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In an incredible world first, astrophysicists detected multiple planets in another galaxy earlier this year, ranging from masses as small as the Moon to ones as great as Jupiter.
Given how difficult it is to find exoplanets even within our Milky Way galaxy, this is no mean feat. Researchers at the University of Oklahoma achieved this in February thanks to clever use of gravitational microlensing.
The technique, first predicted by Einstein’s theory of general relativity, has been used to find exoplanets within Milky Way, and it’s the only known way of finding the smallest and most distant planets, thousands of light-years from Earth.
As a planet orbits a star, the gravitational field of the system can bend the light of a distant star behind it.
We know what this looks like when it’s just two stars, so when a planet enters the mix, it creates a further disturbance in the light that reaches us – a recognisable signature for the planet.
So far, 53 exoplanets within the Milky Way have been detected using this method. To find planets farther afield, though, something a little bit more powerful than a single star was required.
Oklahoma University astronomers Xinyu Dai and Eduardo Guerras studied a quasar 6 billion light-years away called RX J1131-1231, one of the best gravitationally lensed quasars in the sky.
The gravitational field of a galaxy 3.8 billion light-years away between us and the quasar bends light in such a way that it creates four images of the quasar, which is an active supermassive black hole that’s extremely bright in X-ray, thanks to the intense heat of its accretion disc.
Using data from NASA’s Chandra X-ray observatory, the researchers found that there were peculiar line energy shifts in the quasar’s light that could only be explained by planets in the galaxy lensing the quasar.
It turned out to be around 2,000 unbound planets with masses ranging between the Moon and Jupiter, between the galaxy’s stars.
“We are very excited about this discovery. This is the first time anyone has discovered planets outside our galaxy,” Dai said.
Of course, we haven’t seen the planets directly, and are unlikely to in the lifetime of anyone alive today. But being able to detect them at all is an incredible testament to the power of microlensing, not to mention being evidence that there are planets in other galaxies.
Of course, common sense would dictate that planets are out there – but evidence is always nice.
“This is an example of how powerful the techniques of analysis of extragalactic microlensing can be,” said Guerras.
“This galaxy is located 3.8 billion light years away, and there is not the slightest chance of observing these planets directly, not even with the best telescope one can imagine in a science fiction scenario.
“However, we are able to study them, unveil their presence and even have an idea of their masses. This is very cool science.”
The research was published in The Astrophysical Journal.
A version of this article was first published in February 2018. | 0.822853 | 3.829045 |
We are discussing the origins of Planet Nine. In part 1 we explored whether it could have been produced during an orbital instability in the early Solar System. Here we will explore a much more exotic origin.
Scenario 2. Planet Nine is a planet that formed around another star and was captured by the Sun
The Sun was born in a cluster with many other stars. It probably looked something like the Trapezium cluster:
We don’t know how dense the Sun’s birth cluster was. It probably contained between a few hundred and a few thousand stars. The cluster lasted about ten million years before expanding and dissolving, sending each star on its own way into the galaxy. (The Sun is not in a cluster now).
Wide binary stars – systems in which two stars orbit each other on very wide orbits – are thought to form in the following way. Young stars feel the combined gravity of all the other stars as they orbit within their birth clusters. Stars frequently come close to other stars and give each other gravitational kicks. As the cluster expands and dissipates, two stars that happen to be close to each other can find themselves gravitationally bound on a wide orbit.
Stars can also capture planets during the cluster phase if there are a lot of planets floating around among the stars in these clusters. And there probably are a lot of free-floating planets wandering among the stars. A dozen or so free-floating (“rogue”) planets have been directly detected. We don’t know exactly how abundant free-floating planets are (some estimates are very high) but we know that there are a lot of them.
Where do rogue planets come from? They probably form like most planets do, in disks of gas and dust orbiting young stars. Then their planetary systems become unstable. Like the Nice model instability but much much stronger. Here is the cartoon version:
When the orbits of two (or more) Jupiter-like planets cross, there is a series of strong encounters and one or more planets is thrown out into interstellar space. Check out this awesome animation by Eric Ford and company:
If an instability happens during the cluster phase, the planets may be launched onto star-like orbits within the cluster. And for every Jupiter-sized planet that is ejected there are several Neptune-sized planets kicked out. We think that the majority of systems of gas giant planets become unstable, creating an abundance of rogue planets.
In its infancy, the Sun’s birth cluster contained only stars (and brown dwarfs) and leftover gas. Planetary systems were born in disks around most stars. Many of the stars formed systems of gas giant planets, and most of these became unstable. By the time the cluster dissipated it must have been teeming with planets. Like kids at a summer camp, each planet was born to a different star but sent away from home.
Could the Sun have captured Planet Nine as its birth cluster dissipated? If so, Planet Nine would have formed around a different star in the cluster. It would be an extrasolar planet lurking within the Solar System.
The answer depends on the orbital dynamics of this complicated system: planets and stars orbiting each other in a cluster as the cluster expands and dissipates. Calculations suggest that this is a low probability event. Only 1-10% of stars like the Sun capture a planet, and there is only a few percent chance of that captured planet being on an orbit like Planet Nine’s. Most of the time, the orbits of captured planets are about ten times wider than Planet Nine’s.
So capture of a rogue Planet Nine during the dissipation of the Sun’s birth cluster is not impossible, but it’s not very likely. It is at best a roughly 1% event according to current models. (Remember, of course, that models are imperfect and can change; still, this idea is not looking good at the moment).
But hope remains: there is another way that planets can be captured in clusters, during stellar fly-bys. Stars in clusters constantly pass near one another. Of course, stars everywhere in the galaxy pass by one another, but in clusters they pass closer and more often.
If a star passes close enough to a planet-hosting star, it can “steal” the planet. This only happens when the passage is close, within 2-3 times the size of the planet’s starting orbit. The captured planet has a much different orbit around its new stellar host: its orbit is much wider and more elliptical. Here is a cartoon of how this works:
Could Planet Nine have been captured during a fly-by with another star? For this to have happened, another star must have passed relatively close to the Sun. However, that star could not have passed so close as to disrupt the orbits of the Solar System’s planets. The limit is roughly 100 Astronomical Units; fly-bys closer than that have a good chance of disrupting the Solar System. This means that the other star’s planet must have been on a much wider orbit than the Solar System’s planets.
Here is one way this could work. The Sun passed relatively close (say, 200 AU away) to another planet-bearing star. That star had a planet on a very wide orbit, 100 or more times larger than Earth’s. Planets on such wide orbits are generally rare; however, in the aftermath of orbital instabilities planets spend time with very wide orbits before being completely ejected. We can imagine that the planet’s wide orbit was elliptical because it was in the process of being kicked by another, larger planet into interstellar space.
The fly-by was such that the Sun could capture the planet from the other star, but the other star could not capture the Solar System’s planets. Here is a cartoon view of how this might have happened:
It’s hard to calculate the probability of this scenario playing out, although the pieces fit relatively nicely. When planetary systems go unstable, the window during which a planet remains on a wide orbit before being ejected is several million years. The type of star cluster typically lasts 10 million years. The typical Sun-like star in a cluster akin to the Sun’s birth cluster has an encounter with another star of a few hundred Astronomical Units. Finally, the probability of capturing a planet on a wide orbit is never 100% because it depends on the planet’s actual position. It can be as high as 30%. (I am getting numbers from this paper).
I think it is entirely possible that Planet Nine was captured from another star during a fly-by. For this to have happened requires specific circumstances but nothing too special. The Sun had to pass close to a star that happened to have a planet on a wide orbit. That is probably not an exceptional event because about 20% of Sun-like stars have giant planets, most systems of giant planets go unstable, and most instabilities happen relatively early. To put numbers on it we need more careful models of this process with particular emphasis on Planet Nine.
To sum up, it’s a real possibility that Planet Nine is an extrasolar planet, born around another star then captured by the Sun. | 0.885475 | 3.868715 |
It was the ‘chirp’ heard around the world. In February scientists announced the discovery of gravitational waves formed by two black holes colliding, confirming the century old predictions of Albert Einstein.
If you’re not a physicist or a physics major, you may have only a passing familiarity with the terms used in the previous sentence. And yet, we just experienced, in a ‘galaxy far far away’, what the New York Times science reporter Dennis Overbye described as a moment “destined to take its place among the great sound bites of science, ranking with Alexander Graham Bell’s “Mr. Watson — come here” and Sputnik’s first beeps from orbit.”
The Saturday Read this week is ‘Seven Brief Lessons on Physics’ by physicist Carlo Rovelli of Aix-Marseille University and the Intitut Universitaire de France. Spend some time with this exquisite book and become a bit more fluent in the language of physics.
“These lessons were written for those who know little or nothing about modern science. Together they provide a rapid overview of the most fascinating aspects of the great revolution that has occurred in physics in the twentieth and twenty-first centuries, and of the questions and mysteries that this revolution has opened up. Because science shows us how to better understand the world, but it also reveals to us just how vast is the extent of what is still not known.”
Beginning with Einstein’s ‘beautiful theory’ of relativity, Rovelli follows the science beyond gravity to quantum mechanics and quantum gravity.
Is your hair is hurting? Hang in there.
“Physics opens windows through which we see far into the distance. What we see does not cease to astonish us. We realize that we are full of prejudices and that our intuitive image of the world is partial, parochial, inadequate. Earth is not flat; it is not stationary. The world continues to change before our eyes as we gradually see it more extensively and more clearly.”
Are we still talking about science? The magic of Rovelli’s prose is its simplicity in conveying painfully complex theories.
We learn the value of ‘wasting’ time.
“In his youth Albert Einstein spent a year loafing aimlessly. You don’t get anywhere by not ‘wasting’ time – something, unfortunately, that the parents of teenagers tend frequently to forget.”
And that we live in “A world of happenings, not of things.”
Rovelli describes concepts visually.
“…before experiments, measurements, mathematics, and rigorous deductions, science is about all about visions. Science begins with a vision. Scientific thought is fed by the capacity to ‘see’ things differently than they have been previously seen.”
And reminds us that “Genius hesitates.”
The essays originally appeared as a series for the culture section of Il Sole 24 Ore, the Italian newspaper. Released last month in the U.S., the book is ranked third on the New York Times combined print & e-book nonfiction list.
Why read ‘Seven Brief Lessons on Physics’? Because it will take you on an adventure beyond your comfort zone in the time it takes you to commute to work.
“We are made of the same stardust of which all things are made, and when we are immersed in suffering or when we are experiencing intense joy, we are nothing other than what we can’t help but be: a part of our world.” | 0.85757 | 3.13926 |
Image credit: Hubble
On August 27, 2003 the Planet Mars will be a mere 55.76 million kilometres away from the Earth – the closest it’s been in 50,000 years. Visible in the early morning, Mars is the brightest object in the sky, after the Moon and Venus, and almost any small telescope will be able to show details on the planet’s surface. Make sure you enjoy Mars’ close approach this summer, as it won’t make another visit this close for nearly 300 years.
Living too close to a neighbor may not be very appealing, but when Earth?s neighboring red planet moves closer than it?s been in 60,000 years, observers expect nothing but acclaim.
This August, scientists and amateur astronomers will benefit from the spectacular view of Mars as it appears bigger and brighter than ever before, revealing its reflective south polar cap and whirling dust clouds.
On August 27, 2003, the fourth rock from the sun will be less than 55.76 million kilometers (34.65 million miles) away from the Earth. In comparison to the space between your house and your neighbor?s yard, that may seem like a large distance, but Mars was about five times that distance from Earth only six months ago.
“Think of Earth and Mars as two race cars going around a track,” said Dr. Myles Standish, an astronomer from NASA?s Jet Propulsion Laboratory, Pasadena, Calif. “Earth is on a race track that is inside the track that Mars goes around, and neither track is perfectly circular. There is one place where the two race tracks are closest together. When Earth and Mars are at that place simultaneously, it is an unusually close approach, referred to as a ‘perihelic opposition’.”
Opposition is a term used when Earth and another planet are lined up in the same direction from the Sun. The term perihelic comes from perihelion, the point of orbit in which a celestial body is closest to the Sun. This August, Mars will reach its perihelion and be in line with Earth and the Sun at the same time.
The average opposition occurs about every two years, when Earth laps Mars on its orbit around the Sun. In 1995, the opposition brought Mars 101.1 million kilometers (62.8 million miles) from the Earth, twice as far as this most recent approach.
“It gets more complicated as the race tracks are changing shape and size and are rotating, changing their orientation,” Standish explains. “So this place where the two tracks are closest together constantly changes, changing the opposition closeness as well. This is why a ‘great’ approach, like the one this month, hasn?t happened in 60,000 years. But with the tracks closer together now, there will be even closer approaches in the relatively near future.”
Aside from visiting a local observatory, peering through a telescope is the best way to take advantage of this unique opportunity. Since June, Mars has been noticeably bright in the night?s sky, only outshined by Venus and the Moon. Observers in the Northern Hemisphere will see it glowing remarkably in the southern sky in the constellation Aquarius, best seen just before dawn.
“You’re not going to go outside and see some big red ball in the sky. It will look like a bright red star,” said Standish.
The word ‘planet’ is derived from the Greek expression for ?wanderer.? At such a close distance, Mars remains true to this expectation as it consistently wanders across the night?s sky. Tracking the “red star?s” movement from week to week is yet another way to appreciate the opposition as Mars appears to dart across the sky in comparison to more distant planets, such as Jupiter.
Although Mars will be closest on August 27, astronomers suggest viewing the planet earlier, as dust storm season is just beginning on the red planet and can obstruct a more detailed view.
Whether you are viewing through a telescope, glancing through a pair of binoculars, or star-gazing outside the city, be sure to take advantage of this once-in-a-lifetime opportunity, for Mars will not make another neighborly visit this close until 2287.
Original Source: NASA/JPL News Release | 0.864465 | 3.680001 |
In the 21st century, we know a decent amount about astronomy. There’s plenty of phenomena still shrouded in mystery — that’s what keeps it exciting! — but we’ve explored a decent amount of our corner of the universe. The words we use to describe space, however, come from way before we had this understanding. Despite being a field we consider incredibly scientific, astronomy is filled with words that allude to Roman mythology, archaic terms and ancient misconceptions. We explored 10 of our favorite space name origins to find out how our ancestors named the sky.
Asteroids can easily be confused with a comet or a meteor (see below), but they are larger than both and they’re also in a stable orbit around a star. The asteroid belt, for example, is the huge number of rocks that orbit our Sun. The word can be sourced all the way back to the Proto-Indo-European *ster-, meaning “star,” combined with *-eidos, which means “form” or “shape.” Asteroids aren’t actually star-like, based on our current understanding, but the word is still used.
Comets are balls of ice and rock left over from the formation of planets billions of years ago. They often have long tails that trail behind them, which is caused by their ice melting as they pass by stars (this is not the same as shooting stars, which we will discuss later). Comets have been observed for thousands of years, but their name comes from the Greek word komē, which means “long hair.” The Greeks called these rocks komētēs because their tails looked like long strands of hair in the sky.
Constellations are the shapes that humans have discerned out of the stars that dot the sky. Various societies have created their own constellations, but the ancient Greeks named most of the constellations we know today (though they may have ripped them off from earlier civilizations). The word “constellation” itself, however, comes from Latin. It combines the prefix com, meaning “together,” with stellare, the past participle of “to shine,” which itself derives from stella (“star”).
Cosmos refers to the whole universe and everything we know in it. Unlike many words on this list, “cosmos” hasn’t been around for that long, at least in the sense we use it today. It comes from the Greek kosmos, meaning “order” or “world,” but it didn’t become popularized as a way to describe the universe until the publication of naturalist Alexander von Humboldt’s Cosmos (or Kosmos in the original Greek). The book was based on a lecture series in which Humboldt attempted to describe the order of the universe. It has since become strongly associated with wonder and mystery thanks to Carl Sagan’s documentary series Cosmos, originally aired in 1980, and revived by Neil deGrasse Tyson in 2014.
The seven other planets in our solar system (and the one dwarf planet; sorry Pluto) are all named after Roman gods. Earth, however, is not. In fact, every language has a different word for Earth, and what unites them all is that the word originally referred not to a whole planet, but to the literal ground beneath our feet. English’s word comes from the Proto-Germanic ertho, which was indeed a word for “dirt” or “soil.”
The Milky Way Galaxy
“The Milky Way” is a weird term, even by space standards. It might be even more shocking to learn that galaxy comes from the Greek phrase galaxias kyklos, which literally means “milky circle.” Milky Way, on the other hand, was translated from the Latin via lactea. Both of these terms come from a time in history when scientists assumed that there was only one galaxy. And when they looked at it, well, it looked kind of milky. When other massive space structures were discovered, the word “galaxy” then had to be applied to other parts of the universe.
The naming of other galaxies has been eclectic. One of our closest neighbors, the Andromeda Galaxy, gets its name from a figure in Greek mythology. There are also galaxies named for their appearance, like the Whirlpool Galaxy, the Pinwheel Galaxy and the Sombrero Galaxy. There are also a few named after their discoverers, including Bode’s Galaxy and Hoag’s Object.
Like asteroids, meteoroids are in orbit around the Sun (or any other star), but they’re smaller. When a meteoroid enters the Earth’s atmosphere, it becomes a meteor. You might know that better as a “shooting star.” And if the meteor doesn’t entirely burn up on its passage down to Earth, it becomes a meteorite. The word “meteor” comes from the Greek ta meteōra, which was used to refer to any celestial phenomenon at all. It was formed by using meta (“by means of”) and -aoros (“lifted, suspended”). It wasn’t until the late 16th century that the term was specifically used to describe what are now called meteors.
The Earth has the Moon, and other planets have their own moons with various names (usually from Roman mythology). The word “moon” can be traced back a long way, all the way to Proto-Indo-European me(n)ses-. This word is also the root of “month,” and is itself derived from the Proto-Indo-European me-, which meant “to measure.” The Moon, way back in the day, was the main method of measuring time because of its phases, so it makes sense the Moon and the months are forever entwined. The word was applied to other moons when they first started being discovered in the 17th century.
As a brief aside, the first attestation of “moon” as a verb to refer to someone exposing their buttocks dates back to 1968, when it popped up in American slang. Comparing butts to moons, however, has been done since the mid-18th century.
A nebula is a cloud of dust or gas that exists in space, and they’re the basis of the beautiful space photography that’s filled with colors and textures. The word nebula comes from the Latin nebula, which means “mist, vapor, fog” (and it can be traced back even further to a Proto-Indo-European root). The word wasn’t applied to space clouds until the 1730s, however, so the choice of the Latin term was somewhat arbitrary (though Latin is a common choice in many scientific fields).
To round out the list comes the Sun, which doesn’t have a very exciting etymology, mainly because the Sun didn’t exactly need to be discovered. It’s just always been up there, shining over us. Thus, the word also goes all the way back to Proto-Indo-European — the oldest ancestor of English we know of — where the great fire in the sky was called *s(u)wen-.
*Please note: we don’t actually have a written or spoken record of Proto-Indo-European, so all words with an asterisk next to them are a reconstructed guess of what the word would be. The parentheses and hyphen also allude to this. | 0.899984 | 3.869577 |
Advanced alien life is still one of the best explanations for the mysterious behavior of the star “KIC 8462852,” according to a new study that observed the star for 15 months.
“We spent a long time trying to convince ourselves this wasn’t real. We just weren’t able to,” Ben Montet, a Caltech astronomer who co-authored a study on the star, told Gizmodo. “None of the considered phenomena can alone explain the observations.”
So far, astronomers haven’t found a good single naturalistic explanation for the star’s unusual behavior. Astronomers examined 500 other stars in the vicinity of KIC 8462852, and saw nothing else like it. The new study debunked several other possible explanations for the star.
KIC 8462852 is dimming in an odd manner, which would require it to be orbited by huge and dense formations that would block out its light. The dense formations near KIC 8462852 appear to be similar to “Dyson Spheres,” hypothetical, energy-harvesting “megastructures” aliens could build by rearranging the solar system. However, the kind of naturally formed large masses that cause KIC 8462852’s dimming aren’t consistent with the star’s age.
Scientists have pondered the existence of Dyson Spheres since the 1960s, thinking they could be a potential solution to energy problems faced by an extremely old civilization. SETI scientists have long argued humans could detect distant alien civilizations by looking for technological artifacts like Dyson Spheres orbiting other stars.
The best naturalistic explanation favored by astronomers, involves a huge mass of comets erratically orbiting the star and creating enough dust to dim the light, but a January analysis of the star’s history renders that hypothesis implausible, since the unprecedented dimming has continued for over a century. In order to dim for such a long time period, the star would need to have millions of times more dust and comets orbiting it than is actually the case.
Astronomers estimate that the dimming would require roughly 648,000 giant comets of 200 kilometers in diameter, all aligned to pass in front of the star. The chances of such a formation are so low they render it essentially impossible.
Researchers at the University of California-Berkeley Breakthrough Listen project of SETI are directing the program’s $100 million budget towards investigating the star’s unique behavior.
The star’s behavior being unusual doesn’t necessarily mean it is the result of alien life, a caveat followers of the phenomenon are careful to mention.
Astronomers previously misjudged abnormal stellar occurrences and, usually, the abnormalities are simply a new occurring natural phenomenon.
A graduate student in astronomy found an usual pulsing radio signal so predictable it seemed to be a sign of intelligent life in 1967. The astronomers even nicknamed the signal LGM-1, for “little green men,” and believed they had detected a signal from an extraterrestrial civilization, but it turned out to be the first pulsar.
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Content created by The Daily Caller News Foundation is available without charge to any eligible news publisher that can provide a large audience. For licensing opportunities of our original content, please contact [email protected]. | 0.851142 | 3.516563 |
The dominance of the Lunar Highlands by feldspar-rich anorthosites, which form when feldspars that crystallise from magmas float because of their lower density, gave rise to the idea that the Moon initially formed as a totally molten mass. That this probably resulted because the early Earth collided with a Mars-sized protoplanet stems from the almost identical chemical composition of the lunar and terrestrial mantles, as worked out from the composition of younger basalts derived from both, together with the vast energy needed to support a large molten planetary body condensing from a plasma cloud orbiting the Earth. Such a giant impact is also implicated in the final stages of core formation within the Earth.
A core formed from molten iron alloyed with nickel would have acted as a chemical attractor for all other elements that have an affinity for metallic iron: the siderophile elements, such as gold and platinum. Yet the chemistry of post-moon formation basaltic melts derived from the Earth’s mantle contain considerably more of these elements than expected, a feature that has led geochemists to wonder whether a large proportion of the mantle arrived – or was accreted – after the giant impact.
A tool that has proved useful in geochemistry on the scale of entire planets – well, just the Earth and Moon so far – is measuring the isotopic composition of tungsten, a lithophile metal that has great affinity for silicates. One isotope is 182W that forms when a radioactive isotope of hafnium (182Hf) decays. The proportion of 182W relative to other tungsten isotopes has been shown to be about the same in Lunar Highland anorthosites as it is in the Earth’s mantle. This feature is believed to reflect Moon formation and its solidification after the parent 182Hf had all decayed away: the decay has a half-life of about 9 Ma and after 60 Ma since the formation of the Solar System (and a nearby supernova that both triggered it and flung unstable isotopes such as 182Hf into what became the Solar nebula) vanishingly small amounts would remain.
Oddly, two papers on tungsten and Earth-Moon evolution, having much the same aims, using similar, newly refined methods and with similar results appeared in the same recent issue of Nature (Touboul, M. et al. 2015. Tungsten isotopic evidence for disproportional late accretion to the Earth and Moon. Nature, v. 520, p. 530-533. Kruijer, T.S. et al. 2015. Lunar tungsten isotopic evidence for the late veneer. Nature, v. 520, p. 534-537). The two of them present analyses of glasses produced by large impacts into the lunar surface and probably the mantle, which flung them all over the place, maintaining the commonality of the ventures that might be explained by there being a limited number of suitable Apollo samples. Both report an excess of 182W in the lunar materials: indeed, almost the same excess given the methodological precisions. And, both conclude that Moon and Earth were identical just after formation, with a disproportional degree of later accretion of Solar nebula material to the Earth and Moon.
So, there we have it: it does look as if Earth continued to grow after it was whacked, and there is confirmation. Both papers conclude, perhaps predictably, that the early Solar System was a violent place about which there is much yet to be learned… | 0.829329 | 4.058855 |
December 23, 2015 report
Could fast radio bursts be produced by collisions between neutron stars and asteroids?
(Phys.org)—Fast radio bursts (FRBs) are short bursts of radio emissions from the sky lasting only few milliseconds. However, their origin is still unknown, perplexing astronomers for years since the discovery of the first FRB in 2007. According to various studies, these peculiar radio bursts could be a product of a supernova, two black holes colliding, a spinning neutron star, or they could be related to hyperflares of magnetars. Now, astronomers from the Nanjing University in China are offering another explanation for this puzzling question, asking if collisions of asteroids with neutron stars are producing FRBs.
A paper, detailing the latest finding, co-authored by Yong Feng Huang and Jin-Jun Geng, was published online in the arXiv journal on Dec. 21.
The authors of the paper, using the data from about ten FRBs, obtained key parameters that could help solve the mystery of these radio bursts. FRBs were generally discovered through single-pulse search methods by using archive data of wide-field pulsar surveys at the multi-beam 64-meter Parkes radio telescope in Australia and the 305-meter Arecibo telescope, located in Puerto Rico.
FRBs are usually detected by large radio telescopes at 1.4 GHz. These events are of extremely short duration, typically lasting for less than a few milliseconds, but are detected with high intensity. The researchers noted that there are four main stages of detecting fast radio bursts.
"First, the radio telescopes are uniformly pointing toward the sky at the time of the detections. Second, for the multi-beam receiver system, usually the signal was recorded only in very few beams, typically less than four, especially by adjacent beams. Third, FRBs are characterized by large dispersion measure (DM) values, significantly larger than terrestrial sources of interference. Fourth, the observed behaviors of time delay and frequency evolution of FRBs strongly indicate that cold-plasma dispersion should have been engraved in the radio signal," the scientists wrote in the paper.
The astronomers noted also that FRBs cannot be quickly followed up to catch the counterparts in other wavelengths, as they are generally screened out from archive data, as was done by Huang and Geng in their latest research. Thus, the absence of counterparts poses great difficulties in understanding the true nature of FRBs.
The authors of the paper insist that the explanations offered by previous studies are unsatisfactory when it comes to the origin of these radio bursts. They imply that a very strong electromagnetic outburst or multi-band afterglow would be triggered and should be observed tin association with the FRB event. However, non of these phenomena have been observed.
The new hypothesis, presented in the study, can account for many of the observational characteristics of FRBs, such as the duration, the energetics and the event rate. They suggest that the collision between asteroids and neutron stars can reasonably explain many of the observed features.
Scientists have expected that the collision of small bodies with neutron stars can give birth to some kinds of X-ray bursts or some special gamma-ray bursts. The new research accounts for the possibility that these collisions are behind fast radio bursts.
"Our model can naturally explain the millisecond duration of FRBs. It can also well account for various other aspects of FRBs," the scientists wrote.
They hope that the future Chinese 500-meter Aperture Spherical Radio Telescope (FAST), which is expected to be ready for observations in late 2016, can contribute to the study of the multidimensionality of such collisions and will reveal new insights into the nature of FRBs.
As a new kind of radio transient sources detected at ∼1.4 GHz, fast radio bursts are specially characterized by their short durations and high intensities. Although only ten events are detected so far, fast radio bursts may actually frequently happen at a rate of ∼103 —- 104 sky−1 day−1. We suggest that fast radio bursts can be produced by the collisions between neutron stars and asteroids. This model can naturally explain the millisecond duration of fast radio bursts. The energetics and event rate can also be safely accounted for. Fast radio bursts thus may be one side of the multifaces of the neutron star-small body collision events, which are previously expected to lead to X-ray/gamma-ray bursts or glitch/anti-glitches.
© 2015 Phys.org | 0.813698 | 3.932527 |
How to see stars and tackle light pollution in your own backyard
The dark skies of the great outdoors help people to see the wonders of space, either with the naked eye or using telescopes. That’s why observatories are usually placed in high altitudes or remote locations, where there’s often outstanding natural beauty and little light pollution.
In my research I’ve noticed the awe and wonder that young people feel while watching the stars in dark sky sites such as the stone circle at Callanish in Scotland. The stones here are made from Lewisian Gneiss – the oldest rock in Britain – formed three billion years ago and erected by people more than 5,000 years ago. Here, the immensity of time and our universe can be felt in every fibre of the body.
Exploring the night sky in a national park could be a transformative experience for both young and old. They might see the dust lanes of the Milky Way galaxy for the first time, stretching across the night sky. Learning that this band is made from millions of stars, each not too different to our sun, gives us a new appreciation of the universe and our place within it.
Perhaps they might spot the closest galaxy to ours – Andromeda, 2.5m light years away – and marvel at how the light they’re seeing set off just before our species walked the Earth.
The sky at home
But protecting dark sky sites in national parks is only half the story. It’s a shame that light pollution means these wonderful experiences are only possible far from home. Connecting everyone with the wonders of the universe should be taken up where people live.
In the UK the Dark Sky Discovery partnership – a network of astronomy and environmental groups – has developed dark sky discovery sites that offer safe and accessible stargazing in towns and cities. Urban parks are often perfect for this if the lighting can be reduced and shielded.
Outside of these sites, there are many things that stargazers can do to see more of the night sky close to home, like picking somewhere away from direct street light or switching off outdoor security lights. Turning off all the lights in the house can make a big difference to how much of the night sky is visible from outside.
The brightest objects in the solar system, such as Jupiter, Saturn, Venus and the moon, are still visible in cities. But these simple steps to limit light pollution near your home can make it possible to see more stars and even some of the brightest constellations. It’s possible to spot and track these objects from night to night and understand the pattern of their movements.
Noticing how the moon seemingly changes shape and colour while rising, setting and moving through the surrounding stars from night to night is a memorable experience. The regular crazes around super moons suggest that people have sadly forgotten the nightly pleasure of tracking the moon.
It’s still nearly always possible to find the Plough on a clear night in the northern hemisphere. The two stars at its back – opposite the handle and known as the pointer stars – can also help people locate the pole star, which gives the direction of north. But, it’s interesting to remember that this is only a coincidence. Over thousands of years the Earth’s axis tumbles and points to many different stars that become, in each of their era, the new pole star.
You can even tell the time using the position of the pointer stars in the Plough, as if the whole constellation were a giant clock with the pole star at the centre.
Spotting Orion is also simple enough when looking for his belt – three bright stars in a line. Looking below the belt reveals three much fainter stars forming the sword. The object at the middle of this is not a star, but the Orion Nebula – a cosmic nursery of new stars.
Local action on light pollution – by people in their homes or local councils dimming and reducing non-essential lighting in parks – might seem small in scale, but the results can be impressive.
While dark sky sites remind us of how beautiful the night sky is, bringing that opportunity back to where most people live could broaden the appeal of stargazing to those who’ve never tried it before. School trips to these places are still a wonderful idea, but allowing children and their families to experience the majesty of space in their own neighbourhood could connect them to the stars for life.
Daniel Brown received funding from both STFC as well as IoP to develop and embed light pollution education as well as develop Dark Sky Discovery Sites in the Peak District National Park, UK.
Source: The Conversation: Technology http://theconversation.com/how-to-see-stars-and-tackle-light-pollution-in-your-own-backyard-125005 | 0.86323 | 3.387592 |
A Cepheid, more commonly referred to as a Cepheid variable, is a type of pulsating variable star whose periods of variability is directly related to their absolute luminosity. This precise relationship between the star's pulsation period and luminosity makes the stars invaluable indicators of astronomical distances. Today Cepheid variables are one of the methods astronomers use to determine the distances to celestial objects in the universe, known collectively as the cosmic distance ladder. They are seen as standard candles, that is astronomical objects that have a known luminosity. The best known and closest Cepheid variable to us is the current North Star Polaris.
Cepheid stars pulsate in regular intervals typically in the range from 1 to 100 days. The stars themselves are yellowish giants or supergiants, five to twenty times more massive than and up to 30,000 times as luminous as the Sun. This intense brightness allows for Cepheids to be measured in other galaxies for extra-galactic distances.
Discovery and History
The star Eta Aquilae was the first star to be discovered to have observable variability in 1784, and is the first known representative of a Cepheid. A few months later, Delta Cepheid was also discovered to be a regular variable star and became the namesake of Cepheid variables. It wasn't until 1908 though, that the regular period-luminosity relation of Cepheids were discovered when Henrietta Swan Leavitt observed the effect in her observations of thousands of variable stars in the Magellanic Clouds.
In the early 20th century it was debated wither or not other galaxies existed independent of the Milky Way, which accumulated in the 1920 Curtis-Shapley debate, of which the period-luminosity relationship of Cepheid variables was a point of contention. This debate was finally settled in the discovery of Cepheid variables in the Andromeda galaxy by Edwin Hubble in 1924, showing once and for all the Milky Way and the Universe were not synonymous, and that other galaxies do exist.
Characteristics and Causes of Cepheid variation
The cause of this regular variation in luminosity is the result of the Cepheid regularly oscillating between two states, compact and expanded. In the compact state increasing temperature and pressure builds up in the star, eventually causing it to expand and become more luminous. As the star expands to maximum, there pressure from within the star weakens considerably. At this point there is no longer enough pressure against gravity to maintain the expanded size, and the star contracts once again. This cycle repeats itself in regular, timed intervals.
The shape of the light curve of a Cepheid is commonly referred to as the shark fin when plotted as luminosity versus periods of time. This characteristic shape shows during the Cepheid's regular period of variation, there is a rapid rise to maximum brightness, followed by a brief period at peak brightness before a smooth and slow decline to minimum. Although this curve is considered the normal behavior of such a star, in observations and plotting, there is considerable scatter around such a curve.
Types of Cepheids
Cepheid variables fall into one of two categories, Type I, also known as classical Cepheids or Delta Cepheid stars, and Type II, also known as W Virginis stars. The Type I Cepheids are extreme population I stars located in the spiral arms of galaxies. Metal rich and some 4 times as luminous as Type II Cepheids, these stars typically have a variation period lasting 5 to 10 days in length. Type II Cepheids on the other hand are metal-poor population II stars. Their periods of variability typically ranges from 10 to 30 days in length, and are primarily found in elliptical galaxies, globular clusters, and galactic halos. | 0.864478 | 4.161608 |
From: NASA HQ
Posted: Friday, October 19, 2007
WASHINGTON - After an eight-year run that gave astronomers a completely new perspective on the universe, NASA has concluded the Far Ultraviolet Spectroscopic Explorer mission. The satellite, known as FUSE, became inoperable in July when the satellite lost its ability to point accurately and steadily at areas of interest. NASA will terminate the mission Oct. 18.
"FUSE accomplished all of its mission goals and more," said Alan Stern, associate administrator for the Science Mission Directorate at NASA Headquarters, Washington. "FUSE vastly increased our understanding of our galaxy's evolution and many exotic phenomena and left a strong legacy on which to build the next generation of investigations and missions."
Launched in 1999, FUSE helped scientists answer important questions about the conditions in the universe immediately following the Big Bang, how chemicals disperse throughout galaxies, and the composition of interstellar gas clouds that form stars and solar systems.
"FUSE helped pioneer low-cost, principal investigator-led astronomy missions," said Jon Morse, director of the Astrophysics Division at NASA Headquarters.
Examples of the many successes FUSE achieved during its mission are:
- By measuring abundances of molecular hydrogen (made of two hydrogen atoms), FUSE showed that a large amount of water has escaped from Mars, enough to form a global ocean 100 feet deep.
- FUSE observed a debris disk that is surprisingly rich in carbon gas orbiting the young star Beta Pictoris. The carbon overabundance indicates either the star is forming planets that could end up as exotic, carbon-rich worlds of graphite and methane, or Beta Pictoris is revealing an unsuspected phenomenon that also occurred in the early solar system.
- FUSE discovered far more deuterium, a form of hydrogen with a proton and a neutron instead of just one proton, in the Milky Way galaxy than astronomers had expected. Deuterium was produced in the early universe, but this isotope is destroyed easily in stellar nuclear reactions. "FUSE showed that less deuterium has been burned in stars over cosmic time, in agreement with modern models for the evolution of the galaxy and the recent Wilkinson Microwave Anisotropy Probe results," said Warren Moos, FUSE principal investigator, Johns Hopkins University, Baltimore.
- FUSE saw that an atmosphere of very hot gas surrounds the Milky Way. The ubiquity of hot gas around our galaxy demonstrates the galaxy is even more dynamic than expected.
- By detecting highly ionized oxygen atoms in intergalactic space, FUSE showed that about 10 percent of matter in the local universe consists of million-degree gas floating between the galaxies. This discovery might help resolve the long-standing mystery of the universe's "missing baryons." Baryons are subatomic particles, often protons and neutrons. Calculations of how many baryons were produced in the very early universe predict about twice as many baryons as astronomers have observed. The rest of the missing baryons might exist as even hotter gas, which could be observed by future X-ray observatories such as NASA's Constellation-X.
"FUSE collected quality science data for eight years, longer than its five-year goal. By any measure, FUSE was a success," said George Sonneborn, FUSE project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md.
Although FUSE's mission has ended, NASA's ultraviolet study of the universe continues. In 2008, NASA will conduct a servicing mission to the Hubble Space Telescope to install a new ultraviolet spectrograph on the telescope and repair another. The new Cosmic Origins Spectrograph, or COS, is designed to study remote galaxies and nearby stars in the ultraviolet. Hubble's Space Telescope Imaging Spectrograph also will be repaired. That instrument had ultraviolet capabilities complementary to the COS and was used in conjunction with FUSE when both were operational. The spectrograph failed due to an electronic short in August 2004 after more than seven years of in-orbit operations.
FUSE was a joint mission of NASA, the Canadian Space Agency and the French Space Agency, the Centre National d'Etudes Spatiales. The Johns Hopkins University built the telescope and managed the mission. The University of Colorado, Boulder, built FUSE's spectrograph. The University of California, Berkeley, made the detectors. For more information, visit: http://fuse.pha.jhu.edu
// end // | 0.900675 | 3.659953 |
Tardigrades, often called water bears or moss piglets, are near-microscopic animals with long, plump bodies and scrunched-up heads. They have eight legs, and hands with four to eight claws on each. While strangely cute, these tiny animals are almost indestructible and can even survive in outer space. The microscopic animals are virtually indestructible invertebrates: able to survive in a pot of boiling water, at the bottom of a deep-sea trench or even in the cold, dark vacuum of space. The animal that seems to come from another planet and learn to observe them in your home if you have a microscope.
In August, an Israeli spacecraft carrying tardigrades as part of a scientific experiment crashed on the moon, and scientists believe they may have survived.
WHAT IS A TARDIGRADE?
Tardigrades or water bears, are a group of invertebrates 0.05-1.5 mm long that preferably live in damp places. They are especially abundant in the film of moisture covering mosses and ferns, although there are oceanic and freshwater species, so we can consider they live anywhere in the world. Even a few meters away from you, in the gap between tile and tile. In one gram of moss they have find up to 22,000 individuals. They are found in Antarctica under layers of 5 meters of ice, in warm deserts, hot springs, in mountains 6,000 meters high and abyssal ocean depths: they are extremophiles. It is estimated that over 1,000 species exist.
These creatures look like the hookah-smoking caterpillar from “Alice in Wonderland.” They can range from 0.05 millimeters to 1.2 mm (0.002 to 0.05 inches) long, but they usually don’t get any bigger than 1 mm (0.04 inches) long.
Water bears can live just about anywhere. They prefer to live in sediment at the bottom of a lake, on moist pieces of moss or other wet environments. They can survive a wide range of temperatures and situations.
Research has found that tardigrades can withstand environments as cold as minus 328 degrees Fahrenheit (minus 200 Celsius) or highs of more than 300 degrees F (148.9 C), according to Smithsonian magazine. They can also survive radiation, boiling liquids, massive amounts of pressure of up to six times the pressure of the deepest part of the ocean and even the vacuum of space without any protection. A 2008 study published in the journal Current Biology found that some species of tardigrade could survive 10 days at low Earth orbit while being exposed to a space vacuum and radiation.
In fact, water bears could survive after humanity is long gone, researchers found. Scientists from Harvard and Oxford universities looked at the probabilities of certain astronomical events — Earth-pummeling asteroids, nearby supernova blasts and gamma-ray bursts, to name a few — over the next billions of years. Then, they looked at how likely it would be for those events to wipe out Earth’s hardiest species. And while such catastrophic events would likely wipe out humans, the researchers found little tardigrades would survive most of them, they reported in a study published online July 14, 2017, in the journal Scientific Reports.
“To our surprise, we found that although nearby supernovas or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected,” David Sloan, a co-author of the new study and researcher at Oxford, said in a statement. “Therefore, it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on.”
Its popular name refers to their appearance, and the scientific name to their slow movements. Their bodies are divided into five segments: cephalic, with its tube-shaped mouth (proboscis) with two internal stilettos and sometimes simple eyes (ommatidia) and sensory hairs, and the remaining 4 segment with a pair of legs per segment. Each leg has claws for anchoring to the ground.
Look at this video of Craig Smith to see tardigrade’s movements in more detail:
With its mouth stilettos, tardigrades perforate plants and absorbe the products of photosynthesis, but they can also feed absorbing the cellular content of other microscopic organisms such as bacteria, algae, rotifers, nematodes… Some are predators too and can eat whole microorganisms.
Their digestive system is basically the mouth and a pharynx with powerful muscles to make sucking motions that opens directly into the intestine and anus. Some species defecate only when they shed.
They have no circulatory or respiratory system: gas exchange is made directly by the body surface. They are covered by a rigid cuticle which can be of different colors and is shed as they grow. With each moult, they lose oral stilettos, to be segregated again. They are eutelic animals: to grow they only increase the size of their cells, not their number, that remains constant throughout life.
Tardigrades reproduce through sexual and asexual reproduction, depending on the species. They lay one to 30 eggs at a time. During sexual reproduction, the female will lay the eggs and the males will fertilize them.Fertilization is external and development is direct: they don’t have larval stages. In asexual reproduction, the female will lay the eggs and then they will develop without fertilization.
The tardigrades are incredibly resilient animals that have survived the following conditions:
- Dehydration: they can survive for 30 years under laboratory conditions without a single drop of water. Some sources claim that resist up to 120 years or have been found in ice 2000 years old and have been able to revive, although it is likely to be an exaggeration.
- Extreme temperature: if you boil one tardigrade survives. If you put it to temperatures near the absolute zero (-273ºC), survives. Their survival rate ranges from -270ºC to 150ºC.
- Extreme pressure: they are capable of supporting from vacuum to 6,000 atmospheres, ie 6 times the pressure in the deepest point on Earth, the Mariana Trench (11,000 meters deep).
- Extreme radiation: tardigrades can withstand bombardment of radiation at a dose 1000 times the lethal to a human.
- Toxic substances: if they are immersed in ether or pure alcohol, survive.
- Outer space: tardigrades are the only animals that have survived into space without any protection. In 2007 the ESA (European Space Agency) within the TARDIS project (Tardigrades In Space) left tardigrades (Richtersius coronifer and Milnesium tardigradum) for 12 days on the surface of the Foton-M3 spacecraft and they survived the space travel. In 2011 NASA did the same placing them in the outside of the space shuttle Endeavour and the results were corroborated. They survived vacuum, cosmic rays and ultraviolet radiation 1,000 times higher than that of the Earth’s surface. The project Biokis (2011) of the Italian Space Agency (ASI) studied the impact of these trips at the molecular level.
HOW DO THEY DO THAT?
The tardigrades are able to withstand such extreme conditions because they enter cryptobiosis status when conditions are unfavorable. It is an extreme state of anabiosis (decreased metabolism). According to the conditions they endure, the cryptobiosis is classified as:
- Anhydrobiosis: in case of environmental dehydration, they enter a “barrel status” because adopt barrel shaping to reduce its surface and wrap in a layer of wax to prevent water loss through transpiration. To prevent cell death they synthesize trehalose, a sugar substitute for water, so body structure and cell membranes remain intact. They reduce the water content of their body to just 1% and then stop their metabolism almost completely (0.01% below normal). Tardigrade dehydrated. Photo by Photo Science Library
- Cryobiosis: in low temperatures, the water of living beings crystallizes, it breaks the structure of cells and the living being die. Tardigrades use proteins to suddenly freeze water cells as small crystals, so they can avoid breakage.
- Osmobiosis: it occurs in case of increase of the salt concentration of the environment.
- Anoxybiosis: in the absence of oxygen, they enter a state of inactivity in which leave their body fully stretched, so they need water to stay perky.
Referring to exposures to radiation, which would destroy the DNA, it has been observed that tardigrades are able to repair the damaged genetic material.
These techniques have already been imitated in fields such as medicine, preserving rat hearts to “revive” them later, and open other fields of living tissue preservation and transplantation. They also open new fields in space exploration for extraterrestrial life (Astrobiology) and even in the human exploration of space to withstand long interplanetary travel, ideas for now, closer to science fiction than reality.
ARE THEY ALIENS?
The sparse fossil record, the unclear evolutionary relatedness and great resistance, led to hypothesis speculating with the possibility that tardigrades have come from outer space. It is not a crazy idea, but highly unlikely. Panspermia is the hypothesis that life, or rather, complex organic molecules, did not originate on Earth, but travelled within meteorites in the early Solar System. Indeed, amino acids (essential molecules for life) have been found in meteorites composition, so panspermia is a hypothesis that can not be ruled out yet.
But it is not the case of tardigrades: their DNA is the same as the rest of terrestrial life forms and recent phylogenetic studies relate them to onychophorans (worm-like animals), aschelminthes and arthropods. What is fascinating is that is the animal with more foreign DNA: up to 16% of its genome belongs to fungi, bacteria or archaea, obtained by a process called horizontal gene transfer. The presence of foreign genes in other animal species is usually not more than 1%. Could be this fact what has enabled them to develop this great resistance?
DO YOU WANT TO SEARCH TARDIGRADES BY YOURSELF AND OBSERVE THEM IN ACTION?
Being so common and potentially livIng almost anywhere, if you have a simple microscope, you can search and view living tardigrades by yourself:
- Grab a piece of moss of a rock or wall, it is better if it is a little dry.
- Let it dry in the sun and clean it of dirt and other large debris.
- Put it upside down in a transparent container (such as a petri dish), soak it with water and wait a few hours.
- Remove moss and look for tardigrades in the water container (put it on a black background for easier viewing). If lucky, with a magnifying glass you’ll see them moving.
- Take them with a pipette or dropper, place them on the slide and enjoy! You could see things like this: | 0.815554 | 3.474946 |
When you hear someone talk about Betelgeuse, the first thing you think of may be the undead prankster from the movie of the same name—Beetlejuice.
However, if you’re in a room full of astronomers and the word Betelgeuse comes up, they’re likely talking about the star with that same name, one of the brightest celestial objects that we can see in our sky. It is also the subject of some fascination because there are those who believe that it could spell destruction for our planet and species!
What is Betelgeuse?
Betelgeuse is a Class M Red Supergiant, and is approximately 100,000 times more luminous as our sun, and approximately 20 times more massive. This powerful star is found in the Orion constellation, and is estimated to be approximately 400-650 light-years away from our solar system. It is also one of the largest known stars, with a variable diameter of between 550-900 million miles, depending on what phase of its expansion and contraction is being measured. This massive size means that Betelgeuse would extend from the center of our solar system past the orbit of Mars, possibly even matching the size of the orbit of Jupiter, completely engulfing Earth without a second thought. Good thing it’s not our next-door neighbor!
Its age has been estimated at about 10 million years, and for a star as massive as Betelgeuse, that means it is approaching the end of its lifetime. “Approaching the end” is a relative term, of course, since we’re talking about cosmological time, which is measured in millions or even billions of years, rather than centuries, like human life! Although it has 20 times the mass of the sun, larger stars burn through their fuel much faster than smaller stars. For example, our sun is already 4.6 billion years old, and isn’t expected to run out of hydrogen (fuel) for another 5 billion years.
