and resurrection of Christ, but in reality it is fiction with fallacy. It was not an original intention. The evidence is that Easter was before Christ and was only attached to Christ, 326 years after his death by Emperor Constantine at Council of Nicea. This convenient marriage of old Roman paganism, Easter, with Christ’s name was a political and civil decision to appease the followers of Christ and continue the old mystery religion of Rome.
Christ died on Friday and not Wednesday? Fiction and fallacy. It is is myth and mistaken belief or faulty reasoning. Friday to Sunday is not three days and three nights.
The logic of Jonas:“For as Jonas was three days and three nights in the whale’s belly; so shall the Son of man be three days and three nights in the heart of the earth.” (Matthew 12:38-40).
Most people tend to agree that by early Sunday morning Christ had risen from the dead. They tend to disagree about when he was killed. Counting backward, from his resurrection, Sunday, logically, three days and three nights would be Wednesday.
What, wasn’t Christ crucified on a Friday? Let us check. The fact is the bible said he was killed the day before the Sabbath. We normally assume that the day before the sabbath is Friday. Most times this is true but did you notice that there were two Sabbaths mentioned in the week when Christ was crucified. A High Sabbath and the Saturday Sabbath. Well, it is the key to unlocking the day of death of Christ.
According to John 19:31, “the Jews therefore, because it was the preparation, that the bodies should not remain upon the cross on the sabbath day, (for that sabbath day was an high day,) besought Pilate that their legs might be broken, and that they might be taken away”
According to Leviticus 23, there are seven (7) High Sabbaths, and one is celebrated annually on Nisan 14 which is roughly March/April. These High Sabbaths and the regular Saturday Sabbath are different. The High Sabbath in March/April can fall on any day of the week. it is always Nisan 14. It is celebrated after the Passover in remembrance of the Israelite’s exodus from Egypt, not the killing of Christ.
You may recall, Christ rode into town on an ass on “palm” Sunday for the upcoming Passover, spent Monday in Jerusalem, the next day Tuesday; after he had the Passover dinner with his disciples, he was arrested in the garden of Gethsemane in the night. He was tried and killed the next day Wednesday by 3 pm, which was the preparation day for the High Sabbath, the following day, Thursday. The High Sabbath, Thursday came and went.
On Friday, the day after the High Sabbath, the women bought and prepared spices for Christ’s body but could not get it done on time as they had to prepare for the upcoming Saturday Sabbath, which began Friday evening. They decided that they would wait until Sunday, after the Saturday Sabbath, to put the spice on Christ, but when they had reached his tomb early Sunday morning he was already risen as they were told by an angel.
So in practice, every year, the week with Nisan 14 has two Sabbaths unless Nisan 14 also falls on the Saturday. So in actuality, Christ was killed the day before the High Sabbath, not the day before the Saturday Sabbath.
Still a bit fuzzy? Get your Bible and remember that in Christ’s time, a day begun at sun set or in the evening. Not at midnight as we now do. So Saturday actually begun Friday evening and ended Saturday evening with Sunday beginning Saturday evening and finishing Sunday evening.
|DAY/TIME||EVENTS||Days/night of death|
||First night (6 pm – 6 am)|
||First day (6 am to 6 pm)
Second night (6 pm – 6 am)
||Second day (6 am to 6 pm)
Third night (6 pm – 6 am)
(6 am to 6 pm)
Hence, we can count three days and nights backwards from Sunday to Wednesday, and we can count forward, three days and three nights if we go forward from being killed the day after Passover dinner to his resurrection before end of day Saturday or beginning of Sunday.
Evidence of Easter in the Bible
The spring equinox (Easter) is mentioned multiple times in the Old Testament and once in the New Testament indicating its existence before and during the time of Christ.
2 Kings 23:13 which Solomon the king of Israel had builded for Ashtoreth the abomination of the Zidonians,
1 Kings 11:5-6. He followed Ashtoreth the goddess of the Sidonians, and Molech the detestable god of the Ammonites.
1 Kings 11:33. I will do this (split the nation) because they have forsaken me and
worshiped Ashtoreth the goddess of the Sidonians…., ,
So the people of Israel removed the Baals and images of Ashtoreth. They served only Yahuwah. (1 Samuel 7:3,4)
The women were engaged in kneading dough and baking cakes of bread for the “Queen of Heaven” (Jeremiah 7:18). Ezek 8:14 behold, there sat women weeping for Tammuz. (Lent)
Acts 12: 4 state that 4 And when he (Herod) had apprehended him (Peter), he put him in prison, and delivered him to four quaternions of soldiers to keep him; intending after Easter to bring him forth to the people.