Betelgeuse, however, is guzzling its fuel and pumping out light an an incredible rate, making it the 10th brightest star in the night sky for most of the year, and in the infrared scale, there is nothing brighter! While all of these facts about Betelgeuse mean that it is a brilliant, unique and wildly luminous star in our sky, it also means that when it runs out of fuel, it’s going to go out in truly dramatic fashion. Yes, you guessed it… Betelgeuse is going to go supernova!
The Death of Betelgeuse
One of the most dramatic celestial events in our universe is a supernova, the explosive death of a massive star. Once all of the fuel in such a star has been expended through nuclear fusion, it will collapse under its own massive weight. At a certain point, however, once the density at the core becomes untenable, it rebounds outwards in a devastating supernova.
Considering that Betelgeuse is one of the largest stars we’ve ever detected, its eventual explosive end could also be one of the most spectacular supernovae in millions of years. The actual explosive event of a supernova can be extremely fast—less than two minutes—but the radiation that is then pushed out into the universe at the speed of light may remain at peak luminosity for months before finally dropping off and dimming. Since Betelgeuse is such a massive star, and will supernova due to core collapse, it is categorized as a Type 2 supernova. Type 1 Supernovae, on the other hand, are believed to be caused by mass being drawn into a white dwarf when a star is in a binary system.
Some superluminous supernovae can be brighter than an entire galaxy of stars, and given the size of Betelgeuse, it is going to put on quite a show when it finally goes! As mentioned earlier, this star is definitely approaching the end of its life, and is expected to go supernova at some point in the next million years. That being said, estimates about star life spans and death dates are just that… approximations. There is also some debate between astronomers as to the life expectancy of the star, with some saying that the star is nearing its peak size, and could collapse at some point in the next 100,000 years, a veritable blink in cosmological time scales. In truth, Betelgeuse could blow up tomorrow, but that doesn’t mean that the world is going to end.
Betelgeuse may be very close to us—600 light-years—in relative terms to other objects that are millions of light-years away, but 600 light-years is still a huge distance. The closest star to Earth is Alpha Centauri, coming in just over 4 light-years away, meaning that it takes four years for the light from that star to reach our eyes on Earth! In fact, Betelgeuse may have already gone supernova, and the light of the explosion simply hasn’t reached us yet!
However, for those of you who have just been flung into a panic at the meaningless of the universe and the inevitable destruction of Earth at the hands of the Betelgeuse supernova, don’t worry. Even if it does generate one of the largest supernovae ever, Betelgeuse is still far enough away from our planet that it wouldn’t be our death knell. The physical ejection of material from the explosion would eventually reach Earth, but it would be cooled off long before hitting our atmosphere, and would have a negligible effect. The radiation from such a massive explosion would have slightly more of an impact, but not enough to blow away or ionize out atmosphere.
It is difficult to 100% accurately predict the effects of a supernova, but we do know that more than 1 supernova has occurred in our cosmic neighborhood in the past few million years. Both of those supernovae studied occurred in stars that were twice as close as Betelgeuse to us, and they don’t appear to have caused any harm to life, according to the fossil record from that period. Some chemical evidence points to their occurrence, but we can find no proof of any dramatic or climatic effects on the planet.
A Final Word
The next time someone brings up Betelgeuse at a party, you’ll be able to calm everyone’s nerves and explain that, while that star’s eventual death will make for one incredible sight, there is only a 0.1% chance that it will happen in your lifetime, and even on the minuscule odds of that happening, it probably won’t have any effect on our pale blue dot!
- Forbes Magazine
- Space.Com (Link 1)
- Cornell University
- Space.Com (Link 2) | 0.875382 | 3.651833 |
I recently began wondering if there was life on Jupiter. I know… For any of you astronomy buffs out there, Jupiter’s just a great big ball of poisonous gas, right? The weather is always stormy (on average, perhaps 100 times worse than the biggest hurricane or tropical storm ever to hit our planet), on a good day the winds are still about 1000 miles per hour, and once you start descending into the lower levels of Jupiter’s atmosphere (a feat once attempted by one of NASA’s very own space probes), there’s so much Jupiterian “air” and gases above you that the sheer weight of it all will crush you – that is, if your space ship hasn’t been ripped apart by the harsh winds already! So how could anything survive on that God forsaken hell hole?! To make matters worse, Jupiter also allegedly serves as “the vacuum cleaner” of our solar system. Most asteroids or comets from further out in space that would otherwise have hit our world and destroyed all life as we know it, usually instead just hit and get swallowed up by Jupiter, making our chances of suffering a life shattering impact fortunately much lower. “Definitely not suitable for extraterrestrials,” they’d probably say.
But I couldn’t help but wonder: Could there still be life on The Gas Giant…?
There’s this funny thing that scientists are discovering about life at least on our planet: It can survive just about anywhere! At the bottom of the ocean where no sunlight ever penetrates, to dark poisonous caverns deep within the earth, to inside of our bodies, to molten hot geysers and lava fissures, to even various levels of our own atmosphere, life always flourishes. It may not be the kind of life which you or I may want to encounter – just a boring little amoeba or bacterium swimming under a microscope – but it still qualifies as some kind of living thing, and once again, it is alive! There’s also a funny thing which scientists are just now beginning to discover about asteroids and comets (once again, two things that have hit Jupiter in great abundance): They can be transporters or even factories for life! That’s right! Not only have scientists speculated that frozen bacteria and microorganisms could theoretically hitch a ride to another world aboard an asteroid, but comets, in particular, are already teaming with the water, chemicals and gunk which life often uses as “building blocks.” In other words, the water we drink and all the “stuff” which makes up our bodies – and ourselves, for that matter – all may have been brewed and cooked up on a comet that eventually hit Earth! The very things that we are sometimes most afraid of may have also been the very same things that gave rise to Mother Nature.
So, could we at least say that there are scores of little critters (becteria, germs, amoebas, viruses, slime, etc.) who are now bobbing along quite happily in Jupiter’s air…? Who’s to say! But aside from the simple little creatures who can’t really talk to you, and possibly don’t have much of a mind, could there also be intelligent and complex life forms on the gas giants, however, aliens who would of course be a little bit different than what you’d find on, say, a more rocky world. Since you would once again have to deal with some pretty harsh winds, temperatures and nasty weather once you grew to a certain size, maybe “The Jupiterians” as I’d like to call them – and perhaps the beings who could very well inhabit the other gas giants as well (Neptune, Saturn and Uranus) – are beings comprised mostly of, well…. GAS! That brings me to another point to ponder: Could consciousness (whatever that thing is inside of you, and me, and that makes you realize that you’re alive and really you, and me realize that I’m alive and really me) live in just about any body? Could intelligent life take on just about any form imaginable?! Like Mr. Spock once said on a bygone episode of Star Trek,
“It’s life, Jim, but not as we know it.”
And no…. I don’t think I’m just blowing hot air out my anus! (And believe me, that would really STINK!!)
So yes. The beings I’ve currently imagined as the perfect fit for the volatile gas worlds such as Saturn, Neptune, Uranus and Jupiter are highly intelligent gas beings composed of atmosphere and electricity. They might resemble talking clouds, thunderheads, or even bizarre but intelligent whirlwinds. They might even happily swirl and flow at thousands of miles per hour within a gas giant’s various levels – since it’s a paradise to them – and they may have even become aware of our own existence quite some time ago, although we are still completely unaware or even appreciative of them, and they may have still had little or no interest in visiting our own puny and relatively airless planet. But how awesome it would be if we could someday observe them in their world! (…assuming we could even survive the journey.)
Now can you imagine that??? A being resembling a talking, glowing thunderhead? Also, considering the gas giants are all many times larger than our own little rock (like perhaps with a marble when placed next to a fully inflated beach ball), these beings could all be the size of thunderheads too – with plenty of space left aside to float around!
Hey, and you thought all life forms had to be made of meat! 😉
>>> Michael Bok, co-founder of ABloggersUniverse.com | 0.896446 | 3.120308 |
Pluto and Charon
Of The Planets, Asteroids and Trans-Neptunian Objects
Rights for Pluto, Xena and Sedna?
How many planets are there? Eight, nine, ten, more? Is Pluto a planet? What about the other so-called
heavenly bodies astronomers are discovering?
14-25, 2006 Pluto and some of its neighbors are getting a turn in the celestial spotlight, or finding themselves on the chopping block, depending on how you look at it. During this time the International
Astronomical Union will decide on the definition of a planet as
well as what to officially name some of the newest denizens of the solar system.
Pluto was discovered in 1930 by 24-year-old Clyde Tombaugh. Crowned the ninth planet and named for
the Roman god of the underworld, it became an international sensation and drummed up plenty of good PR for astronomy. People went so Pluto-crazy that Walt Disney even named a cartoon
character in Pluto's honor, leaving many children born in later
years assuming that the planet had been named after the dog, not
the other way around.
Pluto has since faded in importance compared to the rest of the planets. My science teacher once taught us this mnemonic device for remembering the planets: "Mercury, Venus, Earth, Mars and Jupiter form Mary Very Easily Makes Jam, then SUN, which stands for Saturn, Uranus and Neptune, and then there's Pluto, out in the doghouse."
We forget how much there is to appreciate about Pluto. According to
Dr. Alan Stern in Pluto
at 75: A Uniquely American Anniversary: "Not even Tombaugh
and his mentors could have forecast how fascinating their new planet
would turn out to be. For eventually, when the technology of astronomy
made the detailed investigations of bodies as far away and faint
as Pluto-Charon possible, this distant planet-satellite pair turned
out to be full of enticing surprises. For the ninth planet was revealed
to be the first known world with a satellite so large it could be
called a double planet, a world with complex seasons and a chaotic
orbit, and the only planet with an atmosphere that freezes out and
then is reborn every orbit. Pluto, replete with polar caps and fresh
snows of not one, but three exotic surface icesmethane, nitrogen,
and carbon monoxideis an exotic wonderland on the ragged edge
of the solar system's vast outer wilderness."
just discover Pluto, he also opened the door to the discovery of
what Stern calls the solar system's third major zone, "the
distant and icy Kuiper Belt."
So what is a planet?
If size is an indicator, Pluto doesn't have much going for it. Its
mass is only .2 percent of Earth's. It's smaller than not only all
the other eight planets but also than seven of their moons, including
our own moon. There's speculation that Pluto and its moons are simply
some of Neptune's moons knocked off course or just one of many
Kuiper Belt objects that have wandered into the Sun's gravitational
pull. In fact, the American Museum of Natural History demoted Pluto
to "Kuiper Belt object."
Pluto and the
moons: Charon, Hydra and Nix
Pluto appears to consist of rock and ice. The fact that it does
have a moon should count for something. As if realizing its status
was shaky, Pluto seemed to conveniently muster up two additional
moons (discovered in February 2006 and named Hydra and Nix) as if
to say, "Hey, guys, look! I've got three moons, not just one!
How about it?"
We know now that the solar system is a lot more crowded than was presumed in 1930. Rather than being out in the doghouse, Pluto has plenty of company in the Kuiper Belt, and the Oort cloud.
along came 2003 UB313. It's larger than Pluto. It has a moon. Some astronomers
say you don't let Pluto in the club without letting it in as well.
Brown, one of the discoverers of UB313: "There is no good
scientific way to keep Pluto a planet without doing serious disservice
to the remainder of the solar system."
The IAU currently
refers to UB313 as a Trans-Neptunian
object. At the conference, the organization will determine its status,
as well as its name. UB313 is currently code-named Xena after TV's
warrior princess character; its moon is called Gabrielle
after Xena's sidekick.
Planet Xena with
its moon, Gabrielle
Lucy Lawless as
Xena, warrior princess
Xena and Gabrielle are only code names and "There is no chance
whatsoever that these will become the permanent names of these objects!"
What could beat Xena? Not only is it the coolest name ever for a
planet, but it rather adequately describes how Xena the warrior
planet stole the thunder of Sedna (2003 VB12), discovered in 2004 and code-named
for an Inuit goddess who mostly stays under water. Sedna has gone
from being a possible tenth planet contender to merely
an asteroid (its official name is to be decided by the IAU
Committee on Small Bodies Nomenclature).
Okay, if the
name "Xena" doesn't cut it, how about "Mrs. Peel"
in honor of the character played by Diana Rigg on "The Avengers"? Or better yet, "Diana," which is, after all, also the
name of a Greco-Roman goddess and can thus keep purists happy.
Diana Rigg as Mrs.
Emma Peel in "The Avengers"
what is the answer? Do we grandfather in Pluto, giving it honorary planetary
status for its 76 years of good behavior? Do we extend our hands and welcome
everyone to the party? Or do we treat Pluto, Sedna and Xena like a bunch
of pathetic wanna-be social climbers? After all, as Christine Lavin so
eloquently put it in her song "Planet
X": "It's Pluto the planet they love, it's not Pluto the
comet, it's not Pluto the asteroid they wonder about above."
So far, it appears
that the IAU will
not demote Pluto. According to the IAU: "Recent news reports
have given much attention to what was believed to be an initiative by
the International Astronomical Union (IAU) to change the status of Pluto
as the ninth planet in the solar system. Unfortunately, some
of these reports have been based on incomplete or misleading information
regarding the subject of the discussion and the decision making procedures
of the Union. No proposal to change the status of Pluto as the ninth planet
in the solar system has been made by any Division, Commission or Working
Group of the IAU responsible for solar system science. "
But it's a rather hollow victory. While the the rest of us ignoramuses may rejoice at Pluto's reprieve, astronomers know better. In a sort of insider-ish, wink-wink, nudge-nudge fashion they are indulging in the knowledge that Pluto has simply been given cultural, historical, and sociological planetary status to please the populace, and this doesn't add up to much from a scientific standpoint.
Perhaps the solution
is for us to simply thumb our noses at the whole planetary status thing.
Who wants to be a planet anyway, when it's way cooler (literally and figuratively)
to be a Kuiper Belt or Oort Cloud object? Who needs those insular planets who can't
see past their own sun when you can have one eye on the solar system
and the other looking far out over the rest of the galaxy? Being a KBO or OCO could
be the ultimate in outsider chic!
Fans of Pluto, Xena,
Sedna et al await the IAU's decision and look forward to what the future
Horizons, carrying a canister with Tombaugh's ashes, is set to encounter
Pluto in 2015 and head into the Kuiper Belt in 2016.
Update: Pluto was
in fact demoted, saddled with the designation of "dwarf planet."
Fellow dwarf planet and moon Xena and Gabrielle were named Eris and Dysnomia,
respectively. Eris is the Greek goddess of discord and strife; Dysnomia
is her daughter, the spirit of lawlessness. According to the IAU Eris's
claim to fame is that after being left off the guest list to an exclusive
wedding, she retaliated by causing a quarrel that led to the Trojan War.
fans are rallying to the cause. You can read up on their doings at the
for the Preservation of Pluto as a Planet (and make a donation to
the cause?) or buy a "Honk if Pluto is still a planet" bumper
sticker or a "Save Pluto" T-shirt . Yes, there's money to be
made from Pluto's plight.
Box 580, New York, NY 10113 ©2006 | 0.909377 | 3.016481 |
Change is the one constant in our world– moving in ways tiny and enormous, constructive and destructive.
We’re living now in a time when a rampaging pandemic circles the globe and when the climate is changing in so many worrisome and potentially devastating ways.
With these ominous changes as a backdrop, it is perhaps useful to spend a moment with change as it happens in a natural world without humans. And just how complete that change can be:
For years now, planetary scientists have debated whether Mars once had a large ocean across its northern hemisphere.
There certainly isn’t one now — the north of Mars is parched, frigid and largely featureless. The hemisphere was largely covered over in a later epoch by a deep bed of lava, hiding signs of its past.
Because our sun sent out significantly less warmth at the time of early Mars (4.2-3.5 billion years ago,) climate modelers have long struggled to come up with an explanation for how the planet — on average, 137 million miles further out than Earth — could have been anything but profoundly colder than today. And if that world was so unrelentingly frigid, how could there be a surface ocean of liquid water?
But discoveries in the 21st century have strongly supported the long-ago presence of water on a Mars in the form of river valleys, lakes and a water cycle to feed them. The work done by the Curiosity rover and Mars-orbiting satellites has made this abundantly clear.
An ocean in the northern lowlands is one proposal made to explain how the water cycle was fed.
And now, In a new paper in Journal of Geophysical Research: Planets, scientists from Japan and the United States have presented modelling and analysis describing how and why Mars had to have a large ocean early in its history to produce the geological landscape that is being found.
Lead author Ramses Ramirez, a planetary scientist with the Earth-Life Science Institute in Tokyo, said it was not possible to determine how long the ocean persisted, but their team concluded that it had to be present in that early period around 4 billion to 3.5 billion years ago. That is roughly when what are now known to be river valleys were cut in the planet’s southern highlands.
Only a northern ocean of some size on early Mars, he said, would provide sufficient water on the planet — via a water cycle — to produce all the fossil rivers, lakes and deltas that have been found. The alternate theory that seasonal melt water created the rivers and lakes simply cannot provide enough H2O.
“We show that without a relatively large northern ocean and corresponding hydrologic cycle, no cold-and-icy early Mars scenario can explain the valley networks and other observed surface erosion,” Ramirez wrote in an email.
“The northern ocean had to come in before the valleys could be incised. Without an ocean, there could be no water source, and no valleys.”
As described by Ramirez, who authored the paper with Robert Craddock of the Smithsonian Air & Space Museum and Tomohiro Usui of the Japanese space agency, the precipitation that originally filled the northern ocean could have come in much the same way that it did for the Earth.
This means that a condensing steam atmosphere early on would have brought in the initial water, and perhaps some more could have been supplied via successive impacts early on.
Subsurface groundwater could also have contributed to the formation of some of the early water features. But that too, Ramirez said, requires an aquifer to be charged by precipitation.
Some scientists argue that the riverbeds and deltas seen now could have been formed when the planet was not too different in terms of climate from today — arid and cold.
As measured by the Viking landers in the 1970s, surface temperatures today range from 1 degree F to -160 F. Mars scientists have since found that can get well above freezing at the equator in summer, but the average surface temp for the planet is -81. So under this scenario, river carving would have been the result of seasonal melts, briny water or localized heat caused by geological events.
The Ramirez et al paper takes the view that the planet once had to be significantly warmer to be wet enough to leave behind the features now being found. And to produce those conditions, something in the atmosphere clearly had to be supplying a kind of greenhouse effect.
So how did the planet warm sufficiently to allow for an ocean of water?
The authors propose that the rise of the Tharsis volcanoes, as well as the enormous Olympus Mons shield volcano, took place at around the time that Mars was getting wetter and warmer — rather than millions of years earlier, as is often described.
The volcanoes would spit out hydrogen and carbon dioxide which, when the molecules collide at high atmospheric pressure, produce a thick greenhouse atmosphere. (There is not nearly enough carbonate now on the surface of Mars to propose an earlier substantially carbon dioxide greenhouse.)
The result of the hydrogen-carbon dioxide greenhouse, they write, was hardly a tropical Mars. Rather, it was a planet that had temperatures slightly above freezing, which was enough to produce an ocean over about 35 percent of the planet. The lakes and riverbeds detected on Mars, he said, are consistent with that kind of semi-arid environment.
But for their model to work, they also needed modifications to the often cited narrative of volcanism and mountain-building on Mars.
The previous models presupposing a cold and icy Mars had also assumed that Mars’ biggest mountains were already fully-formed before this river valley period. If the mountains had already risen, then they would have caught snow and ice at high elevations — produced melt water in warmer seasons – and created an super-arid rain shadow in precisely the areas where the river valleys were cut.
An earlier rise for this Tharsis range is a motivator for many present cold and icy scenarios, Ramirez said.
“The problem is that such scenarios do not agree with the geologic evidence. The most up-to-date geologic mapping shows that Tharsis was much flatter during valley network formation. Indeed the entire complex was forming during and after this time, suggesting that Tharsis volcanism may have been an important component to the warm temperatures required during this period.”
So if the appearance of the Tharsis occurred early in the history of Mars, then a melt water source for the river valleys is all that’s available. But if the mountains came later, there would be no rain shadow over the river valley area and a water cycle could develop.
And when water was flowing, why would it head north?
That the water would have pooled in the northern lowlands makes sense because the region — some 40 percent of the surface of Mars — is as much as 5 kilometers (3.5 miles) below the southern highlands, creating what is called the “dichotomy.”
As with most everything regarding the northern ocean, there is rigorous debate about how the lowlands were formed, with a huge impact in the very early history of Mars being a leading expIanation. But however it was formed, the so called Borealis Basin is the largest flat piece of real estate in our solar system.
How long might a Northern Ocean have lasted?
“We do not give an estimate for how long the ocean could have existed there, but we give an estimate for how long it takes to form the observed surface valleys. Based on the level of observed surface erosion, we estimate that it would have taken no longer than 10 million years, and possibly considerably less than that.”
So the Northern Ocean might also have existed for a relatively short time, geologically speaking. An additional big question is whether an ocean would have been present for a long enough time to help jump start potential life on Mars, but that is a complete unknown.)
The relatively short lifetime of a northern ocean is consistent with evidence that the atmosphere of Mars began to be stripped away rather early, and as a result the ocean would have frozen or disappeared into space.
Those unconvinced by the science of the Northern Ocean point to the absence of thick glaciers left behind after the oceans froze at the end of the warm period. Ramirez counters that the proposed ocean would only cover that 35 percent of the planet, compared with 70 percent of the surface of the Earth covered by water. So the hydrologic cycle would have produced a warm and semi-arid climate, rather than the broad array of climates on Earth, including tropical. There are no thick left-behind glaciers on Mars, and Ramirez says that is consistent with the model they present.
This will certainly not be the final word on the Northern Ocean theory. Unanswered questions remain and the theory involves processes at work and conditions that existed so long ago.
But with the likelihood growing that Mars did once have a substantial ocean, it is quite remarkable — and a testament to the power of change — that it would have disappeared with hardly a trace. Or without a trace identifiable with certainty from those, on average, 137 million miles away.
Marc Kaufman is the author of two books about space: “Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. He began writing the column in October 2015, when NASA’s NExSS initiative was in its infancy. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone. | 0.839223 | 3.758018 |
Using data collected by NASA’s Dawn spacecraft, an international team of astronomers has created a Map of the dwarf planet Ceres’ northern hemisphere detailing regions that exist in permanent shadow. According to the study, these dark zones house conditions favorable to the existence of water ice.
The relatively low mass of Ceres compared to the fully fledged planets that make up our solar system prevents it from maintaining any significant atmosphere when compared to the potent protective shield hosted by Earth, or even the tenuous shell that clings to the Mars. However, Ceres’ gravity is strong enough to prevent water particles from floating off into space.
Should these icy particles migrate to a very cold location on the surface of the planetoid, such as the bottom of a deep crater situated near one of Ceres’ poles, the water would be unable to escape. These permanently-shadowed regions that are devoid of the Sun’s warming influence all year round are known as “cold traps.”
Over time, enough of the tiny particles could accumulate in the cold traps to form a shallow deposit of water ice. Cold traps, which have been discovered on solar system bodies such as Mercury and Earth’s moon had been theorized to exist on Ceres for some time, however planetary scientists were unable to isolate their potential locations until now.
A new study focused on the dwarf planet’s northern hemisphere, as this was the region that experienced the most illumination from the Sun during the period in which the images were captured.
The team created a detailed 3D model of the hemisphere compiled from data harvested by the Dawn spacecraft, and ran it through a series of complex computer simulations. The simulations, which were developed by scientists at NASA’s Goddard Space Flight Center in Maryland, calculated the areas of Ceres’ surface that received the least sunlight and solar radiation over the course of a year, which lasts 1,693 Earth days.
It was discovered that dozens of large areas comprising roughly 695 sq miles (1,800 sq km) of Ceres’ northern hemisphere experience a state of perpetual shadow. This lack of direct sunlight, combined with Ceres distant orbit in relation to our star, result in a temperature that consistently stays below minus 240º F (-151º C) in the cold traps.
Each year on Ceres, it is estimated that 1 out of every 1,000 water molecules circulating the dwarf planet would become imprisoned in the shadowed regions. At these glacial rates, it takes around 100,000 years for the particles to coalesce into a thin layer of ice. However, as these deposits are estimated to be trapped for around a billion years at a time, it is possible that they still exist to this day, and that they would be detectable in follow up observations.
Earlier this month, NASA announced that the Dawn spacecraft would remain in orbit around Ceres, instead of making a planned transition to the main belt asteroid Adeona.
The NASA video below highlights the locations of the various ice deposits in the context of Ceres’ northern hemisphere.
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The term Black Hole has only recently been coined. It was first used in 1969 by the physicist John Wheeler and described effectively a two-century old idea.
The studies began in 1783, when John Mitchell, one of the great forgotten scientists of the XVIII century published an essay in The Philosophical transactions of the Royal Society of London where he stated that a star with a large mass and density would present such a gravity as to prevent light from getting out. A beam of light emitted from the surface of this star would be drawn back by the star gravitational attraction. Mitchell understood that a great lot of stars with such characteristics could exist. His great intuition was to imagine that the light leaves a star as we consider it a rocket leaving the surface of the planet. To completely escape Earth’s gravitational attraction and travel through space, a rocket needs a 11/Km/sec velocity n upwards, that is to say, more than the terrestrial gravity attracts it downwards. Mitchell knew nothing about rockets on the moon but he did know that, theoretically a largest star could exert a gravitational attraction such as to swallow the light rays that travel at the speed of 300,000 Km/s. John Mitchell calculated that in a celestial a body with a big mass the gravity would be such as to prevent light to escape from its surface, and theorized that an object with the bigger mass than the universe could be invisible. In 1795, the great French mathematician Pierre Simon de Laplace calculated that light could not have got out of quite massive bodies, the dark bodies as he called them. However, it was only in 1939 that scientists found out that Black Holes could really exist, and in the atomic era it finally became known how a black hole is formed. In 1939 J. Robert Oppenheimer and a student of his, Hartland Snyder, showed that a cold, big mass star is bound to collapse indefinitely, thus becoming a Black Hole. Oppenheimer and Snyder’s work, which came out almost contemporarily to Oppenheimer-Volkoff’s about neutron stars, drew the same conclusions: black holes could exist. They could be real objects, not only mathematic games of people sharing an interest in Einstein’s theory. In the Sixties, when Einstein’s theory of general relativity came back in fashion, black holes were thoroughly studied and their features clarified in detail. Furthermore, in the mid-sixties, scientists calculated that there can’t be stable dead stars bigger than three solar masses and as we commonly observe stars (not yet collapsed) which have much bigger masses, astrophysicists have taken into serious consideration the idea that black holes are scattered about in the cosmic space. To completely understand how a black hole is generated, men have had to wait and live the atomic era, when scientists began to comprehend what happens inside a star. A star is composed of three main parts: the visible surface, called photosphere, a gas mass containing most of the star mass, and a small central nucleus. The nucleus has to counterbalance the mass gravitational push and carries out this task exerting a pressure. A star can realize such pressure through the nucleus’contorsion: the gas is compressed, heats up and generates enough pressure to sustain itself. This contraction, however, would provide a star with energy for only 15 million years, whereas we know that the Sun is 4.57 billion years old. Therefore, there must be another source of pressure: this source is the thermonuclear fusion. In a star like the Sun, thermonuclear fusion reaction occurs between two atoms of hydrogen that generate one of helium. When hydrogen is over, a star begins to contract. If, during the contraction temperatures of 108 K are reached, the reaction of fusion occurs between the Helium atoms. As helium fuses, it produces Carbon and Oxygen, Carbon fuses into Neon and Magnesium; Oxygen into Silicium and Sulfur and Neon, Magnesium, Sulfur and the rest fuse into a series of reactions (so far only partly understood) to generate Iron. From iron no other reaction takes place, and so the nucleus starts to contract. If the star is less than 1.5 solar masses big, (one and a half the sun mass) the matter density itself generates enough pressure to sustain the star (degenerating pressure). A white dwarf is born, a super dense star, not bigger than our earth. One of the first dwarfs to be discovered was the one which orbits around Sirius, the brightest star in the sky, a winter sky colossus called Sirius B. This star concentrates a mass close to that of the Sun in a volume nearly equal to the earth’s. It is then extremely dense. One has to imagine that a box of matches full of solar matter would weigh 15 grams, while filled with Sirius B matter would have a weight of 10 tons if it were on the Earth. Instead, if the star features more than 1.5 the solar mass, the degenerating pressure is no more sufficient. The neutrons collapse onto the nucleus and the star becomes a super dense star with a mass equal to the sun enclosed in a sphere with a 20 Km diameter, about the size of New York. There, the matter collapses and becomes so dense that the quantity of matter equal to 1/100th of a pin-head would weigh as much as 24 elephants. A neutron star is born. Yet, if the star features more than 3 solar masses, the collapse is inevitable. The mass of the star gets concentrated in an infinitely small as well as infinitely dense point. Gravity is so high it doesn’t even let the light out; that’s why it looks black: only a black hole is visible in space. However, how a black hole may show up all its power is a matter which Professor William Hawking is closely concerned with. Born exactly 300 years after Galileo Galilei’s death, Hawking has the same professorship as Isaac Newton at Cambridge University. Hawking’s mind moves freely not in Newton’s universe, but in Einsteins’s one. We are used to thinking about gravity – Hawking says – as a force which attracts objects to the earth and the earth to the Sun, but Einstein had the great idea of considering gravity as an effect of the space and time curvature in presence of very big bodies. Einstein understood that nothing can exist in a certain space without existing in a certain time simultaneously. Space and time are linked together to form the flexible frame dimensional structure of the universe: the so-called space-time. Space-time is almost impossible to imagine because our sensory universe is limited to our everyday three-dimension experience.
The best way for us to get into Einstein’s universe is to imagine that space and time are like an elastic plan. If space-time were empty, the plan would have absolutely no reliefs, but big bodies like the earth and the sun bend the elastic surface of space-time producing a curve. This curvature represents Einstein’s concept of gravity. The bigger is the mass of a star or a planet, the deeper is the curvature of space-time around it and consequently the bigger is its gravity. Imagine to launch onto a plan something extremely heavy like a star collapsing on itself and you will find a universe full of holes. While a giant star gets cold as long as it implodes, it bends the space-time around itself more and more. When it reaches a particular critical mass, it will literally create a black hole in the space-time. Objects can precipitate into it but can never get out of it. One of the most brilliant experts of black holes, Phil Charles, looks for them. Phil has found strong signals that show the presence of a black hole in a not far area of our galaxy. As he points out, looking for these objects is an extraordinary way of get ting closer to the borders of modern physics. By day Phil Charles holds lessons of theoretical astrophysics at Oxford university and by night he passes from theory to practice looking for black holes with the biggest telescopes on the Earth: Las Palmas and Hawaii in the north hemisphere, in South Africa, Chile and Australia in the southern one. The searchers of black holes exploit the best instruments to peruse the deep space looking for these mysterious objects: from the x-ray satellites and the orbited telescope Hubble, to the best optical or radio-wave telescopes on earth. Black holes cannot be seen by definition since light can’t get out of them. Official science accepted the idea that black holes could exist only in the 90s. Theory tells us that inside black holes all that man knows about the universe and its laws is no longer worth.
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Victor Rogus is an amateur astronomer, a Fellow of the Royal Astronomical Society, in London, and this is the ninth in his series of exclusive Space.com posts about amateur astronomy. He contributed this article to Space.com's Expert Voices: Op-Ed & Insights.
The moon has always been a companion to the people of the Earth. We give it names for the various seasons, write songs about it, use it in artwork and consider it romantic. It causes the tides to rise and fall, and sometimes lights our way in the dark. The moon has fascinated me since I was a small child; I have heard it said that an infant held outside under the moon will often reach out for it as if it were within grasp. It is often the first target for beginning astronomers with their new telescopes, as it is bright and easy to find, and offers a world of fantastic sights unlike any we see anywhere in the visible universe. It is truly the Earth's own.
A friend of mine once pointed out how it has been his extreme pleasure to just watch the faces of people he invites to view the moon for the very first time through his telescope. I can understand, as I have introduced a few folks to a telescopic view of the lunar surface for the first time myself, and I must admit it is a thrill. Many amateur astronomers, eager to view "deep space," seem to overlook our nearest neighbor after a couple of viewings. Sometimes, they do not feel it worthwhile to set up their equipment on moonlit nights, as the reflected sunlight on the lunar surface makes it difficult to see fainter, more distant objects. I, myself, have grumbled when the moon is bright during certain meteor showers, or when I am trying to photograph a faint comet. Just a lovers' spat — I could never be angry with my friend the moon, as it is just doing its thing; never mind about me.
To those who desire to rush past the quarter-million miles (more or less) in their haste to find more distant objects, I say, "Hold on; there is much to see here!" The moon holds many fantastic sights: the great craters (many named for astronomers and scientists from the past), mountain ranges, ridges, valleys, great "seas" — the maria with romantic names. The maria are areas with relatively flat and un-cratered surfaces, once thought to be actual lakes, oceans and seas. These areas were formed by ancient volcanic eruptions. An investment in a good lunar globe or map will aid in your exploration of the lunar surface. And each time you do, you will see something new. As the "terminator" — the line between the light of the sun and the dark of its shadow — slowly moves, the lunar landscape is illuminated in different ways, and more features will be revealed.
One of my favorite things to do while viewing the moon is to study the way the craters are arranged. It is sometimes easy to see which craters are older and which are younger, as the edges of the older craters are often peppered by newer, younger craters. Some observers suggest that the younger the crater is, the lighter in color it is. The brightest crater (or object) on the moon is Aristarchus — it can be seen near the moon's northwestern edge. Also be sure to look for where the effects of lunar gravity have caused crater walls to fall in. While erosion on the moon is much slower than on the Earth, gravity there is still at work!
While these are all fascinating subjects for the small telescope — and I highly encourage my fellow stargazers not to waste those moonlit nights — there is much excitement to be had in imaging the full lunar disc. A great project is to try and capture all of the major lunar phases, but not just at any time during the night — try to make your exposure is as close to the exact moment of the lunar phase as possible.
The exact timing for lunar phases can be found on the U.S. Naval Observatory website. Attempting to make an exposure as close to the moment of the actual event adds a new level of accuracy in its documentation.
Preparing for your best photographs takes a bit of planning and effort. Consider polar aligning your mount the night before, so if your event is early evening, the mount should be pretty well set to use, even if aligning stars are not yet visible. It's also a good idea to make practice exposures, so when the moment comes, you will be ready! To capture the best image, take no shortcuts. [Blood Moon Photos: Total Lunar Eclipse Pictures from April 15, 2014 ]
Of course, there are special occasions when the moon plays a starring role: solar and lunar eclipses , conjunctions, occultations, transits and more. Again, timing is crucial.
Here, we have an image of the moon in total eclipse on April 15, 2014 — a stunningly beautiful sight. As some of you know, I live deep in the backwoods of Missouri, and there are many creatures of the night that lurk nearby while I do my imaging. On this night, the forest was very quiet and calm — that was, until the moment of totality, when the moon turned a shade of blood red, when seemingly hundreds of coyotes all around me howled in an eerie chorus unseen. They carried on for the longest time, until the familiar color and brightness of the moon began to re-emerge. That experience followed a recurring theme for me here in the backwoods, as I follow lunar eclipses and have witnessed the deep connection between coyotes and the moon — especially when the moon is in total eclipse.
This is my story, my love affair with the moon. I can tell you for certain that the moon loves all of us who inhabit planet Earth, and it holds special gifts for those who spend time with it and seek those gifts out. And as for my wife, it’s OK — she's cool with it.
Space.com is hosting a slideshow of Rogus' night sky images.
Rogus' most recent Op-Ed was "Capturing a Comet-Galaxy Conjunction." The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com. | 0.824503 | 3.518939 |
From: ESA Mars Express Mission
Posted: Thursday, October 16, 2008
European space scientists are getting closer to unravelling the origin of Mars' larger moon, Phobos. Thanks to a series of close encounters by ESA's Mars Express spacecraft, the moon looks almost certain to be a 'rubble pile', rather than a single solid object. However, mysteries remain about where the rubble came from.
Unlike Earth, with its single large moon, Mars plays host to two small moons. The larger one is Phobos, an irregularly sized lump of space rock measuring just 27 km x 22 km x 19 km.
During the Summer, Mars Express made a series of close passes to Phobos. It captured images at almost all flybys with the High Resolution Stereo Camera (HRSC). A team led by Gerhard Neukum, Freie Universitaet Berlin, also involving scientists from the German Aerospace Centre (DLR), is now using these and previously collected data to construct a more accurate 3D model of Phobos, so that its volume can be determined with more precision.
In addition, during one of the nearest flybys, the Mars Express Radio Science (MaRS) Experiment team led by Martin Paetzold, Rheinisches Institut fuer Umweltforschung at the University of Cologne, carefully monitored the spacecraft's radio signals. They recorded the changes in frequency brought about by Phobos' gravity pulling Mars Express. This data is being used by Tom Andert, Universitaet der Bundeswehr Muenchen and Pascal Rosenblatt, Royal Observatory of Belgium, both members of the MaRS team, to calculate the precise mass of the martian moon.
Putting the mass and volume data together, the teams will be able to calculate the density. Eventually, this will be a new important clue to how the moon formed.
Previously, radio tracking from the Soviet Phobos 88 mission and from the spacecraft orbiting Mars in the past decades had provided the most accurate mass. "We can be ten times more precise in our frequency shift measurements today," says Rosenblatt.
The team's current mass estimate for Phobos is 1.072 1016 kg, or about one billionth the mass of the Earth.
Preliminary density calculations suggest that it is just 1.85 grams per cubic centimetre. This is lower than the density of the martian surface rocks, which are 2.7-3.3 grams per cubic centimetre, but very similar to that of some asteroids.
The particular class of asteroids that share Phobos' density are known as D-class. They are believed to be highly fractured bodies containing giant caverns because they are not solid. Instead, they are a collection of pieces, held together by gravity. Scientists call them rubble piles.
Also, spectroscopic data from Mars Express and previous spacecraft show that Phobos has a similar composition to these asteroids. This suggests that Phobos, and probably its smaller sibling Deimos, are captured asteroids. However, one observation remains difficult to explain in this scenario.
Usually captured asteroids are injected into random orbits around the planet that gravitationally tie them, but Phobos orbits above Mars' equator a very specific case. Scientists do not yet understand how it could do this.
In another scenario, Phobos could have been made of martian rocks that were blasted into space during a large meteorite impact. These pieces have not fallen completely together, thus creating the rubble pile.
So the question remains, where did the original material come from Mars' surface or the asteroid belt? The MARSIS radar on board Mars Express has also collected historic data about Phobos' subsurface. This data, together with that from the moon's surface and surroundings gathered by the other Mars Express instruments, will also help put constraints on the origin. It's clear though that the whole truth will only be known when samples of the moon are brought back to Earth for analysis in laboratories.
This exciting possibility might soon become reality because the Russians will attempt to do this with the Phobos-Grunt mission, to be launched next year. To land on Phobos, they will require the precise knowledge of the mass as measured by the MaRS Experiment in order to navigate correctly, and are also making use of the HRSC images to select the landing site.
Note for editors Between 23 July and 15 September 2008 Mars Express performed a series of eight fly-bys of the martian moon Phobos, at distances ranging between 4500 and 93 km from the centre of the moon, conducting some of the most detailed investigations of the Moon to date. In observing Phobos, Mars Express benefits from its highly elliptical orbit which takes it from a closest Mars approach of 270 km above the surface up to a maximum of 10 000 km from the planet's centre, crossing the 9 400 km orbit of the moon. Like our Moon, Phobos always shows the same side to the planet, so it is only by flying outside the orbit that it becomes possible to observe the far side. The other spacecraft presently orbiting Mars do so at much lower altitudes, and therefore only see the planet-facing side of the moon.
The High-Resolution Stereo Camera (HRSC) collected pictures of the moon's surface with the highest resolution possible, in colour and in 3-D, and provided images of areas never glimpsed before. By September, also the Super Resolution (SRC) Camera, part of the HRSC experiment, collected plenty of images. During the second fly-by, all efforts were concentrated on accurately determining the mass of the moon using the MaRS experiment.
The Visible and Infrared Mineralogical Mapping Spectrometer, OMEGA, the Planetary Fourier Spectrometer, PFS, and the Ultraviolet and Infrared Atmospheric Spectrometer, SPICAM, gathered details on the surface composition, geochemistry and temperature of Phobos.
The MARSIS radar collected information on the topography of the moon's surface and on the structure of its interior. The Energetic neutral atoms analyser, ASPERA studied the environment around Phobos, in particular the plasma that surrounds the moon and also the interaction of the moon with the solar wind.
// end // | 0.856341 | 3.819412 |
Astrological event december 2 2019
Several times a year at the moon's first quarter phase, a feature called the Lunar X becomes visible in strong binoculars and small telescopes. For a few hours centered on approximately 11 p. But it has occasionally been much more prolific. The best time to watch for Draconids will be after dusk, when the radiant in Draco is high in the northern sky.
Unfortunately, the bright, waxing gibbous moon will wash out many of the fainter meteors. On the evening of Thursday, October 10, the waxing gibbous moon will pass four degrees below to the celestial south of distant, blue Neptune. While the bright moonlight will overwhelm the nearby dim planet, take note of Neptune's location among the modest stars of Aquarius, and observe Neptune on a subsequent date, when the moon has left the scene.
From time to time, the little round, black shadows cast by Jupiter's four Galilean moons become visible in backyard telescopes as they cross or transit the planet's disk. On Friday evening, October 11, between and p. Only observers located west of the Great Lakes will see the entire transit. Since it's opposite the sun on this day of the lunar month, the full moon rises at sunset and sets at sunrise. This full moon will occur a few days after apogee, producing the smallest full moon of On Sunday evening, October 13, observers in the Americas can see a rare double-shadow transit on Jupiter.
At dusk, Europa's shadow will be midway across the northern hemisphere of the planet — accompanied by the Great Red Spot. Shortly before 8 p. EDT, Io's shadow will join in the fun. Two shadows will be visible for approximately 35 minutes — until Europa's shadow moves off the planet at about p. Io's shadow transit will end at 10 p.
EDT — after the planet has set for more easterly observers. Starting in mid-evening on Monday, October 14, and continuing through dawn on Tuesday, the bright, full moon will pass within five degrees below or to the celestial south of the planet Uranus.kessai-payment.com/hukusyuu/espionner-whatsapp/wuto-localisation-cellulaire.php
Chinese Calendar of December 12222
While Uranus is bright enough to be seen in binoculars under dark sky conditions, the nearby moon will overwhelm it. Take note of Uranus' location in the sky, east of the stars of Pisces, and observe the planet on a subsequent evening, after the moon has moved away.
On the evening of Sunday, October 20, Mercury orbit shown as red curve will reach its widest separation for the current apparition, 25 degrees east of the Sun.
With Mercury sitting below a shallowly dipping evening ecliptic in the west-southwestern sky, this will be a poor appearance of the planet for Northern Hemisphere observers, but an excellent one for those at more southerly latitudes. The optimal viewing period for mid-northern latitudes is between and 7 p. Viewed in a telescope inset the planet will exhibit a waning gibbous phase.
Look for much brighter Venus sitting seven degrees to Mercury's right. At its last quarter phase, the moon rises around midnight and remains visible in the southern sky all morning. At this phase, the moon is illuminated on its western side, towards the pre-dawn sun. Last quarter moons are positioned ahead of the Earth in our trip around the sun. Date Roman Zodiac. How old am I if I was born on December 2, ? Years Months Days Hours Minutes. Date Facts: December 2, was a Monday Zodiac Sign for this date is: Sagittarius This date was 55 days ago December 2nd is on a Monday Someone born on this date is 0 years old If you were born on this date: You've slept for 18 days or 0 years!
Your next birthday is 55 days away You've been alive for 1, hours You were born on a Monday in early December You are 79, minutes old Your next birthday is on a Monday. Most popular baby names of ranked:. Rank Name Total 1. Noah 2. Liam 3.
Best Night Sky Events of October (Stargazing Maps) | Space
William 4. Mason 5. James 6. Benjamin 7. Jacob Olivia 2. Ava 3. Sophia 4. Isabella 5. Mia 6. Charlotte 7. Abigail How popular is your name?
Search to find out! Search your name: Girl: Boy:. Celebrities Birthdays: December 2nd, Frederic Tuten. Lunar eclipses only happen during full moons , and the one that rises in late January will be bigger and brighter than average, making it a so-called supermoon. Totality, or total coverage of the moon, will begin at p. The entire 3. Sky-watchers in eastern Europe and eastern Africa will witness only the partial eclipse, while people in most of Asia will not see any part of the sky show.
Look toward the southern sky at local dawn to see the waning gibbous moon make an eye-catching close encounter with the bright planet Jupiter. The cosmic duo will rise in the east at about 1 a. While the event is an impressive sight with just the naked eye, it will be equally striking to spy the pair together through binoculars and telescopes.
While both the Perseid and Geminid meteor showers will have to contend with a bright moon washing out some of their shooting stars, a dark new moon will make the Eta Aquarids the best meteor shower of Astronomers expect rates of up to 30 meteors an hour to be streaking through the northeast skies starting around 10 p.
Astro Events You Should Keep Your Eye on in 12222
The individual shooting stars of the Eta Aquarids will appear to come from the eastern part of the sky, where their namesake constellation Aquarius, the water bearer, can be seen this time of year. How well do you know the constellations? Take our quiz. This famous ball of ice and rock last visited our corner of the solar system back in , and it won't return until In the meantime, we can see the sand grain-size particles shed by this icy visitor burn up high above our heads each May.
The moon will pass between Earth and the sun on July 2, , creating an awe-inspiring total solar eclipse for lucky sky-watchers in the South Pacific, Chile, and Argentina. The entire event will last from p. ET to p. ET UT. The sun will be covered up for two to two-and-a-half minutes as seen from locations along the path of totality, which cuts across South America from La Serena, Chile, to Buenos Aires, Argentina.
While the full eclipse, including totality, will only be visible along a narrow band in these regions, people in Ecuador, Brazil, Uruguay, and Paraguay will be able to see the partial solar eclipse, weather and cloud cover permitting. Starting at p. Lasting about five-and-a-half hours, the eclipse will cover up roughly 60 percent of the full moon at its peak. | 0.870547 | 3.423991 |
Comet Lovejoy glows brightest during mid-January
Comet Lovejoy, already being tracked by backyard astronomers worldwide, is entering its best and brightest two weeks for viewing. From about January 7th through 24th the comet is predicted to be glowing at 4th magnitude—bright enough that skywatchers with clear, dark skies might be able to just glimpse it by eye, without optical aid. And the early-evening sky during this time will be dark and moonless, allowing the best views.
On January 7th, Comet Lovejoy passes closest by Earth at a distance of 44 million miles (70 million km), nearly half the distance from Earth to the Sun. But its distance will change only a little for many nights after that, so you'll have plenty of opportunities to track it down.
"If you can find Orion shining high in the southeast after dinnertime," says Sky & Telescope senior editor J. Kelly Beatty, "you'll be looking in the right direction to track down Comet Lovejoy." From there, use Sky & Telescope's sky maps (see below) to find the right spot for each date.
To the unaided eye, Comet Lovejoy might be dimly visible as a tiny circular smudge under dark-sky conditions. Through binoculars or a wide-field telescope, it will be more obvious as a softly glowing ball. Light pollution will make it less apparent.
During the next two weeks, the comet crosses the constellations Taurus, Aries, and Triangulum, climbing higher and higher in early evening. It passes 10° to the right (west) of the Pleiades star cluster on the evenings of January 15th through 17th. Although by then Comet Lovejoy will be receding from Earth, it doesn't come closest to the Sun until January 30th, at a rather distant 120 million miles (193 million km). By that date moonlight will begin to interfere, and the comet should be starting to fade as seen from Earth's point of view.
This is the fifth comet discovery by Australian amateur astronomer Terry Lovejoy, and he found it in images taken with his backyard 8-inch telescope. It's a very long-period comet, meaning that it has passed through the inner solar system before, roughly 11,500 years ago. Slight gravitational perturbations by the planets will alter the orbit a bit, so that the comet will next return in about 8,000 years. Astronomers have given it the official designation C/2014 Q2.
Hints of Green and Gold
Based on its steady, uninterrupted brightening, observers estimate that the comet's solid, ice-rich nucleus is at least 2 or 3 miles across, slightly larger than typical. But the glowing object we actually see is vastly larger and less substantial. The comet's visible head, or coma, is a cloud of gas and dust roughly 400,000 miles across, that has been driven off the nucleus by the warmth of sunlight.
Human eyes can't perceive color in dim nighttime objects well, but photographs show that Comet Lovejoy has a lovely green hue. The green glow comes from molecules of diatomic carbon (C2) in the coma that fluoresce in response to ultraviolet sunlight. By contrast, Comet Lovejoy's long, delicate gas tail is tinted blue, thanks to carbon monoxide ions (CO+) that are likewise fluorescing.
In addition, dust in a comet's coma and tail simply reflects sunlight, so dust features appear pale yellowish white. The most memorable comets tend to have dramatic dust tails, such as spectacular Comet Hale-Bopp in 1997 and another discovery by Lovejoy, C/2011 W3, in 2011.
The current Comet Lovejoy is not producing enough dust to create a bright tail - and in fact this interloper wasn't expected to become so obvious at all. But by late 2014 amateur astronomers had noticed that the comet was brightening steadily and faster than predicted. | 0.824326 | 3.665766 |
Explosive astrophysical phenomena have historically played a significant role in understanding the universe and our place within it. Stellar explosions are important distance indicators, allowing exploration of the structure and evolution of the universe. They also form and disperse heavy elements that are recycled into new astrophysical objects. Stellar explosions are not a uniform group; the progenitors and mechanisms of stellar explosions vary tremendously. I used multidimensional simulations to study two distinct types of explosions that are believed to result from similar progenitor systems: compact white dwarf stars that accrete matter from stellar companions. The two types of explosions I studied are type Ia supernovae and classical novae.
Type Ia supernovae are thought to arise from a thermonuclear explosion originating in the core of an accreting white dwarf and leave no remnant. These events are the premier distance indicators in cosmological studies, but questions remain about systematic biases and intrinsic scatter. My investigation centered on the systematic impact of the central density of the progenitor on the brightness of the supernova. Relating the progenitor's central density to its age provided a theoretical explanation of the observed trend that type Ia supernovae from older stars are dimmer. I also demonstrated the importance of a statistical study of such problems, due to the strongly nonlinear evolution during the explosion.
Classical novae are important for the study of circumstellar dust formation and are significant contributors of specific isotopes found in our galaxy. They result from a thermonuclear runaway occurring in the accreted envelope on a white dwarf. Only the envelope is consumed, so the white dwarf remains and the event may recur on time scales of 104 to 10 5 years. My study made use of a new simulation code specialized for low-Mach number flows, such as convection just prior to the explosion. I developed hydrostatic initial models and physics modules necessary for simulations of classical novae. This problem provided unexpected challenges, but preliminary simulations of convection-driven mixing between the accreted envelope and the underlying white dwarf are underway. Future results will explore the effects of convection, particularly the quantity and mechanisms of mixing.
My research into stellar explosions provided important insight into their mechanisms and required considerable development work, which improved our models and will allow more realistic simulations in the future.
|Advisor:||Calder, Alan C.|
|Commitee:||Pleier, Marc-Andre, Stephens, Peter, Walter, Frederick M., Zingale, Michael|
|School:||State University of New York at Stony Brook|
|School Location:||United States -- New York|
|Source:||DAI-B 74/02(E), Dissertation Abstracts International|
|Subjects:||Astrophysics, Physics, Astronomy|
|Keywords:||Classical novae, Computational fluid dynamics, Stellar explosions, Type ia supernovae|
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NEW YORK - Scientists have found two Earth-sized planets orbiting a star outside the solar system, an encouraging sign for prospects of finding life elsewhere.
The discovery shows that such planets exist and that they can be detected, said Francois Fressin of the Harvard-Smithsonian Center for Astrophysics. The fact that Earth-size planets have been found to exist around other stars like the sun marks the beginning of an era, he said.
They're the smallest planets found so far that orbit a star resembling our sun. The discovery also marks the next key milestone in the ultimate grail: the search for planets like Earth.
Scientists are seeking Earth-sized planets as potential homes for extraterrestrial life. The new findings are reported in a paper published online Tuesday by the journal Nature. One planet's diameter is only 3 percent larger than Earth's, while the other's diameter is about nine-tenths that of Earth. They appear to be rocky, like our planet.
But they are too hot to contain life as we know it, with calculated temperatures of about 1,400 degrees and 800 degrees Fahrenheit (815 degrees and 426 degrees Celsius), he said.
Any life found on another plant may not be intelligent; it could be bacteria or mold or some completely unknown form.
Since it was launched in 2009, NASA's planet-hunting Kepler telescope has found evidence of dozens of possible Earth-sized planets. But Fressin's report is the first to provide confirmation, said Alan Boss of the Carnegie Institution for Science in Washington. He's a member of the Kepler science team but not an author of the paper.
The researchers ruled out a possible alternative explanation for the signals that initially indicated the planets were orbiting the star Kepler-20. The star is 950 light-years from Earth in the direction of the constellation Lyra.
The planets are called Kepler-20e and Kepler-20f.
Earlier this month, scientists said they'd found a planet around another distant star with a life-friendly surface temperature of about 72 degrees (22 degrees Celsius). But it was too big to suggest life on its surface. At 2.4 times the size of Earth, it could be more like the gas-and-liquid Neptune with only a rocky core and mostly ocean, scientists said. | 0.845998 | 3.283396 |
New Horizons team prepares for stellar occultation ahead of Ultima Thule flyby
(31 July 2018 - Johns Hopkins University Applied Physics Laboratory) Successfully observing an object from more than four billion miles away is difficult, yet NASA's New Horizons mission team is banking that they can do that—again.
Preparations are on track for a final set of stellar occultation observations to gather as much information about the size, shape, environment, and other conditions around New Horizons' next flyby target, the ancient Kuiper Belt object 2014 MU69, nicknamed Ultima Thule.
The occultation team used data from the Hubble Space Telescope and European Space Agency's Gaia satellite to pinpoint two roughly 18.5-mile (30-kilometer) strips on Earth where Ultima Thule will cast its shadow on August 4th. Telescopes will be placed at multiple points in those strips to attempt to observe the occultation when Ultima Thule passes in front of a star and momentarily blocks its light. In a similar effort in 2017, the team struck observation gold from multiple sites in Patagonia, Argentina. Fighting high winds and extreme winter conditions from multiple sites in Patagonia, team members captured a similar occultation from five sites, a major success that taught them much about the flyby target and helped define the flyby distance of 2,175 miles (3,500 kilometers).
(courtesy: NASA/APL/SwRI/Steve Gribben)
"Gathering occultation data is an incredibly difficult task," said New Horizons occultation event leader Marc Buie of the Southwest Research Institute, Boulder, Colorado, who also discovered Ultima Thule about a year before New Horizons flew past Pluto in July 2015. "We are literally at the limit of what we can detect with Hubble and the amount of computer processing needed to resolve the data is staggering."
The final occultation observations of Ultima Thule are scheduled for Aug. 4 in Senegal and Colombia, with Buie again leading the effort. "Our team of almost 50 researchers using telescopes in Senegal and in Colombia are certainly hoping lightning will strike twice and we'll see more blips in the stars," he said. "This occultation will give us hints about what to expect at Ultima Thule and help us refine our flyby plans."
Preparations for the occultation are intense. Travel to the remote locations while carrying sensitive equipment is a challenge. Several days ahead of the observations, the teams will begin to rehearse every detail of the observation, so they can adapt to variable weather conditions and other adverse conditions. Enthusiasm and support for this effort from the Senegal and Colombia governments has been exceptional, as well as that from the resident U.S. embassies and the French, Senegalese, Colombian, and Mexican astronomy communities — resulting in a truly multinational collaboration.
"If the team is successful, the results will help guide our planning for the flyby," said Alan Stern, New Horizons mission principal investigator, also of the Southwest Research Institute.
Ultima Thule and other Kuiper Belt objects hold clues to the formation of planets and the "third zone" of our solar system in which they reside, the wide expanse beyond the giant planets. Last year's observations showed that Ultima Thule could be either two objects that orbit each other (a "binary"), two objects that touch (a "contact binary"), and may possibly also sport a moon. Its size is estimated to be 20 miles (30 kilometers) long if a single object or 9-12 miles each (15-20 kilometers) if two objects.
For the past several weeks, the New Horizons mission team has been collecting navigation tracking data and sending commands to New Horizons' spacecraft onboard computers to begin preparations for the Ultima Thule flyby; the flyby activities include memory updates, Kuiper Belt science data retrieval, and a series of subsystem and science-instrument checkouts. Next month, the team will command New Horizons to begin making distant observations of Ultima Thule, images that will help the team refine the spacecraft's course to fly by the object.
When New Horizons whizzes past Ultima Thule on New Year's Day, at a distance of more than 4 billion miles (6.5 billion kilometers) from Earth, the object will become the most distant object ever explored. | 0.884646 | 3.325476 |
Humans have good reason to fear comets, asteroids and other massive space objects.
Now we’d like to add ‘mini-moons’ to the list of heavenly bodies we should be worried about.
Scientists have claimed our planet was recently hit by one of these mysterious rocks, which exploded in a gigantic fireball.
A mini-moon is an object which becomes entangled in Earth’s orbit as it’s zooming through space.
It will either whirl around the planet harmlessly forever, zoom off back off on its journey through the solar system or, in the worst case, smash into our planet.
‘Objects gravitationally captured by the Earth–Moon system are commonly called temporarily captured orbiters, natural Earth satellites, or minimoons,’ scientists wrote in a new study published in The Astromomical Journal.
‘TCOs are a crucially important subpopulation of near-Earth objects (NEOs) to understand because they are the easiest targets for future sample-return, redirection, or asteroid mining missions.
‘Only one TCO has ever been observed telescopically, 2006 RH 120, and it orbited Earth for about 11 months.’
However, it’s believed that an ‘extremely slow fireball’ which exploded over South Australia may have been a mini-moon.
It was picked up by six different detectors when it went kaboom in August 2016.
No-one was hurt in the incident, but it shows that the movement of objects through the region of space close to Earth is highly unpredictable.
If the rock had been larger, it could have done some major damage.
It’s very difficult to guess what’s going to happen to an object when it encounters Earth’s gravity because its movements are ‘chaotic in nature and predicting its pre-impact trajectory is very difficult’.
What this means is that if we saw a big asteroid in our planet’s orbit, we wouldn’t necessarily be able to say where and when it was going to hit Earth – or even if it was going to simply zoom around humanity’s homeworld and then travel off into space.
This year, Nasa has discovered two asteroids which could be on a collision course with our planet.
The space agency keeps a database called Sentry that contains details of all the space rocks with a chance of smashing into Earth.
This list is updated every time a new object that could hit humanity’s homeworld is discovered.
In the past six months alone, two separate rocks have been discovered which could crash into us.
The first is called 2019 ND7 and was observed in July.
This beast is almost 200 metres wide, which is large enough to wipe out an entire city.
It could be bigger than a meteor which detonated over Tunguska, Russia, in 1908 and flattened trees over an area of 770 square miles.
The ‘Tunguska event’ caused an explosion of 15-megatons – which is roughly 1,000 times greater than that of the atomic bomb dropped on Hiroshima, Japan.
The rock which caused this mighty kaboom was between 60 and 1,000 metres wide, although most estimates indicate it was at the smaller size of this range.
Describing this incident, Nasa wrote: ‘Although a meteor the size of the Tunguska can level a city, metropolitan areas take up such a small fraction of the Earth’s surface that a direct impact on one is relatively unlikely.
‘More likely is an impact in the water near a city that creates a dangerous tsunami.’
Luckily, there is only a very small chance of the asteroid hitting Earth. Nasa has calculated the risk at 1 in 310,000, meaning there’s a 99.99968% chance the asteroid will miss the Earth.
The second asteroid is called 2019 WG2 and was observed this month. It’s much smaller and stretches to just 35 metres wide.
However, this could still cause a huge explosion. It’s estimated that a crater outside Winslow, Arizona, was blasted into the Earth 50,000 years ago by a similarly-sized object which exploded with 10 megatons of energy.
However, we’re glad to report that the chance of it hitting is us is quite small. There’s a 1 in 4000 risks of the object ploughing into our planet.
We also have a grace period, because neither is at risk of colliding into Earth until the end of the century.
There’s a chance of 2019 ND7 crashing into Earth between 2097-2117 on 20 different occasions, while 2019 WG2 could hit between 2098 and 2119 at 56 different times.
On its Sentry page, Nasa said: ‘One must bear in mind that an Earth collision by a sizable near-Earth asteroid is a very low probability event.’ | 0.817848 | 3.167489 |
On this date, the Italian mathematician Galileo Galilei marched the Doge of Venice (Leonardo Donato), his counsellor, the Chiefs of the Council of Ten, and the Sages of the Order, who commanded the Venetian navy, up the Bell Tower (Campanile) in St. Mark’s Square in Venice, Italy. Once at the top, Galileo showed them views of distant cities, ships on the horizon, and parishioners entering a church on the island of Murano – all of which had been invisible to the eye alone – with the aid of his first telescope. The Doge was awestruck. The military had a powerful new secret weapon. Venice was confirmed again as a triumph. Galileo presented the Doge with the telescope on his knees and received a doubled salary, a lifetime appointment, and a bonus amounting to a year’s wages.
Throughout the the rest of 1609, particularly during the winter, Galileo made many astronomical studies. On January 7, 1610 Galileo observed with his telescope what he described at the time as “three fixed stars, totally invisible by their smallness,” all close to Jupiter, and lying on a straight line through it. Observations on subsequent nights showed that the positions of these “stars” relative to Jupiter were changing in a way that would have been inexplicable if they had really been fixed stars. On January 10 Galileo noted that one of them had disappeared, an observation which he attributed to its being hidden behind Jupiter. Within a few days he concluded that they were orbiting Jupiter. He had discovered three of Jupiter’s four largest satellites (moons): Io, Europa, and Callisto. He discovered the fourth, Ganymede, on January 13. Galileo named the four satellites he had discovered Medicean stars, in honor of his future patron, Cosimo II de’ Medici, Grand Duke of Tuscany, and Cosimo’s three brothers. [Later astronomers, however, renamed them the Galilean satellites in honor of Galileo himself.] On March 12, 1610 Galileo published the results of his studies in a brief treatise entitled Sidereus Nuncius (Starry Messenger).
These observations over a six night period, from January 7 through January 13, provided a view to Galileo that revealed that perhaps not everything orbited the Earth (geocentric model), as Ptolemy as well as the Catholic Church had adopted. And, if these small, but bright points of light went around Jupiter and not the Earth, perhaps there were other objects that did not orbit the Earth. His findings allowed him to confirm the Sun-centered theory of Copernicus. This short period of time from the summer of 1609 through to March of 1610, when Siderius Nuncius was published, had a revolutionary impact on astronomy almost overnight and it catapulted Galileo into the scientific spotlight and into the fire and wrath of the Catholic Church.
The Catholic Church condemned Galileo for his theories on June 22, 1633. He was forced to disown them and to live on his own for the rest of his life. In the following century the Vatican began changing its attitude. A mausoleum was built in 1734 to honor him. In 1822 Pope Pius VII gave permission for Galileo’s theory to be taught in schools. In 1968 Pope Paul VI had the trial against Galileo reassessed, then Pope John Paul II took the final step in the Church’s rehabilitation of the scientist in 1984 when he formally acknowledged that the Catholic Church had erred when it condemned the Italian astronomer for maintaining that Earth revolved around the Sun. | 0.819178 | 3.574674 |
You can read in detail about The Sky of September here. It will be the same year after year, Pluto and all.
Relax, Pluto WILL not go anywhere soon
In fact Pluto takes 248 years to orbit the Sun as it orbits at an average distance of 5.9 billion km from the Sun, while Earth only orbits at 150 million km. This means that it will take Pluto almost 20 years to shift into another constellation.
Everything else you need to know about Pluto is below and xkcd.com does a great job at explaining all this chaos:
Unlike Pluto, the other planets and the Moon are all over the place in the sky from month to month let alone from year to year.
This is what they will do this month:
The planets and the Moon are changing their position on a daily, monthly, and yearly basis; unlike the stars, which repeat their patterns once a year. This is the reason why the planets were called by the ancient Greek the wanderers. Their positions are called ephemerides and can be calculated.
The harbinger of this spring is a Supermoon, which is when the full Moon coincides with when the Moon is closest to Earth, also known as perigee. This happens roughly once every 13 months, which is every 14th Full Moon.
The opposite of a Supermoon is a micromoon…
The Moon in Māori is called Mārama which literally can mean the white light coming from the sun Ra.
When the Moon does not take over the entire sky with her light we can see the following planets:
In the evening
Mercury (Māori: Whiro) and Saturn (Māori: Pāre-a-Rao) are bright planets in the evening sky. At the beginning of the month Mercury is making its best evening sky appearance of the year, low in the west. Cream-coloured Saturn is northwest of the zenith at dusk and midway down the western sky by late evening.
and the Morning stars are
Just one, brilliant Venus, ‘Kopu Rere Ata’ . The morning star of the Māori rises in the east two hours before the Sun. A telescope shows Earth-sized Venus as a thin crescent from 60 million km away. On 21 of September Venus displays its greatest illuminated extent as the morning “star”, which means that for the next several days our morning star Venus will be shining at or near its greatest brilliancy. Remember that Venus shines the most when is in crescent phase. | 0.851689 | 3.164212 |
NASA's Seven-Planet Discovery: Are We Alone in the Universe?
“For most of human history, we have been asking an identity question: ‘Are we alone [in the universe]?'” said Fady Morcos, associate professor of practice in the School of Sciences and Engineering. NASA’s recent discovery of seven Earth-size planets orbiting around a single star may provide the answer.
Representing the single largest group of Earth-like planets orbiting a single star ever to be found, this discovery is a dramatic step forward in the search for life on other planets outside the solar system. “NASA's recent discovery is significant because three of the seven discovered Earth-like planets reside in the habitable zone of the Trappist-1 star, which increases the probability of finding liquid surface water and, thus, potentially life.”
These seven planets orbit the Trappist-1 star, which although much smaller than the sun, still allows for potentially habitable candidates in its planetary system. Expanding on what qualifies as a potentially habitable planet, Morcos explained that liquid water is a crucial component for life.
“According to our current understanding of origins,” he said, “the existence of liquid water is a prerequisite for the origin and evolution of life. However, surface liquid water could only exist if the planet has the right size and orbits at the right distance from the parent star. There is a region around every star where temperature is just right to keep surface water in liquid form. We call this region the habitable zone. Thus, in our search for potential habitable planets, we focus the search on Earth-size planets that orbit inside the habitable zone of their parent star.”
Although NASA has been searching for Earth-like planets for years, they have rarely found those that are also in a star’s habitable zone. “Extremely few planets met both criteria of size and location,” said Morcos.
This discovery is poised to dramatically change the field of astronomy moving forward, both at NASA and beyond. “The discovery of the Trappist system provides great support to the hypothesis that the conditions necessary for life are not rare as we originally thought and are definitely not unique to planet Earth,” noted Morcos.
Moreover, since these Earth-like planets were found orbiting a smaller star than most scientists would have predicted, it suggests that billions of other planets might host the conditions necessary for life.
“We need to revisit our understanding of planetary formation theory,” said Morcos. “The data does not meet -- in fact it far exceeds -- the predictions. Just in our Milky Way, there are suddenly tens of billions of new candidate stars, those that were previously thought to be too small to host planets, to observe for planetary systems. Now, astronomers are pointing their telescopes at stars that were prejudged to be loners, with the hope of finding new planetary systems like Trappist. This discovery has expanded the search space, which will dramatically increase the detection frequency of potentially habitable planets in the coming years.” | 0.896536 | 3.690345 |
Caltech astronomers have identified an asteroid that runs around the Sun every 151 days, which makes this asteroid the one with the shortest year among those identified. 2019 LF6 has a diameter of about one mile and travels with an orbit that is just above Venus, oscillating slightly beyond it and approaching Mercury.
It is an Atira-type asteroid (a group that includes all the asteroids whose orbit is located entirely within the terrestrial one). This is an interesting discovery also because it is a fairly large asteroid, as specified by Quanzhi Ye, the student at Caltech who made the discovery, who admits that finding such asteroids today has become quite rare as the largest orbiting near almost all have been identified in the Sun.
The orbit of LF6, according to the scholar, is also very unusual, which explains the fact that it was never identified despite its rather bulky size. The researchers used the Palomar Observatory which has a special state-of-the-art camera, the Zwicky Transient Facility, which scans the skies every night to find these objects as well as other phenomena such as explosions and particular stars. 2019 LF6 joins 2019 AQ3, another Atira asteroid from the very short year that orbits the Sun every 165 days.
Both asteroids orbit far outside the plane of the solar system, something that suggests that they have somehow been “thrown out” gravitationally because they are too close to Mercury or Venus, as recalled by Tom Prince, professor of physics Caltech, another author of the research together with George Helou, executive director of the IPAC.
Latest posts by Henry Wright (see all)
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- Spektr-RG space telescope carried in Russian rocket orbit - January 11, 2020 | 0.85083 | 3.359192 |
Last fall, astronomers were surprised when the Kepler mission reported some anomalous readings from KIC 8462852 (aka. Tabby’s Star). After noticing a strange and sudden drop in brightness, speculation began as to what could be causing it – with some going so far as to suggest that it was an alien megastructure. Naturally, the speculation didn’t last long, as further observations revealed no signs of intelligent life or artificial structures.
But the mystery of the strange dimming has not gone away. What’s more, in a paper posted this past Friday to arXiv, Benjamin T. Montet and Joshua D. Simon (astronomers from the Cahill Center for Astronomy and Astrophysics at Caltech and the Carnegie Institute of Science, respectively) have shown how an analysis of the star’s long-term behavior has only deepened the mystery further.
To recap, dips in brightness are quite common when observing distant stars. In fact, this is one of the primary techniques employed by the Kepler mission and other telescopes to determine if planets are orbiting a star (known as Transit Method). However, the “light curve” of Tabby’s Star – named after the lead author of the study that first detailed the phenomena (Tabetha S. Boyajian) – was particularly pronounced and unusual.
According to the study, the star would experience a ~20% dip in brightness, which would last for between 5 and 80 days. This was not consistent with a transitting planet, and Boyajian and her colleagues hypothesized that it was due to a swarm of cold, dusty comet fragments in a highly eccentric orbit accounted for the dimming.
However, others speculated that it could be the result of an alien megastructure known as Dyson Sphere (or Swarm), a series of structures that encompass a star in whole or in part. However, the SETI Institute quickly weighed in and indicated that radio reconnaissance of KIC 8462852 found no evidence of technology-related radio signals from the star.
Other suggestions were made as well, but as Dr. Simon of the Carnegie Institute of Science explained via email, they fell short. “Because the brief dimming events identified by Boyajian et al. were unprecedented, they sparked a wide range of ideas to explain them,” he said. “So far, none of the proposals have been very compelling – in general, they can explain some of the behavior of KIC 8462852, but not all of it.”
To put the observations made last Fall into a larger context, Montet and Simon decided to examine the full-frame photometeric images of KIC 8462852 obtained by Kepler over the last four years. What they found was that the total brightness of the star had been diminishing quite astonishingly during that time, a fact which only deepens the mystery of the star’s light curve.
As Dr. Montet told Universe Today via email:
“Every 30 minutes, Kepler measures the brightness of 160,000 stars in its field of view (100 square degrees, or approximately as big as your hand at arm’s length). The Kepler data processing pipeline intentionally removes long-term trends, because they are hard to separate from instrumental effects and they make the search for planets harder. Once a month though, they download the full frame, so the brightness of every object in the field can be measured. From this data, we can separate the instrumental effects from astrophysical effects by seeing how the brightness of any particular star changes relative to all its neighboring stars.”
Specifically, they found that over the course of the first 1000 days of observation, the star experienced a relatively consistent drop in brightness of 0.341% ± 0.041%, which worked out to a total dimming of 0.9%. However, during the next 200 days, the star dimmed much more rapidly, with its total stellar flux dropping by more than 2%.
For the final 200 days, the star’s magnitude once again consistent and similar to what it was during the first 1000 – roughly equivalent to 0.341%. What is impressive about this is the highly anomalous nature of it, and how it only makes the star seem stranger. As Simon put it:
“Our results show that over the four years KIC 8462852 was observed by Kepler, it steadily dimmed. For the first 2.7 years of the Kepler mission the star faded by about 0.9%. Its brightness then decreased much faster for the next six months, declining by almost 2.5% more, for a total brightness change of around 3%. We haven’t yet found any other Kepler stars that faded by that much over the four-year mission, or that decreased by 2.5% in six months.”
Of the over 150,000 stars monitored by the Kepler mission, Tabby’s Starr is the only one known to exhibit this type of behavior. In addition, Monetet and Cahill compared the results they obtained to data from 193 nearby stars that had been observed by Kepler, as well as data obtained on 355 stars with similar stellar parameters.
From this rather large sampling, they found that a 0.6% change in luminosity over a four year period – which worked out to about 0.341% per year – was quite common. But none ever experienced the rapid decline of more than 2% that KIC 8462852 experienced during that 200 days interval, or the cumulative fading of 3% that it experienced overall.
Montet and Cahill looked for possible explanations, considering whether the rapid decline could be caused by a cloud of transiting circumstellar material. But whereas some phenomena can explain the long-term trend, and other the short-term trend, no one explanation can account for it all. As Montet explained:
“We propose in our paper that a cloud of gas and dust from the remnants of a planetesimal after a collision in the outer solar system of this star could explain the 2.5% dip of the star (as it passes along our line of sight). Additionally, if some clumps of matter from this collision were collided into high-eccentricity comet-like orbits, they could explain the flickering from Boyajian et al., but this model doesn’t do a nice job of explaining the long-term dimming. Other researchers are working to develop different models to explain what we see, but they’re still working on these models and haven’t submitted them for publication yet. Broadly speaking, all three effects we observe cannot be explained by any known stellar phenomenon, so it’s almost certainly the result of some material along our line of sight passing between us and the star. We just have to figure out what!”
So the question remains, what accounts for this strange dimming effect around this star? Is there yet some singular stellar phenomena that could account for it all? Or is this just the result of good timing, with astronomers being fortunate enough to see a combination of a things at work in the same period? Hard to say, and the only way we will know for sure is to keep our eye on this strangely dimming star.
And in the meantime, will the alien enthusiasts not see this as a possible resolution to the Fermi Paradox? Most likely!
Further Reading: arXiv | 0.856451 | 3.944051 |
Every year in August between the 10th and 13th, we get the opportunity under good weather circumstances to observe the anual meteor showers caused by the Perseids. These small particles mainly made of dust are falling through the earth’s atmosphere from a radiant point in the sky located close by the Perseus and Cassiopeia constellations. These meteor showers are nonetheless remains of an old comet which passes close by our planet over a period of 130-135 years and was last seen in 1992 by the Japaneese astronomer Tsurukiko Kiuchi. The comet is named Swift-Tuttle after the two astronomers who independently were the first observers in modern history during the comet apperance in August 1862 (Lewis Swift and Horace Parnell Tuttle). Spectral analysis points out that this comet shares similarities with Halley’s comet which is rich in ammonia, water and carbon dioxide and also clasified as NEO (Near Earth Object) as it is approaches earth in a distance of 4 miljion kilometers. The chances of an impact with our planet is 1 in a 1,000,000 which is much less then the frightening asteroid called Apophis were chances are much larger; 1 in 15,000.
This year our observatory will be opento public between 11th to 13th of August 21:30 to midnight allowing all interested to come and visit us under guidance from the observatory staff.
During June-July at Tycho Brahe observatory we were preparing for a large project that would involve the cooperation between many amateur astronomers from different locations in Sweden. The Swedish assosiation for amateur astronomers (SAAF: Svenska Amatörastronomiska Föreningen) helped us to get in touch with other amateur astronomers across the country. Together with my collegue Arne L Ohlsson we started to put hard work on planning, coordinating meetings, assembling nessesary instrumentation and dealing with time pressure.
The ockultation is all about a large rock out in space, or more commonly called an asteroid named 472 Roma passing infront of the delta star (Yed Prior) in the constellation of Ophiucus, causing this large red giant star to dissappear for a around 5 seconds. This asteroidal passage was meant to be easily observed from our location, but negative observations outside the occultation shadow would provide a lot of information regarding the star itself.
It has been mistaken for a long time that the delta star in Ophiucus would be a double and for the first time an asteroid would occult this star and reveal it’s secrets for us. Unfortunately just before the occultation occurred, heavy clouds surounded our area. That was our worse case scenario that just took place, leaving us with unanswered questions.
In the morning we heard that the German and Belgian astronomers were more lucky then us and that many positive reports started to fall in! | 0.840491 | 3.791209 |
Moon ♏ Scorpio
Moon phase on 5 November 2067 Saturday is Waning Crescent, 28 days old Moon is in Libra.Share this page: twitter facebook linkedin
Previous main lunar phase is the Last Quarter before 6 days on 30 October 2067 at 01:08.
Moon rises after midnight to early morning and sets in the afternoon. It is visible in the early morning low to the east.
Moon is passing about ∠25° of ♎ Libra tropical zodiac sector.
Lunar disc appears visually 6.1% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1821" and ∠1936".
Next Full Moon is the Beaver Moon of November 2067 after 15 days on 20 November 2067 at 23:50.
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 28 days old. Earth's natural satellite is moving from the second to the final part of current synodic month. This is lunation 838 of Meeus index or 1791 from Brown series.
Length of current 838 lunation is 29 days, 14 hours and 46 minutes. It is 55 minutes longer than next lunation 839 length.
Length of current synodic month is 2 hours and 2 minutes longer than the mean length of synodic month, but it is still 5 hours and 1 minute shorter, compared to 21st century longest.
This lunation true anomaly is ∠237.7°. At the beginning of next synodic month true anomaly will be ∠274.8°. 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°).
5 days after point of apogee on 31 October 2067 at 06:44 in ♌ Leo. The lunar orbit is getting closer, while the Moon is moving inward the Earth. It will keep this direction for the next 9 days, until it get to the point of next perigee on 14 November 2067 at 16:11 in ♒ Aquarius.
Moon is 393 580 km (244 559 mi) away from Earth on this date. Moon moves closer next 9 days until perigee, when Earth-Moon distance will reach 370 093 km (229 965 mi).
10 days after its descending node on 25 October 2067 at 14:38 in ♊ Gemini, the Moon is following the southern part of its orbit for the next 3 days, until it will cross the ecliptic from South to North in ascending node on 9 November 2067 at 00:25 in ♐ Sagittarius.
23 days after beginning of current draconic month in ♐ Sagittarius, the Moon is moving from the second to the final part of it.
10 days after previous North standstill on 26 October 2067 at 02:13 in ♊ Gemini, when Moon has reached northern declination of ∠22.333°. Next 3 days the lunar orbit moves southward to face South declination of ∠-22.290° in the next southern standstill on 9 November 2067 at 11:57 in ♐ Sagittarius.
After 1 day on 7 November 2067 at 00:14 in ♏ Scorpio, the Moon will be in New Moon geocentric conjunction with the Sun and this alignment forms next Sun-Moon-Earth syzygy. | 0.848363 | 3.164933 |
For the first time, astronomers have been able to determine how fast a supermassive black hole spins - which is fast enough to push the limits of the laws of physics.
Astronomers using observations from NASA's NuStar space telescope and the ESA's XMM-Newton have finally solved an astronomical mystery. By doing so, they've finally been able to find a definitive measurement for how fast a supermassive black hole spins.
"This is hugely important to the field of black hole science," said NuStar scientist Lou Kaluzienski in a NASA press release.
The main problem with determining how fast that a black hole can spin is that there were two different models that both did a pretty good job of explaining what astronomers see when they look at black holes. However, those models give very different rates of spin for the black hole.
Astronomers typically use X-ray telescopes when they examine black holes. The X-rays emanating from the black holes will be at different frequencies depending on what type of material that the X-rays are bouncing off of. For example, hydrogen will look different than iron. Those results show up on a graph as "peaks" at different points, and astronomers in particular look at the iron peak to see how sharp it is. If it's not sharp, then something is happening to the iron.
Astronomers had two models to explain those iron results, shown in the figure below. In the first model, the gravitational distortions caused by the black hole itself was causing the iron to spread out. If that was the case, then astronomers could use the data from the iron peak to derive the spin of the black hole. In the second model, the iron peak is simply being obscured by the hot gasses that surround the black hole. If the second model was accurate, then astronomers can't use the iron to determine spin.
With the new study, the astronomers were able to rule out the second model entirely. That means that the iron is being distorted by the gravity of the black hole, and so astronomers were able to determine its spin. That was thanks to NuStar's ability to better observe high-energy X-rays.
"If I could have added one instrument to XMM-Newton, it would have been a telescope like NuSTAR," said XMM-Newton Project Scientist Norbert Schartel in the NASA release. "The high-energy X-rays provided an essential missing puzzle piece for solving this problem."
With that issue settled, the astronomers then took the next step of ascertaining the speed of the black hole they were observing, which is about 56 million light years away in the Galaxy NGC 1365. The black hole itself is about 2 million times as massive as our own Sun.
And what was that speed? Well - that's hard to put your finger on. It's about 84% of the speed theoretically allowed by Einstein's theory of relativity. You could think of that as being close to the speed of light, but it's difficult to translate into a particular velocity. That's because both the speed and intense gravity of the Black Hole create conditions that make a mathematical conversion to, say, miles per hour extremely difficult. But however it converts, the fact is that its moving incredibly fast.
These findings will make this and other supermassive black holes even more interesting subjects of study for scientists going forward. That's both because it allows them to see what happens to objects at the extremes of Relativity, and because it provides still more information about the evolution of the universe.
"These monsters, with masses from millions to billions of times that of the sun, are formed as small seeds in the early universe and grow by swallowing stars and gas in their host galaxies, merging with other giant black holes when galaxies collide, or both," said the study's lead author, Guido Risaliti in the NASA release.
"The black hole's spin is a memory, a record, of the past history of the galaxy as a whole," he added in a separate statement.
(Image credits: NASA/JPL-Caltech) | 0.84906 | 4.002037 |
You might think having the opportunity to watch a star go supernova would be a rather rare occurrence—in fact, it really is—but there’s one star that has been exploding over and over again. Well, not really. Scientists think it exploded once 9 billion years ago, but thanks to a trick of optics, they’ve been able to watch the explosion in reruns.
Help for the Hubble Space Telescope
Dennis Overbye of The New York Times compares the phenomenon to the 1993 film Groundhog Day, in which a character played by Bill Murray experiences the same day repeatedly. The star that exploded is so far away from Earth that it requires the help of several galaxies in order for the Hubble Space Telescope to be able to see it.
Four of the galaxies create the shape of what scientists call an Einstein Cross. They surround another galaxy, and since each of those galaxies reflect a different angle of the light rays from the explosion, each of them send an image of a different moment of the explosion.
Supernovae are rare
Supernova experts say being able to watch one is indeed a rare event that happens only about every hundred years or so. When a star explodes, it is one of the most violent events in the universe and the brightest, outshining entire galaxies. Astronomers say the explosions send particles into the universe that end up forming new worlds and leave black holes behind.
Patrick Kelly with the University of California, Berkeley discovered the rerun supernova by examining images captured by the Hubble Space Telescope in November. He is the lead author on the paper about the findings of his research on those images, which was published in the journal Science.
Same supernova to repeat again
This is the first time scientists have been able to see a supernova repeat itself multiple times. They had scene supernova captured through “gravitational lenses” in the past, however. The cluster of galaxies around the exploding star created multiple gravitational lenses, which is what allowed them to see the supernova four times.
Astronomers expect this same supernova to pop up yet again sometime in the next ten years. They were able to time the delays between each of the explosion’s appearances. They believe by continuing to measure the time between each appearance of the supernova that they will be able to better measure the speed at which the universe seems to be expanding. They also want to map the dark matter, which is what most of the universe is made of. | 0.868777 | 3.639843 |
The Full Moon on May 18, 2019, is at 27+ degrees of Scorpio. The Sun in Taurus is in strict conjunction with Sedna, one of the most distant icy bodies in our solar system, named after the Inuit goddess of the Arctic Ocean. Sedna represents the utmost edge, both in the solar system as well as in our consciousness.
Sedna’s orbit is exceptionally long and elongated, taking approximately 11,400 years to complete. Sedna never comes inside Neptune’s orbit, not even when it is nearest to the Sun in its orbit, which happens next time in 2076. Sedna is possibly the first known member of the inner Oort cloud. In the astrological chart it moves so slowly that it works almost like a fixed star.
Sedna was discovered in 2003. It has given its name to a group of distant bodies, the sednoids, of which only three including Sedna are discovered so far, but scientists suspect that there are a lot more of them. The sednoids belong to the category of ETNOs (the extreme trans-Neptunian objects), whose orbits could have been disrupted by an as-yet-unknown planet beyond the Kuiper belt, the hypothesized Planet Nine, a body at least ten times more massive than the Earth.
In astrology we observe planetary cycles and when we try to define the nature of a certain transit, we find it helpful to study events in history. We don’t know much about the life 11,000 years ago, when Sedna last time was this close to the Sun and Earth. The climate was warming up, as the Earth was coming out of the ice age. People were hunter-gatherers. The last woolly mammoths were dying in extinction. Why this happened is not quite clear, but a climate change alone was probably not the reason, because mammoths had survived similar changes previously. Advanced hunting might have had something to do with their extinction.
Amazingly some concrete things have stood the test of the millennia up till our time. Göbekli Tepe, located in southeastern Turkey, is one of the most important archaeological discoveries ever. It was built around the same time that the last ice age ended. It is presumed to be a ceremonial site, perhaps for shamanic practices. There are various temples and massive stone pillars at the site. Hundreds of people and massive efforts have been needed to erect the structures. The site proves that at least some humans created permanent settlements long before farming practices started. For unknown reasons the site was then abandoned.
One of the world’s oldest art pieces is a wooden sculpture found in Siberia near Yekaterinburg. The radiocarbon dating has showed that the Shigir Idol is approximately 11,500 years old, carved from a trunk shortly after the end of the ice age. It is about five meters tall and its decoration resembles that of some stone sculptures found at Göbekli Tepe. Scholars think it is possible that the culture which emerged after the ice age and which created big symbolical artifacts, possibly having to do with religious rituals, did not originate in one place, but in several centers in different parts of the world.
The world’s oldest living tree is a 9,550 year-old Norway spruce growing in Sweden. The discovery of this spruce in 2004 coincides with Sedna emerging into our awareness. The tree has survived by pushing out another trunk as soon as the old one has died. It is rebirthing itself.
Astrologically Sedna has been associated with the climate change. We are damaging our planet and civilization dramatically. It is estimated that a million species are at risk, and one third of world’s nature will be destroyed by 2050. The extinction of plants and animals threatens also us humans. We Finns are at the forefront of destroying the planet. This year’s overshoot day of the Finns – the point at which consumption exceeds the capacity of nature to regenerate – was on April 5, a week earlier than last year. If people all over the world were consuming like us, we would need almost four Earths to sustain it. Immediate actions for better are required from each and every one of us.
In mythology Sedna was a beautiful Inuit girl, who became betrayed first by a suitor in disguise and then by her own father. Through a powerful transformation she became the mighty goddess of icy waters. She wants to be heard. If she is happy, she allows the humans to eat from the bounty of the sea. If she is not respected, she sends storms and starvation. The myth gives us hope.
In spite of the dreadful state of our planet, there is still hope. Our youngsters have taken the lead in the combat against time. Greta Thunberg, a Swedish schoolgirl, has initiated the School strike for climate, an international movement of students, who are not attending classes and instead are protesting for immediate action to prevent further global warming. Greta Thunberg was born in 2003, the same year when Sedna was discovered. | 0.856577 | 3.225624 |
In general, galaxy clusters grow in size by merging with each other due to gravitations forces despite the expansion of the universe. El Gordo is the biggest known cluster of galaxies, and is in turn the result of the collision between two large clusters. The simulation believes that the collision process compresses the gas within each cluster to very high temperatures so that it is shining in the X-ray region of the spectrum. In the X-ray spectrum this gas cloud is comet shaped with two long tails stretching between the dense cores of the two clusters of galaxies.
This distinctive configuration has allowed the researchers to establish the relative speed of the collision, which is extreme (~2200km/second), as it puts it at the limit of what is allowed by current hypotheses for dark matter. These rare, extreme examples of clusters caught in the act of colliding would challenge the accepted view that dark matter is made up of heavy particles, since no such particles have actually been detected yet. In the opinion of Tom Broadhurst, the Ikerbasque researcher of the UPV/EHU-University of the Basque Country, "it's all the more important to find a new model that will enable the mysterious dark matter to be understood better."
An image comparing the data showing the many galaxies and the X-ray emission from the hot gas (left) with the model of the hot gas (right). The "comet" shape of the X-ray data is well reproduced by the model
The recent work entailed interpreting the gas observed and the dark matter of El Gordo "hydrodynamically" through the development of an in-house computational model that includes the dark matter, which comprises most of the mass, and which can be observed in the Xray region of the visible spectrum because of its extremely high temperature (100 million kelvin).
Their computational solution for this collision because of the comet-like shape of the hot gas, and the locations and the masses of the two dark matter cores that have passed through each other at an oblique angle at a relative speed of about 2200 km/s. This means that the total energy release is bigger than that of any other known phenomenon, with the exception of the Big Bang.
Citation: Molnar, SM and Broadhurst, T. Hydrodynamical Solution for the "Twin-Tailed" Colliding Galaxy Cluster "El Gordo" Astrophysical Journal, ApJ 800 37. doi:10.1088/0004-637X/800/1/37
- El Gordo- One Fat Galaxy
- Cosmic Train Wreck Of Abell 520 Makes Dark Matter Mystery More Complex
- Abell 521- A Ghostly Galaxy Cluster Just In Time For Halloween
- MACSJ0025.4-1222 Cluster Shows Clear Separation Between Dark Matter, Ordinary Matter
- Seeing Normal And Dark Matter Clearly- Collision In The Bullet Cluster | 0.835219 | 4.061417 |
In this series of talks presented by the Faculty of Science in collaboration with the Toronto Public Library, we take you on a dazzling cosmic journey to explore some of the most fascinating corners of our universe.
Quasar, Quasar, Burning Bright
October 11, 2017 at 6:30-7:30 pm, Danforth/Coxwell Branch
Quasars are the brightest objects in our Universe and are formed when matter spirals into supermassive black holes. They contain rotating disks as big as our solar system and hotter than the Sun. Professor Patrick Hall (Faculty of Science) discusses these fascinating objects and how they tap the strong gravity of black holes.
How to Get to Mars
October 12, 2017 at 6:30-7:30 pm, Lillian H. Smith Branch
For decades, NASA has been sending orbiters, landers and rovers to Mars and other planets within our solar system for research and exploration. In pushing the frontier, each of these robotic probes gives us a window onto strange new worlds beyond our imagination while providing a taste of what it is like to be an explorer from the comfort of our living rooms. Professor John Moores (Lassonde School of Engineering) provides an overview of our past, present and future planetary exploration missions.
The Social Habits of Galaxies
October 17, 2017 at 7:00-8:00 pm, S. Walter Stewart Branch
November 16, 2017 at 7:00-8:00 pm, Don Mills Branch
Most galaxies enjoy the company of other galaxies and organize into various shapes known as the “cosmic web.” Many of them also like to spin – creating beautiful, disks of stars and gas. PhD student George Conidis (Faculty of Science) examines copies our own galaxy, The Milky Way, and its friends to better understand the social habits of disk galaxies and how they spin.
The Secrets of Our Dark Universe
November 11, 2017 at 2:00-3:00 pm, Brentwood Branch
Most of our Universe is made up of dark matter and dark energy, but so far scientists have had a hard time detecting or explaining them. PhD student Alexandra Terrana (Faculty of Science) explores some of the big open questions in cosmology, what dark matter and energy are, and how an alternative theory of gravity might solve these mysteries.
Is Anyone Home?
November 14 at 6:30-7:30 pm, Barbara Frum Branch
Since 1995 thousands of planets have been detected orbiting other stars. Many of these worlds could possibly contain liquid water and even life. Professor Paul Delaney (Faculty of Science) describes our current understanding of exoplanets, the ongoing search for them and the implications for the search for life. | 0.855393 | 3.197856 |
Update: March 18 - The answers to the 2019 NASA Pi Day Challenge are now available online. View the illustrated answer key.
NASA's Jet Propulsion Laboratory is celebrating Pi Day with a set of illustrated planetary puzzlers that will test your skill as a rocket scientist. The NASA Pi Day Challenge, now in its sixth year, has four problems that scientists and engineers at NASA solve by using pi - an irrational number with infinite decimals often rounded to 3.14 and the inspiration of Pi Day, which is held on March 14.
Used for millennia to derive the characteristics of a circle, sphere or ellipse, pi comes in handy at NASA whether you're calculating the surface area of a planet or an orbit's circumference. Imagine sitting in JPL's Mission Control in Pasadena, California, trying to communicate with the Opportunity rover on Mars. The solar-powered rover has been blanketed by a dust storm, and you need to figure out how much of the planet the storm covers.
That particular problem is the basis of this year's Deadly Dust challenge, which asks participants to use pi to calculate the size of the dust storm that ended Opportunity's mission. In the Storm Spotter challenge, participants figure out how much Jupiter's iconic Great Red Spot is shrinking. Then they turn their sights back to Earth for the Cloud Computing challenge to discover how much water is in a cloud, before determining how much power a laser beam needs to explode ice in the Icy Intel challenge.
Although everyone is invited to try their hand at them, the puzzlers are designed for students grades six through 12. "We design the challenge for students because we want them to see how pi, which they're learning about in math, is used at NASA. But it's a challenge we have found so many people really get onboard with because adults and kids alike get excited about pi," said Lyle Tavernier, who helped develop the problems for the challenge with JPL's Education Office.
Pi's history extends back to the mathematician Archimedes in ancient Greece. For thousands of years, mathematicians all over the world have searched for the exact value of pi. Modern computers have calculated the figure into the trillions of digits, and people compete to see how many digits they can recite from memory (the record is 70,000). Pi pops up in pop culture, from TV shows ("The Simpsons") to movies ("Life of Pi") to songs (Kate Bush's "Pi"). And appropriately enough, Pi Day falls on the same day as Albert Einstein's birthday.
Find out if you have the chops to meet the Pi Day challenges here:
If you run into trouble, don't worry: We'll post the step-by-step solutions on March 15.
News Media ContactArielle Samuelson
Jet Propulsion Laboratory, Pasadena, Calif. | 0.877093 | 3.012245 |
Mark your calendar for April 15th and set your alarm clock to get you up just before 2:00 a.m. that morning. A spectacular lunar eclipse will occur beginning then and be widely visible from all of North America. (It’s actually the first of two such events this year, the second one happening in October, so you’ll have another chance to experience an eclipse should this one happen to be clouded out!)
This beautiful celestial show begins with the left edge of the full Moon entering the Earth’s dark inner shadow (the “umbra”) at 1:57 a.m. EDT on April 15th and continuing to become ever-more fully immersed in it for the next 69 minutes. Totality itself will occur at 3:06 a.m. and last well over an hour, after which the Moon begins to slowly emerge from the cone of darkness at 4:25 a.m. in reverse order. The right edge of our satellite finally clears the umbra at 5:33 a.m., concluding the show as it continues on in its never-ending journey around the sky.