SPRING EQUINOX, EASTER AND CHRIST
The deification of the spring equinox as the goddess of fertility has been a natural development due to astronomical events. The spring equinox is simply nature doing its work of rebirth, balance and fertility. However, man’s attempt to control his destiny, has led to the deification of the beginning of spring as Ishatr, goddess of fertility or queen of heaven. Today, Christianity has embraced Easter as the death and resurrection of Christ. Although this might seem naive if not dubious, it has accomplished what Constantine, Emperor of Rome intended and decreed at the council of Nicea AD 326: the marrying of Christ’s name with pagan Easter will allow for Christianity to be legalized, the gods continuing being happy and the republic of Rome flourish. | 0.80276 | 3.119344 |
Using the 10-meter Keck-11 Telescope on Mauna Kea, Hawaii, a team of researchers discovered a dark dwarf galaxy 9.8 billion light years from Earth. This is the most distant, and only the second, galaxy of this type to ever be observed outside our local region of the universe. The galaxy has remained dark due to its inability to form many or any stars and has been classified as a satellite galaxy.
Galaxies such as our own Milky Way are believed to form over billions of years through the coming together of many smaller galaxies. As a result, it is expected that there should be many smaller dwarf galaxies scattered around the Milky Way. However, very few of these tiny relic galaxies have been observed, which has led astronomers to conclude that many of them must have very few stars or may be made almost exclusively of dark matter.
In a discovery announced Jan. 18, a team of researchers including an MIT postdoc has found a dark dwarf galaxy about 10 billion light years from Earth. It is only the second such galaxy ever observed outside our local region of the universe, and is by far the most distant.
The newly discovered dwarf galaxy is a satellite, meaning it clings to the edges of a larger galaxy. “For several reasons, it didn’t manage to form many or any stars, and therefore it stayed dark,” says Simona Vegetti, a Pappalardo Fellow in MIT’s Department of Physics and lead author of a paper on the work appearing in the Jan. 18 online edition of Nature.
Scientists theorize the existence of dark matter to explain observations that suggest there is far more mass in the universe than can be seen. They believe that dark matter should comprise about 25 percent of the universe; however, because the particles that make up dark matter do not absorb or emit light, they have so far proven impossible to detect and identify.
Computer modeling suggests that the Milky Way should have about 10,000 satellite galaxies, but only 30 have been observed. “It could be that many of the satellite galaxies are made of dark matter, making them elusive to detect, or there may be a problem with the way we think galaxies form,” Vegetti says.
In the new study, Vegetti worked with her former PhD supervisor, Professor Leon Koopmans of the University of Groningen in the Netherlands; David Lagattuta and Professor Christopher Fassnacht of the University of California at Davis; Matthew Auger of the University of California at Santa Barbara; and John McKean of the Netherlands Institute for Radio Astronomy.
The team turned to more distant galaxies to search for dark satellites, using a method called gravitational lensing. To use this technique, researchers find two galaxies aligned with each other, as viewed from Earth. The more distant galaxy emits light rays that are deflected by the closer galaxy (which acts as a lens). By analyzing the patterns of light rays deflected by the foreground lens galaxy, the researchers can determine if there are any satellite galaxies clustered around it and measure how massive they are.
“It’s really exciting that we not only have a method in hand to test predictions from the cold dark matter model, but also made a discovery of such a low mass dark satellite hundreds of times farther out in the universe compared to our local group of galaxies,” says Koopmans.
The researchers used the Keck-II Telescope in Hawaii to make their observations, taking advantage of a special piece of optical equipment that provides sharp images of the sky. They plan to use the same method to look for more satellite galaxies in other regions of the universe, which they believe could help corroborate or challenge predictions of how dark matter behaves.
“Now we have one dark satellite, but suppose that we don’t find enough of them — then we will have to change the properties of dark matter,” Vegetti says. “Or, we might find as many satellites as we see in the simulations, and that will tell us that dark matter has the properties we think it has.”
For example, because temperature determines the mass and number of satellites that form, it may be necessary to adjust the current temperature estimates for dark matter if the number of dark satellites found is less than projected.
“The existence of this low-mass dark galaxy is just within the bounds we expect if the universe is composed of dark matter that has a cold temperature. However, further dark satellites will need to be found to confirm this conclusion,” says Vegetti.
Andrey Kravtsov, associate professor of astronomy and astrophysics, says the new study is a “very valuable contribution” to the ongoing testing of the prediction that small clumps of dark matter should be found scattered around the edges of large galaxies. “The uncertainties are still quite large, but so far the abundance of such clumps is in accord with expectations of structure formation models based on cold dark matter scenario,” says Kravtsov, who was not involved in the research.
Image: David Lagattuta/W. M. Keck Observatory | 0.826019 | 3.87126 |
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