There are several interesting things to notice as you watch this event unfold. Most obvious are the darkness of the eclipsed Moon and the range of colors displayed, both of which vary from one eclipse to another. These depend on the clarity of the Earth’s atmosphere at the time, which refracts or bends sunlight around and into the umbral shadow. There have actually been eclipses so dark that the Moon remained all-but invisible during totality—and ones so pale that you had to look carefully to see that there was even an eclipse in progress! Among the colors that have been seen are shades of reddish-orange, brown, copper, rose, and even blood-red. Notice, too, that the Earth’s shadow is curved at all phases of the eclipse, as the Moon passes through it. This is direct proof that the Earth itself is round—something recognized by many ancient sky-watchers. And finally, realize that you’re actually seeing our lovely satellite move eastward in its orbit—as it first passes into, through, and then out of the shadow at roughly its own diameter each hour.
While lunar eclipses can certainly be enjoyed with the unaided eye alone (as they have been throughout most of history!), they are best-seen in binoculars. An ideal pair for this would be a 7×50 or 10×50 glass, the first number indicating its magnification and the second the aperture in millimeters. Telescopes themselves, with their relatively narrow fields of view, typically don’t provide enough sky coverage around the Moon to get the full effect of its globe being suspended in space. An exception here, however, is Edmund Scientifics’ amazing Astroscan-Plus wide-field reflecting telescope. Providing a breathtaking 3-degree actual field of view with its 16x eyepiece, it takes in an astounding six full-Moon-diameters of sky—something many have described as looking through the porthole of a spaceship!
— James Mullaney
Former assistant editor at Sky & Telescope magazine & author of nine books on stargazing. His latest, Celebrating the Universe!, is available from HayHouse.com. | 0.831809 | 3.805521 |
报告题目：The induced global looping magnetic fields on Venus and Mars
报告人：柴立晖 中国科学院地质与地球物理研究所 副研究员
报告摘要：Venus and Mars have no significant intrinsic magnetic dipoles, they serve as the prototype of solar wind interaction with unmagnetized planetary bodies with atmospheres. The global magnetic field around them are believed to be formed by the draped interplanetary magnetic field (IMF). However, some of the observed large-scale magnetic fields are inconsistent with the draped field pattern. Here we show that besides the draped fields, there is a second type of induced global magnetic fields on both Venus and Mars. These global looping fields have distributions in cylindrical shell around the magnetotail and counterclockwise directions looking from the planetary tails toward the Sun. The looping field is a common feature of unmagnetized planets with atmospheres. The observed solar wind flows along the azimuth direction towards the –E (conventional electrical field) hemisphere by MAVEN agrees with the looping field morphology and provides a possible cause for the looping field. The current system associated with the looping field and its possible connection with the nightside ionosphere formations and ion escapes on Mars and Venus are discussed. | 0.830061 | 3.609377 |
by Prof. Rory Barnes, University of Washington
The discovery of Proxima b is the biggest exoplanet discovery since the discovery of exoplanets. The planet is not much bigger than Earth and resides in the “habitable zone” of the Sun’s nearest stellar neighbor. This planet may represent humanity’s best chance to search for life among the stars. But is Proxima b habitable? Is it inhabited? These questions are impossible to answer at this time because we know so little about the planet. However, we can extrapolate from the worlds of our Solar System, as well as employ theoretical models of galactic, stellar, and planetary evolution, to piece together realistic scenarios for Proxima b’s history. The possibilities are varied and depend on phenomena usually studied by scientists in fields that are considered distinct, but an integrated perspective — an astrobiological perspective — can provide a realistic assessment of the possibility that life could have arisen and survived on the closest exoplanet.
As an astrobiologist and astronomer at the University of Washington, and a member of NASA’s Virtual Planetary Lab, I have investigated the habitability of planets orbiting red dwarfs for years. My research involves building computer models that simulate how planetary interiors and atmospheres evolve, how stars change with time, and how planetary orbits vary. The discovery of Proxima b has me very excited, but being Earth-sized and in the habitable zone are just the first two requirements for a planet to support life, and the list of requirements is much longer for planets orbiting red dwarfs than for stars like our Sun. If Proxima b is in fact habitable, meaning it possesses liquid water or even inhabited, meaning life is currently present, then it will have traversed a very different evolutionary path than Earth. This difference is frustrating, in that it will make our initial interpretations challenging, but also exciting, as it offers the chance to learn how Earth-sized planets evolve in our universe. Whether Proxima b is a sterile wasteland or teeming with life, we are now embarking on an unprecedented era of discovery, one that may finally provide an answer that age-old question “Are we alone?”.
To evaluate the possibility of life on Proxima b, we must begin with the only habitable planet we know, Earth. Life on Earth has established itself in a stunning diversity of habitats, including acidic hot springs, the deepest reaches of the oceans, microscopic channels in sea ice, and the deepest levels of Earth’s crust. Regardless of how extreme the environment, all life on Earth requires three basic ingredients: energy, nutrients and liquid water. The first two ingredients are very abundant throughout the universe, as is the water molecule. The limiting factor from an astrophysical perspective is that water must be in its liquid phase. The habitable zone is a map of where liquid water could exist on the surfaces of rocky, Earth-like planets, hence its status as the first requirement for a planet to be habitable. Life also requires sufficient time to originate and evolve, but on Earth it has proven resilient to calamities as trivial as a thunderstorm or as traumatic. The variety and tenacity of Earth-bound life encourages astrobiologists to imagine that life can exist not only on Earth-like exoplanets, but also on strange, exotic worlds.
So what to make of Proxima b? It is at least as massive as Earth, and may be several times more massive. Its “year” is just over 11 days and its orbit may be circular or significantly elongated. Its host star is only 12% as massive as our Sun, 0.1% as bright, and it is known to flare. It may be joined to the stars Alpha Centauri A and B, 15,000 astronomical units (AU) away, by their mutual gravitational attraction. All three stars contain substantially more heavy elements than our Sun, but we know very little of the composition of Proxima b, or how it formed. The new data point toward the presence of a second planet orbiting in the system with a period near 200 days, but its existence cannot be proven at this time. These are the facts we have and from them we must deduce whether Proxima b supports life.
Proxima b was detected via the radial velocity method, which does not provide a direct measurement of the planet’s mass, only a minimum mass. So, the first question we’d like to answer is whether the planet’s mass is low enough to be rocky like Earth. If the planet is much larger, it may be more like Neptune with a thick gaseous envelope. While we don’t know where the dividing line between rocky and gaseous exoplanets is, models of planet formation and analyses of Kepler planets suggest the transition is between 5 and 10 times the mass of Earth. Only about 5% of allowed orbits place Proxima b’s mass above 5 Earth masses, so it is very likely that this planet is in the rocky range.
The next question to ask is if the planet actually formed with water. Water consists of hydrogen and oxygen, the first and third most common elements in the galaxy, so we should expect it to be everywhere. Close to stars, however, where Proxima b resides, water is heated into its vapor phase while planets are forming, and hence it is difficult for planets to capture it. Planets that form at larger distances can gather more water, so if Proxima b formed farther out and moved to its current orbit later, it is more likely to be water-rich. At this time, we don’t know how the planet formed, but three scenarios seem most probable: 1) the planet formed where it is from mostly local material; 2) the planet formed farther out while the gas and dust disk that birthed the planetary system still existed, and forces from that disk drove the planet in to its present orbit; or 3) the planet formed elsewhere and some sort of system-wide instability rearranged the planets and b ultimately arrived in its current orbit. The first method is how Earth and Venus formed, and so Proxima b may or may not possess significant water if it formed in this way. The second method produces planets that are very water-rich because water is more likely to be in its ice phase farther out in the disk and so the forming planet could easily gather it up. The third method is inconclusive as the planet could have come from an interior orbit and formed without water or farther out and be water-rich. We conclude that it is entirely possible that this planet has water, but we cannot be certain.
Next let us consider the clues from the stars themselves. Computer models of the evolution of our galaxy suggest that stars enriched in heavy elements like Proxima cannot form locally (25,000 light-years from the galactic center) as there just aren’t enough heavy elements available. But closer to the galactic center, where star formation has been more vigorous and transpiring for longer, stars like Proxima are possible. Recent work by Dr. Sarah Loebman and colleagues has found that stars in our local solar neighborhood with compositions like Proxima must have formed at least 10,000 light-years closer to the galactic center. It would seem Proxima Centauri has wandered through our galaxy and this history may have played an important role in the evolution of Proxima b.
The orbit of Proxima around Alpha Centauri A and B, assuming they are gravitationally connected, is large compared to other multiple star systems. In fact, it is so large that A and B’s hold on Proxima is weak and the effects of the Milky Way galaxy have shaped Proxima’s orbit significantly. The mass of the Milky Way as a whole causes Proxima’s orbit to vary both in shape and orientation continuously. Proxima is also susceptible to gravitational encounters from passing stars that can change its orbit. Recent simulations by Prof. Nate Kaib have found that these two effects can often lead to close passages between the stars in a multiple star system that disrupt their planetary systems. The disruption is often powerful enough to eject planets from the system and completely rearrange the orbits of the planets that remain. New simulations by Russell Deitrick are revealing that this scenario is a real concern for Proxima, too; there is a significant probability that at some point in the past, Proxima swooped in close enough to Alpha Centauri A and B to cause its planetary system to break apart, hurling Proxima b’s siblings into deep space. If such a disruption occurred, Proxima b may not have formed where we find it today because its orbit would have been affected by this disruption.
Even if Proxima is not currently bound to Alpha Cen A and B, it appears to be travelling with them, and it is very likely the stars formed from the same cloud of dust and gas. If they formed together, they should have similar compositions and nearly identical ages. Connecting their ages is important because it is very difficult to measure the ages of low mass stars like Proxima Centauri. Astronomers can estimate the age of Alpha Cen A via asteroseismology, the study of “starquakes.” Stars bigger than the Sun vibrate with large enough amplitudes that brightness fluctuations can be observed, and careful monitoring of the pulsations can reveal a star’s age. Recent work by Dr. Michaël Bazot has found that Alpha Cen A is between 3.5 and 6 billion years old. This range is larger than we would like, but Proxima is certainly old enough to support life, and Proxima b might even be about the same age as Earth!
Next we turn to clues from the Proxima Centauri planetary system. The vast majority of the energy used by life on Earth comes from our Sun, and small stars like Proxima can produce energy for trillions of years. The host star is almost as small as stars come, so for a planet to receive as much stellar energy as Earth, Proxima b must be about 25 times closer in than Earth is from the sun. This distance is where the habitable zone lies. While Proxima is much dimmer than the Sun, it is still a thermonuclear explosion, and, everything else equal, life seems more likely at larger distances. And indeed the close-in orbit does produce numerous obstacles that life on Earth did not have to overcome. These include a long formation time for the star, short and energetic bursts of energy in UV and X-ray light, strong magnetic fields, larger starspots, larger coronal mass ejections, and gravitational tidal effects that cause rotational properties to change and frictional heating in oceans (if they exist) and the rocky interior.
The history of Proxima’s brightness evolution has been slow and complicated. Stellar evolution models all predict that for the first one billion years Proxima slowly dimmed to its current brightness, which implies that for about the first quarter of a billion years, Proxima b’s surface would have been too hot for Earth-like conditions. As Rodrigo Luger and I recently showed, had our modern Earth been placed in such a situation, it would have become a Venus-like world, in a runaway greenhouse state that can destroy all of the planet’s primordial water. This desiccation can occur because the molecular bonds between hydrogen and oxygen in water can be destroyed in the upper atmosphere by radiation from the star, and hydrogen, being the lightest of the elements, can escape the planet’s gravity. Without hydrogen, there can be no water, and the planet is not habitable. Escaping or avoiding this early runaway greenhouse is the biggest hurdle for Proxima b’s chances for supporting life.
As the star dims, the water destruction process halts, and so total desiccation is not inevitable. If some water remains, the atmosphere may also contain large quantities of oxygen leftover from the water vapor destruction. While having large amounts of water and oxygen may sound like a good recipe for life, it almost certainly is not. Oxygen is one of the most reactive elements, and its presence in the young atmosphere of Proxima b would likely prevent the development of pre-biotic molecules that require conditions with little oxygen to form. Life on Earth formed when no oxygen was present, and photosynthesis ultimately produced enough oxygen for it to become a major component of our atmosphere. Note that the destruction of only some water leads to the rather surprising possibility that the planet could possess oceans and an oxygen-rich atmosphere, but has been unable to support life!
Another intriguing possibility is that Proxima b started out more like Neptune and the early brightness and flaring eroded away a hydrogen-rich atmosphere to reveal a habitable Proxima below. Such a world was investigated by Rodrigo Luger, myself and others, and was found to be a viable pathway to avoid total desiccation. Essentially the hydrogen atmosphere protects the water. If Proxima b formed with about 0.1-1% of its mass in a hydrogen envelope, the planet would lose the hydrogen but not its water, potentially emerging as a habitable world after the star reached its current brightness.
This wide range of possible evolutionary pathways presents a daunting challenge as we imagine using space- and ground-based telescopes to search for life in the atmosphere of Proxima b. Fortunately my colleagues in the Virtual Planetary Lab, Prof. Victoria Meadows, Giada Arney and Edward Schwieterman, have been developing techniques to distinguish the possible states of Proxima b’s atmosphere, whether habitable or not. Nearly all the components of an atmosphere imprint their presence in a spectrum, so with our knowledge of the possible histories of this planet, we can begin to develop instruments and plan observations that pinpoint the critical differences. For example, at high enough pressures, oxygen molecules can momentarily bind to each other and produce an observable feature in a spectrum. Crucially, the pressures required to be detectable are large enough to discriminate between a planet with too much oxygen, and one with just the right amount for life. As we learn more about the planet and the system, we can build a library of possible spectra from which to quantitatively determine how likely it is that life exists on Proxima b.
While the early brightness of the host star is the biggest impediment to life, other issues are also important. One of the original concerns for the habitability of planets orbiting red dwarfs was that they would become “tidally locked”, meaning that one hemisphere permanently faces the host star. This state is similar to the rotation of our Moon, in which the same tidal forces that raise waves in our ocean have caused the Moon to show only one face to Earth. Because it is so close to its star, Proxima b may be in this state, depending on the shape of its orbit. For decades, astronomers were concerned that such a tidally locked planet would be uninhabitable because they believed the atmosphere would freeze and collapse to the surface on the permanently dark side. That possibility is now viewed as very unlikely because winds in the atmosphere will transport energy around the planet and maintain sufficient warmth on the backside to prevent this freeze out. Thus, as far as atmospheric stability is concerned, tidal locking is not a concern for this planet’s potential habitability.
Although tidal locking is not very dangerous for life, it is possible for tides to provide large amounts of energy to the planet’s atmosphere and interior. This energy is often called “tidal heating” and is a result of the deformation of the planet due to changes in the host star’s gravitational force across the planet’s diameter. For example, if the planet is on an elliptical orbit, when it is closer to the star, it feels stronger gravity than when it is farther away. This variation will cause the shape of the planet to change, and this deformation can cause friction between layers in the planet’s interior, producing heat. In extreme cases, tidal heating could trigger the onset of a runaway greenhouse like the one that desiccated Venus, independent of starlight. Proxima b is not likely to be in that state, but the tidal heating could still be very strong, causing continual volcanic eruptions as on Jupiter’s moon Io, and/or raising enormous ocean waves. Based on the information we have now, we don’t know the magnitude of tidal heating, but we must be aware of it and explore its implications.
The host star’s short, high energy bursts, called flares, are also a well known concern for surface life on planets of red dwarfs. Flares are eruptions from small regions of the surfaces of stars that cause brief (hours to days) increases in brightness. Crucially, flares emit blasts of positively-charged protons, which have been shown by Prof. Antigona Segura and colleagues to deplete ozone layers that can protect life from harmful high-energy UV light. Proxima flares far more often than our Sun and Proxima b is much closer to Proxima than Earth is to the Sun, so Proxima b is likely to have been subjected to repeated bombardments. If the atmosphere could develop a robust shield to these eruptions, such as a strong magnetic field that then flaring could be unimportant. Alternatively if it exists under just a few meters of water. Therefore, flares should not be considered fatal for life on Proxima b.
The concern over flaring naturally leads to the question of whether the planet actually does have a protective magnetic field like Earth’s. For years, many scientists were concerned that such magnetic fields would be unlikely on planets like Proxima b because tidal locking would prevent their formation. The thinking went that magnetic fields are generated by electric currents moving in the planetary core, and the movement of charged particles needed to create these currents was caused by planetary rotation. A slowly rotating world might not transport the charged particles in the core rapidly enough to generate a strong enough magnetic field to repel the flares, and hence planets in the habitable zones of M dwarfs have no atmospheres. However, more recent research has shown that planetary magnetic fields are actually supported by convection, a process by which hot material at the center of the core rises, cools, and then returns. Rotation helps, but Dr. Peter Driscoll and I recently calculated that convection is more than sufficient to maintain a strong magnetic field for billions of years on a tidally locked and tidally heated planet. Thus, it is entirely possible that Proxima b has a strong magnetic field and can deflect flares.
So is Proxima b habitable? The short answer is “It’s complicated.” Our observations are few, and what we do know allow for a dizzying array of possibilities. Did Proxima b move halfway across the galaxy? Did it endure a planetary-system-wide instability that launched its sibling planets into deep space and changed its orbit? How did it cope with the early high luminosity of its host star? What is it made of? Did it start out as a Neptune-like planet and then become Earth-like? Has it been relentlessly bombarded with flares and coronal mass ejections? Is it tidally heated into an Io-like (or worse) state? These questions are central to unlocking Proxima’s potential habitability and determining if our nearest galactic neighbor is an inhospitable wasteland, an inhabited planet, or a future home for humanity.
The last point is not as rhetorical as it might seem. Since all life requires an energy source, it stands to reason that, in the long term — by which I mean the loooong term — planets like Proxima b might be the ideal homes for life. Our Sun will burn out in a mere 4 billion years, but Proxima Centauri will burn for 4 trillion more. Moreover, if a “planet c” exists and slightly perturbs b’s orbit, tidal heating could supply modest energy to b’s interior indefinitely, providing the power to maintain a stable atmosphere. If humanity is to survive beyond the lifetime of our Sun, we must leave our Solar System and travel to the stars. If Proxima b is habitable, then it might be an ideal place to move. Perhaps we have just discovered a future home for humanity! But in order to know for sure, we must make many more observations, run many more computer simulations, and, hopefully, send probes to perform the first direct reconnaissance of an exoplanet. The challenges are huge, but Proxima offers a bounty of possibilities that fills me with wonder. Whether habitable or not, Proxima b offers a new glimpse into how planets and life fit into our universe.
Thanks to Victoria Meadows, Edward Schwieterman, Giada Arney, and Peter Kelley.
Editorial note. This is an outreach article based on the scientific report “The habitability of Proxima b I : Evolutionary scenarios”, http://adsabs.harvard.edu/abs/2016arXiv160806919B , which was submitted to the Journal Astrobiology on Aug 25th. Proxima’s b putative habitability assessments are crucial to interpret the significance of the detection of Proxima b, design follow-up observations and even reshape instruments and space missions. The Pale Red Dot team contacted two expert groups in advance to provide these early habitability assessments at the time of the announcement. Prof. Rory Barnes led one of the teams. The results from the other team (led by I. Ribas + M. Turbat) are summarized at: http://proximacentauri.info and are also technically explained on two research papers. More studies are surely underway.
About the author. Rory Barnes is a professor of astronomy and astrobiology at the University of Washington in Seattle, USA. He obtained his Ph.D. in astronomy from the University of Washington in 2004. After a post-doctoral position at the Lunar and Planetary Laboratory at the University of Arizona in Tucson, he returned to the University of Washington and NASA’s Virtual Planetary Lab in 2009, joining the UW faculty in 2013. He has studied exoplanets through computer models, initially focusing on the orbital dynamics, but has now broadened his investigations to include the roles of the Milky Way galaxy, stellar evolution, atmospheric effects and the thermal and magnetic evolution of terrestrial planet interiors. | 0.934842 | 4.000253 |
Earth’s stratosphere is similar to the surface of Mars: rarified air which is dry, cold, and irradiated. E-MIST is a balloon payload that has 4 independently rotating skewers that hold known-quantities of spore-forming bacteria isolated from spacecraft assembly facilities at NASA. Knowing the survival profile of microbes in the stratosphere can uniquely contribute to NASA Planetary Protection for Mars.
1. Collect environmental data in the stratosphere to understand factors impacting microbial survival.
2. Determine % of surviving microbes (compared to starting quantities).
3. Examine microbial DNA mutations induced by stratosphere exposure.
Introduction: We designed, built and flew a self-contained payload, Exposing Microorganisms in the Stratosphere (E-MIST), on a large scientific balloon launched from New Mexico on 24 Aug 2014 . The payload carried Bacillus pumilus SAFR-032, a highly-resilient spore-forming bacterial strain originally isolated from a NASA spacecraft assembly facility. Our balloon test flight evaluated microbiological procedures and overall performance of the novel payload. Measuring the endurance of spacecraft-associated microbes at extreme altitudes may help predict their response on the surface of Mars since the upper atmosphere also exerts a harsh combination of stresses on microbes (e.g., lower pressure, higher irradiation, desiccation and oxidation) .
Materials and Methods: Our payload (83.3 cm x 53.3 cm x 25.4 cm; mass 36 kg) mounted onto the exterior of a high altitude balloon gondola. Four independent "skewers" rotated 180° to expose samples to the stratosphere. During ascent or descent, the samples remained enclosed within dark cylinders at ~25 °C. Each skewer had a base plate holding ten separate aluminum coupons with Bacillus pumilus spores deposited on the surface. Before and after the flight, B. pumilus was sporulated, enumerated and harvested using previously described techniques [3–5].
Major payload components were a lithium-ion battery, an ultraviolet (UV) radiometer (400 to 230 nm), humidity and temperatures sensors, and a flight computer. During the test flight, samples remained in a sealed position until the payload reached the lower stratosphere (~ 20 km above sea level). Next, the flight computer rotated the skewers into the outside air. After a short rotation demonstration (2 seconds), all skewers reverted to the closed position for the remainder of the flight. The payload continued floating at an altitude of 37.6 km for 4 hours before beginning a 23 minute descent on parachute.
Results and Discussion: Our first test flight examined unknowns associated with sample transportation, gondola installation, balloon ascent/descent, and time lingering in the New Mexico desert awaiting payload launch and recovery. We created a batch of experimental control coupons (each containing approximately 1 x 106 spores) used throughout the investigation for ground and flight test purposes. Several treatment categories were evaluated: Lab Ground Coupons (kept in the KSC laboratory); Transported Ground Coupons (traveled to New Mexico and back but not installed in payload); and Flight Coupons (flown). A subset of coupons from each treatment category were processed, resulting in statistically equivalent viability (Kruskal–Wallis rank-sum test at a 95% confidence level). Taken together, nearly identical viability from all coupons indicate that balloon flight operations and payload procedures did not influence spore survival. A negative control (blank, sterile coupon) was also flown to verify payload seals prevented outside contamination.
A species-specific inactivation model that predicts the persistence of microbes on the surface of Mars is one of many possible outcomes from balloon experiments in the stratosphere. The simplicity of the payload design lends itself to customization. Future investigators can easily reconfigure the sample base plate to accommodate other categories of microorganisms or molecules relevant to the Planetary Protection community. If future flights exposed microbes for hours, we would expect to see a rapid inactivation. Smith et al. simulated stratospheric conditions and measured a 99.9% loss of viable Bacillus subtilis spores after only 6 hours of direct UV irradiation. Earth’s stratosphere is extremely dry, cold, irradiated, and hypobaric, and it may be useful for microorganisms isolated from NASA spacecraft assembly facilities to be evaluated in this accessible and robust Mars analog environment.
A second, science test flight launching from Ft. Sumner, NM, is scheduled for September 2015.
References: D. J. Smith et al. (2014) Gravitational and Space Research, 2, 70–80. D. J. Smith (2013) Astrobiology, 13, 981–990. P. A. Vaishampayan et al. (2012) Astrobiology, 12, 487–497. R. L. Mancinelli and M. Klovstad (2000) Planetary and Space Science, 48, 1093–1097. R. Moeller et al. (2012) Astrobiology, 12, 457–468. D. J. Smith et al. (2011) Aerobiologia, 27, 319–332.More »
NASA Astrobiology Roadmap: Broadening our knowledge both of the range of environments on Earth that are inhabitable by microbes and of their adaptation to these habitats will be critical for understanding how life might have established itself and survived in habitats beyond Earth.
•Astrobiology Roadmap GOAL 5 – Understand the evolutionary mechanisms and environmental limits of life; Objective 5.3 – Biochemical adaptations to extreme environments.
E-MIST will carry spore-forming bacteria (extremophiles resistant to harsh conditions) that were previously isolated from spacecraft assembly facilities at KSC. We know these microbes are traveling to Mars on NASA spacecraft assembled at KSC; our objective is to measure if they can survive once reaching the Red Planet.
Microbes must survive pressure ~1 to 10 mbar, temperatures from 0 to -100 °C, low water availability at < ~20% relative humidity, and high ionizing radiation levels). Knowing the survival profile of microbes in the stratosphere can uniquely contribute to NASA Planetary Protection policies. If a microbe can survive in the stratosphere, it can probably survive on the surface of Mars as well. Back here on Earth, the upper atmosphere is a natural laboratory for mining genes that guard or restore radiation-damaged biomolecules.
Next Generation Manufacturing Technologies (3D printed E-MIST hardware components)
Space Technology Grand Challenges: Theme 1 – Economical Space Access (Provide economical, reliable and safe access to space, opening the door for robust and frequent space research…)More »
|Organizations Performing Work||Role||Type||Location|
|Kennedy Space Center (KSC)||Lead Organization||NASA Center||Kennedy Space Center, FL|
|Ames Research Center (ARC)||Supporting Organization||NASA Center||Moffett Field, CA|
|Engineering Services Contract||Supporting Organization||Industry|
|California Institute of Technology/JPL||Academic||Pasadena, CA| | 0.880694 | 3.483473 |
So far, the only direct evidence we have for the existence of dark matter is through gravity-based effects on the matter we can see. And these gravitational effects are so pronounced that we know it must make up about 85 percent of all matter in the universe.
But we know little else about dark matter, including whether it is made up of as-yet-undiscovered particles.
There are many competing theories for the composition and properties of dark matter, and for whether dark matter has any visible markers to at last unmask it.
Among the theorized dark matter particle candidates are WIMPs (weakly interactive massive particles), axions, and sterile neutrinos – and physicists have searched for each type using a variety of Earth and space-based instruments and methods.
Nearly 20 years ago, physicists suggested that the theorized sterile neutrino form of dark matter could be responsible for emitting light at a specific energy as its particles decay away in space, and in 2014 a study detailed a light signature, called the “3.5 keV line,” found in very large galaxy clusters – keV is a measure of energy that represents a thousand electron volts or kilo electron volts.
The study theorized that this line, which had no confirmed source, could be the smoking gun for dark matter decay that scientists had been searching for.
But a new study by scientists at the U.S. Department of Energy’s (DOE’s) Lawrence Berkeley National Laboratory (Berkeley Lab), UC Berkeley, and the University of Michigan – publishing this week in the journal Science – concludes that this explanation of sterile neutrino decay is now essentially ruled out as the source of this line.
“Our finding does not mean that the dark matter is not a sterile neutrino, but it means that … there is no experimental evidence to-date that points towards its existence,” said Benjamin Safdi, a study co-author and an assistant professor of physics at the University of Michigan.
The researchers’ approach, which analyzed X-ray telescope observations of dark places within our own galaxy where dark matter was expected, did not find evidence of the 3.5 keV line.
“Our limits are so strong that they are likely to cause difficulty for any simple models of dark matter,” said Nicholas Rodd, study co-author and a physicist affiliated with the Berkeley Lab theory group and the Berkeley Center for Theoretical Physics, which has faculty members from UC Berkeley and Berkeley Lab. Rodd has been working with Safdi for several years in researching possible visible manifestations of dark matter in space.
The technique the researchers developed, which is detailed in the latest study, also has the potential to analyze, with extreme sensitivity, other possible dark matter signatures in space.
“While this work does, unfortunately, throw cold water on what looked like might have been the first evidence for the microscopic nature of dark matter, it does open up a whole new approach to looking for dark matter which could lead to a discovery in the near future,” Safdi said.
Instead of looking at other galaxies and galaxy clusters – places expected to be especially rich in dark matter – for signs of this 3.5 keV line, the researchers analyzed data from more than 20 years’ worth of X-ray telescope images of “empty” space within our own Milky Way galaxy where you might expect the presence of dark matter but nothing else.
Based on observed gravitational effects associated with dark matter, galaxies including our own Milky Way galaxy are expected to be surrounded by so-called halos of dark matter. Such halos would explain observations showing that objects nearer to a galaxy’s center orbit as the same speed as objects at the outskirts, which defies explanation if you only take into account visible matter.
“Everywhere we look, there should be some flux of dark matter from the Milky Way halo,” Rodd said, owing to our solar system’s location in the galaxy. “We exploited the fact that we live in a halo of dark matter” in the study.
Christopher Dessert, a study co-author who is a physics researcher and Ph.D. student at the University of Michigan, said galaxy clusters where the 3.5 keV line has been observed also have large background signals, which serve as noise in observations and can make it difficult to pinpoint specific signals that may be associated with dark matter.
“The reason why we’re looking through the galactic dark matter halo of our Milky Way galaxy is that the background is much lower,” Dessert said.
The researchers used data from the XMM-Newton (X-ray Multi-Mirror) mission, a space-based X-ray telescope launched in 1999 by the European Space Agency. They restricted the data they used to a collection of images from about 800 so-called “blank sky” regions in space that were sampled within 5 to 45 degrees of the Milky Way’s galactic center – areas expected to have higher concentrations of dark matter.
They compared their own analysis to others’ analyses that were based on observations of regions in space thought to be rich in dark matter, such as the Perseus Cluster of galaxies and the Andromeda Galaxy.
Rodd said the team’s analysis technique could be used to reanalyze data taken from other X-ray telescopes’ observations to scan in high detail for other light signals emitted across a far broader range of energies.
“How can we extend this technique to look at more cases?” Rodd said. “There are tons of other datasets out there that we don’t say anything about in this study. If you are looking generically for dark-matter decay and you want to have more sensitivity, this is the way. This is a general tool that anyone searching for dark matter can use.”
Thanks for reading Eurasia Review. For more of our reporting make sure to sign up for our free newsletter! | 0.840783 | 4.09239 |
About This Chapter
Below is a sample breakdown of the Formation & Phases of the Moon chapter into a 5-day school week. Based on the pace of your course, you may need to adapt the lesson plan to fit your needs.
|Day||Topics||Key Terms and Concepts Covered|
|Monday||The moon's formation||Condensation, capture, fission and giant impact theories|
|Tuesday||Lunar geology||Maria, terrae, terminator, ejecta, porous rock, low-density rock, moon dust|
|Wednesday||The moon's atmosphere and phases||Lunar, thinness, hydrogen, helium, neon and other properties; new moon, first quarter, waxing gibbous, full, waning gibbous|
|Thursday||How moon phases are affected by the Earth and sun||Same side facing Earth, lunar illumination, new moon, experiment, synchronous rotation|
|Friday||The motion of the moon and predictions for rising and setting||Counterclockwise, roughly four weeks, half a degree, full orbit around Earth, lunar month; above the horizon, below the horizon, new, full and quarter moons|
1. Formation of the Moon: Theories
Explore the four major theories on the formation of the Moon. The theories include the fission theory, capture theory, condensation theory and giant impact theory. Also look at both information supporting and flaws found in these theories.
2. The Moon's Atmosphere
This lesson will go over the lunar atmosphere, its composition, where it gets it atmosphere from, how it may lose its atmosphere, and what the technical term for the lunar atmosphere is.
3. How Earth & the Sun Affect the Phases of the Moon
This lesson will describe how the moon, Earth, and sun combine to form the phases of the moon. We'll also discuss the important concept of synchronous rotation.
4. Moon Phases: Names & Sequence
This lesson will go over the phases of the moon. The full moon, new moon, waxing, waning, and gibbous phases and the order in which they occur and what they look like are discussed.
5. Motion of the Moon: Sidereal Month vs. Synodic Month
This lesson will teach you about the sidereal month and synodic month, how long they are, and how they are measured with respect to the stars and sun.
6. Predicting When The Moon Will Rise and Set
In this lesson, you'll learn when the moon will rise or set during four distinct phases: full moon, new moon, first quarter moon, and third quarter moon.
7. Lunar Geology: Types of Moon Rocks
This lesson will discuss the layers of the Moon's interior, the dark and light colored areas of the Moon's surface, the Moon's craters, and how moon dust has formed over the ages.
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Other chapters within the Astronomy 101 Syllabus Resource & Lesson Plans course
- The History of Astronomy Lesson Plans
- How Scientists Think & Work Lesson Plans
- Matter in Astronomy Lesson Plans
- Light in Astronomy Lesson Plans
- Newton's Laws in Astronomy Lesson Plans
- Momentum & Energy Lesson Plans
- Rotational Motion & Momentum Lesson Plans
- Earth's Spheres Lesson Plans
- Climate Influences Lesson Plans
- Orbits, Gravity & Orbital Motion Lesson Plans
- The Earth, Sky & Moon Lesson Plans
- Earth & Planet Atmospheres Lesson Plans
- The Sun & Energy Lesson Plans
- The Solar System Formation Lesson Plans
- The Solar System Characteristics Lesson Plans
- The Solar System's Smaller Objects & Satellites Lesson Plans
- Star Qualities Lesson Plans
- Star Types Lesson Plans
- The Birth & Life of Stars Lesson Plans
- Star Death & Stellar Remnants Lesson Plans
- The Milky Way Galaxy Lesson Plans
- Properties of Galaxies Lesson Plans
- Universe Theories Lesson Plans
- Life in the Universe Lesson Plans
- Celestial Time & Navigation Lesson Plans
- Relativity in Time & Space Lesson Plans
- Telescopes Lesson Plans | 0.876982 | 3.259103 |
Just over a year ago, on 12 April 2019, the LIGO-Virgo collaboration made a detection of gravitational waves, rippling out across space-time from the epic collision of two black holes from 2.4 billion light-years away. By now, marvellously, this is nothing out of the ordinary in and of itself.
But, as astronomers have now revealed, the actual GW 190412 collision was something we have never seen before. Rather than two roughly equal-mass black holes between 20 and 40 times the mass of the Sun, GW 190412 was produced by a wildly uneven binary.
Based on analysis of those rippling gravitational waves, astronomers have discovered that one of the black holes tipped the scales at around 29.7 solar masses, while the other was over three times smaller – just 8.4 solar masses.
This is also the lowest-mass black hole binary detected to date – which is tremendously exciting, because it means their merger produced a longer signal than any other black hole merger – a wealth of data to probe.
“Neither of these masses is too surprising on their own. We know black holes come in these sizes. What is new is the ratio of the masses,” explained astronomer Christopher Berry of Northwestern University and the LIGO Collaboration in a blog post.
“This observation lets us test our predictions for gravitational wave signals in a new way, and is another piece in the puzzle of understanding how binary black holes form.”
The Collaboration’s findings were presented at the Virtual April Meeting of the American Physical Society.
Because other gravitational wave events have been generated by roughly equal-mass black hole binaries, this is reflected in the signal. Because the black holes are the same mass, they return to the same relative position with each orbit.
This results in a gravitational wave frequency that’s around twice the orbital frequency of the binary system, that is, how long it takes the black holes to orbit each other. But when the system has a significant mass imbalance, the orbit is uneven. This produces a second, weaker gravitational wave frequency.
This was observed in GW 190412, which produced (among the family of chirps usually found in a black hole merger) two distinct frequencies, as though two guitar strings were vibrating simultaneously, a dyad of frequencies.
Amazingly, these frequencies were the equivalent of five notes apart – what is known as a perfect fifth. When you start singing Twinkle, Twinkle, Little Star, the first two twinkles constitute this musical interval.
As well as being really awesome, these frequencies allowed the team to perform yet another test of general relativity, too. Basically, they split the gravitational wave signal into an earlier part and a later part, and used equations based on general relativity to calculate the other part of the signal for each half.
The halves matched up with the calculations, producing some of the most robust results from this test to date.
Based on the merger’s unusual signal, the team was able to make a few more measurements, too. They were able to determine that the larger of the black holes was spinning – usually quite a difficult thing to measure, and only achieved previously (and tentatively) in two other mergers.
In GW 190412, this spin seemed to be quite fast, which could be a clue as to how such an uneven binary came to exist. You see, there are several astrophysical models for the formation of black hole binaries, but most of them result in more-or-less equal-mass pairs.
The most obvious one is a binary star system in which each star collapses into a black hole. However, it’s thought that these can’t produce binary black holes with large mass discrepancies, ruling out GW 190412.
It’s possible that the black holes formed separately, then somehow came together, capturing each other in orbit. But the high spin of the larger black hole suggests that it could have merged with other black holes previously, before GW 190412.
If the black holes were in a triple or quadruple system, it could be that the larger black hole had already merged with the others. If they were just floating around in normal space, the recoil kick from the merger would disrupt the system – but there’s one scenario where it could work: in the disc around an active supermassive black hole at the heart of a galaxy.
There, the extreme gravitational environment could allow stellar-mass black holes to go through several successive mergers without being booted out by the recoil kick.
It’s impossible to know for certain at this stage, but with the LIGO-Virgo collaboration making detections every few days, we may not have to wait too long for answers.
The dyad wasn’t the only coincidence produced by GW 190412, by the way. The mass ratio between the two black holes is “roughly equal to the ratio of filling in a regular Oreo to in a Mega Stuf Oreo,” Berry noted.
“Investigations of connections between Oreos and black hole formation are ongoing.”
You can read the team’s full paper on the LIGO website. | 0.840416 | 4.043829 |
The case of the vanishing exoplanet
In 2008, astronomers using the Hubble Space Telescope announced the discovery of an exoplanet orbiting the star Fomalhaut a scant 25 light years away. First seen in 2004 and again in 2006, the presumed planet – Fomalhaut b – was brighter than would normally be expected and appeared to be following an unusual trajectory just inside a vast cloud of icy debris orbiting the star. Then, in 2014, astronomers were stunned to find Fomalhaut b had disappeared. A search through archived data revealed it had slowly faded from view over several years. Astronomers now think Fomalhaut b was never a fully evolved planet in the first place. Instead, the data suggest the bright object Hubble originally spotted was, in fact, a huge cloud of expanding dust in the aftermath of a collision between two asteroid-size bodies. Gáspár, George Rieke of the University of Arizona’s Steward Observatory and a team of collaborators believe the apparent collision occurred shortly before the first images of Fomalhaut b were collected in 2004. By 2014, the object had disappeared from view after fading over several years. Along with its slow fading, Fomalhaut b is likely on an escape trajectory, not in a planet-like elliptical orbit, a natural result of the host star’s influence on a massive, expanding dust cloud. | 0.856393 | 3.501518 |
In 2013, astronomers stumbled into one of the most spectacular events the Universe has to offer: a star while turning supernova. The event helped change our understanding of stellar death, as detailed by a new study published by Nature.
Four years ago, the Samuel Oschin 48-inch telescope — working as part of the Palomar Transient Factory Survey at the time — spotted the explosion mere hours after its light became visible on Earth. Once researchers figured out what the automated system had picked up, every telescope that could point to the blast was scrambled for follow-up observations — several international facilities, Palomar’s 60-inch telescope, the Las Cumbres Observatory, the WM Keck Observatory in Hawaii, and NASA’s Swift satellite among others turned their lenses to this tiny point on the sky.
Dubbed SN 2013fs, it marked the youngest supernova known to date, taking place in the NGC 7610 galaxy some 160 million years ago. It was a once in a lifetime event. Unlike most supernovae, who are really elusive and usually go unnoticed for days or even weeks, astronomers had the chance to see the first moments of a star’s death.
“It is likely that not even a single star that is within one year of explosion currently exists in our Galaxy,” a paper published by a 33-strong team of international researchers reports.
SN 2013fs revealed several surprises. One of these was the gas cloud the star expelled in the year prior to explosion, the paper reads. This phenomenon was never picked up on before, as a supernova’s massive blast sweeps away everything that’s close to the star.
The gasses poured from 2013fs at 360,000 km/h, and totaled an estimated one-thousand of a solar mass in weight over one year. Since 2013fs is a Type II supernova — the most common type — it suggests that other Type IIs also have similar discharges of matter before explosion. This ejection shows that we need to revise our understanding of stellar bodies.
“The structure of the outer envelope of massive stars during the very late stages of evolution may significantly differ from what is predicted by stellar evolution models”, the authors write.
The full paper “Confined dense circumstellar material surrounding a regular type II supernova” has been published in the journal Nature. | 0.88318 | 3.833502 |
Two little cubesats will fly with a planned European asteroid mission to get some extra space-rock studies done.
The candidate Hera mission to the two-asteroid Didymos system will include two briefcase-size spacecraft, European Space Agency (ESA) officials announced last Monday (Jan. 7).
"We're very happy to have these high-quality cubesat missions join us to perform additional bonus science alongside their Hera mothership," Hera manager Ian Carnelli said in a statement. [The Greatest Asteroid Encounters of All Time!]
"Carrying added instruments and venturing much closer to our target bodies, they will give different perspectives and complementary investigations on this exotic binary asteroid," Carnelli added. "They will also give us valuable experience of close proximity operations relayed by the Hera mothercraft in extreme low-gravity conditions. This will be very valuable to many future missions."
The binary asteroid system consists of the 2,550-foot-wide (780 meters) Didymos and its 525-foot (160 m) satellite, dubbed "Didymoon."
NASA plans to launch a planetary-defense mission called DART (Double Asteroid Redirection Test) toward these rocks in mid-2021. If all goes according to plan, DART will slam into Didymoon in October 2022. Telescopes here on Earth will then scrutinize Didymoon's path around its parent rock, gauging how much the impact affected the moon's orbit.
Such information will help researchers better understand the "kinetic impactor" asteroid-deflection technique, one of the strategies humanity could use to deal with a space rock that lines Earth up in its crosshairs.
Hera is part of this picture as well. The proposed mission would study the crater blasted out by DART and get up-close measurements of Didymoon's shifted orbit. (A decision about whether to fly Hera is expected toward the end of this year, ESA officials have said.)
Current plans call for Hera to launch in 2023 and get to the Didymos system in 2026. An earlier incarnation of the concept, the Asteroid Impact Mission, called for a larger and more expensive ESA spacecraft, which would have gotten to Didymos before DART and observed the impact.
The newly selected Hera cubesats are the Asteroid Prospection Explorer (APEX), which was provided by a Swedish-Finnish-Czech-German consortium, and Juventas, which was developed by the Danish company GomSpace and the Romanian company GMV.
APEX will study the surface composition and interior structure of Didymos and Didymoon, and Juventa will investigate Didymoon's gravity field and structure. Both cubesats will perform asteroid landings, ESA officials said.
APEX and Juventa won't be the first cubesats to explore deep space. NASA's twin MarCO probes blazed that trail last year when they flew along with the American space agency's InSight Mars lander. The MarCO mission beamed home data from InSight during the lander's touchdown in November 2016, helped researchers gather data about the Martian atmosphere and captured imagery of the Red Planet. (The cubesats didn't follow InSight onto Mars' surface; both probes flew past the Red Planet, their missions complete at that point.)
And more than a dozen cubesats are manifested on the first flight of NASA's huge new Space Launch System rocket, which is known as Exploration Mission-1. EM-1, which is scheduled to launch in June 2020, will send NASA's Orion capsule on an uncrewed voyage around the moon.
Among the EM-1 cubesats are Lunar Flashlight, which will hunt for lunar water ice, and Near-Earth Asteroid Scout, which will use a solar sail to cruise to a space rock and study it up close.
DART may also fly with a cubesat — a probe called Light Italian Cubesat for Imaging of Asteroids, which would be provided by the Italian Space Agency.
Mike Wall's book about the search for alien life, "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate) is out now. Follow him on Twitter @michaeldwall. Follow us @Spacedotcom or Facebook. Originally published on Space.com. | 0.819961 | 3.04244 |
There is much debate as to the most promising place to find extraterrestrial life, but even those who don't think Jupiter's moon Europa is top of the list, still place it high. That's why several ideas for missions to study the moon are under consideration, with funding current support for the Europa Clipper flyby. Unfortunately, a new attempt to envisage Europa's surface suggest any attempt to land might risk being spiked by sharp blades of ice as high as four-story buildings.
We're used to ice melting on Earth when exposed to sunlight. The runoff tends to smooth out rough edges, and often pools in places where it refreezes at night. However, Dr Daniel Hobley of Cardiff University points out this isn't always the case.
At high altitudes close to the equator, if conditions are dry enough, ice exposed to the Sun will sometimes sublime, or turn directly to water vapor. This produces blades of ice 1-5 meters (3-16 feet) high known as penitentes. Hobley and co-authors from NASA have noted conditions on Europe could be even more suited to penitente production.
Sublimation is the norm when ice on astronomical objects with minimal atmospheres warms up – such as when comets enter the inner Solar System. Even out as far as Europa, Hobley argues in Nature Geoscience, the Sun's heat is enough to cause ice to sublime, at least in a moon's equatorial belt.
The paper models the rate at which sublimation would occur, and the extremely slow weathering that would smooth ice structures on a world with an atmosphere a trillion times thinner than Earth's. The result, the authors argue, is that Europa's equatorial belt is probably made up of penitentes that dwarf those seen on Earth – 15 meters (50 feet) high and an average of 7.5 meters (25 feet) apart. The authors think something similar occurs on Pluto, where the ice is frozen methane.
Trying to land a spacecraft in this would be like jumping onto a phalanx of medieval soldiers raising pikes. “We suggest that penitentes could pose a hazard to a future lander on Europa,” Hobley and co-authors write dryly.
None of the spacecraft that have visited the Jovinian system have got close enough to Europa to take pictures that would reveal objects of this size, but the authors claim “Radar and thermal data are consistent with our interpretation.” This data shows a previously unexplained difference between the way Europa reflects radar above and below 25° latitude.
On a larger scale, Europa is exceptionally smooth – the smoothest object in the Solar System. The ocean beneath its surface ice has prevented the build-up of mountain ranges and caused the erosion of impact craters, but that may not be enough to make for an easy landing. | 0.817599 | 3.872149 |
Credits: Artist conception, credit NASA/JPL-Caltech, NASA/Dawn Mission site
The Dawn spacecraft entered the asteroid belt and orbited and explored the giant protoplanet Vesta in 2011-2012. As of August, 2015, it is in orbit about and exploring a second new world, dwarf planet Ceres.
Credits: NASA/Dawn Mission site
The Dawn spacecraft was launched on September 27, 2007 and achieved orbit around Vesta on July 15, 2011. It used a gravity boost from Mars in February 2009 to assist on its journey to the asteroid belt. Leaving its Vesta orbit on September 4, 2012 it reached Ceres on March 6, 2015. Among its instruments are framing cameras, a visible and infrared mapping spectrometer, and gammma and neutron detectors.
Dawn accomplished the largest propulsive acceleration of any spacecraft to date, with a change in velocity of more than 4.2 miles per second (6.7 kilometers per second), due to its ion engines. The engines expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available. The Dawn ion propulsion system ionizes xenon atoms with an electron beam, accelerates the resulting ions with >1000 volts to achieve an ejection speed as high as 40 km/s (89,000 mi/hr), which is about 10 times the ejection speed for typical propellants. This leads to an efficiency high enough that it can be powered by the energy collected by the onboard solar collectors as long as the spacecraft is less than twice the Earth's distance from the Sun.
Solar System Illustration
Solar System Concepts | 0.855042 | 3.04234 |
Scientists may have detected an example of an entirely new class of black hole — one that is smaller than any previously known.
Black holes are often found in so-called binary systems, where two stars once orbited around each other, until one ran out of fuel and exploded.
These ‘supernova’ explosions either leave behind a dense core called a neutron star, or — if there is enough mass — a black hole so dense not even light can escape it.
However, there was a gap between the densest known neutron star and the least massive known black hole from which no neutron stars or black holes were known.
Experts scoured data on 100,000 binary star systems until they found one with an unusually small black hole — only 3.3 times the Sun’s mass.
The find may help physicists understand the black hole-forming supernova process— which is key to the formation of certain elements and the universe’s evolution.
Scroll down for video
Scientists may have detected an example of an entirely new class of black hole — one that is smaller than any previously known. Pictured, an artist’s impression of a black hole
Astrophysicist Todd Thompson of the Ohio State University and colleagues analysed data collected by the so-called Apache Point Observatory Galactic Evolution Experiment on the light coming from around 100,000 stars in the Milky Way.
Changes in the light spectra from stars can indicate that a star is orbiting around another, possibly unseen, object like a black hole.
Hunting for stars that could potentially have a neighbouring black hole, the team narrowed down on 200 that appeared to be of particular interest.
From this, they were able to compile thousands of images of each of these star system captured by the 20 robotic telescopes that make up Ohio State’s All-Sky Automated Survey for Supernovae program.
One star system stood out. Dubbed ‘J05215658’, this giant red star appears to be orbiting a massive, hidden body some 3.3 times the mass of the Sun — much smaller than any black hole previously known to science.
‘What we’ve done here is come up with a new way to search for black holes, but we’ve also potentially identified one of the first of a new class of low-mass black holes that astronomers hadn’t previously known about,’ said Professor Thompson.
Professor Thompson compares the search for black holes to date with a census that only counted people over 5 feet 9 inches in height — leaving experts with an incomplete understanding of the overall population.
As it stood, scientists had for a long time only been aware of black holes that had masses between 5–15 times that of the Sun’s mass.
Meanwhile, neutron stars — the cool, dense, other possible product of a star going supernova — have only been found with around 2.1 times the Sun’s mass.
Were neutron stars to reach more than 2.5 times the Sun’s mass, they would themselves collapse to form a black hole.
This left a gap in the lower end of possible masses for black holes that had not been seen in reality — until Professor Thompson and colleagues identified J05215658.
Experts scoured data on 100,000 binary star systems until they found one with an unusually small black hole — only 3.3 times the Sun’s mass. Pictured, the supermassive black hole at the heart of the galaxy Messier 87, which was imaged by the the Event Horizon Telescope in April
‘We’re showing this hint that there is another population out there that we have yet to really probe in the search for black holes,’ said Professor Thompson.
‘If we could reveal a new population of black holes, it would tell us more about which stars explode, which don’t, which form black holes, which form neutron stars.
‘It opens up a new area of study.’
The finding compliments the observation in 2017 of two ‘giant’ black holes — one 31 times the mass of the Sun, the other 25 times — that were merging together in a galaxy around 1.8 million light years away from the Earth
The finding compliments the observation in 2017 of two ‘giant’ black holes — one 31 times the mass of the Sun, the other 25 times — that were merging together in a galaxy around 1.8 million light years away from the Earth.
The observation was made by the Laser Interferometer Gravitational-Wave Observatory (LIGO), which is comprised of two telescopes based in Hanford, Washington State and Livingston, Louisiana in the US.
‘Immediately, everyone was like “wow”, because it was such a spectacular thing,’ said Professor Thompson.
‘Not only because it proved that LIGO worked, but because the masses were huge. Black holes that size are a big deal — we hadn’t seen them before.’
The full findings of the study were published in the journal Science.
WHAT’S INSIDE A BLACK HOLE?
Black holes are strange objects in the universe that get their name from the fact that nothing can escape their gravity, not even light.
If you venture too close and cross the so-called event horizon, the point from which no light can escape, you will also be trapped or destroyed.
For small black holes, you would never survive such a close approach anyway.
The tidal forces close to the event horizon are enough to stretch any matter until it’s just a string of atoms, in a process physicists call ‘spaghettification’.
But for large black holes, like the supermassive objects at the cores of galaxies like the Milky Way, which weigh tens of millions if not billions of times the mass of a star, crossing the event horizon would be uneventful.
Because it should be possible to survive the transition from our world to the black hole world, physicists and mathematicians have long wondered what that world would look like.
They have turned to Einstein’s equations of general relativity to predict the world inside a black hole.
These equations work well until an observer reaches the centre or singularity, where, in theoretical calculations, the curvature of space-time becomes infinite. | 0.881005 | 4.000793 |
In what seems to be a newly-evolved form of the 15-year-old Mars Hoax people have recently been asking me about a “double Moon” that they heard is supposed to occur. I hadn’t come across it myself (maybe because I follow too much *actual* science news) but it sounded suspiciously familiar and, now being August, I figured it must have something to do with the old Mars-will-look-as-big-as-the-Moon nonsense that resurfaces every year around this time. Lo and behold there it was, in a poor Clark Kent-style disguise no less. So once again everyone: NO, Mars and the Moon will not be performing as twins tonight in the night sky—not tonight, not ever. Earth has one Moon, love it or leave it, and there will never be a natural satellite of its apparent size in orbit around our world.
(And certainly not ever the planet Mars.)
Now where did this nonsense all even come from? Gather ’round, kids…
In 2003 Mars and Earth came closer to each other than they had in over 60,000 years. This was due to an extreme case of a very natural event we call opposition and it actually happens every couple of years—most recently on July 31, 2018—because of how long it takes Mars to orbit the Sun (687 days to be exact.) But even at “extreme close range” in 2003 Mars was still about 35 million miles away…much farther than the Moon’s ~252,000 mile max distance! Still, that led somebody to casually note that “at a modest 75-power magnification Mars will look as large as the full Moon to the naked eye” which, through the telephone-game of news reporting and the popularity of email chain letters in the early aughts magically turned into “ALERT: Mars will look as big as the Moon.”
And so 15 years later here we are: still debunking this come every August (this year it started even earlier because of the July opposition.)
FACT: Based on its size Mars would have to be about 478,000 miles away to look as large as the full Moon from Earth. (Thanks to Scott from Frosty Drew Observatory.) But even at its closest possible Mars is still over 71 times farther than that. Planets, despite the Greek roots of the term, don’t just wander around the Solar System. So…ain’t no way.
What will you see? Since it’s a day and a half past full, you’ll see (weather permitting) a bright waning Moon (it’ll still look quite full-ish) rise in the southeastern sky at 8:37 p.m. (that’s Eastern U.S. time) while a bright orangish “star” (Mars) will have already been visible for a while, also in the southeast. Both will appear to move in typical fashion over the night toward the southwest…following Saturn, Jupiter, and Venus which will have already set by moonrise. Mars will look very bright just as it has these past couple of months but obviously nowhere near as large as the Moon…which makes sense as it’s almost 40 million miles away now (and getting farther.)
Image credits: Moon: Jason Major, Aug. 26, 2018. Mars: Hubble Space Telescope, July 5, 2001. Acknowledgements: J. Bell (Cornell U.), P. James (U. Toledo), M. Wolff (Space Science Institute), A. Lubenow (STScI), J. Neubert (MIT/Cornell). Credit: NASA/ESA and The Hubble Heritage Team/AURA | 0.846459 | 3.415945 |
A neutron star growing at the site of a dead supernovae sounds an uncommon event. Combining this with the fact that it does not act like any other similar system yet observed, you would have a conundrum for astronomers indeed.
This system is known as Circinus X-1. The star group “had been a puzzle to x-ray astronomers almost from the moment of its discovery”, said Sebastien Heinz, one of the researchers.
Circinus X-1 is an x-ray binary system consisting of a neutron star, coupled with a second star that is not dissimilar to our sun. Matter from the ordinary star is slowly leached by the neutron star and pulled into clouds around it. Despite the neutron star having a radius of less than half the distance from Oxford to Reading, its huge density results in a large enough gravitational field to attract the second star in the system. X-rays are emitted as these clumps of matter collide with the neutron star and are blasted back out at the poles.
The study carried out on the system have shown its age to be much younger than first estimated – it was formed as recently as 4,600 years ago. This has explained some of its more erratic behaviour, such as low magnetic fields, yet high x-ray emissions.
The x-ray emissions were the main problem in studying the system. Analogous to trying to take a photo of a shaded object when there is a bright light source just behind, the x-ray glare prevented any other detail from being picked up by the instruments used and left only silhouettes.
However, the team managed to catch the system in a state of low flux – that is, when the neutron star was at its dimmest – allowing longer periods of exposure by their equipment. The x-ray measurements obtained, when combined with radio data made with a telescope team based in Australia, lead the researchers to an exciting conclusion: that the neutron star had been formed by the death of the supernovae.
The results are highly significant because it has proven to be the youngest of any such system ever to be observed by scientists. Traces of supernovae disappear very rapidly after the death of the star, so it is very improbable that any systems will be found in this state.
This is the first time that data has been collected on recently extinguished supernovae, with the added bonus of finding a growing neutron star among the debris. “Such objects are exceedingly rare”, their report states, “none were known to exist in our Galaxy”.
The research is a collaboration: Professor Rob Fender of Oxford University, researchers from the University of Wisconsin-Madison, Pensylvania, and Radboud University in the Netherlands are all involved. Top image: an illustration showing the evolution of the Circinus X-1 system. IMAGE/Sebastian Heinz, University of Wisconsin-Madison | 0.853308 | 3.964612 |
Feb. 7, 2013 — The demise of the dinosaurs is the world’s ultimate whodunit. Was it a comet or asteroid impact? Volcanic eruptions? Climate change?In an attempt to resolve the issue, scientists at the Berkeley Geochronology Center (BGC), the University of California, Berkeley, and universities in the Netherlands and the United Kingdom have now determined the most precise dates yet for the dinosaur extinction 66 million years ago and for the well-known impact that occurred around the same time.
The dates are so close, the researchers say, that they now believe the comet or asteroid, if not wholly responsible for the global extinction, at least dealt the dinosaurs their death blow.
“The impact was clearly the final straw that pushed Earth past the tipping point,” said Paul Renne, BGC director and UC Berkeley professor in residence of earth and planetary science. “We have shown that these events are synchronous to within a gnat’s eyebrow, and therefore the impact clearly played a major role in extinctions, but it probably wasn’t just the impact.”
The revised dates clear up lingering confusion over whether the impact actually occurred before or after the extinction, which was characterized by the almost overnight disappearance from the fossil record of land-based dinosaurs and many ocean creatures. The new date for the impact — 66,038,000 years ago — is the same within error limits as the date of the extinction, said Renne, making the events simultaneous.
He and his colleagues will report their findings in the Feb. 8 issue of the journal Science.
The crater of doom
The extinction of the dinosaurs was first linked to a comet or asteroid impact in 1980 by the late UC Berkeley Nobel Laureate Luis Alvarez and his son, Walter, who is a UC Berkeley professor emeritus of earth and planetary science. A 110-mile-wide crater in the Caribbean off the Yucatan coast of Mexico is thought to be the result of that impact. Called Chicxulub (cheek’-she-loob), the crater is thought to have been excavated by an object six miles across that threw into the atmosphere debris still be found around the globe as glassy spheres or tektites, shocked quartz and a layer of iridium-enriched dust.
Renne’s quest for a more accurate dating of the extinction began three years ago when he noticed that the existing date conflicted with other estimates of the timing of the extinction and that the existing dates for the impact and the extinction did not line up within error margins.
Renne and his BGC colleagues first went to work recalibrating and improving the existing dating method,
known as the argon-argon technique. They then collected volcanic ash from the Hell Creek area in Montana and analyzed them with the recalibrated argon-argon technique to determine the date of the extinction. The formation below the extinction horizon is the source of many dinosaur fossils and one of the best sites to study the change in fossils from before and after the extinction.
They also gathered previously dated tektites from Haiti and analyzed them using the same technique to determine how long ago the impact had occurred. The new extinction and impact dates are precise to within 11,000 years, the researchers said.
“When I got started in the field, the error bars on these events were plus or minus a million years,” said paleontologist William Clemens, a UC Berkeley professor emeritus of integrative biology who has led research in the Hell Creek area for more than 30 years, but was not directly involved in the study. “It’s an exciting time right now, a lot of which we can attribute to the work that Paul and his colleagues are doing in refining the precision of the time scale with which we work. This allows us to integrate what we see from the fossil record with data on climate change and changes in flora and fauna that we see around us today.” | 0.834163 | 3.574678 |
Over the past few weeks, a number of bright meteors and fireballs have been reported. On this blog, there have been reports from Colorado, New Jersey, Illinois, Florida, Michigan and Arizona. Over at the Fireball Report page of the American Meteor Society (AMS), multiple fireballs are being reported every night. So what’s going on?
There is a good chance that many of these fireballs are from the Taurid meteor complex. Most meteor showers are only visible for a few weeks to maybe a month. Often most of their activity is concentrated in a few night window around the time of their peak. The Taurids are different, though. Those who have paid close attention to my daily postings will notice that the Taurids have been active since late September. They will continue to produce meteors until the end of November. Another difference between Taurids and most other showers, is when they they take place. Most showers can only be observed after midnight. The Taurids can be seen at all hours of the night, whether morning or evening. As a result, they are active at a reasonable hour when many people are still awake and outside.So for the average person who is out and about in the evening, the months of October and November provide a greater than usual chance of spotting a nice meteor or fireball.
How can you see the Taurids?
The Taurids are visible at any time of the night. There are two separate branches of the Taurids, the Northern and Southern Taurids. Both showers are located within a few degrees of each other. In November, the radiants of both showers are located in the constellation of Taurus. Video data compiled by Sirko Molau find that the Southern Taurids are active from September 8 to November 30 with a broad peak around October 11. The Northern Taurids are active from October 8 to December 13 with a broad peak around November 14. Right now, both showers are active though more of the activity will be from the Northern branch.
The rates for the Taurids is fairly low. These are not major showers and at their best produce 10-15 meteors per hour from a dark site around midnight. For evening observers under suburban skies, the rates will be much lower. The thing to watch out for are evening fireballs. It is predicted that this year will see more fireballs than usual from the Taurids.
Taurid meteors look rather different from most meteors. Unlike the Orionids which are fast and only last a split second, Taurids are much slower and longer lasting. I have seen many early evening Taurids that appear as small green orbs or spheres that can take up to 3 seconds to cross most of the sky. Quite often they will be followed by a thin, short-lasting white tail or trail. They are definitely impressive.
Where do Taurids come from?
Taurid meteors are produced by Comet Encke which is one of the best observed comets in history. The reason for this is that it circles the Sun once every 3.3 years which provide lots of opportunities to observe it when bright. The fact that the comet is rather large and does not get very far from the Earth and Sun means that it is always observable by professional (and even some of the largest amateur) telescopes. But even after centuries of observation, Encke remains an enigma and continues to give professional comet researchers fits.
Comet Encke was first observed by the prolific French comet hunter Pierre Mechain on 1786 January 17. The comet was relatively bright (5th magnitude) but located deep in the bright twilight sky. After a few days, the comet moved to close to the Sun and was no longer observable. As a result, it became lost. Fast forward to 1795 November 7, Caroline Herschel (the first female comet discoverer and brother of William Herschel, the discoverer of Uranus) of Slough, England found a “new” comet which was observed for only a few weeks. There were not enough observations to identify the comet as a short-period comet. The 3rd “discovery” of Comet Encke occurred on 1805 October 20 when Jean-Louis Pons of Marseilles, France (until the last 15 years, Pons was the leading comet discoverer with 26 comets to his credit) discovered a comet which was followed for a month. Pons was so prolific at finding comets that he unknowingly found the same comet again on 1818 November 26.
One may be wondering why this comet is named Comet Encke rather than Comet Mechain-Herschel-Pons. Johann Franz Encke was a German astronomer and mathematician. In 1819, Encke calculated an orbit for Pons’ 1818 comet and noticed that it resembled the orbit of Pons’ 1805 find. Working the orbit, Encke quickly relaized that the two Pons comets were really the same comet returning every ~3 years. Further work identified Mechain’s 1786 comet and Herschel’s 1795 comet as previous apparitions of Pons’ comet. In honor of Encke’s work, the comet was named Comet Encke. It is rare for a comet to be named after the mathematician who computed its orbit rather than its discoverer but there are a few cases of this, especially centuries ago. The most famous example being Comet Halley. Edmund Halley did not discover Comet Halley but he was the first person to recognize that his namesake comet returned at regular intervals. Comets Lexell and Crommelin are other examples of comets being named after an orbit computer.
Since 1818, Comet Encke has been observed at every perihelion (closest approach to the Sun) except for one in 1944 at the height of World War II. Nowadays, it is rare for Comet Encke not to be observed at least once a year. In fact, Encke was the 2nd comet, after Halley, to be observed at more than 1 return, hence its official name of Comet 2P/Encke. The comet is currently located on an orbit that takes 3.3 years to circle the Sun. The comet’s orbit ranges from a perihelion (closest to the Sun) of 0.34 AU to an aphelion of 4.10 AU (farthest from the Sun). Its last perihelion was on 2007 April 19 and the next one will be on 2010 August 6. There is a short window before or after every perihelion when Encke is visible in small telescopes. The comet never gets bright enough for naked eye observations.
Where does Comet Encke come from?
Until a few years ago, it was theorized that all comets formed in the outer solar system beyond the orbit of Jupiter. As the outer planets migrated towards their current orbits, some comets were ejected into the Oort cloud, located out to a quarter of the distance to the nearest star, the Kuiper Belt, a belt of comets located just beyond Neptune’s orbit, or the Scattered Disk, located between the Oort cloud and the Kuiper Belt. Short-period comets, with periods less than ~20 years or so, spent billions of years in the Kuiper Belt or Scattered Disk before being kicked back into the inner solar system by the gravity of the outer planets. As a result, all comets go out as far from the Sun as the orbit of Jupiter or much further out. Encke only goes out to 4.1 AU. Since Jupiter is located at ~5 AU, Encke is safe from most of Jupiter’s gravitational interactions.
The question is how did Encke get there? Computer models find that it is very difficult to get an object from the outer solar system onto a Encke-type orbit. Though not impossible, it would require a very long amount of time. So long, in fact, that Encke should have burned out (run out of ice and volatiles) many 100,000s of years ago and should either appear as an inactive asteroid or perhaps have broken up into nothing more than dust by now. So what happened? It is possible that Encke took a very long time to get to its current orbit but was inactive, or dormant, for most of that time. If true, it would not have run out of ice and its cometary activity is a recent phenomenon. As we saw with the recent re-discoveries of Comets Giacobini and Barnard 3, comets can be inactive or barely active for many orbits.
Another possibility is that Encke is not from the outer solar system but rather from the Asteroid Belt between the orbits of Mars and Jupiter. It was long thought that the asteroids in the Asteroid Belt were all dead, dry objects, but recently a number of asteroids have been found that display the same activity as comets. Perhaps Encke was an asteroid from the Asteroid Belt until a collision or break-up event exposed a large area of ice resulting in cometary activity. Unfortunately, we could know a lot more about Encke but a planned mission to study Encke, and other comets, failed leaving Earth orbit. NASA’s COmet Nucleus TOUR (CONTOUR) mission was to fly-by Encke in 2003. | 0.844263 | 3.216014 |
Announcements • Reading for next class: Chapters 22.6, 23 • Cosmos Assignment 4,Due Wednesday, April 21, Angel Quiz • Monday, April 26Quiz 3 & Review, chapters 16-23 • Wednesday, April 28,Midterm 3: chapters 16-23
What are Galaxies? Galaxies are vast collections of stars (~1011) and sometimes gas and dust as well
Universe is Expanding • You and I are NOT expanding • The solar system is NOT expanding • The Milky Way Galaxy is NOT expanding • Our local group of Galaxies is NOT expanding • Nothing that is bound together by a force is expanding • SPACE between groups of galaxies IS expanding
Hubble’s Law Velocity = Hubble’s Constant x Distance V = HDIf you are twice as far away,you are moving away twice as fast, so you started moving away at the same time! How long ago was that?
Age of the Universe • V=HD • D = VT = V/H • T = D/V = 1/H Age if expansion not accelerated or decelerated
Questions: How did galaxies form? Why are there different types of Galaxies?
Galaxy Formation Similar to star formation • H & He gas filled space almost uniformly • Where density slightly greater, gravity slightly greater • Matter falls into gravitational potential well, increases gravity • Matter pulled in by more gravity, density excess grows • Densest cores became 1st generation massive stars
Galaxy Formation Models • Assumptions: • Matter originally • filled all of space • almost uniformly • Gravity of denser • regions pulled in • surrounding • matter
Clues to Galaxy Formation Halo stars are old, have randomly oriented orbits Disk has young stars with orbits nearly in plane • Initially gravity pulled in matter from all directions. Stars formed during this stage have random orbits passing close to center • Later, rotation made any remaining gas flatten into disk. Stars forming after this have orbits in disk.
Spiral or Elliptical Galaxy? Possible explanations • Rate of star formation • Amount of Rotation • Collisions & mergers
Density Excess? Higher density proto-galactic clouds form stars more rapidly, use up all their gas before it can form a disk.
Rotation? Larger rotation produces more disk-like distribution of matter.
Collisions & Mergers Question 1: If the Milky Way were the size of a grapefruit, where would the Andromeda galaxy (nearest comparable size galaxy) be? • About 1 cm away • About 1 m away • About 1 km away • About San Francisco • About the Moon • About the Sun
Collisions & Mergers Question 1: If the Milky Way were the size of a grapefruit, where would the Andromeda galaxy (nearest comparable size galaxy) be? • About 1 cm away • About 1 m away (~3 m) • About 1 km away • About San Francisco • About the Moon • About the Sun
Galaxies are close together Evidence of galaxy interactions via gravity Burst of star formation
Evidence of Galaxy mergers Super massive galaxies in the centers of clusters of galaxies Merged galaxies See also Fig 21.11
Elliptical galaxies are much more common in huge clusters of galaxies Denser cloud More collisions (hundreds to thousands of galaxies)
How do we know? When we look farther out in space we are looking farther back in time. See galaxies at different stages in their evolution
Problem! • In an expanding universe, gravity takes longer to pull matter together. • Need stronger gravity • Need more mass • Don’t see any more mass • Postulate existence of DARK MATTER
Other evidence for Dark Matter • Rotation of galaxies • Motions in clusters of galaxies • Hot x-ray emitting gas in clusters of galaxies • Gravitational lensing
Rotation Curve A plot of orbital velocity versus orbital radius Solar system’s rotation curve declines because Sun has almost all the mass & gravity gets weaker with Increasing distance
Rotation Curve of Milky Way stays flat with distance Mass must be more spread out than in solar system
Milky Way Significant mass exists outside radius of most stars!
Mass of Milky Way Mass within Sun’s orbit: 1.0 x 1011MSun Total mass: ~1012MSun -> Dark Matter
Motions of Galaxies in Clusters • Galaxies are moving too fast in clusters of galaxies to be held together by the gravity of the visible stellar material • Total Mass ~ 10x visible mass
Hot Gas in Galaxy Clusters • Galaxy clusters are filled with hot gas that emits x-rays. Temperature ~ 100 million K • Pressure of hot gas must be balanced by gravity to hold it together in the cluster. • Total Mass ~ 10x visible mass
Gravitational Lensing • Mass produces gravity • Gravity bends light • Gravity can distort the image of an object behind the mass
Galaxy cluster acts as gravitational lens. Focuses image of galaxy behind it into blue arcs.
What is Dark Matter? • We DON’T KNOW!!! • We only know what it is not • It is not ordinary matter composed of protons, neutrons, electrons, etc.
Galaxies are arranged like soap bubbles with voids devoid of galaxies inside | 0.829523 | 3.711515 |
By now, you may have seen the incredible pictures of the five-hundred-metre Aperture Spherical Radio Telescope or FAST, an enormous telescope in the Guizhou province of China that just turned on last year. You’ve also probably heard that, yes, many hope it will find signs of alien life. It’s already beginning to make discoveries.
China’s Xinhua news agency reports that the half-dome telescope the size of 30 football pitches has spotted dozens of pulsar candidates, several of which have been confirmed by the Parkes telescope in Australia. There are plenty of reasons why pulsars are cool: They’re constantly flashing beacons like distant clocks, which makes them useful astronomical tools for measuring distances, for example.
Also, maybe aliens have built megastructures around them. Just speculating, here.
Pulsars are neutron stars or white dwarves—dense star corpses that spin quickly and look like they blink from our vantage point on Earth. That’s because they send collimated beams outward like lighthouses. But all of the pulsars scientists have spotted until now have been within the confines of the Milky Way galaxy.
As Xinhua reports, two of the pulsars are 16,000 light years and 4,100 light years away, named J1859-01 and J1931-01, respectively—still in the Milky Way. But the press release continues that FAST might be capable of searching for extragalactic pulsars by next year.
That would be a big deal. “Pulsars are useful for studying the ionized material in our galaxy, their radio pulses travel through the interstellar medium and allow us to measure its properties,” pulsar expert Emily Petroff from the Netherlands Institute for Radio Astronomy told Gizmodo. “So having a pulsar in another galaxy would be a super powerful tool from probing the interstellar (and intergalactic) medium in between us and another galaxy. That’s never been done before.”
But even exploring pulsars in our own galaxy is exciting. Most other telescopes are too faint to spot them, said Petroff, but there are probably lots that astronomers haven’t found yet. Maybe FAST could help.
FAST has had its share of controversy. The New York Times reported last year that China planned to move more than 9,000 residents from the very poor area in order to reduce the potential for extra radiation clogging the telescope’s signal. It now has a tourist problem. And of course, this is not the first time a large science experiment has caused turmoil in a local community, as others have protested the thirty-metre telescope beginning construction above Mauna Kea.
This is just the beginning for FAST, and it will surely release many more exciting results—after all, it’s the most sensitive radio telescope in the world, said Petroff.
As for aliens, we’ll just need to wait and see. [Xinhua via Newsweek] | 0.888214 | 3.433346 |
Astronomers have used NASA’s Hubble Space Telescope to uncover a vast, complex dust structure, about 150 billion miles across, enveloping the young star HR 4796A.
A bright, narrow, inner ring of dust is already known to encircle the star and may have been corralled by the gravitational pull of an unseen giant planet. This newly discovered huge structure around the system may have implications for what this yet-unseen planetary system looks like around the 8-million-year-old star, which is in its formative years of planet construction.
The debris field of very fine dust was likely created from collisions among developing infant planets near the star, evidenced by a bright ring of dusty debris seen 7 billion miles from the star. The pressure of starlight from the star, which is 23 times more luminous than the Sun, then expelled the dust far into space.
“The dust distribution is a telltale sign of how dynamically interactive the inner system containing the ring is,” said Glenn Schneider of the University of Arizona, Tucson, who used Hubble’s Space Telescope Imaging Spectrograph (STIS) to probe and map the small dust particles in the outer reaches of the HR 4796A system, a survey that only Hubble’s sensitivity can accomplish.
“We cannot treat exoplanetary debris systems as simply being in isolation. Environmental effects, such as interactions with the interstellar medium and forces due to stellar companions, may have long-term implications for the evolution of such systems. The gross asymmetries of the outer dust field are telling us there are a lot of forces in play (beyond just host-star radiation pressure) that are moving the material around. We’ve seen effects like this in a few other systems, but here’s a case where we see a bunch of things going on at once,” Schneider further explained.
But the puffy outer dust structure has much more to offer. It is like a donut-shaped inner tube that got hit by a truck. It is also much more extended in one direction than in the other and so looks squashed on one side even after accounting for its inclined projection on the sky.
This may be due to the motion of the host star plowing through the interstellar medium, like the bow wave from a boat crossing a lake. Or it may be influenced by a tidal tug from the star’s red dwarf binary companion (HR 4796B), located at least 54 billion miles from the primary star. | 0.907743 | 4.05266 |
ABOUT THE MAGAZINE
Stars are just fascinating altogether with many facts. Stars are huge balls of Hydrogen and Helium that are formed in galaxies from great big clouds of gas and dust over billions….
The birth of a star begins when massive clouds of dust and gas start to collapse and break…. So you have learned about the birth of stars, and have also learned about our own star. Now, let us look into the life of a star and the stages…. With an infinite amount of stars in the universe, and the billions in our own galaxy, as we search through the stars that we can see with current technology, we….
Kids Fun Facts Corner 1.
Birth of stars and evolution to the main sequence
What is a Protostar? What determines the color of a star? What is the name of the force that creates the birth of a star?
- The Whole Truth (Shaw & Katie James, Book 1).
- The Formation of Stars | Wiley Online Books.
- Youngspeak in a Multilingual Perspective;
How Stars Are Born Video. Stars Stars are just fascinating altogether with many facts.
Stars | Science Mission Directorate
Stars are huge balls of Hydrogen and Helium that are formed in galaxies from great big clouds of gas and dust over billions… Read Full Article. The birth of a star begins when massive clouds of dust and gas start to collapse and break… Read Full Article. Star Lifecycle — Supernovas So you have learned about the birth of stars, and have also learned about our own star. Now, let us look into the life of a star and the stages… Read Full Article. Star Sizes With an infinite amount of stars in the universe, and the billions in our own galaxy, as we search through the stars that we can see with current technology, we… Read Full Article.
Figure 3: Orion Nebula. Megeath University of Toledo, Ohio. Compare this with our own solar neighborhood, where the typical spacing between stars is about 3 light-years. Only a small number of stars in the Orion cluster can be seen with visible light, but infrared images—which penetrate the dust better—detect the more than stars that are part of the group Figure 4.
Figure 4: Central Region of the Orion Nebula. The Orion Nebula harbors some of the youngest stars in the solar neighborhood. At the heart of the nebula is the Trapezium cluster, which includes four very bright stars that provide much of the energy that causes the nebula to glow so brightly. In these images, we see a section of the nebula in a visible light and b infrared. The four bright stars in the center of the visible-light image are the Trapezium stars. Notice that most of the stars seen in the infrared are completely hidden by dust in the visible-light image.
Schneider, E. Young, G. Rieke, A. Cotera, H.
Chen, M. Rieke, R. Thompson Steward Observatory, University of Arizona. Studies of Orion and other star-forming regions show that star formation is not a very efficient process. That is why we still see a substantial amount of gas and dust near the Trapezium stars.
The leftover material is eventually heated, either by the radiation and winds from the hot stars that form or by explosions of the most massive stars. We will see in later chapters that the most massive stars go through their lives very quickly and end by exploding. Whether gently or explosively, the material in the neighborhood of the new stars is blown away into interstellar space.
Older groups or clusters of stars can now be easily observed in visible light because they are no longer shrouded in dust and gas Figure 5. Figure 5: Westerlund 2. This young cluster of stars known as Westerlund 2 formed within the Carina star-forming region about 2 million years ago. Stellar winds and pressure produced by the radiation from the hot stars within the cluster are blowing and sculpting the surrounding gas and dust.
The nebula still contains many globules of dust.
Stars are continuing to form within the denser globules and pillars of the nebula. This Hubble Space Telescope image includes near-infrared exposures of the star cluster and visible-light observations of the surrounding nebula. Colors in the nebula are dominated by the red glow of hydrogen gas, and blue-green emissions from glowing oxygen. Although we do not know what initially caused stars to begin forming in Orion, there is good evidence that the first generation of stars triggered the formation of additional stars, which in turn led to the formation of still more stars Figure 6.
Figure 6: Propagating Star Formation. Star formation can move progressively through a molecular cloud.
The oldest group of stars lies to the left of the diagram and has expanded because of the motions of individual stars. Eventually, the stars in the group will disperse and no longer be recognizable as a cluster.source link
What Was It Like When Galaxies Formed The Greatest Number Of Stars?
The youngest group of stars lies to the right, next to the molecular cloud. This group of stars is only 1 to 2 million years old. The pressure of the hot, ionized gas surrounding these stars compresses the material in the nearby edge of the molecular cloud and initiates the gravitational collapse that will lead to the formation of more stars. The basic idea of triggered star formation is this: when a massive star is formed, it emits a large amount of ultraviolet radiation and ejects high-speed gas in the form of a stellar wind.
This injection of energy heats the gas around the stars and causes it to expand. When massive stars exhaust their supply of fuel, they explode, and the energy of the explosion also heats the gas. The hot gases pile into the surrounding cold molecular cloud, compressing the material in it and increasing its density. If this increase in density is large enough, gravity will overcome pressure, and stars will begin to form in the compressed gas. There are many molecular clouds that form only or mainly low-mass stars. Because low-mass stars do not have strong winds and do not die by exploding, triggered star formation cannot occur in these clouds.
There are also stars that form in relative isolation in small cores. Therefore, not all star formation is originally triggered by the death of massive stars. However, there are likely to be other possible triggers, such as spiral density waves and other processes we do not yet understand. Although regions such as Orion give us clues about how star formation begins, the subsequent stages are still shrouded in mystery and a lot of dust.
There is an enormous difference between the density of a molecular cloud core and the density of the youngest stars that can be detected. Direct observations of this collapse to higher density are nearly impossible for two reasons. First, the dust-shrouded interiors of molecular clouds where stellar births take place cannot be observed with visible light. Second, the timescale for the initial collapse—thousands of years—is very short, astronomically speaking.
The formation of stars
Since each star spends such a tiny fraction of its life in this stage, relatively few stars are going through the collapse process at any given time. Nevertheless, through a combination of theoretical calculations and the limited observations available, astronomers have pieced together a picture of what the earliest stages of stellar evolution are likely to be. The first step in the process of creating stars is the formation of dense cores within a clump of gas and dust Figure 7 a.
It is generally thought that all the material for the star comes from the core, the larger structure surrounding the forming star. Eventually, the gravitational force of the infalling gas becomes strong enough to overwhelm the pressure exerted by the cold material that forms the dense cores. The material then undergoes a rapid collapse, and the density of the core increases greatly as a result. During the time a dense core is contracting to become a true star, but before the fusion of protons to produce helium begins, we call the object a protostar. Figure 7: Formation of a Star.
These sketches are not drawn to the same scale. | 0.881716 | 3.202752 |
July 30, 2018
We are often tantalized by the prospect of water on Mars, but thanks to a Teenage Satellite we have found lakes of water on Mars, just beneath the surface. Plus we find out where all that martian dust comes from and check in on everyone's favourite Comet, 67-p.
- R. Orosei, S. E. Lauro, E. Pettinelli, A. Cicchetti, M. Coradini, B. Cosciotti, F. Di Paolo, E. Flamini, E. Mattei, M. Pajola, F. Soldovieri, M. Cartacci, F. Cassenti, A. Frigeri, S. Giuppi, R. Martufi, A. Masdea, G. Mitri, C. Nenna, R. Noschese, M. Restano, R. Seu. Radar evidence of subglacial liquid water on Mars. Science, 2018; eaar7268 DOI: 10.1126/science.aar7268
- Horner, J. (2018, July 26). Discovered: A huge liquid water lake beneath the southern pole of Mars. Retrieved from http://theconversation.com/discovered-a-huge-liquid-water-lake-beneath-the-southern-pole-of-mars-100523
- Lujendra Ojha, Kevin Lewis, Suniti Karunatillake, Mariek Schmidt. The Medusae Fossae Formation as the single largest source of dust on Mars. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-05291-5
- K. L. Heritier, K. Altwegg, J.-J. Berthelier, A. Beth, C. M. Carr, J. De Keyser, A. I. Eriksson, S. A. Fuselier, M. Galand, T. I. Gombosi, P. Henri, F. L. Johansson, H. Nilsson, M. Rubin, C. Simon Wedlund, M. G. G. T. Taylor, E Vigren. On the origin of molecular oxygen in cometary comae. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-04972-5
July 23, 2018
Solar Panels keep getting better, but what if we could have solar power even when it's very overcast? Plus is there a way to make concrete greener and less carbon intensive? What if one of those solutions also helped take care of waste product from Coal Power Plants? We look at innovative green technologies this week in Lagrange Point.
- Joshua Shank, Emil A. Kadlec, Robert L. Jarecki, Andrew Starbuck, Stephen Howell, David W. Peters, Paul S. Davids. Power Generation from a Radiative Thermal Source Using a Large-Area Infrared Rectenna. Physical Review Applied, 2018; 9 (5) DOI: 10.1103/PhysRevApplied.9.054040
- Sarvesh Kumar Srivastava, Przemyslaw Piwek, Sonal R. Ayakar, Arman Bonakdarpour, David P. Wilkinson, Vikramaditya G. Yadav. A Biogenic Photovoltaic Material. Small, 2018; 14 (26): 1800729 DOI: 10.1002/smll.201800729
- Gang Xu, Jing Zhong, Xianming Shi. Influence of graphene oxide in a chemically activated fly ash. Fuel, 2018; 226: 644 DOI: 10.1016/j.fuel.2018.04.033
- Sung Hoon Hwang, Rouzbeh Shahsavari. High calcium cementless fly ash binder with low environmental footprint: Optimum Taguchi design. Journal of the American Ceramic Society, 2018; DOI: 10.1111/jace.15873
July 16, 2018
Dust storms can be hazardous, especially when they engulf an entire planet like on Mars. They can also carry pollution across national borders and contaminate wide areas. But Dust Storms may also hold the secret for how life can spread across vast deserts. This week we look at dust storms of this world and out of this world.
- Authors: J. A. Rivas Jr., J. E. Mohl, R. S. Van Pelt, M.‐Y. Leung, R. L. Wallace, T. E. Gill, E. J. Walsh. Evidence for regional aeolian transport of freshwater micrometazoans in arid regions. Limnology and Oceanography Letters, 2018; DOI: 10.1002/lol2.10072
- Tuyet Nam Thi Nguyen, Kuen-Sik Jung, Ji Min Son, Hye-Ok Kwon, Sung-Deuk Choi. Seasonal variation, phase distribution, and source identification of atmospheric polycyclic aromatic hydrocarbons at a semi-rural site in Ulsan, South Korea. Environmental Pollution, 2018; 236: 529 DOI: 10.1016/j.envpol.2018.01.080
- Penn State. (2018, June 28). Mars dust storm may lead to new weather discoveries. ScienceDaily. Retrieved July 14, 2018 from www.sciencedaily.com/releases/2018/06/180628124412.htm
- NASA/Goddard Space Flight Center. (2018, June 20). Martian dust storm grows global: Curiosity captures photos of thickening haze. ScienceDaily. Retrieved July 13, 2018 from www.sciencedaily.com/releases/2018/06/180620170956.htm
July 9, 2018
How far would you go to find a treatment that helps you or a loved one suffering from a chronic condition? Is it worth the side effects or the pain of jumping through bureaucratic hoops? Is it worth risking the black market? Plus we find out ways to make precision medicine even more precise to rule out side effects.
- Bell, F. (2017, March 01). Sick kids chosen as first patients to receive legal medicinal cannabis in Victoria. Retrieved from http://www.abc.net.au/news/2017-03-01/children-with-epilepsy-receive-legal-medicinal-cannabis-victoria/8313902
- Dunstan, J. (2018, June 08). Dad defends medicinal cannabis program as kids drop out. Retrieved from http://www.abc.net.au/news/2018-06-08/victorian-medicinal-cannabis-trial-kids-drop-out/9848596
- Medical Marijuana and Epilepsy. (n.d.). Retrieved from https://www.epilepsy.com/learn/treating-seizures-and-epilepsy/other-treatment-approaches/medical-marijuana-and-epilepsy
- Understanding Epilepsy. (n.d.). Retrieved from https://www.epilepsy.org.au/about-epilepsy/understanding-epilepsy/
- Zafar, A. (2017, May 26). Cannabis compound shown to slash seizures in kids with rare form of epilepsy | CBC News. Retrieved from https://www.cbc.ca/news/health/dravet-syndrome-epilepsy-cbd-1.4130180
- A. Suraev, N. Lintzeris, J. Stuart, R. C. Kevin, R. Blackburn, E. Richards, J. C. Arnold, C. Ireland, L. Todd, D. J. Allsop, I. S. McGregor. Composition and Use of Cannabis Extracts for Childhood Epilepsy in the Australian Community. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-28127-0
- Lei Zhang, Peng Zhang, Guangfu Wang, Huaye Zhang, Yajun Zhang, Yilin Yu, Mingxu Zhang, Jian Xiao, Piero Crespo, Johannes W. Hell, Li Lin, Richard L. Huganir, J. Julius Zhu. Ras and Rap Signal Bidirectional Synaptic Plasticity via Distinct Subcellular Microdomains. Neuron, 2018; 98 (4): 783 DOI: 10.1016/j.neuron.2018.03.049
July 2, 2018
This week we look into three stories about how oceans tie our planet together. Our ecosystems are often linked in unusual ways that are not immediately obvious. Ocean currents can tie ecosystems across the world together, impacting migratory species, local environments and ecosystems. Sometimes these impacts are short term, other times they play out over years, decades and centuries.
- Carl J. Reddin, Ádám T. Kocsis, Wolfgang Kiessling. Marine invertebrate migrations trace climate change over 450 million years. Global Ecology and Biogeography, 2018; DOI: 10.1111/geb.12732
- Hector M. Guzman, Catalina G. Gomez, Alex Hearn, Scott A. Eckert. Longest recorded trans-Pacific migration of a whale shark (Rhincodon typus). Marine Biodiversity Records, 2018; 11 (1) DOI: 10.1186/s41200-018-0143-4
- Jocelyn Champagnon, Jean-Dominique Lebreton, Hugh Drummond, David J. Anderson. Pacific Decadal and El Niño oscillations shape survival of a seabird. Ecology, 2018; 99 (5): 1063 DOI: 10.1002/ecy.2179 | 0.827317 | 3.146478 |
Titanic life may bloom without water
Hydrocarbon seas on Saturn's moon could be a solvent for biological molecules.
Are those dark patches on Titan really oceans, fed by rivers of liquid ethane? And if so, what are the fish like?
The extraordinary images sent from Saturn's giant moon by the Huygens spacecraft should make speculation about life in liquids other than water more than a scientific parlour game.
In fact, a lifeless Titan would point to a gap in our understanding of carbon-based molecules, says chemist Steven Benner of the University of Florida in Gainesville. Organisms should be comfortable in a hydrocarbon ocean, he says.
University of Florida, Gainesville
Earth demonstrates the logic in this. Life is found just about everywhere there is water and a source of energy, and water seems a prerequisite for every form of life. This makes some scientists pessimistic about life on Titan: "There is no chance for life on the surface because it is too cold and there is no liquid water," says François Raulin, a scientist working on the European Space Agency's Huygens mission.
But does life depend on water? Or could it be that Earth life has evolved to suit its watery home? Anything we might recognize as life probably needs a liquid solvent to transport molecules and bring them together. But who says the solvent must be water?
Benner and his colleagues argue in Current Opinion in Chemical Biology that water-free environments on other worlds might fulfil the conditions for life1. Liquid ammonia is rather similar to water: it dissolves molecules with electrically charged parts, including carbon-based (organic) ones. On Earth, ammonia boils at -33°C; but there are many places in the Solar System where it could exist in liquid state, such as the clouds of Jupiter.
Other worlds could support exotic solvents: all of the gas giants might contain patches of dense, liquid-like hydrogen in their atmospheres, and Venus has clouds composed of droplets of sulphuric acid.
But Titan looks like the best candidate for non-aqueous life. It seems to have rivers and oceans, and its sticky surface is apparently made partly from organic molecules. There are nitrogen-containing organic compounds called nitriles in its atmosphere, which, it has been suggested, could react with water ice to form a rich blend of organic ingredients for possible life forms2.
Non-aqueous solvents such as hydrocarbons can support complex organic reactions, Benner points out. In fact, organic chemists usually prefer them to water, which is reactive and can interfere with delicate chemical processes.
One of the puzzles about the origin of life on Earth is why the first biological molecules were not torn apart by reactions with water. Life evolving in hydrocarbon liquids would not have this problem. "Water is a serious nuisance," Benner says: because of its reactivity, "the human genome survives only because it is constantly being repaired."
Even on Earth, many of the chemical reactions of life take place without water, catalysed by enzymes with water-repellent pockets. And many enzymes work perfectly well in the oily, water-free environment inside cell walls.
Relatively weak bonds, called hydrogen bonds, give terrestrial biomolecules, such as the DNA double helix, the crucial ability to stick together and then separate.
But water molecules form hydrogen bonds too, so groups of molecules bound by hydrogen bonds can fall apart rather easily in water. "In ethane," says Benner, "a hypothetical form of life would be able to use hydrogen bonding more."
So it's not obvious that water is special, apart from the fact that it exists in large quantities on Earth. "If life is an intrinsic property of chemical reactivity," Benner concludes, "life should exist on Titan. We need to go back, with a lander that can survive for weeks, not minutes."
But we'll have to wait a long time: so far, NASA has no firm plans for a return mission.
- Benner S. A., Ricardo A. & Carrigan M. A. Curr. Opin. Chem. Biol., 8. 672 - 689 (2004).
- Hudson R. L. & Moore M. H. Icarus, 172. 466 - 478 (2004). | 0.817599 | 3.881952 |
Prof Laurence Young, the Apollo Program Professor in MIT’s Department of Aeronautics and Astronautics, says artificial gravity (AG) would be a huge benefit for astronauts, particularly those embarking on long-duration space missions, such as a journey to Mars. At the First Asgardia Space Science and Investment Congress (ASIC)Prof Young presents his take on the pressing issue of development of artificial gravity systems for the colonization of the Solar System
Prof Young begins with a look at AG history. 'We’ve learned to look into differences between the results of the early Soviet cosmonauts’ experience and the early American astronauts’ experience. And to ask ourselves why they were so different. The American astronauts were not getting space motion sickness (SMS), while many of the Soviet cosmonauts were. The early experience was that there was no SMS reported, but it doesn’t mean it didn’t exist... The scorecard for the Apollo astronauts says 9 of 25 Apollo astronauts developed SMS. 2 out of those 9 had negative SMS histories, their questionnaire has shown that these people would appear to be immune. We were left with an issue: how do you predict susceptibility to SMS? Which one of us would be likely to be immune?'
'The answer appeared: the size of the vehicle was critical. Soviet vehicles from the beginning were larger and allowed more movement than the American vehicles. When the Americans finally got up to the sizes like Apollo, in which you could actually move around, the incidents of the SMS rose as well. So the revival of interest in what the vestibular functions are like in space and how this relates to artificial gravity were not driven by basic science, they were driven by operational issues.'
Prof Young presents a list of questions which 'would drive the continuing research on artificial gravity and adaptation.'
'Some of the ideas which were suggested seemed sensible, but either didn’t work out or haven’t been sufficiently tested to this time. This is a challenge for all of us: which ones of these need to be followed out further before we can address our primary challenge,' Prof Young explains.
'At first, it was thought that we can avoid DSMS (Dreaded Space Motion Sickness) by selecting only males and only fighter pilots. That looked good for a while but it’s not true!'
We could provide the cervical collar to eliminate or reduce head movements. As an astronaut who tried out cervical collars told Prof Young: ‘Larry, if you have a broken leg, you don’t need anyone to tell you ‘don’t step on the broken leg’, you don’t need a cervical collar to tell you not to make head movements, when whatever head movement induced nausea.'
'We could try bio-feedback, it was tried briefly without conclusion. We could try devices in laboratory in which your linear motion would be associated with the rotation of the visual field to try to reproduce some of the visual vestibular conflict which we feel is present when we’re making movements in orbit,' Prof Laurence Young says.
However, the answer to SMS has still not been found.
The first Asgardia Space Science and Investment Congress (ASIC), held in Darmstadt, Germany, October 14-16, brings together scientists, aerospace industry specialists, and investors to discuss solutions to make humanity’s future in space possible. To ‘Pave the road to living in space,’ we need solutions to overcoming cosmic radiation, learning to live in artificial and lunar gravity, and, most importantly, human children must be born, and grow up, in space. The Congress also addresses topics like life support systems, space tourism, energy harvesting, recycling, human performance, commercial space transportation, space physiology, new materials, space architecture, counter measures, astrobiology, water and oxygen supply, space debris, and space weather.Christina Daumann | 0.857856 | 3.248097 |
The Time Machine
A long time ago in a galaxy far, far away…
Humanity has long dreamed of peering into the past to gain a better understanding of how we got here, where we’ve been, and where we’re headed. Until now, no machine existed that allowed us to time travel to the beginnings of time.
That is all about to change.
When launched in October 2018, NASA’s James Webb Space Telescope will allow us to understand the universe as never before. The most powerful space telescope ever built will give scientists a view of the first galaxies and stars forming in the darkness over 13.5 billion years ago, 200 million years after the Big Bang. In essence, it will allow astronomers to glimpse the end of space’s dark ages and the birth of the universe, as we perceive it today.
The Webb telescope, successor to the Hubble Space Telescope, might also answer the question as to whether we’re alone in the universe. That’s because it will observe smaller exoplanets – planets that orbit a star other than our own sun – and ascertain whether they have Earth-like atmospheres with life-supporting oxygen, nitrogen, carbon dioxide and water vapor.
“We’re enabling a new dawn of discovery,” said Scott Willoughby, M.S. ’91, the vice president and program manager for the James Webb Space Telescope at Northrop Grumman. “We’re creating an instrument that will allow us to see things never seen before. We have a chance to say whether there’s Earth 2.0 out there.”
To gain an appreciation of the Webb telescope’s potential, it is worth noting just how far Hubble has advanced our understanding of space since becoming operational in 1990. That telescope played a major role in the discovery of dark energy, a little known force that contributes to the expansion of the universe by working against gravity. Hubble also helped determine the age of the universe and has captured images of ancient galaxies in all evolutionary stages.
The $8.8 billion Webb telescope, overseen by NASA and 20 years in development, represents an international collaboration of 24 countries, with significant contributions by the European Space Agency and the Canadian Space Agency. It is named after James E. Webb, NASA’s second administrator from 1961 to 1968 who played an integral role in the Apollo program.
In 2002, NASA selected Northrop as the prime contractor to develop the telescope – a major victory for the Falls Church, Virginia-based aerospace firm. The company is designing and building the Webb telescope’s deployable sunshield; providing the spacecraft that will carry the telescope into space; and integrating the entire system. Northrop-led teams, in collaboration with subcontractors, developed the Webb telescope’s mirrors, composite materials and other systems.
USC Viterbi and James Webb
At every phase, USC Viterbi alumni have played an integral role.
The entire project falls under the portfolio of Tom Vice, B.S. AE ’93, Northrop Grumman corporate vice president and president of the company’s Aerospace Systems sector. “The most exciting thing is trying to imagine what we will learn that we haven’t even dreamed about yet,” he said.
Willoughby, as project manager, directs nearly every aspect of the endeavor, ranging from technical issues to budgeting to briefing Congress – “I get up every morning and ensure that we have a plan that’s comprehensive and that each day we mark and measure ourselves and get those steps done,” he said. Supporting him is fellow Trojan and Deputy Program Manager Gus Makrygiannis, MBA ‘92. Among the engineering teams designing, testing and integrating the telescope are scores of USC Viterbi alumni.
The engineering school is so well represented because of the quality of its graduates, Willoughby said. “At USC, I learned how to solve, think about and approach problems and not be intimidated by them,” he said.
Scientists believe the Webb telescope has the potential to revolutionize astronomy. By capturing images never before seen, it will deepen our understanding and knowledge of the evolution of galaxies and the formation of planetary systems and stars. The Webb telescope will have the capacity to detect objects that are 10 to 100 times fainter than Hubble can currently see, experts said.
The telescope will reside in a point in space nearly 1 million miles away called L2, where gravitational forces will enable it to rotate around the sun in the same orbital period as Earth. By contrast, Hubble lives only 250 miles from earth. It will take the Webb telescope 30 days to reach its final destination.
The Webb telescope, by being so far away, will escape the sun’s and earth’s thermal heat, making it possible to capture images in the infrared – “where all this historical knowledge about the universe is,” Willoughby said. Because the universe expands the farther one goes back in time, the early light scientists want to capture falls outside the visible light spectrum, necessitating an instrument that can measure light in the infrared range.
Additionally, the telescope’s location will keep its mirror a cool -388 degrees F, a prerequisite for working in the infrared spectrum.
The Webb telescope is a technological marvel.
When it comes to space telescope mirrors, bigger is better. That’s because larger ones gather more light, allowing them to see fainter objects. Their higher magnification also permits them to identify finer details.
At 21-feet-4-inches, the Webb telescope will become the biggest ever launched into space, featuring a collecting area about seven times larger than Hubble’s. With its deeper infrared sensors, the Webb telescope can better penetrate gas and dust to see more and older stars and galaxies.
Project engineers working on the Webb telescope’s primary mirror needed to build it light enough for a rocket to carry into space but compact enough to fit into a small area. They have addressed the weight issue by making the mirror from beryllium, a rare metal stronger than steel but lighter than aluminum. A thin layer of gold coats its surface to reflect the infrared light.
Making the huge mirror small enough to fit into a rocket required an equal amount of ingenuity. Engineers have done so by building it from 18 hexagonal-shaped mirror segments that fold for transit but will unfold like origami at the final destination. Computer-controlled motors behind the mirror segments will slightly bend them as needed to ensure that they remain in focus.
“It took eight years to make such a segmented mirror with such incredibly precise shapes,” Willoughby said.
Protecting the mirror from the sun’s scorching heat and space’s frigid cold will be a giant sunscreen measuring 80-feet-long, by 40-feet-wide, about the size of a tennis court. The five-layer sunscreen is so thin – each layer is between 1/1,000th to 2/1000th inch thick – that it can “stow like a parachute and deploy into orbit,” Willoughby said.
After Northrop engineers assemble the entire observatory – telescope, instruments and spacecraft – it will be transported to French Guiana. An Ariane 5 rocket will launch the system into space.
Willoughby cannot wait.
“We had to build a telescope bigger than ever before, operating in a colder environment than ever before and at a distance farther away than ever before,” he said. “This has never been done before.” | 0.831749 | 3.15855 |
The countdown has begun. In less than 24 hours, the Indian Space Research Organisation (ISRO) will launch India’s ambitious Moon mission Chandrayaan-2 from Sriharikota, Andhra Pradesh. To be precise, July 15 (Monday) 2.51 am.
According to ISRO, everything has been checked and is going according to plan.
The aim of the mission is to land a robotic rover on the moon near the lunar South Pole. The mission will carry out various experiments to understand the extent and significance of the presence of water on Moon as confirmed by the Chandrayaan-1 mission earlier.
#First For World
This is the first space mission to conduct a soft landing on the Moon’s South Pole region, which has a lunar surface area much larger than that of the North Pole and remains in shadow. According to ISRO, “The moon is the closest cosmic body at which space discovery can be attempted and documented. But its south polar region has never been explored by any country before.”
#First For India
This is the first time that India is trying to land a robotic rover on Moon. If the mission is successful, India would become the fourth country in the world to make a soft landing on Moon and put a rover on it.
ISRO is using India’s strongest launcher GSLV MKIII for the Chandrayaan-2 mission. India’s Chandrayaan-2 is unique in its own way. There’s a lander, one rover and an orbiter in it.
After launch, Chandrayaan-2 will be projected in an oval orbit, leaving the rocket over and over again for the next 17 days and increasing the scope of its orbit. After increasing the radius, the space mission will move towards the Moon. From there, Chandrayaan-2 will take five days to reach the Moon’s radius. The distance between the Moon and the Earth is 3.84 lakh km.
After reaching the Moon’s radius, Chandrayaan-2’s orbiter will start rotating around it. It will be 100 km away from the Moon’s surface. The lander rover would be then made a soft landing on the Moon’s surface.
It is being assumed that the lander rover will make its landing on the Moon’s surface on September 6. The rover, named Pragyaan, would then come out of the lander, named Vikram.
After making a soft landing, Pragyaan rover can stroll around for one Moon day, which is equal to 14 days on Earth. It will carry out various experiments to understand the extent and significance of the presence of water on Moon.
The success of Chandrayaan-2 may prove an important step in giant leap towards space exploration by India.
The ready access to water at the poles has both scientific and utilitarian interest, says ISRO. A sample of primordial water would be key to understanding the origin of water on the Moon and possibly the earth as well. It may unravel the mystery of water in the solar system.
ISRO hopes that the Moon could form the base for fuel and oxygen and other critical raw materials. And, if our nearest solar neighbour can be considered a pit-stop for resources including water, space transportation could be more affordable.
Finding a home way from the earth may not be that far in future! | 0.854557 | 3.007916 |
This reflector was originally built for the Melbourne Observatory in 1868 for visual (look and sketch) observations. Rather than glass, it had a mirror made of speculum (a heavy alloy of copper and tin) that made the telescope cumbersome to balance. Also, it was used without a dome, exposing the telescope to vibrations from the wind. These problems rendered the reflector inadequate for photography, and from 1893 the telescope sat unused. Mount Stromlo purchased the telescope when Melbourne Observatory closed in 1944. With some significant modifications it became one of Stromlo’s most productive telescopes.
In the 1990s the reflector joined the MACHO project to investigate one of the big mysteries of the universe – ‘dark matter’. Observations of distant galaxies had demonstrated the gravitational presence of an invisible matter that neither emitted nor absorbed light. The Great Melbourne Telescope was used to test a theory that the missing mass is attributed to ‘Massive Astrophysical Compact Halo Objects’ (MACHOs), such as black holes or neutron stars. Over the course of five years, the astronomers observed less than 20 occurrences of this event outside our own galaxy, ruling out MACHOs as primary contributors to dark matter. The composition of dark matter remains one of the Universe’s big unanswered questions.
Just before its destruction in the 2003 bushfire, The Great Melbourne Telescope had been automated to generate a digital map of the southern skies – the ‘Skymapper’ project has since been transferred to Siding Spring Observatory. | 0.819441 | 3.502112 |
On August 20th, 1977, Voyager 2 was launched. Her sister spacecraft, Voyager 1, followed two weeks later. The goal of these two explorers was to shed light on the mysteries of our solar system by getting up close and personal with our planetary neighbours.
Artist’s concept of Voyager in flight.
The missions scope and engineering ingenuity have yet to be matched and forty years later, both the pioneering craft are still operating, sending back data, and heading on their way out of our solar system to explore further than any spacecraft ever launched.
The spacecraft was built with 3 Multihundred-Watt radioisotope thermoelectric generators (MHW RTG). Each RTG includes 24 pressed plutonium oxide spheres and provides enough heat to generate approximately 157 watts of power at launch. Collectively, the RTGs supply the spacecraft with 470 watts at launch and will allow operations to continue until at least 2020
29 July 1977 – Gold-Plated Record is attached to Voager 1. The title of the record is Sound of Earth
2 August 1977 – The 1800 pound heavy Voyager 2 spaceprobe is encapsulated for the launch to the planets Jupiter and Saturn. Later the mission was extended to the planets Uranus and Neptun
Voyager Golden Record – The Voyager Golden Records are phonograph records that were included aboard both Voyager spacecraft launched in 1977. The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for future humans, who may find them
Planetary Grand Tour
The mission was driven, in part, by a rare planetary alignment which occurred in the late 1970s. Jupiter, Saturn, Uranus, Neptune and Pluto perfectly align every 175 years – NASA engineers took advantage of this to propel the craft quickly between most of the Solar System’s outer planets using gravitational slingshots to leap from planet to planet.
The name of the Voyager project came only a few months before launch in 1977. The clunkily named ‘Mariner Jupiter-Saturn mission’ was renamed in a public competition to ‘Voyager’ and the two Voyager probes were launched in August and September 1977.
August 20, 1977 – The Voyager 2 aboard Titan III-Centaur launch vehicle lifted off on August 20, 1977. The Voyager 2 was a scientific satellite to study the Jupiter and the Saturn planetary systems including their satellites and Saturn’s rings.
Where no probe has gone before – Encounter with Jupiter
Voyager 2’s closest approach to Jupiter occurred on July 9, 1979. It came within 570,000 km (350,000 mi) of the planet’s cloud tops
July 1979 – This picture shows a region of the southern hemisphere extending from the Great Red Spot to the south pole. The white oval is seen beneath the Great Red Spot, and several small scale spots are visible farther to the south. Some of these organized cloud spots have similar morphologies, such as anticyclonic rotations and cyclonic regions to their west. The presence of the white oval causes the streamlines of the flow to bunch up between it and the Great Red Spot.
9 July 1979 – Jupiter and Io photographed by the Voyager 2 probe.
An Eruption on Io, photographed by Voyager 2
This mosaic of Europa, the smallest Galilean satellite, was taken by Voyager 2. This face of Europa is centered at about the 300 degree meridian. The bright areas are probably ice deposits, whereas the darkened areas may be the rocky surface or areas with a more patchy distribution of ice. The most unusual features are the systems of long linear structures that cross the surface in various directions. Some of these linear structures are over 1,000 kilometers long and about 2 or 3 kilometers wide. They may be fractures or faults which have disrupted the surface.
The hemisphere of Ganymede that faces away from Jupiter displays a great variety of terrain. In this Voyager 2 mosaic, photographed at a range of 300,000 kilometres, the ancient dark area of Regio Galileo lies at the upper right.
Below it, the ray system is probably caused by water-ice, splashed out in a relatively recent impact.
The original NASA image has been cropped, and some non-full-color areas have been blacked out.
7 July 1979 – This false color picture of Callisto was taken by Voyager 2 on July 7, 1979 at a range of 1,094,666 kilometers (677,000 miles) and is centered on 11 degrees N and 171 degrees W. This rendition uses an ultraviolet image for the blue component. Because the surface displays regional contrast in UV, variations in surface materials are apparent. Notice in particular the dark blue haloes which surround bright craters in the eastern hemisphere. The surface of Callisto is the most heavily cratered of the Galilean satellites and resembles ancient heavily cratered terrains on the moon, Mercury and Mars. The bright areas are ejecta thrown out by relatively young impact craters. A large ringed structure, probably an impact basin, is shown in the upper left part of the picture. The color version of this picture was constructed by compositing black and white images taken through the ultraviolet, clear and orange filters.
11 July 1979 – Voyager 2 captures Jupiters rings (that’s right – Jupiter has rings)
6 May 1979 – An eruptive event in the southern hemisphere of Jupiter over a period of 8 Jupiter days. Prior to the event, an undistinguished oval cloud mass cruised through the turbulent atmosphere. The eruption occurs over a very short time at the very center of the cloud. The white eruptive material is swirled about by the internal wind patterns of the cloud. As a result of the eruption, the cloud then becomes a type of feature seen elsewhere on Jupiter known as “spaghetti bowls.”
As Voyager 2 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 8 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Violet filter around May 6, 1979. The spacecraft was about 50 million kilometers from Jupiter at that time.
This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979
Next Stop Saturn
The closest approach to Saturn occurred on August 26, 1981. Voyager 2 returned scientific data via radio link about everything from the planets atmospheric temperature to density profiles.
This true color picture was assembled from Voyager 2 Saturn images obtained Aug. 4 from a distance of 21 million kilometers (13 million miles) on the spacecraft’s approach trajectory. Three of Saturn’s icy moons are evident at left. They are, in order of distance from the planet: Tethys, 1,050 km. (652 mi.) in diameter; Dione, 1,120 km. (696 mi.); and Rhea, 1,530 km. (951 mi.). The shadow of Tethys appears on Saturn’s southern hemisphere. A fourth satellite, Mimas, is less evident, appearing as a bright spot a quarter-inch in in from the planet’s limb about half an inch above Tethys; the shadow of Mimas appears on the planet about three-quarters of an inch directly above that of Tethys. The pastel and yellow hues on the planet reveal many contrasting bright and darker bands in both hemispheres of Saturn’s weather system. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California, United States
The north polar region of Saturn is pictured in great detail in this Voyager 2 image obtained Aug. 25 from a range of 633,000 kilometers (393,000 miles).
Two oval cloud systems some 250 km (150 mi) across are visible at about 72 degrees north latitude. The bright spot in the center of the leftmost cloud is a convective cloud storm about 60 km. (37 mi.)across. The outer ring of material rotates in an anti-cyclonic sense(counterclockwise in the northern hemisphere). A similar cloud structure of comparable dimension appears at 55 degrees north (bottom center of this picture). These northern latitudes contain many bright, small-scale cloud spots–only a few tens of kilometers across–representative of convective cloud systems. Across the top of this image stretch several long, linear, wavelike features that may mark the northernmost east-flowing jet in Saturn’s atmosphere.
In this orange-and-violet-image composite, the smallest features visible are about 16 km. (10 mi.) across.
This Voyager 2 mosaic of Enceladus was made from images taken through the clear, violet and green filters Aug. 25, 1981, from a distance of 119,000 kilometers (74,000 miles).
In many ways, the surface of this satellite of Saturn resembles that of Jupiter’s Galilean satellite Ganymede. Enceladus, however, is only one-tenth Ganymede’s size. Some regions of Enceladus show impact craters up to 35 kilometers (22 miles) in diameter, whereas other areas are smooth and uncratered. Linear sets of grooves tens of kilometers long traverse the surface and are probably faults resulting from deformation of the crust. The uncratered regions are geologically young and suggest that Enceladus has experienced a period of relatively recent internal melting. The rims of several craters near the lower center of the picture have been flooded by the smooth terrain. The satellite is about 500 kilometers (310 miles) in diameter and has the brightest and whitest surface of any of Saturn’s satellites.
Features as small as 2 kilometers (1.2 miles) are visible in this highest-resolution view of Enceladus
Voyager 2 obtained this image of Tethys on Aug. 25, when the spacecraft was 594,000 kilometers (368,000 miles) from this satellite of Saturn. This photograph was compiled from images taken through the violet, clear and green filters of Voyager’s narrow-angle camera. Tethys shows two distinct types of terrain–bright, densely cratered regions; and relatively dark, lightly cratered planes that extend in a broad belt across the satellite. The densely cratered terrain is believed to be part of the ancient crust of the satellite; the lightly cratered planes are thought to have been formed later by internal processes. Also clearly seen is a trough that runs parallel to the terminator (the day-night boundary, seen at right). This trough is an extension of the huge canyon system Voyager 1 saw last fall. This system extends nearly two-thirds the distance around Tethys.
This Voyager 2 photograph of Titan, taken Aug. 23 from a range of 2.3 million kilometers (1.4 million miles), shows some detail in the cloud systems on this Saturnian moon.
The southern hemisphere appears lighter in contrast, a well-defined band is seen near the equator, and a dark collar is evident at the north pole. All these bands are associated with cloud circulation in Titan’s atmosphere. The extended haze, composed of submicron-size particles, is seen clearly around the satellite’s limb.
This image was composed from blue, green and violet frames.
This Voyager 2 narrow-angle camera image of Titan was taken through the Clear filter from a distance of 0.9 million km on 25 August 1981. With a phase angle of 155 degrees, the thick atmosphere can be seen illuminated completely around the disk. A distinct upper haze layer is present over much of the circumference of the disk.
August 22, 1981 – Saturn’s outermost large moon, Iapetus, has a bright, heavily cratered icy terrain and a dark terrain, as shown in this Voyager 2 image taken on August 22, 1981. Amazingly, the dark material covers precisely the side of Iapetus that leads in the direction of orbital motion around Saturn (except for the poles), whereas the bright material occurs on the trailing hemisphere and at the poles. The bright terrain is made of dirty ice, and the dark terrain is surfaced by carbonaceous molecules, according to measurements made with Earth-based telescopes. Iapetus’ dark hemisphere has been likened to tar or asphalt and is so dark that no details within this terrain were visible to Voyager 2. The bright icy hemisphere, likened to dirty snow, shows many large impact craters. The closest approach by Voyager 2 to Iapetus was a relatively distant 600,000 miles, so that our best images, such as this, have a resolution of about 12 miles. The dark material is made of organic substances, probably including poisonous cyano compounds such as frozen hydrogen cyanide polymers. Though we know a little about the dark terrain’s chemical nature, we do not understand its origin. Two theories have been developed, but neither is fully satisfactory–(1) the dark material may be organic dust knocked off the small neighboring satellite Phoebe and “painted” onto the leading side of Iapetus as the dust spirals toward Saturn and Iapetus hurtles through the tenuous dust cloud, or (2) the dark material may be made of icy-cold carbonaceous “cryovolcanic” lavas that were erupted from Iapetus’ interior and then blackened by solar radiation, charged particles, and cosmic rays. A determination of the actual cause, as well as discovery of any other geologic features smaller than 12 miles across, awaits the Cassini Saturn orbiter to arrive in 2004
22 August 1981 – Voyager 2 obtained this high-resolution picture of Saturn’s rings Aug. 22, 1981, when the spacecraft was 4 million kilometers (2.5 million miles) away. Evident here are the numerous “spoke” features, in the B-ring; their very sharp, narrow appearance suggests short formation times. Scientists think electromagnetic forces are responsible in some way for these features, but no detailed theory has been worked out. Pictures such as this and analyses of Voyager 2’s spoke movies may reveal more clues about the origins of these complex structures
The fly-by of Saturn almost ended Voyagers 2 mission.
The camera platform used by the spacecraft locked up, but engineers on the ground were able to remotely fix the problem which had been caused by the overuse (temporarily depleted the system’s lubricant)
Voyager 2 was given the go-ahead to explore the Uranian system.
A first look at the Uranian system
The closest approach to Uranus occurred on January 24, 1986, when Voyager 2 came within 81,500 kilometres (50,600 mi) of the planet’s cloud tops.
The fly-by resulted in the discovery of the moons Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Perdita and Puck.
22 January 1986 – Voyager 2 picture of Uranus’ rings taken on January 22, 1986, from a distance of 2.52 million kilometers. Nine rings are visible in this image, a 15-second exposure through a clear filter. The most prominent and outermost of the nine, called epsilon, is seen at top. The next three in toward Uranus — called delta, gamma and eta — are much fainter and more narrow than the epsilon ring. Then come the beta and alpha rings and finally the innermost grouping, known simply as the 4, 5 and 6 rings. The last three are very faint and are at the limit of detection for the Voyager camera. The bright dots are imperfections on the camera detector. The resolution scale is approximately 50 km (30 mi).
16 December 1986 – An image of the planet Uranus taken by the spacecraft Voyager 2
This view of Uranus was recorded by Voyager 2 on Jan 25, 1986, as the spacecraft left the planet behind and set forth on the cruise to Neptune Voyager was 1 million kilometers (about 600,000 miles) from Uranus when it acquired this wide-angle view. The picture — a color composite of blue, green and orange frames — has a resolution of 140 km (90 mi). The thin crescent of Uranus is seen here at an angle of 153 degrees between the spacecraft, the planet and the Sun. Even at this extreme angle, Uranus retains the pale blue-green color seen by ground-based astronomers and recorded by Voyager during its historic encounter. This color results from the presence of methane in Uranus’ atmosphere; the gas absorbs red wavelengths of light, leaving the predominant hue seen here. The tendency for the crescent to become white at the extreme edge is caused by the presence of a high-altitude haze Voyager 2 — having encountered Jupiter in 1979, Saturn in 1981 and Uranus in 1986 — will proceed on its journey to Neptune. Closest approach is scheduled for Aug 24, 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.
January 24, 1986 – Miranda reveals a complex geologic history in this view, acquired by Voyager 2 on January 24, 1986, around its close approach to the Uranian moon. At least three terrain types of different age and geologic style are evident at this resolution of about 700 meters (2,300 feet). Visible in this clear-filter, narrow-angle image are, from left: (1) an apparently ancient, cratered terrain consisting of rolling, subdued hills and degraded medium-sized craters (2) a grooved terrain with linear valleys and ridges developed at the expense of, or replacing, the first terrain type: and (3) a complex terrain seen along the terminator, in which intersecting curvilinear ridges and troughs are abruptly truncated by the linear, grooved terrain. Voyager scientists believe this third terrain type is intermediate in age between the first two.
This picture is part of the highest-resolution Voyager 2 imaging sequence of Ariel, a moon of Uranus about 1,300 kilometers (800 miles) in diameter. The clear-filter, narrow-angle image was taken Jan. 24, 1986, from a distance of 130,000 km (80,000 mi). The complexity of Ariel’s surface indicates that a variety of geologic processes have occurred. The numerous craters, for example, are indications of an old surface bombarded by meteoroids over a long period. Also conspicuous at this resolution, about 2.4 km (1.5 mi), are linear grooves (evidence of tectonic activity that has broken up the surface) and smooth patches (indicative of deposition of material).
24 January 1986 – This high-resolution color composite of Titania was made from Voyager 2 images taken Jan. 24, 1986, as the spacecraft neared its closest approach to Uranus. Voyager’s narrow-angle camera acquired this image of Titania, one of the large moons of Uranus, through the violet and clear filters. The spacecraft was about 500,000 kilometers (300,000 miles) away; the picture shows details about 9 km (6 mi) in size. Titania has a diameter of about 1,600 km (1,000 mi). In addition to many scars due to impacts, Titania displays evidence of other geologic activity at some point in its history. The large, trenchlike feature near the terminator (day-night boundary) at middle right suggests at least one episode of tectonic activity. Another, basinlike structure near the upper right is evidence of an ancient period of heavy impact activity. The neutral gray color of Titania is characteristic of the Uranian satellites as a whole. The Voyager project is managed for NASA by the Jet Propulsion Laboratory
The southern hemisphere of Umbriel displays heavy cratering in this Voyager 2 image, taken Jan. 24, 1986, from a distance of 557,000 kilometers (346,000 miles). This frame, taken through the clear-filter of Voyager’s narrow-angle camera, is the most detailed image of Umbriel, with a resolution of about 10 km (6 mi). Umbriel is the darkest of Uranus’ larger moons and the one that appears to have experienced the lowest level of geological activity. It has a diameter of about 1,200 km (750 mi) and reflects only 16 percent of the light striking its surface; in the latter respect, Umbriel is similar to lunar highland areas. Umbriel is heavily cratered but lacks the numerous bright ray craters seen on the other large Uranian satellites; this results in a relatively uniform surface albedo (reflectivity). The prominent crater on the terminator (upper right) is about 110 km (70 mi) across and has a bright central peak. The strangest feature in this image (at top) is a curious bright ring, the most reflective area seen on Umbriel. The ring is about 140 km (90 miles) in diameter and lies near the satellite’s equator. The nature of the ring is not known, although it might be a frost deposit, perhaps associated with an impact crater. Spots against the black background are due to ‘noise’ in the data. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.
February 1986 – A reprojected view of Oberon
Last Official Stop – Neptune
Voyager 2’s closest approach to Neptune occurred on August 25, 1989.
This was the last planet of the Solar System 2 which the probes would visit. The Chief Project Scientist, his staff members, and the flight controllers decided to also perform a close fly-by of Triton.
Voyager 2 discovered the “Great Dark Spot”, which has since disappeared, according to observations by the Hubble Space Telescope. It was hypothesized to be a hole in the visible cloud deck of Neptune.
The decision in 2006 by the International Astronomical Union to reclassify Pluto as a “dwarf planet” means that the flyby of Neptune by Voyager 2 in 1989 became the point when every known planet in the Solar System had been visited at least once by a space probe.
Two 591-second exposures of the rings of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera on Aug. 26, 1989 from a distance of 280,000 kilometers (175,000 miles).
August 1989 – This picture of Neptune was produced from the last whole planet images taken through the green and orange filters on the Voyager 2 narrow angle camera. The images were taken at a range of 4.4 million miles from the planet, 4 days and 20 hours before closest approach in August 1989. The picture shows the Great Dark Spot and its companion bright smudge; on the west limb the fast moving bright feature called Scooter and the little dark spot are visible. These clouds were seen to persist for as long as Voyager’s cameras could resolve them. North of these, a bright cloud band similar to the south polar streak may be seen.
28 August 1989 – This dramatic view of the crescents of Neptune and Triton was acquired by Voyager 2 approximately 3 days, 6 and one-half hours after its closest approach to Neptune (north is to the right). The spacecraft is now plunging southward at an angle of 48 degrees to the plane of the ecliptic. This direction, combined with the current season of southern summer in the Neptune system, gives this picture its unique geometry. The spacecraft was at a distance of 4.86 million kilometers (3 million miles) from Neptune when these images were shuttered so the smallest detail discernible is approximately 90 kilometers (56 miles). Color was produced using images taken through the narrow-angle camera’s clear, orange and green filters. Neptune does not appear as blue from this viewpoint because the forward scattering nature of its atmosphere is more important than its absorption of red light at this high phase angle (134 degrees).
Despina as seen by Voyager 2. There is significant horizontal smearing due to the combination of long exposure needed at this distance from the Sun, and the rapid relative motion of the moon and Voyager.
These Voyager 2 images of satellite Larissa at a resolution of 4.2 kilometers (2.6 miles) per pixel reveal it to be and irregularly shaped, dark object. The satellite appears to have several craters 30 to 50 kilometers (18.5 to 31 miles) across. The irregular outline suggests that this moon has remained cold and rigid throughout much of its history. It is about 210 by 190 kilometers (130 by 118 miles), about half the size of Proteus. It has a low albedo surface reflecting about 5 percent of the incident light. The Voyager Mission is conducted by JPL for NASA’s Office of Space Science and Applications.
25 August 1989 – Proteus is the second largest moon of Neptune behind the mysterious Triton. Proteus was discovered only in 1989 by the Voyager 2 spacecraft. This is unusual since Neptune has a smaller moon – Nereid – which was discovered 33 years earlier from Earth. The reason Proteus was not discovered sooner is that its surface is very dark and it orbits much closer to Neptune. Proteus has an odd box-like shape and were it even slightly more massive, its own gravity would cause it to reform itself into a sphere.
25 August 1989 – Global colour mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. The color was synthesized by combining high-resolution images taken through orange, violet, and ultraviolet filters; these images were displayed as red, green, and blue images and combined to create this color version. With a radius of 1,350 km (839 mi), about 22% smaller than Earth’s moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn’s giant moon, Titan). Triton has the coldest surface known anywhere in the Solar System (38 K, about -391 degrees Fahrenheit); it is so cold that most of Triton’s nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby. The bluish-green band visible in this image extends all the way around Triton near the equator; it may consist of relatively fresh nitrogen frost deposits. The greenish areas include what is called the cantaloupe terrain, whose origin is unknown, and a set of “cryovolcanic” landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton’s interior.
25 August 1989 -This Voyager 2 high resolution color image, taken 2 hours before closest approach, provides obvious evidence of vertical relief in Neptune’s bright cloud streaks.
These clouds were observed at a latitude of 29 degrees north near Neptune’s east terminator. The linear cloud forms are stretched approximately along lines of constant latitude and the Sun is toward the lower left. The bright sides of the clouds which face the Sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun. These shadows are less distinct at short wavelengths (violet filter) and more distinct at long wavelengths (orange filter). This can be understood if the underlying cloud deck on which the shadow is cast is at a relatively great depth, in which case scattering by molecules in the overlying atmosphere will diffuse light into the shadow.
Because molecules scatter blue light much more efficiently than red light, the shadows will be darkest at the longest (reddest) wavelengths, and will appear blue under white light illumination.
The resolution of this image is 11 kilometers (6.8 miles per pixel) and the range is only 157,000 kilometers (98,000 miles). The width of the cloud streaks range from 50 to 200 kilometers (31 to 124 miles), and their shadow widths range from 30 to 50 kilometers (18 to 31 miles). Cloud heights appear to be of the order of 50 kilometers (31 miles).
Solar to Interstellar
Once its planetary mission was over, Voyager 2 was described as working on an interstellar mission.
February 14, 1990 – The “family portrait” of the Solar System taken by Voyager 1 from a distance of ~6 billion km’s from Earth
It features individual frames of six planets and a partial background indicating their relative positions. The picture is a mosaic of 60 individual frames taken through the Wide Angle and Narrow Angle cameras using the Methane, Violet, Blue, Green, and Clear Filters.
NASA is now using the craft to find out what the Solar System is like beyond the heliosphere and Voyager 2 is currently transmitting scientific data at about 160 bits per second.
Voyager 1 crossed into interstellar space in 2012. Voyager 2 should enter interstellar space in late 2019 or early 2020.
Voyager 2 is not headed toward any particular star, but in ~40,000 years it should pass 1.7 light-years from the star Ross 248. She is expected to keep transmitting weak radio messages until at least 2025, over 48 years after her launch. | 0.813679 | 3.211166 |
In late August 1922 a group of astronomers, naval men, and Aboriginal stockmen began the arduous task of unloading their complicated scientific equipment and stores from boats onto a deserted beach on the coast of Western Australia. The shallow nature of the approach meant the boats were anchored three or four miles from the high-water line and the stores, after being brought to shore, were then transported by donkey wagons to the observation site at Wallal. This was no ordinary expedition and its members knew the eyes of the world were on them waiting to see if they would be the ones to finally prove Einstein’s controversial ‘Theory of General Relativity‘.
To do this they would have to photograph the light from stars bending around the sun and then measure their placement extremely accurately. At stake was the whole concept of universe as envisaged by Sir Isaac Newton over 250 years before. Everyone involved in the project was well aware of how difficult this task was and that they were only one of eight other astronomical expeditions who were also setting up their equipment at sites across Australia. The largest group of observers, based near the Wallal post and telegraph station consisted of three international parties, the Lick Observatory party, under the direction of W. W. Campbell, a group from the University of Toronto, under C. A. Chant and the Indian expedition supervised by J. Evershed. In addition Australia provided a fourth group from the Perth Observatory. They were directed Mr. Nossiter and included Mr. Nunn, Mr. Matthews, Mr. Dwyer and Mr. Yates. On top of this were four others set up on the east coast under the direction of the Sydney Observatory and W. E.Cooke
All this preparation was for the solar eclipse predicted on 22 September 1922 and the hope they would be the ones to resolve the scientific problem Einstein had set in train 17 years previously. In 1905 Einstein (then an unknown patent clerk) had published four groundbreaking scientific papers in what is commonly referred to as his ‘miracle year’. While these included his famous equation E=Mc2 which determined how energy became matter and matter in turn became energy, it also included a mind-blowing paper describing how the fabric of space and time are woven together; this paper he titled ‘The Special Theory of Relativity’.
This radical new concept had come to him in Berne while he was riding in a bus and looking back at the local town clock. As he describes it a ‘storm broke in my mind’ as he imagined what would happen if the bus was travelling at the speed of light. If this was the case then the light from the clock couldn’t catch up with the bus and thus time would appear to stop. For Einstein this implied that space and time were one and the same and were in fact a flexible fabric he labelled space/time.
There was no instant acclaim for his theories but he did have an important supporter, Max Planck, one of the foremost physicists of the day. As a result of discussions with other scientists Einstein started to write a new article on special relativity in 1907 but realised his original concept was limited as it only dealt with objects moving in one direction and at one speed. Clearly this was not the way things work in the real world and so he rewrote his paper taking into account gravity calling this one the Theory of General Relativity.
The problem Einstein was addressing was this, if an apple falls we traditionally say a mysterious force, which Newton called gravity, is pulling it down. But Einstein knew from his working with physics that objects usually moved if they were pushed and instead he posited the idea that there was no such thing as gravitational pull. Instead he suggested that the earth has curved space around it and it is this that is keeping our feet firmly planted on the ground by pushing on the atmosphere and all the objects on the earth. In the case of the earth going around the sun most people would say it was the gravitational force of the sun pulling the earth around it. Instead Einstein suggested it was the gravitation of the sun distorting the space around the earth and that this was the force pushing the earth around the sun.
But while Einstein could propose this new theory of the universe and of gravity using maths and physics it was another thing to prove it by experiment. Thus his ‘General Theory of Relativity’, unlike his photon, energy and mass equations, remained an interesting but unproven theory in the eyes of the scientific community. He needed to find a way to measure the effects of gravity on the straight beams thrown from a light source. If he could show this he could also prove his theory that space/time was flexible. But where could he possibly find something with enough gravity to bend light.
It was then that he came up with a great idea, what about using light from distant stars and the sun which has around 300,000 times more mass than the earth. Einstein hypothesised that if his theory was correct light from a star would bend as it passed through the sun’s gravitational field. The problem was that the sun was too bright to see this happen – UNLESS THERE WERE A SOLAR ECLIPSE!
When the sun’s rays are blocked out by the moon during a solar eclipse we can see the stars around it. And if his theory was correct these should appear to be slightly out of place from their actual positions as measured in the night sky because the light they emitted was bent as it went past the sun.
Of course to do this Einstein needed someone to photograph the event. So in 1912 he published his thoughts on this experiment and appealed to astrophysicists to take up his challenge. Instead of a chorus of willing voices his challenge was initially met with silence. Except for an assistant astronomer at the Berlin Observatory Erwin Finlay-Freundlich who although still in his early 20s saw Einstein’s call as an opportunity to make his name. A total solar eclipse is only visible over a small area of the earth and the next one was on the 21 of August 1914, and would be best seen from the Crimea in Russia.
After being refused by his boss Freundlich wrote to William Wallace Campbell, a pioneer in solar eclipse photography, at the Lick Observatory in USA. He asked him to come to Russia and prove or disprove Einstein’s theory. As a result Freundlich and Campbell both made their way to Russia in 1914 with Freundlich setting up his instruments in the Crimea while Campbell sets his up near to Kiev. Unfortunately for everyone involved the political events unfolding in the background and bad weather would destroy their chances for capturing the event.
On June 28 1914 Archduke Franz Ferdinand of Austria was assassinated and Germany declared war on Russia. As a result Russian officers seized Freundlich’s equipment, (in fact he and his assistants are held as POWs for a number of months afterwards). Campbell as an American was allowed to continue his project but unfortunately clouds obscure the eclipse and he was not able to take good enough photographs of the event.
Einstein is initially devastated by the failure but it turns out that these particular clouds had a silver lining. In the wake of the eclipse fiasco and while locked down in Germany by the war Einstein begins going over his initial calculations and finds he has made some fundamental errors. He now recognises that if the 1914 eclipse expedition had been a success they would have used these calculations, and they would have been wrong and discredited his theory. So Einstein sets about redoing his calculations and finally on 25 November 1915 he presents his General Theory of Relativity to the Prussian Academy of Sciences. In 1916 he finally submits his paper, with correct calculations, and a completely different view of the universe. But while many accept to work the scientific community remains divided, particularly given the theory had yet to be proven.
Help came in the form of an Englishman, Arthur Stanley Eddington. He was not only an astronomer at Cambridge University, he was also a conscientious objector and saw in Einstein a fellow scientist opposed to the war. In February 1916 he received a package from a friend in Holland which contained a copy of Einstein’s theory translated into English. Eddington was astounded, and decided to see if they could prove, or disprove, Einstein’s theory by making observations at the next solar eclipse, on 8 June, 1918.
The limited viewing window for this eclipse made the United States a prime site for setting up his equipment but unfortunately the war made it difficult for Eddington to travel there. Instead he contacted Campbell at the Lick Observatory and asked if he would be able to try one more time to photograph the eclipse. Campbell agrees but his equipment had been confiscated by the Russians in 1914 and this forced him to improvise from existing equipment lying around at the Lick Observatory. Thus it turned out that although Campbell had the solar eclipse observations all to himself he was forced to take his photographs using sub-standard equipment, and this was to have some serious implications for this story.
On Saturday June the 8 the clouds parted in time to allow Campbell to take some photographic plates which he gave to Heber Curtis to make the measurements from. So after doing his measurements Curtis gives Campbell the news that he believes the stars are actually in the same position and thus Einstein is wrong. However this is a momentous decision and Campbell, realising his reputation could be at stake holds off announcing the results as he is worried his sub-standard equipment may have affected the results. Instead he asks Curtis to re-do his measurements.
On the 11 November 1918 World War One ended. This took away the restrictions on travel which had been holding back astronomers and as a result tEddington was free to travel to observe the next solar eclipse. The event happened on May 29 1919 and this time Eddington carved his way through the jungle on the island of Principe (off the west coast of Africa) to set up his equipment. He spent a month there building the telescope but as luck would have it on the day clouds affected the view forcing Eddington to take his photographs in quick succession hoping all the time they caught the moment of full eclipse when the stars would be most visible.
Eddington was so concerned about the results that he started measuring the plates then and there while still in the middle of the jungle. Many proved worthless but a few showed enough stars visible for him to make some preliminary results. And unlike Campbell’s his confirmed Einstein’s theory.
In a strange twist of fate Eddington’s cable confirming Einstein’s theory arrives in London at the same time as Campbell physically arrives to present his results, disproving the theory. As a result Campbell gets nervous again about the quality of the equipment and Curtis’s measurements and decides to again delay the presentation of his negative results to London’s Royal Astronomical Society. Instead it is Eddington who on 6 November 1919 presents his positive results and word of this momentous decision spreads quickly spreads around the world. Very quickly Einstein becomes the face of genius and a world renown scientist – BUT still there many sceptics in the scientific community who questioned Eddington’s results and a backlash began, helped in part by anti-German sentiment in the wake of War.
It quickly becomes clear that another expedition needed to be organised to settle the issue once and for all. The next scheduled solar eclipse was on the 21 September 1922, and would be visible over the continent of Australia. By now Einstein was 42 years old, a household name, and yet his theory of relativity published eight years previously had yet be confirmed to the satisfaction of the scientific community. It seemed that Australia would be the place where the controversy would be settled once and for all and so it is no surprise to find the event generated huge media and scientific interest.
So we come full circle back to the astronomers loading their donkeys on a remote beach in Western Australia with the world’s gaze upon them as they prepared their equipment to photograph the solar eclipse.
This time the weather and the equipment would provide optimal conditions for Campbell and his group at Wallal. In this photograph we can see the polar axis set up to hold the spectrographs, the Floyd telescope and the two short focus camera. The woman on the left is probably the wife of W. W. Campbell as during the eclipse she was responsible for the exposures of the solar corona by means of the Floyd camera.
Also in Campbell’s arsenal was a specially made 1.52 metre (5 foot) solar telescope camera named fittingly the ‘Einstein camera’. campbell himself directed this camera but looking after the changing of the glass plates was left to two Australian naval men, Messers. Rhoades and Kenny, under Commander Quick. It is quite possible that these are the two men seen here.
Finally amongst the Lick Observatory’s 35 tons of stores and equipment was a forty foot coronal camera which required supporting towers 36 feet high. This photograph of the eclipse during total phase was taken by Dr. Adams using this astrograph and it was the measurements from these plates that finally led to H. Spencer Jones of Greenwich Observatory announcing in May 1923, … as a result of the observations secured last September, together with the two previous confirmations from the 1919 eclipse, leave little room for doubting that the deflection deduced from Einstein’s theory is the correct one.
After years of controversy, a World War, and several failed eclipse expeditions, Einstein’s Theory of General relativity was finally proved, and science’s understanding of how the world around us worked was completely overturned.
Post by Geoff Barker, 2012
Campbell, W. W., ‘The Total Eclipse of the Sun, September 21, 1922’, Astronomical Society of the Pacific, provided by the NASA Astrophysics Data Sy
stem, May 2008
Evershed, J., ‘Report of the Indian Eclipse Expedition to Wallal, West Australia’, Kodaikanal Observatory, Bulletin, number LXI
Spencer Jones, H., ‘The Total Solar Eclipse of 1922 September 21’, The Observatory, May 1923
Thomas Levenson, Einstein in Berlin
Jefferson Crelinsten, Einstein’s Jury
Walter Isaacson, Einstein; his life and his Universe
Amir D Aczel, God’s Equation
Michio Kaku, Physics of the Impossible | 0.829094 | 3.193801 |
Presentation on theme: "Dark Matter. Either dark matter exists or we do not understand how gravity operates across galaxy-sized distances. We have many reasons to have confidence."— Presentation transcript:
Either dark matter exists or we do not understand how gravity operates across galaxy-sized distances. We have many reasons to have confidence in our understanding of gravity, so the majority of astronomers believe that dark matter is real.
Measurements of the mass and luminosity of galaxies and galaxy clusters indicate that they contain far more mass in dark matter than in stars.
Despite the fact that dark matter is by far the most abundant form of mass in the Universe, we still have little idea what it is.
MACHOS = Massive Compact Halo Objects Trillions of faint red stars, brown dwarfs and Jupiter-sized objects left over from the formation of the Milky Way still roam our galaxies halo, providing much of its mass. Brown dwarfs are “failed stars” that did not have enough mass to sustain nuclear fusion (and thus be on the Main Sequence). WIMPS = Weakly Interacting Massive Particles Unusual particles that have no electrical charge and thus cannot emit any kind of electromagnetic energy. Regions of density can grow into galaxies because the extra gravity in these regions draws matter together even while the rest of the universe expands. Detailed calculations show that, to explain that galaxies formed within a few billion years of the Big Bang, the density enhancements at the end of the “era of nuclei” must have been extremely significant. Perhaps WIMPS are particles not yet discovered??
Superclusters, walls and voids much larger than clusters of galaxies extend many millions of light years across the Universe. Each of these structures probably began as a very slight enhancement in the density of dark matter early in time, and these enormous structures are still in the process of forming.
Gravity can bend light, allowing huge clusters of galaxies to act as telescopes, and distorting images of background galaxies into elongated strands. Almost all of the bright objects in this Hubble Space Telescope image are galaxies in the cluster known as Abell 2218. The cluster is so massive and so compact that its gravity bends and focuses the light from galaxies that lie behind it. As a result, multiple images of these background galaxies are distorted into long faint arcs -- a simple lensing effect analogous to viewing distant street lamps through a glass of wine. The cluster of galaxies Abell 2218 is itself about three billion light-yearsaway in the northern constellation of the Dragon (Draco). The power of this massive cluster telescope has allowed astronomers to detect a galaxy at the distant redshift of 5.58. Hubble Space Telescopecluster gravity bends and focuses the lightgalaxies that liemultiple imageslensing effectwinecluster of galaxieslight-yearsDracoallowed astronomersredshift
For many years it was thought that all the mass of the universe was present in a form that we can detect due to its emission of electromagnet radiation. Since the 1930’s evidence has mounted that this assumption was incorrect. This change of thought was based on the observations that galaxies in clusters had orbits that could not be accounted for by the amount of luminous matter. Studies of the rotation of galaxies also indicated the presence of more matter than that observed. This lead to what is called the dark matter (DM) problem. Today we know that only 4% of matter in the universe is in a form that emits electromagnet radiation (Carrol & Ostlie 2007, 1232). Many studies have been initiated to find exactly what this matter is and how it is distributed.
DEFINITION: Critical density – the precise density marking the dividing line between between external expansion and eventual collapse. If the matter density of U. > CD, then the collective gravity of all of it’s matter will eventually halt the U. expansion and reverse it! The galaxies will come crashing back together, and the entire U. will end in a fiery “Big Crunch!” If the matter density of U. = CD, then the collective gravity of all of it’s matter is exactly the amount needed to balance the expansion. In this case, the U. will never collapse but will expand more and more slowly as time progresses. If the matter density of U. < CD, then the collective gravity of all matter cannot halt the expansion. The U. will keep expanding forever with little change in its rate of expansion. This is often referred to as an “Open Universe.” THE FOUR SCENARIOS FOR THE FATE OF THE UNIVERSE
Because observations of distant supernovae suggest that a repulsive force opposes gravity on very large scales, astronomers are now seriously considering a fourth possibility: If repulsive forces cause the expansion of the U. to accelerate with time, then we live in an accelerating universe In this case, galaxies will recede from one another increasingly faster and it will become cold and dark more quickly than a coasting universe.
In a black hole the force of gravity ( attraction ) is so strong, that all matters are attracted. The space curvature is so strong that even light cannot escape any longer. Thus, the diameter of a sun for e.g. 1.4 million kilometers are shortened to 6 kilometers and the matter are pressed together.attraction | 0.832012 | 4.072715 |
Universities Space Research Association |
Lunar & Planetary Institute | 2020 May 11
Several recent observations of Mars have hinted that it might presently harbor liquid water, a requirement for life as we know it. However, in a new paper in Nature Astronomy, a team of researchers have shown that stable liquids on present-day Mars are not suitable environments for known terrestrial organisms. ...
Due to Mars' low temperatures and extremely dry conditions, should a liquid water droplet be placed on Mars, it would nearly instantaneously either freeze, boil, or evaporate away. That is unless that droplet had dissolved salts in it. Such salt water, or brine, would have a lower freezing temperature and would evaporate at a slower rate than pure liquid water. Because salts are found across Mars, brines could form there. “We saw evidence of brine droplets forming on the strut of the Phoenix lander, where they would have formed under the warmed spacecraft environment”, noted Dr. Germán Martínez, a USRA scientist at the LPI, co-investigator of the Mars 2020 Perseverance rover, and co-author of the study.
Further, some Martian salts can undergo a process called deliquescence. When a salt is at the right temperature and relative humidity, it will take in water from the atmosphere to become a salty liquid. “We've been conducting experiments under Martian simulated conditions at the University of Arkansas for many years now to study these types of reactions. Using what we've learned in the lab, we can predict what will likely happen on Mars,” says Dr. Vincent Chevrier, co-author of the investigation at the University of Arkansas.
The team of researchers used laboratory measurements of Mars-relevant salts along with Martian climate information from both planetary models and spacecraft measurements. They developed a model to predict where, when, and for how long brines are stable on the surface and shallow subsurface of Mars. They found that brine formation from some salts can lead to liquid water over 40% of the Martian surface but only seasonally, during 2% of the Martian year. ...
SwRI scientist modeled Mars climate to understand habitability
Southwest Research Institute | 2020 May 11
Salty water everywhere, nor any drop to drink!
Astronomy | Nature Research | 2020 May 11
Distribution and habitability of (meta)stable brines on present-day Mars ~ Edgard G. Rivera-Valentín et al
- Nature Astronomy (online 11 May 2020) DOI: 10.1038/s41550-020-1080-9 | 0.880607 | 3.807817 |
4 min readAstronomers Use Slime Mold Model to Reveal Dark Threads of Cosmic Web
Santa Cruz, CA — A computational approach inspired by the growth patterns of a bright yellow slime mold has enabled a team of astronomers and computer scientists at UC Santa Cruz to trace the filaments of the cosmic web that connects galaxies throughout the universe.
Their results, published March 10 in Astrophysical Journal Letters, provide the first conclusive association between the diffuse gas in the space between galaxies and the large-scale structure of the cosmic web predicted by cosmological theory.
According to the prevailing theory, as the universe evolved after the big bang, matter became distributed in a web-like network of interconnected filaments separated by huge voids. Luminous galaxies full of stars and planets formed at the intersections and densest regions of the filaments where matter is most concentrated. The filaments of diffuse hydrogen gas extending between the galaxies are largely invisible, although astronomers have managed to glimpse parts of them.
None of which seems to have anything to do with a lowly slime mold called Physarum polycephalum, typically found growing on decaying logs and leaf litter on the forest floor and sometimes forming spongy yellow masses on lawns. But Physarum has a long history of surprising scientists with its ability to create optimal distribution networks and solve computationally difficult spatial organization problems. In one famous experiment, a slime mold replicated the layout of Japan’s rail system by connecting food sources arranged to represent the cities around Tokyo.
Joe Burchett, a postdoctoral researcher in astronomy and astrophysics at UC Santa Cruz, had been looking for a way to visualize the cosmic web on a large scale, but he was skeptical when Oskar Elek, a postdoctoral researcher in computational media, suggested using a Physarum-based algorithm. After all, completely different forces shape the cosmic web and the growth of a slime mold.
But Elek, who has always been fascinated by patterns in nature, had been impressed by the Physarum “biofabrications” of Berlin-based artist Sage Jenson. Starting with the 2-dimensional Physarum model Jenson used (originally developed in 2010 by Jeff Jones), Elek and a friend (programmer Jan Ivanecky) extended it to three dimensions and made additional modifications to create a new algorithm they called the Monte Carlo Physarum Machine.
Burchett gave Elek a dataset of 37,000 galaxies from the Sloan Digital Sky Survey (SDSS), and when they applied the new algorithm to it, the result was a pretty convincing representation of the cosmic web.
“That was kind of a Eureka moment, and I became convinced that the slime mold model was the way forward for us,” Burchett said. “It’s somewhat coincidental that it works, but not entirely. A slime mold creates an optimized transport network, finding the most efficient pathways to connect food sources. In the cosmic web, the growth of structure produces networks that are also, in a sense, optimal. The underlying processes are different, but they produce mathematical structures that are analogous.”
Elek also noted that “the model we developed is several layers of abstraction away from its original inspiration.”
Of course, a strong visual resemblance of the model results to the expected structure of the cosmic web doesn’t prove anything. The researchers performed a variety of tests to validate the model as they continued to refine it.
Until now, the best representations of the cosmic web have emerged from computer simulations of the evolution of structure in the universe, showing the distribution of dark matter on large scales, including the massive dark matter halos in which galaxies form and the filaments that connect them. Dark matter is invisible, but it makes up about 85 percent of the matter in the universe, and gravity causes ordinary matter to follow the distribution of dark matter.
Burchett’s team used data from the Bolshoi-Planck cosmological simulation–developed by Joel Primack, professor emeritus of physics at UC Santa Cruz, and others–to test the Monte Carlo Physarum Machine. After extracting a catalog of dark matter halos from the simulation, they ran the algorithm to reconstruct the web of filaments connecting them. When they compared the outcome of the algorithm to the original simulation, they found a tight correlation. The slime mold model essentially replicated the web of filaments in the dark matter simulation, and the researchers were able to use the simulation to fine-tune the parameters of their model.
“Starting with 450,000 dark matter halos, we can get an almost perfect fit to the density fields in the cosmological simulation,” Elek said.
Burchett also performed what he called a “sanity check,” comparing the observed properties of the SDSS galaxies with the gas densities in the intergalactic medium predicted by the slime mold model. Star formation activity in a galaxy should correlate with the density of its galactic environment, and Burchett was relieved to see the expected correlations.
Now the team had a predicted structure for the cosmic web connecting the 37,000 SDSS galaxies, which they could test against astronomical observations. For this, they used data from the Hubble Space Telescope’s Cosmic Origins Spectrograph. Intergalactic gas leaves a distinctive absorption signature in the spectrum of light that passes through it, and the sight-lines of hundreds of distant quasars pierce the volume of space occupied by the SDSS galaxies.
“We knew where the filaments of the cosmic web should be thanks to the slime mold, so we could go to the archived Hubble spectra for the quasars that probe that space and look for the signatures of the gas,” Burchett explained. “Wherever we saw a filament in our model, the Hubble spectra showed a gas signal, and the signal got stronger toward the middle of filaments where the gas should be denser.”
In the densest regions, however, the signal dropped off. This too matched expectations, he said, because heating of the gas in those regions ionizes the hydrogen, stripping off electrons and eliminating the absorption signature.
“For the first time now, we can quantify the density of the intergalactic medium from the remote outskirts of cosmic web filaments to the hot, dense interiors of galaxy clusters,” Burchett said. “These results not only confirm the structure of the cosmic web predicted by cosmological models, they also give us a way to improve our understanding of galaxy evolution by connecting it with the gas reservoirs out of which galaxies form.”
Burchett and Elek met through coauthor Angus Forbes, an associate professor of computational media and director of the UCSC Creative Coding lab in the Baskin School of Engineering. Burchett and Forbes had begun collaborating after meeting at an open mic night for musicians in Santa Cruz, focusing initially on a data visualization app, which they published last year.
Forbes also introduced Elek to the work of Sage Jenson, not because he thought it would apply to Burchett’s cosmic web project, but because “he knew I was a nature pattern freak,” Elek said.
Coauthor J. Xavier Prochaska, a professor of astronomy and astrophysics at UCSC who has done pioneering work using quasars to probe the structure of the intergalactic medium, said, “This creative technique and its unanticipated success highlight the value of interdisciplinary collaborations, where completely different perspectives and expertise are brought to bear on scientific problems.”
Forbes’ Creative Coding lab combines approaches from media arts, design, and computer science. “I think there can be real opportunities when you integrate the arts into scientific research,” Forbes said. “Creative approaches to modeling and visualizing data can lead to new perspectives that help us make sense of complex systems.”
Article adapted from a University of California Santa Cruz news release.
Publication: Revealing the Dark Threads of the Cosmic Web. Burchett, JN et al. Astrophysical Journal Letters (March 10, 2020): Click here to view. | 0.874734 | 3.872506 |
NASA has successfully smashed two satellites into the dark side of the moon, the space agency has confirmed, naming the new crater after Sally Ride, the first American woman in low Earth orbit. The mission, to crash the spent GRAIL spacecraft and glean some valuable internal structure and composition data about the moon from their demise, culminated in impact at 5:28pm EST and 5:29pm, at a speed of 3,760 mph, though the scale of the crater they created won’t be known until the Lunar Reconnaissance Orbiter catches sight of it in a few weeks time.
The Gravity Recovery and Interior Laboratory (GRAIL) mission saw two satellites, Ebb and Flow, orbit the moon for nearly a year, snapping more than 115,000 images of the moon’s surface. NASA has said the results of GRAIL is the highest-resolution gravity field map of any celestial body; “the scientists tell me it will take years to analyze all the great data they got,” project manager David Lehman said in a statement, “and that is why we came to the moon in the first place.”
However, neither satellite was equipped with sufficient fuel to continue with the scientific mission, and Ebb and Flow’s orbits were decreasing past the point of usefulness. The decision was made to crash both into a specific point on the lunar surface, with the destruction opening up new opportunities for investigating what makes up the crust of the moon.
Even the final fuel burn – intended to deplete the GRAIL satellite’s onboard stores to the bare minimum for the crash – will contribute to NASA’s future missions. The length of time it took for the engines to drain supplies to that minimum will be used to check NASA computer simulations of fuel tank modeling. In the end, Ebb required a 4 minute 3 second burn, while Flow took longer at 5 minutes 7 seconds.
The subsequent crash took place on the southern face of a 1.5 mile tall mountain; the Jet Propulsion Lab team responsible for the GRAIL project estimates that most of the debris will have been buried in shallow craters around the area. Since the site is in the dark side of the moon, no photos or video showing it taking place has been captured. Instead, NASA will wait until the Lunar Reconnaissance Orbiter is nearby to snap some shots from orbit.
NASA’s decision to name the new crater after astronaut Sally Ride follows her death in July this year. Ride was member of the GRAIL mission team, and was the first American woman in space back in 1983. After her time with NASA, Ride established Sally Ride Science, an organization dedicated to promoting science learning among girls, as well as writing a number of science-themed children’s books with partner Tam O’Shaughnessy. | 0.806984 | 3.034637 |
October 2016 – SPACE – A large space rock is going to come fairly close to Earth later tonight. Fortunately, it’s not going to hit Earth, something astronomers are sure of thanks in part to a new tool NASA is developing for detecting potentially dangerous asteroids. The tool is a computer program called Scout, and it’s being tested at NASA Jet Propulsion Laboratory in Pasadena, Calif. Think of Scout as a celestial intruder alert system. It’s constantly scanning data from telescopes to see if there are any reports of so-called Near Earth Objects. If it finds one, it makes a quick calculation of whether Earth is at risk, and instructs other telescopes to make follow-up observations to see if any risk is real.
NASA pays for several telescopes around the planet to scan the skies on a nightly basis, looking for these objects. “The NASA surveys are finding something like at least five asteroids every night,” says astronomer Paul Chodas of JPL. But then the trick is to figure out which new objects might hit Earth. “When a telescope first finds a moving object, all you know is it’s just a dot, moving on the sky,” says Chodas. “You have no information about how far away it is. The more telescopes you get pointed at an object, the more data you get, and the more you’re sure you are how big it is and which way it’s headed. But sometimes you don’t have a lot of time to make those observations. Objects can come close to the Earth shortly after discovery, sometimes one day, two days, even hours in some cases,” says JPL’s Davide Farnocchia. “The main goal of Scout is to speed up the confirmation process.”
The rock whizzing past Earth tonight was discovered on the night of Oct. 25-26 by the NASA-funded Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) on Maui, Hawaii. Within a few hours, preliminary details about the object appeared on a web page maintained by the Minor Planet Center at the Smithsonian Astrophysical Observatory. Scout did a quick analysis of the preliminary details and determined that the object was headed for Earth, but would miss us by about 310,000 miles.
Additional observations by three telescopes, one operated by the Steward Observatory, another called Spacewatch, and a third at the Tenagra Observatories, confirmed the object would miss Earth by a comfortable margin. Astronomers were also able to estimate the size of the object: somewhere between 5 meters and 25 meters across. In case you’re interested, full details about the object’s trajectory can be found here. Scout is still in the testing phase. It should become fully operational later this year. Now Scout is mainly dealing with smallish, very nearby objects. Complementing Scout is another system which is already operational called Sentry.
Sentry’s job is to identify objects large enough to wipe out a major city that might hit Earth in the next hundred years. “Our goal right now is to find 90 percent of the 140 meter asteroids and larger,” says Chodas, but right now he estimates they’re only able to find 25-30 percent of the estimated population of objects that size. That number should get better when a new telescope being built in Chile called the Large Synoptic Survey Telescope comes on line. NASA is also considering a space telescope devoted to searching for asteroids. OK, so let’s say you find one of these monster rocks heading for Earth. What then? Astronomer Ed Lu says there is something you can do. He’s CEO of an organization called B612. It’s devoted to dealing with asteroid threats.
“If you know well in advance, and by well in advance I mean 10 years, 20 years, 30 years in advance which is something we can do, “ says Lu, “then you can divert such an asteroid by just giving it a tiny nudge when it’s many billions of miles from hitting the Earth.” NASA and the European Space Agency are developing a mission to practice doing just that. Lu says in the last decade people who should worry about such things have begun to make concrete plans for dealing with dangerous asteroids. “I believe in the next 10 to 15 years we’ll actually be at the point where we as humans can say, ‘Hey, we’re safe from this danger of large asteroids hitting the Earth,’” he says. In the meantime, we’ll just have to hope that luck is on our side. –NPR | 0.81623 | 3.433114 |
Astronomers discover distant building site of giant planetary system
Sen—A team of Japanese astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found evidence of a planetary system being formed a long way from its star -- about five times further out than Neptune is from the Sun.
The star, labelled HD142527, lives in the constellation of Lupus, the Wolf. The research team, led by astronomers at Osaka University and Ibaraki University, used ALMA to observe the ring of cosmic dust -- the building blocks of planets -- swarming around the star. After measuring the densest part of the dust ring the researchers concluded it was highly possible that planets are now being formed.
Of particular interest to students of planet formation was the location of the planet forming region which is much further away from the star than previously discovered protoplanetary disks. Though exoplanets have been found orbiting their stars at greater distances than Neptune, the planet formation process is yet to be fully understood.
Planet formation takes place when dust particles in a disk collide and coalesce together to form protoplanets, which are the cores of planets. Some continue to clump together with more dust to form rocky worlds, whilst other protoplanets capture gas particles to form gas giants. Prior to the teams's findings around HD142527 it was generally assumed that such planet formations occurred much closer to their parent star.
The submillimeter emission from the dust ring showed a non-uniform distribution, with part of the ring much denser than the rest. Misato Fukagawa, leader of the team and an assistant professor at Osaka University, said: "The brightest part in submillimeter wave is located far from the central star, and the distance is comparable to five times the distance between the Sun and the Neptune. I have never seen such a bright knot in such a distant position. This strong submillimeter emission can be interpreted as an indication that large amount of material is accumulated in this position. When a sufficient amount of material is accumulated, planets or comets can be formed here. To investigate this possibility, we measured the amount of material."
Dust and gas disk around HD142527. The dust and gas distributions observed by ALMA are shown in red and green, respectively. Near-infrared image taken by the NAOJ Subaru Telescope is shown in blue. The circle in the image shows the position of the dust concentration, in which planets are thought to be formed. Credit: ALMA (ESO/NAOJ/NRAO), NAOJ, Fukagawa et al.
The team's research led them to consider that it was highly possible planets are being formed in the dense part of the disk.
"Seeing the site of planet formation directly is one of the most important goals for ALMA" explained Munetake Momose, a team member and a professor at Ibaraki University. "Our observations successfully located a unique candidate in an unexpectedly distant place from the central star. I believe that ALMA will bring us more surprising results."
The researchers are planning further observations with ALMA to measure the amount of gas in the disc in order to determine whether the planets forming are rocky worlds or gas giants. If the dense region has the same amount of gas as is typically found in the Universe (a mass ratio of dust to gas being 1 to 100) then there would be enough gas to form giant gaseous planets several times more massive than Jupiter. If, however, the dense region is a dust trap, an area in the disc of dust where the dust concentration is exceptionally higher than in other parts of the disk, then another possibility would be the formation of rocky worlds like Earth and Mars.
Misato Fukagawa concluded: "Our final goal is to reveal the major physical process which controls the formation of planets. To achieve this goal, it is important to obtain a comprehensive view of the planet formation through observations of many protoplanetary disks."
ALMA is a powerful telescope array located 5,000 meters above sea level on the remote Chajnantor Plateau in the Atacama desert in Chile. The observatory is operated by the European Southern Observatory and other international partners including the US National Science Foundation (NSF), the National Research Council of Canada (NRC) and the National Institute of Natural Sciences (NINS) in Japan. | 0.898481 | 3.926651 |
Ajunior version of the famous Perseid meteor shower thought to have originatedfrom the remains of Halley's Comet will hit its peak over the next week, butthe light of the moon may intrude on the sky show.
Thisupcoming meteor display is known as the Orionids because the meteors seem tofan out from a region to the north of the Orion constellation's secondbrightest star, ruddy Betelgeuse.
Theannual event peaks before sunrise on Thursday (Oct. 21) but several viewingopportunities arise before then for skywatchers in North America. [Where tolook to see the Orionids]
Theshooting stars are created by small bits of space dust— most no larger than sand grains — thought to be left overfrom the famed Halley's Comet, which orbits the sun once every 76 years.
Currently,Orion appears ahead of us in our journey around the sun, and has not completelyrisen above the eastern horizon until after 11 p.m. local daylight time.
Theconstellation is at its best several hours later. At around 5 a.m. –Orion will be highest in the sky toward the south – Orionids typicallyproduce around 20 to 30 meteors per hour under a clear, darksky.
But skywatchers beware: You will be facing a major obstaclein your attempt to observe this year’s Orionid performance. As bad luckwould have it, the moon will turn full on Oct. 23. Bright moonlight outshinesfainter meteors, seriously reducing the number anyone can see.
Thegradual build up to the full moon will hamper – if not outrightprevent – dark-sky observing during the Orionid meteor shower's peak onOct. 21.
TheOrionids are actually already underway, having been active only in a very weakand scattered form since about Oct. 2. But a noticeable upswing in activity isexpected to begin around Oct. 17, leading up to their peak night.
"Orionidmeteors are normally dim and not well seen from urban locations," notes meteor expert, Robert Lunsford, adding that "it is highlysuggested that you find a safe rural location to see the best Orionidactivity."
Damagecontrol for 2010
Withall this as a background, perhaps the best times to look this year will beduring the predawn hours several mornings before the night of full moon.That’s when the constellation Orion (from where the meteors get theirname) will stand high in the northeast sky.
Infact, three "windows" of dark skies will be available between moonsetand the first light of dawn on the mornings of Oct. 18, 19 and 20.
Generallyspeaking, there will be about 150 minutes of completely dark skies available onthe morning of the 18th.This shrinks to about 100 minutes on the 19th, and toabout 50 minutes by the morning of the 20th.
Thisskywatching tableshows prime Orionid meteor shower viewing times for some select U.S. cities.
In the table,all times are a.m. and are local daylight times. "Dawn" is thetime when morning (astronomical) twilight begins. A "Window" isthe number of minutes between the time of moonset and the start of twilight.
For example: When will the sky be dark and moonless for Orionid viewing on the morningof Oct. 20 from Houston?
Answer: There will be a 50-minute period of dark skies beginning at moonset (5:16a.m.) and continuing until dawn breaks (6:06 a.m.).
Perhapsup to a dozen forerunners of the main Orionid display might appear to steak bywithin an hour’s watch on these mornings, particularly on the 20th, themorning before the peak. It might even be worthwhile to try on Thursdaymorning, Oct. 21, although for most places, the moon will not set until justafter the first light of dawn.
Instudying the orbits of many meteor swarms, astronomers have found that theycorrespond closely to the orbits of known comets.
TheOrionids are thought to result from the orbit of Halley's Comet, as some of thedust that has been shed by this famous object intersect earth’s orbitaround the sun during October.
Thereare actually two points along Halley’s path, where it comes relativelynear to our orbit. Another one of these points occurs in early May causing ameteor display from the constellation Aquarius, the Water Carrier.
Thetiny particles that are responsible for the Orionid and Aquarid meteors are– like Halley itself – moving through space in a direction oppositeto that the earth. This results in meteors that ram through ouratmosphere very swiftly at 41 miles (66 km) per second. Of all the meteordisplays, only the November Leonids movefaster.
Afterthe peak, activity will begin to slowly descend, although most of the meteorswill be squelched by the light of the moon. Rates drop back to around five perhour around Oct. 26. The last stragglers usually appear sometime around Nov. 7.
Itis indeed unfortunate that the Moon will likely obliterate most of the Orionidsin the nights following the peak, but the viewing odds will be much betterbefore the break of dawn on those mornings leading up to the peak. Almostcertainly, you should sight at least a few of these offspring of Halley's Cometas they streak across the sky.
Inthe absence of moonlight a single observer might see at least a couple of dozenmeteors per hour on the morning of the peak, a number that sadly can not behoped to be approached in 2010. In fact, it appears that this year, fans of theOrionids will be uttering the same lament that the old Dodger fans in Brooklynused to: "Wait till next year!"
- Images - The Best of Leonid Meteor Shower
- Video: Brilliant Fireball Over New Mexico Caught on Camera
- Lackluster Meteor Shower Sets Stage for Big Show in 2011 | 0.821375 | 3.471667 |
The Unification Epicenter of True Lightworkers
Interstellar dust interacts with the structure of our Galaxy's magnetic field.
Credit: ESA/Planck Collaboration. Acknowledgment: M.-A. Miville-Deschênes, CNRS – Institut d’Astrophysique Spatiale, Université Paris-XI, Orsay, France
Take a deep breath.
That air filling up your lungs, that oxygen pulled into your bloodstream, stoking your metabolic fire, making you possible, is old. Older than you, older than the Earth itself. That oxygen once lived in the heart of a star that is now long dead. That calcium in your bones? That iron in your blood? The same.
Pockets of gas pinch off and catastrophically collapse, in some cases reaching such incredible densities and pressures that nuclear fusion begins deep in the heart of a young system: This is the birth of a star .
The shattered remains of the cloud organize themselves into a disk. The disk spawns planets that cannibalize more material as they grow and compete for space around the new sun. In fits and starts and collisions, and in migrations and bursts of intense radiation, the leftover debris is cleared from the system, leaving a family: a star (maybe two), a few rocky planets, gas giants, asteroids and frozen leftovers in the outskirts.
A solar system is born.
A few new elements breeze into the solar system over the millennia, but by and large, what the solar system was born with is all it has.
The elemental mixture of that primordial gas cloud determines the fate of the system. Not enough silicon? No rocky planets. Just a hint of oxygen? No liquid water on those planets. A bare handful of carbon? Nothing to use to build little critters to swim around in that water.
But how did this solar system's particular mixture of elements get in that gas cloud oh so many billions of years ago in the first place? To tell the truth, I already gave the answer: fusion.
In that newborn sun, and in its heart today, a nuclear fire rages. The crushing weight of the sun's own gravity — layer after endless layer of gas trying to squeeze itself into the center — encourages atomic nuclei to overcome their natural repulsion for each other and fuse, like every bad rom-com you've ever seen.
The fusion process leaves a little bit of energy left over , and the countless fusion reactions are enough to power the sun's radiation for billions of years — and give Earth the warmth and light needed to make life possible.
The process just needs to start with hydrogen, a simple proton. And there is plenty of that in the earliest moments of the universe. All else follows. Every star in the sky, including Earth's own sun, is a massive, sleepless factory for creating new elements. Hydrogen to helium. Onward to carbon, nitrogen and oxygen. In more massive stars, the chain pushes even further, to include calcium, magnesium, neon and argon. All the way to iron and nickel.
But there, the party stops. After iron and nickel, fusion doesn't produce energy anymore — it takes it. Fusion still happens, but there's nothing to stop the relentless gravitational collapse, no energy production to re-flate the star and balance the contraction. The infalling material tries to jam onto the core, is stopped by the solid iron ball at the center, and quickly retreats. In other words: boom!
A supernova is one of the most fantastic displays of reckless energy seen across the univ... . Billions of stars' worth of energy, wasted in a single flash lasting a few weeks. In that energetic inferno, anything is possible. Want to waste energy fusing some new heavy elements? Who cares — there's plenty to spare! Have some more! It's party time!
It's in that furious explosion that the rest of the periodic table is filled out. What wasn't fused in the heart of a star is birthed in the star's death throes, in complicated dances of nuclei and stray neutrons.
This isn't just a cute bedtime story — this is science, after all, and it requires some evidence. The theory was sweated out in a landmark paper led by physicist William Fowler, who went on to receive a Nobel Prize for his efforts.
And human beings can see how they really are made of stars — the ashes of long-dead stars, but stars nonetheless.
Those points of light in the night sky are connected to people in a deep and meaningful way. Human blood and bones are a part of the natural cycle of formation, birth, life and death of humanity's heavenly cousins. People come from stars and will return to the stars; every star dies, and in some fashion spreads its material back from where it came. And when the light from Earth's sun finally snuffs out, it will carry humanity's ashes back into the darkness, to be reshaped again into new worlds, and possibly new life.
Learn more by listening to the episode "Are We Really Made of Stars?" on the "Ask a Spaceman" podcast, available on iTunes, and on the Web at http://www.askaspaceman.com. Thanks to the City of Lima, Ohio, for the question that led to this piece! Ask your own question on Twitter using #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter.
Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com .
- See more at: space.com | 0.864475 | 3.660728 |
Comets visible to the naked eye are a rare delicacy in the celestial smorgasbord of objects in the nighttime sky. Scientists estimate that the opportunity to see one of these icy dirtballs advertising their cosmic presence so brilliantly they can be seen without the aid of a telescope or binoculars happens only once every five to 10 years. That said, there may be two naked-eye comets available for your viewing pleasure this year.
"You might have heard of a comet ISON, which may become a spectacular naked-eye comet later this fall," said Amy Mainzer, the principal investigator of NASA's NEOWISE mission at the Jet Propulsion Laboratory in Pasadena, Calif., and self-described cosmic icy dirtball fan. "But if you have the right conditions you don't have to wait for ISON. Within a few days, comet PANSTARRS will be making its appearance in the skies of the Northern Hemisphere just after twilight."
Discovered in June 2011, comet 2011 L4 (PANSTARRS) bears the name of the telescopic survey that discovered it -- the less than mellifluous sounding "Panoramic Survey Telescope and Rapid Response System" which sits atop the Haleakala volcano in Hawaii.
Since its discovery a year-and-a-half ago, observing comet PANSTARRS has been the exclusive dominion of comet aficionados in the Southern Hemisphere, but that is about to change. As the comet continues its well-understood and safe passage through the inner-solar system, its celestial splendor will be lost to those in the Southern Hemisphere, but found by those up north.
"There is a catch to viewing comet PANSTARRS," said Mainzer. "This one is not that bright and is going to be low on the western horizon, so you'll need a relatively unobstructed view to the southwest at twilight and, of course, some good comet-watching weather."
Well, there is one more issue -- the time of day, or night, to view it.
"Look too early and the sky will be too bright," said Rachel Stevenson, a NASA Postdoctoral Fellow at JPL. "Look too late, the comet will be too low and obstructed by the horizon. This comet has a relatively small window."
By March 8, comet PANSTARRS may be viewable for those with a totally unobstructed view of the western horizon for about 15 minutes after twilight. On March 10, it will make its closest approach to the sun about 28 million miles (45 million kilometers) away. As it continues its nightly trek across the sky, the comet may get lost in the sun's glare but should return and be visible to the naked eye by March 12. As time marches on in the month of March, the comet will begin to fade away slowly, becoming difficult to view (even with binoculars or small telescopes) by month's end. The comet will appear as a bright point of light with its diffuse tail pointing nearly straight up from the horizon like an exclamation point.
What, if any, attraction does seeing a relatively dim naked-eye comet with the naked eye hold for someone who works with them every day, with file after file of high-resolution imagery spilling out on her computer workstation?
"You bet I'm going to go look at it!" said Mainzer. "Comet PanSTARRS may be a little bit of a challenge to find without a pair of binoculars, but there is something intimately satisfying to see it with your own two eyes. If you have a good viewing spot and good weather, it will be like the Sword of Gryffindor, it should present itself to anyone who is worthy."
NASA detects, tracks and characterizes asteroids and comets passing relatively close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and predicts their paths to determine if any could be potentially hazardous to our planet.
NASA's Cassini spacecraft will be swooping close to Saturn's moon Rhea on Saturday, March 9, the last close flyby of Rhea in Cassini's mission. The primary purpose will be to probe the internal structure of the moon by measuring the gravitational pull of Rhea against the spacecraft's steady radio link to NASA's Deep Space Network here on Earth. The results will help scientists understand whether the moon is homogeneous all the way through or whether it has differentiated into the layers of core, mantle and crust.
In addition, Cassini's imaging cameras will take ultraviolet, infrared and visible-light data from Rhea's surface. The cosmic dust analyzer will try to detect any dusty debris flying off the surface from tiny meteoroid bombardments to further scientists' understanding of the rate at which "foreign" objects are raining into the Saturn system.
Cassini will fly within about 600 miles (1,000 kilometers) of the surface. The time of closest approach is around 10:17 a.m. PST (1:17 p.m. EST). This is Cassini's fourth close flyby of Rhea.
On Feb. 10, 2015, Cassini will pass Rhea at about 29,000 miles (47,000 kilometers), but this is not considered a targeted flyby. Cassini has been in orbit around Saturn since 2004 and is in a second mission extension, known as the Solstice mission.
I was browsing NASA this morning and came across this photo of a full size mock up of the Hubble successor .... It's huge!
The James Webb Space Telescope (sometimes called JWST) is a large, infrared-optimized space telescope. The project is working to a 2018 launch date. Webb will find the first galaxies that formed in the early Universe, connecting the Big Bang to our own Milky Way Galaxy. Webb will peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own Solar System. Webb's instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range.
Webb will have a large mirror, 6.5 meters (21.3 feet) in diameter and a sunshield the size of a tennis court. Both the mirror and sunshade won't fit onto a rocket fully open, so both will fold up and open once Webb is in outer space. Webb will reside in an orbit about 1.5 million km (1 million miles) from the Earth.
The James Webb Space Telescope was named after the NASA Administrator who crafted the Apollo program, and who was a staunch supporter of space science.
By Richard Branson
We are making fantastic progress on Virgin Galactic's preparations for travel to space. It has been an amazing, at times agonising process to get the space program this far, and as the weeks and months pass we are steadily witnessing more little bits of history.
The team just conducted an extremely significant night rocket motor firing, which has been described by Matt Stinemetze, Scaled Composites' Program Manager for the development and testing of our space vehicles, in the fantastically descriptive piece below. His words show the huge excitement now emanating from the Mojave Desert, as we move closer to breaking the sound barrier and then building up to full spaceflight in the coming months.
This project really means so much to all of the people involved, from the engineers to the future astronauts to supporters around the world who one day dream of going to space. Here are Matt's wonderful words to his team-mates:
"8:00 pm. On the dirt berm north of the test site we’re far enough from the city and the airport lights that it’s dark. It’s dark enough in fact that overhead millions of stars are visible, but no moon. Yet another surreal late night at work for Scaled. The murmur from the 50 or so people on the berm has subsided and there is an eerie silence as you’re inside the last minute. In front of us four large floodlights illuminate the white bug; two red strobes flash on either end. It’s just far enough away and just bright enough that you have to squint to make out the details
Kawoomph!… Instantly any speaking subsides and if it doesn’t, you can’t hear it. A large yellow flame has suddenly erupted 50 feet behind the white structure and a deafening roar has filled the night. Simultaneously, a large column of brown dust billows up a mile behind the flame. A smooth, earthy, roar/rumble unlike anything you’ve heard encompasses you. As the first few seconds tick by the shock wears off and you find yourself wondering what those cars on the bypass must be thinking (I’m sure at least a couple folks wandered onto the sound bumpers at the shoulder, heads straining westward wondering what in the world they were seeing).
The scene is so surreal, so overwhelming that you mentally start and stop the count two or three times not remembering where you left off. You squint, strain and then as quickly as it started it whooshes to an abrupt stop. Your eyes flicker, a white blur stains your vision long after it’s over. Behind you in the far distance, several seconds after the flame subsides, the heavy rumble of the echo across the mountains rattles to a stop. Wahoo!! the hill erupts into jubilation…. This isn’t sci-fi, and it’s not the scene from a book. This is your program and it happened on Thursday night February 28th, 2013. The first in a rapid series of final confirmation firings leading up to SpaceShipTwo's first rocket powered flight was completed in dramatic style!"
Image by Bob Morgan, Scaled Composites
By Richard Branson. Founder of Virgin Group
I've been watching this for a few days to see if they were able to refine the comets path. It looks like it may be a near miss but we will be watching and updating for sure. Here is the full story from NASA
Comet 2013 A1 (Siding Spring) will make a very close approach to Mars in October 2014.
The latest trajectory of comet 2013 A1 (Siding Spring) generated by the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., indicates the comet will pass within 186,000 miles (300,000 kilometers) of Mars and there is a strong possibility that it might pass much closer. The NEO Program Office's current estimate based on observations through March 1, 2013, has it passing about 31,000 miles (50,000 kilometers) from the Red Planet's surface. That distance is about two-and-a-half times that of the orbit of outermost moon, Deimos.
Scientists generated the trajectory for comet Siding Spring based on the data obtained by observations since October 2012. Further refinement to its orbit is expected as more observational data is obtained. At present, Mars lies within the range of possible paths for the comet and the possibility of an impact cannot be excluded. However, since the impact probability is currently less than one in 600, future observations are expected to provide data that will completely rule out a Mars impact.
During the close Mars approach the comet will likely achieve a total visual magnitude of zero or brighter, as seen from Mars-based assets. From Earth, the comet is not expected to reach naked eye brightness, but it may become bright enough (about magnitude 8) that it could be viewed from the southern hemisphere in mid-September 2014, using binoculars, or small telescopes.
Scientists at the Near-Earth Object Program Office estimate that comet Siding Spring has been on a more than a million-year journey, arriving from our solar system's distant Oort cloud. The comet could be complete with the volatile gases that short period comets often lack due to their frequent returns to the sun's neighborhood.
Rob McNaught discovered comet 2013 A1 Siding Spring on Jan. 3, 2013, at Siding Spring Observatory in Australia. A study of germane archival observations has unearthed more images of the comet, extending the observation interval back to Oct. 4, 2012.
NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and plots their orbits to determine if any could be potentially hazardous to our planet.
The gravitational field surrounding this massive cluster of galaxies, Abell 68, acts as a natural lens in space to brighten and magnify the light coming from very distant background galaxies.
Like a fun house mirror, lensing creates a fantasy landscape of arc-like images and mirror images of background galaxies. The foreground cluster is 2 billion light-years away, and the lensed images come from galaxies far behind it.
In this photo, the image of a spiral galaxy at upper left has been stretched and mirrored into a shape similar to that of a simulated alien from the classic 1970s computer game "Space Invaders!" A second, less distorted image of the same galaxy appears to the left of the large, bright elliptical galaxy.
In the upper right of the photo is another striking feature of the image that is unrelated to gravitational lensing. What appears to be purple liquid dripping from a galaxy is a phenomenon called ram-pressure stripping. The gas clouds within the galaxy are being stripped out and heated up as the galaxy passes through a region of denser intergalactic gas.
This image was taken in infrared light by Hubble's Wide Field Camera 3, and combined with near-infrared observations from Hubble's Advanced Camera for Surveys.
The image is based in part on data spotted by Nick Rose in the Hubble's Hidden Treasures image processing competition.
PASADENA, Calif. - NASA's Mars rover Curiosity has transitioned from precautionary "safe mode" to active status on the path of recovery from a memory glitch last week. Resumption of full operations is anticipated by next week.
Controllers switched the rover to a redundant onboard computer, the rover's "B-side" computer, on Feb. 28 when the "A-side" computer that the rover had been using demonstrated symptoms of a corrupted memory location. The intentional side swap put the rover, as anticipated, into minimal-activity safe mode.
Curiosity exited safe mode on Saturday and resumed using its high-gain antenna on Sunday.
"We are making good progress in the recovery," said Mars Science Laboratory Project Manager Richard Cook, of NASA's Jet Propulsion Laboratory. "One path of progress is evaluating the A-side with intent to recover it as a backup. Also, we need to go through a series of steps with the B-side, such as informing the computer about the state of the rover -- the position of the arm, the position of the mast, that kind of information."
The cause for the A-side's memory symptoms observed last week remains to be determined.
NASA's Mars Science Laboratory Project is using Curiosity to assess whether areas inside Gale Crater ever offered a habitable environment for microbes. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate in Washington.
It may look like something from "The Lord of the Rings," but this fiery swirl is actually a planetary nebula known as ESO 456-67. Set against a backdrop of bright stars, the rust-colored object lies in the constellation of Sagittarius (The Archer), in the southern sky.
Despite the name, these ethereal objects have nothing at all to do with planets; this misnomer came about over a century ago, when the first astronomers to observe them only had small, poor-quality telescopes. Through these, the nebulae looked small, compact, and planet-like — and so were labeled as such.
When a star like the sun approaches the end of its life, it flings material out into space. Planetary nebulae are the intricate, glowing shells of dust and gas pushed outwards from such a star. At their centers lie the remnants of the original stars themselves — small, dense white dwarf stars.
In this image of ESO 456-67, it is possible to see the various layers of material expelled by the central star. Each appears in a different hue — red, orange, yellow, and green-tinted bands of gas are visible, with clear patches of space at the heart of the nebula. It is not fully understood how planetary nebulae form such a wide variety of shapes and structures; some appear to be spherical, some elliptical, others shoot material in waves from their polar regions, some look like hourglasses or figures of eight, and others resemble large, messy stellar explosions — to name but a few. | 0.925206 | 3.805393 |
According to the author
"We demonstrate that the detrended annual means of global surface air temperature in 1965–2012 show the maxima during CRs [Cosmic Rays] and Dst index [of the solar wind] minima. It proves that CRs [Cosmic Rays] play essential role in climate change and main part of climate variations can be explained by Pudovkin and Raspopov’s (1992) mechanism of action CRs [Cosmic Rays] modulated by the solar activity on the state of lower atmosphere and meteorological parameters. Following this we have to seek for another ways of looking for global warming reason, first of all, as a man impact on climate."
Data from the paper shows a strong correlation between cosmic rays and detrended surface temperatures in two locations 1966-2006 and 1965-2012:
|Top graph shows changes in cosmic rays correlated to detrended surface temperatures in second graph. Note vertical axis is inverse on the temperature graph because increased cosmic rays are believed to seed cloud formation, which causes cooling. Bottom graph shows sunspot numbers and 3rd graph is an index of solar geomagnetic activity.|
|Graphs on right hand side show correlation between CR cosmic rays and detrended temperature (B,nT)|
|Cosmic Rays [CR] are believe to seed cloud formation and thus inversely related to temperature as bottom two graphs show. |
We previously calculated using the greenhouse equation that a mere 1% change in global cloud cover up or down would change average global surface temperature ~1C, thus if clouds are indeed seeded by cosmic rays, and cosmic rays vary up to 8% over solar cycles (as shown in the first graph above), this theoretically could have a significant effect on local and global temperatures. | 0.802335 | 3.348911 |
eso0007 — Photo Release
Fine Shades of a Sombrero
A New Look at an Unusual Galaxy
23 February 2000
In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104, widely known as the "Sombrero" (the Mexican hat) because of its particular shape.
The colour image was made by a combination of three CCD images from the FORS1 multi-mode instrument on VLT ANTU, recently obtained by Peter Barthel from the Kapteyn Institute (Groningen, The Netherlands) during an observing run at the Paranal Observatory. He and Mark Neeser, also from the Kapteyn Institute, produced the composite images.
The galaxy fits perfectly into the 6.8 x 6.8 arcmin 2 field-of-view of the FORS1 camera. A great amount of fine detail is revealed, from the structures in the pronounced dust band in the equatorial plane, to many faint background galaxies that shine through the outer regions.
The "Sombrero" is located in the constellation Virgo (the Virgin), at a distance of about 50 million light-years. The overall "sharpness" of this colour image corresponds to about 0.7 arcsec which translates into a resolution of about 170 light-years at that distance.
About Messier 104
Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 - 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a "very faint nebula". The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy's rotation.
This galaxy is notable for its dominant nuclear bulge, composed primarily of mature stars, and its nearly edge-on disk composed of stars, gas, and intricately structured dust. The complexity of this dust, and the high resolution of this image, is most apparent directly in front of the bright nucleus, but is also very evident as dark absorbing lanes throughout the disk. A significant fraction of the galaxy disk is even visible on the far side of the source, despite its massive bulge, c.f. ESO Press Photo eso0007c.
A large number of small and slightly diffuse sources can be seen as a swarm in the halo of Messier 104. Most of these are globular clusters, similar to those found in our own Galaxy.
Measurements reveal a steep increase in the mass-to-light ratio and increasing stellar speeds near the nucleus of Messier 104 . This is indicative of the presence of a massive black hole at the centre, estimated at about 10 9 solar masses.
The radio properties of Messier 104 are unusual for a spiral galaxy -- it has a variable core. The optical spectrum of the central region displays emission lines from hot gas (of the "LINER" type -- Low Ionisation Nuclear Emission line Region). This points to Messier 104 harbouring a weak Active Galactic Nucleus (AGN) . Although more commonly known from the much more luminous and distant quasars and powerful radio galaxies, the weak AGN in this galaxy lies at the opposite extreme: the most likely explanation being a central black hole accreting circumnuclear matter at a slow pace. | 0.815652 | 3.805062 |
There are only two objects in the solar system with sustained pools of liquid on their surface: Earth and Titan. On Earth, we have a well-understood water cycle that keeps liquid water flowing on the surface of our planet. On Titan, the process is believed to be conceptually similar but based on liquid methane rather than water. There are signs that Titan has an alkanological cycle similar to the hydrological cycle on this planet. But how Titan actually got its lakes has been something of a mystery until now. Researchers are suggesting that the lakes may actually have formed as the result of explosions, not erosion.
Many of Titan’s lakes are what is known as Sharp Edged Depressions (SEDs). They have circular or irregular shapes that are generally not thought to be impact craters. On Earth, many of these types of lakes are karstic, meaning they form when liquid (water on Earth) undermines the geology beneath an area and it collapses, forming a depression that then fills. However, there aren’t many substances in Titan’s crust that are believed to be susceptible to dissolution in the first place. The organic material that rains out of Titan’s atmosphere and collects at the poles is insufficient to create an erodible organic sedimentary layer. The researchers write:
The presence of raised rims in SED basins undermines the karst lake model for SEDs with raised rims. According to the karst model, the lake basins on Titan should be produced as dolines formed by collapse, dissolution or subsidence of the terrain; such processes do not produce rims. While SEDs with raised rims are not formed by a karstic process, their presence in a karstic-like environment is not excluded.
The team has an alternate proposal for how the lakes may have formed — nitrogen bombs. On Earth, certain characteristic structures are produced by phreatic or phreatomagmatic eruptions. When seawater comes into contact with magma, the result can be a substantial steam explosion. Maars and other forms of tuff produced by this kind of explosion have characteristics that fit the observed characteristics of Titan’s lakes. We see that many Titan lakes have ramparts of material built up around them, and this could correspond to debris ejected from the newly formed crater as a result of a nitrogen explosion.
The theory isn’t perfect, because there’s not as much debris around the various lakes as might be expected on Earth — but this could be explained by differences in Titan’s natural composition and its planetary evolution. One theory is that at some point in the distant past, Titan’s atmosphere was dominated by nitrogen, not methane, and the moon was much colder. This could have been the case if the level of methane in Titan’s atmosphere was lower than it is today. As the amount of methane increased and the planet warmed, small temperature variations could have produced an extreme pressure rise in the nitrogen-dominated aquifers. There may even be evidence of this kind of event occurring on Neptune’s moon Triton during the Voyager 2 flyby.
Scientists are still studying the characteristics of Titan’s geology to determine whether this is a plausible hypothesis, but we could know more in fairly short order. The NASA Dragonfly mission to Titan is set to gather an unparalleled amount of information about this distant moon, shedding new light on its history and continued evolution.
- NASA Will Send Flying ‘Dragonfly’ Robot to Saturn’s Moon Titan
- Titan’s Lakes May Have ‘Bathtub Rings’ of Bizarre Crystals
- Mysterious Band of Ice Stretches Thousands of Miles Across Saturn Moon | 0.88051 | 4.075922 |
Overfed Black Holes Shut Down Galactic Star-Making
A new study has shown that galaxies with the most powerful, active, supermassive black holes at their cores produce fewer stars than galaxies with less active black holes. Researchers compared infrared readings from the Hershel Space Observatory with X-rays streaming from the active central black holes in a survey of 65 galaxies, measured by NASA's Chandra X-ray Observatory.
At lower intensities, the black holes' brightness and star formation increased in sync. However, star formation dropped off in galaxies with the most energetic central black holes. Astronomers think inflows of gas fuel new stars and supermassive black holes. Feed a black hole too much, however, and it starts spewing radiation into the galaxy that prevents raw material from coalescing into new stars.
Supermassive black holes are believed to reside in the hearts of all large galaxies. When gas falls upon these monsters, the materials are accelerated and heated around the black hole, releasing great torrents of energy. In the process, active black holes often generate colossal jets that blast out twin streams of heated matter.
-Megan Watzke, CXC
Please note this is a moderated blog. No pornography, spam, profanity or discriminatory remarks are allowed. No personal attacks are allowed. Users should stay on topic to keep it relevant for the readers.
Read the privacy statement | 0.812814 | 3.107515 |
There are sections devoted to Ptolemy's constellations as well as "modern" constellations such as Microscopium
(the microscope), Fornax (the furnace) and Tucana (the toucan).
As a man of the Enlightenment and unencumbered by classical whimsy, he named most of his new constellations after, as he put it, "principal figures of the arts": The Painter's Easel; the Sculptor's Workshop; Microscopium
and Telescopium; Reticulum, the celestial apotheosis of his little refractor's measuring reticle; Octans, the Octant; Fornax, the Chemist's Furnace; and so on.
Lower still lies the small and insignificant Microscopium
. On a really clear evening it is worth trying to locate its brightest stars; gamma ([gamma]) at magnitude 4.67 and epsilon ([epsilon]) at 4.71 despite their being at an altitude of just over 6[degrees].
Hubble saw a ring around only one, HD 202628, which resides near the southern constellations Grus and Microscopium
Mirabile inquam; nam quod Telescopium in coelestibus corporibus ingentibus longo spatio dissitis, efficit, hoc idem in terrestribus corporibus minutissimis & prope oculos nostros efficit Microscopium
This mutual influence is seen most prominently in the language of the natural sciences (e.g., telescopium, microscopium
, acus nautica, etc.).
This season finds Ceres swinging from the southern tip of the Capricornus star pattern down through little-known Microscopium
and into easternmost Sagittarius.
Dwarf planets in 2015 Name Interval Constellation Ceres Jan 01 to Mar 31 Sagittarius Apr 1 to Jun 29 Capricornus Jun 30 to July 25 Microscopium
Jul 26 to Nov 07 Sagittarius Nov 08 to Nov 18 Microscopium
Nov 19 to Dec 31 Capricornus Pluto Entire year Sagittarius Makemake Entire year Coma Berenices Haumea Entire year Bootes Eris Entire year Cetus
At a press conference last week, researchers announced that the Hubble Space Telescope had detected such radiation from a Milky Way flare star called AU Microscopium
Only five other constellations--Caelum, Mensa, Microscopium
, Sextans, and Vulpecula--have a fainter lucida.
Farther south, 1 Ceres, the first-discovered and largest asteroid (diameter 850 kilometers), brightens past magnitude 8.0 in mid-July, reaches 7.6 at opposition in mid-August, and fades down past 8.6 in early October as it swoops from southern Aquarius through a corner of Piscis Austrinus into Microscopium
. And while you're here, check out the 7.5-magnitude globular cluster M30, which is paired with the 5.2-magnitude yellow star 41 Capricorni 0.4 to its east.
Some of them have been shortened, thankfully: Antlia (the Air Pump), Caelum (the Chisel), Circinus (the Drawing Compass), Fornax (the Furnace), Horologium (the Clock), Mensa (the Table, named for Table Mountain in South Africa), Microscopium
(the Microscope), Norma (the Square), Octans (the Octant), Pictor (the Painter's Easel), Pyxis (the Mariner's Compass), Reticulum (the Net), Sculptor (the Sculptor), and Telescopium (the Telescope). | 0.890574 | 3.121126 |
MACS J1149.5+2233 (MACS J1149 for short) is a system of merging galaxy clusters located about 5 billion light years from Earth. This galaxy cluster was one of six that have been studied as part of the "Frontier Fields" project. This research effort included long observations of galaxy clusters with powerful telescopes that detected different types of light, including NASA's Chandra X-ray Observatory.
Astronomers are using the Frontier Fields data to learn more about how galaxy clusters grow via collisions. Galaxy clusters are enormous collections of hundreds or even thousands of galaxies and vast reservoirs of hot gas embedded in massive clouds of dark matter, invisible material that does not emit or absorb light but can be detected through its gravitational effects.
This new image of MACS J1149 combines X-rays from Chandra (diffuse blue), optical data from Hubble (red, green, blue), and radio emission from the Very Large Array (pink). The image is about four million light years across at the distance of MACS J1149.
The Chandra data reveal gas in the merging clusters with temperatures of millions of degrees. The optical data show galaxies in the clusters and other, more distant, galaxies lying behind the clusters. Some of these background galaxies are highly distorted because of gravitational lensing, the bending of light by massive objects. This effect can also magnify the light from these objects, enabling astronomers to study background galaxies that would otherwise be too faint to detect. Finally, the structures in the radio data trace enormous shock waves and turbulence. The shocks are similar to sonic booms, and are generated by the mergers of smaller clusters of galaxies.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations. | 0.828554 | 3.715027 |
Astronomers using CSIRO’s 64-m Parkes radio telescope in eastern Australia have for the first time seen a ‘fast radio burst‘ – a short, sharp flash of radio waves from an unknown source – happening live.
This brings us a step closer to understanding the phenomenon, which astronomers worldwide are vying to explain. The finding is published today in Monthly Notices of the Royal Astronomical Society.
Lasting only milliseconds, the first such radio burst was discovered in 2007 by astronomers combing the Parkes data archive for unrelated objects. Six more bursts, apparently from outside our Galaxy, have now been found with Parkes and a seventh with the Arecibo telescope in Puerto Rico. “These bursts were generally discovered weeks or months or even more than a decade after they happened! We’re the first to catch one in real time,” said Emily Petroff, a PhD candidate co-supervised by CSIRO and by Swinburne University of Technology in Melbourne, Australia, which is a member institution of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO).
Banking that she’d spot a ‘live’ burst, Petroff had an international team poised to make rapid follow-up observations, at wavelengths from radio to X-rays. After Parkes saw the burst go off the team swung into action on twelve telescopes around the world – in Australia, California, the Canary Islands, Chile, Germany, Hawaï, and India – and in space.
No optical, infrared, ultraviolet or X-ray counterpart showed up. “That in itself rules out some possible candidates, such as long gamma-ray bursts and nearby supernovae,” said team member Dr Mansi Kasliwal of the Carnegie Institution in Pasadena, California.
But short or low-energy gamma-ray bursts and giant flares from distant magnetars (the most magnetic stars in the Universe) are still contenders, she added. So too are imploding neutron stars. One of the big unknowns of fast radio bursts is their distances. The characteristics of the radio signal – how it is ‘smeared out’ in frequency from travelling through space – indicate that the source of the new burst was up to 5.5 billion light-years away. “That means it could have given off as much energy in a few milliseconds as the Sun does in a day,” said team member Dr Daniele Malesani of the University of Copenhagen.
The burst left another clue as to its identity, but a puzzling one. Parkes’s real-time detection system captured its polarization – something that had not been recorded for previous bursts. Polarization can be thought of as the direction electromagnetic waves, such as light or radio waves, ‘vibrate’. It can be linear or circular. The radio emission from the new fast radio burst was more than 20% circularly polarised – which hints that there are strong magnetic fields near the source.
Identifying the origin of the fast radio bursts is now only a matter of time.
The new work appears in a paper by E. Petroff et al., “A real-time fast radio burst: Polarization detection and multi-wavelength follow-up“, Monthly Notices of the Royal Astronomical Society, vol. 447, pp. 246-255, 2015, published by Oxford University Press.
Notes for editors
CAASTRO is a collaboration between Curtin University, the University of Western Australia, the University of Sydney, theAustralian National University, the University of Melbourne, Swinburne University of Technology and the University of Queensland. It is funded under the Australian Research Council Centre of Excellence program and receives additional funding from the seven participating universities and the NSW State Government Science Leveraging Fund.
The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 3800 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.
Follow the RAS on Twitter
Ms Emily Petroff
ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) / Swinburne University of Technology
Tel: +61 3 9214 5368 (office)
Mob: +61 468 780 080
Dr Mansi Kasliwal
Observatories of the Carnegie Institution for Science
Tel: +1 626 375 3307 (office)
Dr Daniele Malesani
Dark Cosmology Centre (DARK), Niels Bohr Institute, University of Copenhagen
Tel: +45 353 25 981
Source: Royal Astronomical Society (RAS) UK | 0.82937 | 3.899331 |
The image of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 3 August 2014 from a distance of 285 km. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
“We’re at the comet! Yes,” exclaimed Rosetta Spacecraft Operations Manager Sylvain Lodiot, confirming the spacecraft’s historic arrival at Comet 67P/Churyumov-Gerasimenko during a live webcast this morning, Aug. 6, from mission control at ESA’s spacecraft operations centre (ESOC) in Darmstadt, Germany.
The European Space Agency’s (ESA) Rosetta comet hunter successfully reached its long sought destination after a flawless orbital thruster firing at 11 AM CEST to become the first spacecraft in history to rendezvous with a comet and enter orbit aimed at an ambitious long term quest to produce ground breaking science.
“Ten years we’ve been in the car waiting to get to scientific Disneyland and we haven’t even gotten out of the car yet and look at what’s outside the window,” Mark McCaughrean, senior scientific adviser to ESA’s Science Directorate, said during today’s webcast. “It’s just astonishing.”
“The really big question is where did we and the solar system we live in come from? How did water and the complex organic molecules that build up life get to this planet? Water and life. These are the questions that motivate everybody.”
“Rosetta is indeed the ‘rosetta stone’ that will unlock this treasure chest to all comets.”
Today’s rendezvous climaxed Rosetta’s decade long and 6.4 billion kilometers (4 Billion miles) hot pursuit through interplanetary space for a cosmic kiss with Comet 67P while speeding towards the inner Solar System at nearly 55,000 kilometers per hour.
The probe is sending back spectacular up close high resolution imagery of the mysterious binary, two lobed comet, merged at a bright band at the narrow neck of the celestial wanderer that looks like a ‘rubber ducky.’
“This is the best comet nucleus ever resolved in space with the sharpest ever views of the nucleus, with 5.5.meter pixel resolution,” said Holger Sierks, principal investigator for Rosetta’s OSIRIS camera from the Max Planck Institute for Solar System Research in Gottingen, Germany, during the webcast.
“We now see lots of structure and details. Lots of topography is visible on the surface. We see the nucleus and outgassing activity. The outbursts are seen with overexposed images. It’s really fantastic”
“There is a big depression on the head and 150 meter high cliffs, rubble piles, and also we see smooth areas and plains. The neck is about 1000 meters deep and is a cool area. There is outgassing visible from the neck.”
“We see a village of house size boulders. Some about 10 meters in size and bigger they vary in brightness. And some with sharp edges. We don’t know their composition yet.”
“We don’t understand how its created yet. That’s what we’ll find out in coming months as we get closer.”
“Rosetta has arrived and will get even closer. We’ll get ten times the resolution compared to now.”
“The comet is a story about us. It will be the key in cometary science. Where did it form? What does it tell us about the water on Earth and the early solar system and where it come from?”
Following the blastoff on 2 March 2004 tucked inside the payload fairing of an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana, Rosetta traveled on a complex trajectory.
It conducted four gravity assist speed boosting slingshot maneuvers, three at Earth and one at Mars, to gain sufficient velocity to reach the comet, Lodiot explained.
The 1.3 Billion euro robotic emissary from Earth is now orbiting about 100 kilometers (62 miles) above the comet’s surface, some 405 million kilometers (250 million mi.) from Earth, about half way between the orbits of Jupiter and Mars.
The main event today, Aug. 6, was to complete an absolutely critical thruster firing which was the last of 10 orbit correction maneuvers (OCM’s). It started precisely on time at 11:00 AM CEST/09:00 GMT/5:00 AM EST, said Lodiot. The signal was one of the cleanest of the entire mission.
The orbital insertion engine firing dubbed the Close Approach Trajectory – Insertion (CATI) burn was scheduled to last about 6 minutes 26 seconds. Confirmation of a successful burn came some 28 minutes later.
“We’re at the comet! Yes,” Lodiot excitedly announced live whereupon the crowd of team members, dignitaries and journalists at ESOC erupted in cheers.
For the next 17 months, the probe will escort comet 67P as it loops around the Sun towards perihelion in August 2015 and then continue along on the outbound voyage towards Jupiter.
ESA’s incredibly bold mission will also deploy the three-legged piggybacked Philae lander to touch down and drill into and sample its incredibly varied surface a little over three months from now.
Together, Rosetta and Philae are equipped with a suite of 21 science instruments to conduct an unprecedented investigation to characterize the 4 km wide (2.5 mi.) comet and study how the pristine frozen body composed of ice and rock is transformed by the warmth of the Sun.
Comets are believed to have delivered a vast quantity of water to Earth. They may have also seeded Earth with organic molecules.
Rosetta and Philae will also search for organic molecules, nucleic acids and amino acids, the building blocks for life as we know it by sampling and analyzing the comets nucleus and coma cloud of gas and dust.
“The first coma sampling could happen as early as next week,” said Matt Taylor, ESA’s Rosetta project scientist on the webcast.
“Is this double-lobed structure built from two separate comets that came together in the Solar System’s history, or is it one comet that has eroded dramatically and asymmetrically over time? Rosetta, by design, is in the best place to study one of these unique objects.”
After thoroughly mapping the comet, the team will command Rosetta to move even lower to 50 km altitude and then even lower to 30 km and less.
The scientists and engineers will search for up to five possible landing sites for Philae to prepare for the touchdown in mid-November 2014.
“We want to characterize the nucleus so we can land in November,” said Taylor. “We will have a ringside along with the comet as it moves inwards to the sun and then further out.”
Studying comets will shed light on the history of water and life on Earth.
“We are going to places we have never been to before,” said Jean-Jacques Dordain, ESA’s Director General during the webcast.
“We want to get answers to questions to the origin to water and complex molecules on Earth. This opens up even more new questions than answers.”
Watch for updates.
Stay tuned here for Ken’s continuing Rosetta, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.
Read my Rosetta series here: | 0.866117 | 3.301888 |
It's the first mission capable of answering the age-old question: Are other worlds like ours out there?
Kepler, named after the German 17th century astrophysicist, set off on its unprecedented mission at 10:49 p.m., thundering into a clear sky embellished by a waxing moon.
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"It was just magnificent. It looked like a star was being formed in the sky," said Bill Borucki, Kepler's principal scientist. "Everybody was delighted, everybody was screaming, 'Go Kepler!'"
Kepler's mission will last at least 3½ years and cost $600 million.
The goal is to find, if they exist, Earth-like planets circling stars in the so-called habitable zone — orbits where liquid water could be present on the surface of the planets. That would mean there are lots of places out there for life to evolve, Borucki said.
On the other hand, "if we don't find any, it really means Earths are very rare, we might be the only extant life and, in fact, that will be the end of 'Star Trek.' "
Once it's settled into an Earth-trailing orbit around the sun, Kepler will stare nonstop at 100,000 stars near the Cygnus and Lyra constellations, between 600 and 3,000 light years away. The telescope will watch for any dimming, or winks, in the stellar brightness that might be caused by orbiting planets.
Astronomers already have found more than 300 planets orbiting other stars, but they're largely inhospitable gas giants like Jupiter. Kepler will be looking for smaller rocky planets akin to Earth.
Kepler is designed to find hundreds of Earth-like planets if they're common and, perhaps, dozens of them in the habitable zone, Borucki said. The telescope is so powerful that from space, NASA maintains, it could detect someone in a small town turning off a porch light at night.
It won't be looking for signs of life, though. That's for future spacecraft.
NASA was counting on a successful launch to offset the loss last week of the space agency's Orbiting Carbon Observatory. That environmental satellite ended up crashing into the Antarctic because of rocket failure. It was a different type of rocket than the one used for Kepler.
Everything seemed to go well with Kepler's launch. | 0.800929 | 3.358711 |
2020/03/27 | Research | Environment & Matter
Questioning theory can be worth it
Where few thought to look, the NCCR PlanetS co-funded telescope "SAINT-EX" is searching for new worlds. After a year of operation, the project has brought some exciting first results.
By Arian Bastani
Atop a mountainous region, nearly three kilometers above sea level, overlooking pine forests and impressive rock formations it lies: The National Astronomical Observatory of Mexico in San Pedro Mártir.
From there, the robot controlled and fully automatic 1-meter telescope "SAINT-EX" watches the night-sky. The NCCR PlanetS co-funded project aims to locate and describe planets beyond the boundaries of our solar system. Its focus are potentially habitable Earth-like rocky planets orbiting so called "ultra-cool" stars.
A clever alternative
"Ultra-cool", in this case, might be misleading – the surface temperatures of such stars are still up to around 2’500 degrees Celsius. But relative to other stars, that is indeed quite cool. The Sun, for example, is around twice as hot.
There are good reasons to look for Earth-like planets in these kind of star systems, as the project’s principal investigator, Brice Demory, explains: "As of today, we don’t have the instrumental capability to detect Earth-size planets orbiting Sun-like stars in the habitable zone", he says. The reason is that the habitable zone – where liquid water could exist – is relatively far away from stars similar to the Sun. The large distance makes the probability of a transit – the planet passing by between the star and the telescope – very low. It is only about 0.5 percent. This chance increases the cooler the star is, as the habitable zone then falls closer towards the star. "For ultra-cool stars, it is about 5 percent. A factor 10 higher", the Professor at the University’s Center for Space and Habitability tells PlanetS.
And a further factor makes it easier to detect planets orbiting ultra-cool stars: they are much smaller than the Sun. Thus, when a planet passes by, a larger fraction of the light emitted by the star is blocked. This makes the transit more noticeable. The difference in this case is about a factor of 100, according to Demory.
Convincing numbers that beg the question: if it is so much easier to find Earth-like planets in front of ultra-cool stars, why have we only recently begun to look there?
False theories and new instruments
"It was previously thought that there could not be any planets orbiting such stars", Demory answers. And since there was thus little reason to pay any attention to these systems, few suitable telescopes were available to do so.
The SAINT-EX project, named after the author of the Little Prince, Antoine de Saint-Exupéry, set out to change that. It was equipped with instruments specifically suited to observe ultra-cool stars, which are both relatively dim and quite reddish in color.
With its precise instruments, the telescope has already confirmed two new planets that could potentially hold liquid water. Corresponding scientific publications are in preparation, as Prof. Demory tells PlanetS.
Support for CHEOPS
Furthermore, SAINT-EX also provides vital ground support for the space-based CHEOPS telescope. It does so, for example, by precisely monitoring objects that are investigated with CHEOPS. It thus serves as a control, with which it can be verified that measurements taken by the space-telescope are indeed signals caused by the objects and not by the spacecraft itself.
Ultimately, Brice Demory hopes, the data that SAINT-EX provides, will help finding answers to profound research questions, such as the necessary conditions for the emergence of life. So far, we only have one data point: Earth. But other environments might also support biological activity. Only by exploring the variety of exoplanets in habitable zones can we increase our understanding, the scientist tells us.
One thing is certain: we should expect to be surprised. If the research that motivated SAINT-EX has taught us anything, as Demory puts it, it’s that "We should not always trust the theory!". Further results from the telescope in the Mexican mountains may strengthen his point.
"THE OBSERVER": NEWSLETTER of the NCCR PLANETS
This article was originally published in "The Observer", the newsletter of the National Centre of Competence in Research PlanetS.
Bernese space exploration: With the world’s elite since the first moon landing
When the second man, "Buzz" Aldrin, stepped out of the lunar module on July 21, 1969, the first task he did was to set up the Bernese Solar Wind Composition experiment (SWC) also known as the "solar wind sail" by planting it in the ground of the moon, even before the American flag. This experiment, which was planned and the results analysed by Prof. Dr. Johannes Geiss and his team from the Physics Institute of the University of Bern, was the first great highlight in the history of Bernese space exploration
Ever since Bernese space exploration has been among the world’s elite. The numbers are impressive: 25 times were instruments flown into the upper atmosphere and ionosphere using rockets (1967-1993), 9 times into the stratosphere with balloon flights (1991-2008), over 30 instruments were flown on space probes, and with CHEOPS the University of Bern shares responsibility with ESA for a whole mission.
The successful work of the Department of Space Research and Planetary Sciences (WP) from the Physics Institute of the University of Bern was consolidated by the foundation of a university competence center, the Center for Space and Habitability (CSH). The Swiss National Fund also awarded the University of Bern the National Center of Competence in Research (NCCR) PlanetS, which it manages together with the University of Geneva.
About the author
Arian Bastani is a scientific journalist and works for the National Centre of Competence in Research NCCR PlanetS. | 0.845442 | 3.682664 |
Doctor of Philosophy
Royal Ontario Museum
The characterization of meteorites formed in early melt and impact environments helps deepen our understanding of the processes involved in the formation and modification of terrestrial bodies in the solar system. The main objective of this thesis is to interpret and describe a range of igneous and metamorphic environments on asteroidal bodies, through the chemical, microstructural and isotopic analysis of meteorites, and to place these in the context of evolving rocky bodies in the early protoplanetary disk. Study of the meteorite Northwest Africa (NWA) 869 has led to the novel discovery of a eucrite impactor clast in chondritic regolith material. Secondary heating from additional impact(s) formed a basaltic melt, in a rim surrounding the clast, which has bulk characteristics similar to some planetary achondrites. This finding reveals an alternate pathway to achondrite formation and illustrates the mixing of chemical reservoirs in the solar system. Phosphate thermochronology measurements carried out in situ on NWA 7680 and 6962 revealed that they have remained below 350-550 °C since the time of the early protoplanetary disk (4578 ± 17 Myr ago for NWA 7680). Both meteorites have compositions and textures consistent with formation through short-lived differentiation processes on a primitive CR chondrite-like parent body, preserve evidence of some of the earliest known asteroidal melts, and contain Cr and O isotopic evidence for rapid (within several million years) establishment of chemical reservoirs within the protoplanetary disk. Finally, a textural analysis of graphite and diamond disposition in the ureilites NWA 11950 and 11951 was conducted to test recent planetary models invoking diamond as a relic of static metamorphism within an early planet-sized body. The results of the textural study are instead consistent with a paragenesis by shock waves passing from lower (carbon) to higher (silicates) shock impedance materials. This thesis has established the nature and timescale of some of the earliest formation and modification processes on rocky bodies in our solar system, providing physical evidence with which to improve our models of planetary evolution.
Summary for Lay Audience
Meteorites provide snapshots of our solar system’s formation and evolution through time. Key processes in the transition from the presolar disk to planets include melting and collision. These processes are important because they ultimately led to the formation of the Earth and other planets and the outgassing of volatiles to their surfaces. The main objective of this thesis is to describe some of the earliest melting processes which initiated on asteroids, as represented in meteorites, to obtain a better understanding of how and for what duration rocky bodies experienced melting and differentiation. The results of this research include evidence of rocks that have gone through the differentiation process impacting and mixing with more primitive rocks on the surface of an asteroid. Information about the melt mixing occurring during impact processes is vital to our understanding about how distinct objects accrete, grow and evolve over time. The study of a second set of meteorites has revealed new insights into the diversity and timing of melt processes; including evidence of previously unknown early (> 4.5 billion years ago) melt environments on a primitive asteroid in the outer solar system. Additional work carried out on a third set of meteorites has found evidence of high pressure impact shock-related diamonds in meteorites from a partially differentiated parent body. The shock formation of diamonds in these meteorites challenges the views of early melt processes, as some studies suggest the requirement of a large planet to form the diamonds at depth. The knowledge gained through this thesis stems from customized methodologies and integrating analytical techniques, enabling a deepening of our understanding of early formation and modification processes on rocky bodies in our solar system.
Hyde, Brendt, "Early Meteoritic Records of Asteroidal Melt and Impact Environments" (2020). Electronic Thesis and Dissertation Repository. 6962. | 0.856036 | 3.765387 |
Introduction to electron-molecule collision
The process of electron-molecule scattering can be described by:
inelastic excitationionization (dissociation)
These processes extensively exist in the atmosphere, nuclear fusion confined by magnetic field or inertia and gases discharge. Therefore, the data of cross sections and oscillator strengths for electron-molecule impact are significant not only for the development of atomic and molecular physics but also for the advancement of astrophysics, plasmas physics, confined nuclear fusion, X-ray laser and the safety of aerocraft.
The accurate measurement of oscillator strength is always one of the most important contents for electron-molecule impact, and this kind of data have already been extensively used in astrophysics [1, 2]. For example, the Hubble Space Telescope (Fig. 1) and space satellites have observed a number of spectra for different interstellar clouds (Fig. 2), and from these spectra the information of element constituents can be determined. In this procedure, the data of absolute oscillator strengths and cross sections must be used, and large numbers of data are provided by the experiment of electron-molecule impact . We know that carbon monoxide is the second most abundant molecule, after H2, in interstellar clouds. In diffuse clouds, the amount of CO is mainly derived from measurements of absorption at UV wavelengths. But due to the inaccuracy of the data measured by early experiments, the observed spectra are hard to be explained. However, the recently measured oscillator strengths by electron impact have resolved this problem, and the measured spectra for the stars Ophiuchi A and have been well simulated .
The data of cross sections also have significant application in planet science. For example, of all of the fascinating questions in contemporary astrophysics, those relating to the origin and formation of the solar system must rank high in the curiosity of everyone. Comets，often lumped in texts under the heading ‘solar system debris’, are pursued because their chemical composition holds unique clues to the early history of our solar system, this is accessible by analyzing its constitute .
Another application of the cross-section data determined by electron impact is the gases discharge process, which is directly related to the development of applied techniques such as laser, plasma deposition and etching of semiconductors, and plasma display . Our everyday life is benefited from this great progresses of these techniques [Fig. 4].
In order to obtain the differential cross sections and oscillator strengths of electron-molecule impact, the energy dispersion and angular distribution of scattering electron intensity should be determined and this can be achieved by electron-energy-loss spectrometer. In recent years, the important progresses in experiment technique are: (1) the progress of relatively flux technique ; (2) the experimental realization of high energy resolution ; (3) the spread of multi-channel measurement ; (4) the development of preparation technique of excitation target ; (5) the realization of the large angular measurement technique and so on. The accuracy and extent of experimental data are greatly improved with the progresses of these experimental techniques. With the progress of the experiment technique, there will be more development for electron-molecule impact, and the data will be also updated constantly.
S. R. Federman , D. L. Lambert, J. Electro. Spec. Relat. Phenom., 123, 161(2002)
B. L. Rachford et al., Astrophys. J. 555, 839(2001)
M. J. Mumma, H. A. Weaver, H. P. Larson, M. Williams and
M. J. Brunger and S. J. Buckman, Phys. Rep. 357, 215(2002) and the references therein
G. Knoth, M. Gote, M. Radle, K. Jung and H. Ehrhardt, Phys. Rev. Lett. 62, 1735 (1989)
X. J. Liu, L. F. Zhu, X. M. Jiang, Z. S. Yuan, B. Cai, X. J. Chen and K. Z. Xu, Rev. Sci. Instrum., 72,3357-3361(2001)
S. Trajmar and J. C. Nickel, Adv. At. Mol. Opt. Phys. 30, 5(1992)
F. H. Read and J. M. Channing, Rev. Sci. Instrum. 67, 2372(1996) | 0.852535 | 4.050782 |
Quarter* ♏ Scorpio
Moon phase on 6 February 2067 Sunday is Waning Gibbous, 21 days old Moon is in Scorpio.Share this page: twitter facebook linkedin
Previous main lunar phase is the Full Moon before 7 days on 30 January 2067 at 10:29.
Moon rises in the evening and sets in the morning. It is visible to the southwest and it is high in the sky after midnight.
Moon is passing about ∠8° of ♏ Scorpio tropical zodiac sector.
Lunar disc appears visually 2.6% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1896" and ∠1946".
Next Full Moon is the Worm Moon of March 2067 after 22 days on 1 March 2067 at 04:42.
There is low ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at big angle, so their combined tidal force is weak.
The Moon is 21 days old. Earth's natural satellite is moving from the middle to the last part of current synodic month. This is lunation 829 of Meeus index or 1782 from Brown series.
Length of current 829 lunation is 29 days, 10 hours and 40 minutes. It is 9 minutes longer than next lunation 830 length.
Length of current synodic month is 2 hours and 4 minutes shorter than the mean length of synodic month, but it is still 4 hours and 5 minutes longer, compared to 21st century shortest.
This New Moon true anomaly is ∠2.4°. At beginning of next synodic month true anomaly will be ∠18.4°. 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°).
8 days after point of apogee on 28 January 2067 at 14:45 in ♋ Cancer. The lunar orbit is getting closer, while the Moon is moving inward the Earth. It will keep this direction for the next 6 days, until it get to the point of next perigee on 12 February 2067 at 19:54 in ♒ Aquarius.
Moon is 378 064 km (234 918 mi) away from Earth on this date. Moon moves closer next 6 days until perigee, when Earth-Moon distance will reach 358 905 km (223 013 mi).
10 days after its descending node on 26 January 2067 at 22:59 in ♊ Gemini, the Moon is following the southern part of its orbit for the next 3 days, until it will cross the ecliptic from South to North in ascending node on 10 February 2067 at 02:51 in ♐ Sagittarius.
23 days after beginning of current draconic month in ♐ Sagittarius, the Moon is moving from the second to the final part of it.
11 days after previous North standstill on 26 January 2067 at 00:50 in ♊ Gemini, when Moon has reached northern declination of ∠23.887°. Next 2 days the lunar orbit moves southward to face South declination of ∠-23.790° in the next southern standstill on 9 February 2067 at 10:40 in ♐ Sagittarius.
After 7 days on 13 February 2067 at 21:57 in ♒ Aquarius, the Moon will be in New Moon geocentric conjunction with the Sun and this alignment forms next Sun-Moon-Earth syzygy. | 0.848363 | 3.114788 |
NASA Will Tell You What Hubble Space Telescope Saw On Your Birthday
The year 2020 marks a very important moment in the history of space exploration, with the Hubble Space Telescope celebrating its thirtieth birthday.
Yup. One of the most famous objects ever to be sent out into orbit has been going strong for 30 years, capturing countless breathtaking sights. Talk about making the rest of us feel unaccomplished.
To celebrate this important anniversary, NASA is giving star gazers across the world the opportunity to find out what the telescope saw on their own birthday.
All you have to do is select the month and date of your birthday on the NASA website, and you can find out what extraordinary things were going on in the universe while you were cutting your cake.
Many are sharing their results on Twitter and Instagram using #Hubble30, and the results are – quite literally – out of this world.
For example, on my ninth birthday, Hubble spotted NGC 1999, a reflection nebula that doesn’t emit any visible light on its own but ‘shines only because the light from the star just to the left of the center illuminates the nebula’s dust’.
Of course, at the time I was completely unaware of such goings on, and was only interested in zooming around on my new micro scooter. However, it’s kind of cool to look back and realise how many secrets of the universe have been unravelled at the same time as ordinary moments in your own life.
Described as being the approximate size of a school bus, the Hubble telescope was originally launched in 1990, and has since made more than 1.4 million observations of numerous stars, planets and galaxies.
Speeding around Earth at a breezy 27,000 kilometres per hour (17,000mph), according to ScienceAlert, this telescope can point towards faraway objects with the accuracy of a laser beam directed towards one particular detail of a coin placed around 320 kilometres away (200 miles).
The telescope is even able to observe events that happened in the unimaginably distant past – looking at occurrences that took place 13.4 billion light-years from Earth.
According to the NASA website:
Hubble explores the universe 24 hours a day, 7 days a week. That means it has observed some fascinating cosmic wonder every day of the year, including on your birthday.
Examples shared on social media include images of the stars at the galactic core, and gorgeous shots of Jupiter.
You can check out the NASA birthday tool for yourself here.
If you have a story you want to tell, send it to UNILAD via [email protected] | 0.870796 | 3.025789 |
|- Brown Dwarfs|
|- Galactic Halos|
|- Dark Matter|
|- Distant Quasars|
|Details of the Data|
The Sloan Digital Sky Survey began operating on June 8, 1998. Since that time, SDSS scientists have been hard at work analyzing data and drawing conclusions. This page describes seven of the SDSS's most important discoveries so far. Many more discoveries are still waiting in the data.
Asteroids are small objects made of rock or metal that orbit the Sun. Most asteroids are found between the orbits of Mars and Jupiter, about 200 to 400 million miles from the Sun. They orbit the sun quickly enough, and close enough to the Earth, that they move during the five minutes it takes for the SDSS to scan a piece of sky. Very fast asteroids appear as colored streaks in SDSS images; slower asteroids appear as two or three colored dots close together. You can look for asteroids yourself in the Asteroids Project.
In 2001, a team of SDSS scientists led by Zeljko Ivezic of Princeton used the imaging data pipeline to find over 10,000 asteroids in SDSS data. The team studied the asteroids' brightnesses to learn about their sizes, and the asteroids' colors to learn about their compositions. The team drew two important conclusions from this study.
First, the scientists concluded that the asteroid belt probably contains about 500,000 asteroids - only 25% as many as astronomers previously thought. Second, the SDSS scientists confirmed previous suggestions that the asteroid belt is actually two belts: an inner belt of rocky asteroids and an outer belt of icy asteroids. The scientists showed that asteroids can be classified into these two belts based only on their colors, a process significantly faster than other methods. The SDSS will continue to be a rich resource for scientists - the SDSS team estimates that the survey will eventually discover 100,000 asteroids!
Brown dwarfs are missing links in the story of the universe: objects too big to be planets but too small to be stars. For forty years, scientists have known that they must exist, but since they do not emit light from nuclear reactions, they are very dim and hard to see.
Brown dwarfs come in two types. Class L dwarfs have about 50 to 80 times the mass of Jupiter, while class T dwarfs have about 20 to 50 times the mass of Jupiter. Class T dwarfs are cooler and fainter than class L dwarfs. By the time the SDSS began in 1998, ten years of searching had produced a handful of class L brown dwarfs and only one class T brown dwarf.
But in 1999, SDSS astronomers Xiaohui Fan and Michael Strauss of Princeton found a faint red object in the SDSS data. When they looked at its spectrum, they found a line for methane - a clear signal of a class T dwarf. Two weeks later, Zlatan Tsvetanov and Wei Zheng of the Johns Hopkins University found another class T dwarf in the SDSS data. Astronomers are now studying both objects closely - although scientists now know for sure that brown dwarfs exist, they still know very little about them.
All galaxies, including our own Milky Way, have thin spherical "halos" of stars that surround them. Astronomers have two theories about where these halos came from. Either the halo formed first, and the galaxy condensed out of them, or the halo formed later, built up from smaller galaxies that crashed into the main galaxy.
SDSS astronomers have been trying to decide between the two theories. A team led by Heidi Newberg of Rensselaer Polytechnic Institute and Brian Yanny of Fermilab carefully mapped a large part of the Milky Way's halo. They found five sections where the halo was unusually thick.
They made H-R diagrams of the stars in these thick areas - graphs that show how bright different types of stars shine (you can make your own diagrams in the H-R Diagram Project.) The diagrams they made looked similar to diagrams for a small galaxy called the Sagittarius Dwarf Galaxy, which orbits the Milky Way. This discovery suggests that the stars in these five thick areas of the Milky Way's halo were pulled out of the Sagittarius Dwarf by the Milky Way's gravity. These areas lend support to the idea that galactic halos are built up over time as smaller galaxies crash into larger ones.
For about 25 years, astronomers have known that what we see is not all there is. In the mid-1970s, Vera Rubin, an astronomer at the Carnegie Institute of Washington, studied the rotation of galaxies and realized that they must contain much more matter than we could see. Further studies showed that about 90% of the matter in the universe does not emit light - it is "dark matter." Although scientists knew then that dark matter must exist, they still did not know what it was or where it was hiding.
In 1999, a team of SDSS astronomers led by Phillippe Fischer and Timothy McKay of the University of Michigan set out to find dark matter in nearby galaxies. They used a technique called "gravitational lensing" predicted by Einstein's General Theory of Relativity. Massive objects like galaxies bend light rays that travel near them, just as a glass lens does. So when you look at a distant galaxy behind a nearby galaxy, light from the distant galaxy will be bent, and the distant galaxy will look smeared out. However, the amount of smearing is very small, less than 1% of the width of the galaxy. Since galaxies look fuzzy anyway, astronomers have a hard time telling how much of the smearing is due to gravitational lensing by the nearby galaxy.
Fischer and McKay added up the smeared images of distant galaxies around 30,000 nearby galaxies, guessing that the random variations in galaxy shape would cancel out, but the effect of gravitational lensing would add together. Then, they used a computer program to find what mass distribution in the nearby galaxies would be required to generate the observed lensing.
They found that the galaxies were twice as big as anyone had previously thought. In fact, the Milky Way's dark matter probably stretches out so far that it touches the dark matter of the Andromeda Galaxy, 2 million light-years (18,921,600,000,000,000,000 kilometers) away!
So now astronomers know that much of the universe's dark matter forms a part of galaxies like our own. But they still do not know what dark matter is.
Quasars, galaxies with very active centers, are the most distant objects in the universe. A typical quasar is the size of our Solar System, but produces as much energy as an entire galaxy. Because quasars are so bright, we can see them on Earth even though they are very far away.
Because light travels at a finite speed of about 300,000 kilometers per second, it takes light a long time to get from quasars to us. Because of this time delay, when we see a quasar, we are looking at it as it was billions of years ago. Therefore, studying quasars can tell us many things about the early universe.
The SDSS was specially designed to find quasars. In fact, since 1998, the SDSS has found 26 of the 30 most distant quasars ever seen. In 2000, a team of SDSS scientists found the most distant quasar yet - a quasar that emitted its light when the universe was less than one-tenth of its current age. By the end of the survey, SDSS astronomers expect to find 100,000 quasars - ten times as many as were known before the survey.
The Gunn-Peterson Trough
As soon as astronomers found distant quasars, they began to think of ways they could use them to understand the early universe. In 1965, Jim Gunn (who went on to work for SDSS) and Bruce Peterson of Caltech predicted that distant quasars should show evidence of the end of the cosmic dark ages. But until recently, no one had ever seen an object distant enough to check their prediction.
About a million years after the big bang, the universe was full of a thick gas of hydrogen atoms. Hydrogen atoms absorb ultraviolet light well, so any light traveling through early the universe was quickly absorbed by a hydrogen atom. The universe was dark. Over time, the gas clumped together to form the first stars, which began to emit light - but this light too was quickly absorbed. Eventually, the stars became bright enough that their light had enough energy to break the hydrogen atoms into protons and electrons. After this happened, light could pass freely through the universe. The cosmic dark age was over.
Gunn and Peterson realized that even a small amount of remaining hydrogen atoms - as little as 1 remaining atom for every 100,000 broken - should have enough of an effect to be noticed in the spectrum of a distant object. Gunn and Peterson predicted that astronomers should see a "trough" in the ultraviolet part of an object's spectrum - less light than expected - because of the remaining hydrogen atoms. This effect was called the "Gunn-Peterson trough," and astronomers began to look for it.
In the summer of 2001, Robert Becker from the Lawrence Livermore National Laboratory in California led a team of astronomers that examined the spectrum of the distant quasar shown above. Becker's team found an unmistakable Gunn-Peterson trough in the quasar's spectrum. Because the quasar was so far away, its trough was shifted from the ultraviolet into the infrared.
The team's discovery ended a nearly 40-year search. SDSS astronomers will now look for Gunn-Peterson troughs in other distant quasars to try to gain a better understanding of the effect.
The Structure of the Universe
The primary question that SDSS was designed to answer is: what is the large-scale structure of the universe? Scientists know that stars make up galaxies, galaxies make up clusters, and clusters make up superclusters. But do superclusters make up super-superclusters? At what point does the clustering stop?
Although the SDSS has only been operating since 1998, it already has a preliminary answer:
The graph shows the distribution of galaxies in a wedge-shaped section of the universe seen by the SDSS. RA stands for "right ascension," a measure of position in the sky, and z stands for redshift, which is related to distance from Earth. Each dot in the graph is one galaxy. The graph thins out at greater redshifts because galaxies farther away are harder to see.
The graph shows that galaxies organize into long, narrow walls with open spaces between. The universe looks a little like a mass of soap bubbles in a kitchen sink. Now that astronomers have this map, they can start to analyze it in detail. They are now looking at the spacing between the strips of galaxies. Different theories about the history of the universe predict different amounts of spacing, or "characteristic wavelengths." By carefully studying the characteristic wavelengths in the map the SDSS makes, astronomers can decide between different theories. That work will probably take many years.
The SDSS's public website keeps a News page that lists SDSS's press releases and collects links to articles about SDSS in the popular press. Click the link below to go to the SDSS News site.
Most of the research described here has been described in detail in papers published in scientific journals. Click here for a list of publications. | 0.834806 | 3.913325 |
Last Sunday, our corner of the night sky was graced with a full moon called a “Tiny Hunter”. Tiny, because the moon was at the furthest point in its elliptical orbit. Hunter, because this time of year harvested fields leave few places for animals to hide. (Add a full moon and the hunting’s even easier). When our Tiny Hunter rose in the east that night, it was as if a giant flashlight switched on in the heavens, blotting out a typically starry night. But I know it didn’t blot out everything. Venus, beckoning brightly to the west, was saying hey, this is my party too.
Next to the moon, Venus is the brightest bulb in the night sky. Even if you don’t know where she sits, you can find her by simply scanning the western horizon at dusk or eastern at dawn for the most brilliant pinpoint of light. As if outshining all of the stars isn’t enough, Venus is also the most vivid planet. Mars, Saturn, and Jupiter occasionally make an appearance, but Venus always seems to be there. Even in broad daylight.
I’m not gonna lie; Venus gives me a bit of a girl crush. After all, she’s the Roman goddess of love and beauty. Now consider her other “outstanding” attributes:
- She’s the only planet in our solar system to identify as female.
- She’s referred to as our “sister planet”, not only because she’s our closest neighbor, but because she’s virtually the same size.
- She rotates in the opposite direction of seven of the eight planets (including Earth).
- She hosts two continents: Ishtar Terra (named after the Babylonian goddess of love), and Aphrodite Terra (named after the Greek goddess of love).
- Her rotation is so slow, a day in her world is longer than a year in ours. But, a year in her world is shorter than that same day. Say what? You read that right: Venus completes a trip around the sun faster than she completes a rotation on her own axis.
- Her orbit is closer to the shape of a circle (vs. an ellipse) than all other planets.
- She has no moons or rings. Naturally, why would the goddess of love and beauty need adornments?
No wonder the Babylonians referred to Venus as “bright queen of the sky”, eh?
Given her allure, it’s a wonder our earthly culture hasn’t done more to embrace her. I went in search of homage to Venus and here’s all I could come up with:
- Sandro Botticelli’s iconic “The Birth of Venus” (top left), with our girl posed unashamedly naked on a seashell.
- Vincent van Gogh’s post-impressionist “The Starry Night” (top center), with Venus as the bright “star” just to the right of the cypress tree.
- The Bible’s Song of Songs (fitting, if you know the book’s subject matter), Chapter 6, Verse 10.
- John Gray’s bestselling relationship guide, Men are from Mars, Women are from Venus.
- Gillette’s “Venus” line of women’s shaving products.
- The “Venus” women’s clothing line (catalog arrived for my wife just last week).
- A nasty-looking fly-trapping plant.
- Frankie Avalon’s adoring anthem “Venus” (Hey, Venus… oh, VENUS…).
- Shocking Blue’s psychedelic rock hit “Venus” (I’m your Venus… I’m your fire, at your desire…).
If that’s the extent of our tribute to Venus, no wonder we have the phrase “hell hath no fury like a woman scorned”. Venus shows her not-so-lovely side if she wants to. She’s the hottest planet in the solar system (including Mercury), with an average surface temperature of 863 degrees F (462 C). Her atmospheric pressure is 92 times stronger than Earth’s (which is why her surface is beautifully crater-free). She’s covered in a thick layer of sulfuric acid clouds. Her wind speeds are extraordinarily high. And she’s explosive, with a long history of volcanic activity.
Scientists believe – 700 million years ago under drastically different conditions – Venus was temperate enough to host oceans of water and life itself. So…, what in God’s name happened to make her so nasty now? Whatever it was, even our most advanced spacecraft can’t land on her surface today (though we’re working on it).
Considering this brief education on Venus, I suggest you ignore her siren song and simply admire her from afar. Even if you could speed your car along an interstellar highway, you’d need over forty years to get to Earth’s twisted sister. No; stay on her good side lest she show her surface temperatures and atmospheric pressures. That wouldn’t go well for you. I’d rather look Medusa in the eye and be turned to stone. | 0.859805 | 3.151069 |
July 14, 2015 – In 1930, an object smaller than our moon was discovered, labeled the ninth planet from the sun, and named Pluto at the suggestion of 11-year-old British girl Venetia Burney. The name was adopted because it was thought to be fitting as Pluto is the Roman God of the Underworld who is able to make himself invisible.
Invisible no longer.
Pluto, recently recategorized as a dwarf planet, is now visible thanks to the New Horizons space probe, which reached its closest approach to Pluto on its historic flyby this morning after a nine-year, three billion mile journey.
Aboard the spacecraft are seven scientific instruments, including one designed, built and operated by University of Colorado (CU) Boulder students. This instrument, the Venetia Burney Student Dust Counter (SDC), is named after the girl that gave Pluto its name, and is the first instrument on a NASA planetary mission to be designed, built and operated entirely by students.
“We’ve known about Pluto’s existence since 1930 and we’ve never been able to get close to it, never had great pictures,” said Chelsey Krug, a current Laboratory for Atmospheric and Space Physics (LASP) researcher who worked on the dust counter project as a graduate student at CU Boulder. “We’re finally getting to this item that we’ve never been able to explore before.”
While most of the instruments have been hibernating, waiting for the probe’s encounter with Pluto, the SDC has been continuously measuring the density and distribution of space dust particles on the its journey across the solar system beginning mere months after its launch in 2006.
The dust counter, about the size of a briefcase, is situated on the front of the grand piano-sized spacecraft. It works by collecting data from a sensor that records an electric signal when hit by a dust particle. The instrument can detect the size of the particle based on this signal, as well as its location along the probe’s trajectory.
This unprecedented data will help to improve models of dust in the outer solar system, which have been mostly theoretical to this point. By mapping our solar system’s dust, scientists will be able to compare and contrast it with space dust in other solar systems, which could help in the search for Earth-like planets.
“Dust particles are the building blocks of all planetary objects,” said Mihaly Horanyi, LASP researcher and Principal Investigator for the SDC project. “Understanding how they are produced, destroyed and transported provides important and unique clues about the history, evolution, and current workings of our solar system.”
The SDC is already the farthest traveled dust counter ever, having broken that mark in October 2010, and will reach a distance of more than double the next farthest dust counter in the near future.
Originally planned to shut down to save power when the other instruments awakened from their slumber to start monitoring the Pluto system, NASA decided that there was enough power to keep the dust counter on. This data could help to unlock clues about meteoroid collisions on the dwarf plant and its moons, as well as the possibility of invisible rings orbiting Pluto.
Several of the students involved in the project credit it with helping them develop the skills necessary to launch a career in space science.
“It’s one thing to graduate from school knowing in theory how things work, but having actually done it makes you much more valuable,” said Beth Cervelli, a current LASP spacecraft programmer who worked on the dust counter project as an undergraduate student at CU Boulder.
The students were held to high standards, and even faced panels of NASA scientists for questioning.
“They would ask the same types of questions that they would ask professional engineers, and they were asking them to us students,” said Krug. “It was up to us to have the answer.”
Cervelli is grateful for her involvement in the project because it helped her discover what she wanted to do for a career. After working on the software for the dust counter (which she calls “the brain of the instrument”), she took a job with LASP working on software for other space science instruments.
“I’m extremely grateful that I was in the right place and the right time to be involved in it,” she said.
Now that New Horizons has passed Pluto, the other six instruments will turn off again as the probe continues on its path further into the Kuiper Belt, the outer region of our solar system, turning on only if the spacecraft gets close enough to other large objects. But the SDC will stay on, continuing to collect data on space dust particles as long as it can.
“We believe we have enough power to go through 2035 and perhaps later,” said Fran Bagenal, Co-Investigator on the New Horizons mission, and LASP researcher. The probe’s generator runs on decaying plutonium, similar to Voyager 1, the farthest traveled spacecraft from Earth, which is still operating more than 37 years after its launch.
Entering the Kuiper Belt is exciting for those involved in the dust counter project because there will be more dust to measure, but the debris-filled region of our solar system could also pose problems for the probe. Objects as small as a grain of rice could severely damage the spacecraft due to its high speed—over 30,000 miles per hour. (New Horizons set the record for the highest launch speed of a human-made object from Earth at over 36,000 miles per hour. It also received a gravity assist from Jupiter which shaved nearly three years off the mission time.)
In addition to the science equipment, New Horizons is also carrying a variety of cultural artifacts including an American flag, Florida and Maryland state quarters, a CD containing the names of over 400,000 members of the general public who signed up to “travel” with the spacecraft back in 2005, and a small container of Clyde Tombaugh’s ashes. Tombaugh discovered Pluto in 1930, and his ashes will be the first human remains to exit our solar system.
The students and faculty advisors who worked on the SDC look back on the experience with fondness, but also forward to the science that their data will enable.
“The team kind of became a family as we were working on it,” said Krug. “We all went down to the launch together. It kept getting delayed, so our anticipation was building. When it finally went off I think several of us had tears in our eyes, just because it had been so much hard work.”
“They [the students] have moved on to have families and kids and busy lives, but I know that all of them will closely follow the encounter and remember their contributions with tremendous pride,” said Horanyi in a university press release. “The encounter is a landmark event along the way to explore the outskirts of the solar system, even beyond Pluto, for possibly decades to come.” | 0.846677 | 3.73 |
In Solar system, we have Rocky planets as inner planets and Gas Giants are outer ones. Is it similar in other star systems too?
- ANDRE LLv 79 months agoFavorite Answer
What we know now is that the planets in our solar system did not all form in the regions from the Sun that they currently are in.
Jupiter, long settled in its position as the fifth planet from our sun, was a rolling stone in its youth. Over the eons, the giant planet roamed toward the center of the solar system and back out again, at one point moving in about as close as Mars is now. The planet's travels profoundly influenced the solar system, changing the nature of the asteroid belt and making Mars smaller than it should have been. These details are based on a new model of the early solar system developed by an international team that includes NASA's Goddard Space Flight Center in Greenbelt, Md.
- AdamTheAtheistLv 79 months ago
No. It's just a coincidence.
- Ronald 7Lv 79 months ago
In a Normal System like ours it is quite possible
But not every Star System is normal
- 9 months ago
No... we've seen a wide variety of planetary arrangements - including one that has a gas giant as the closest planet, followed by a rocky world, then another gas giant, another rocky world, and the last world detected is a gas giant... when asked to explain how this might've happened, one of the Kepler analysts said, "It looks like God dropped his marbles..."
There's another system where a gas giant as big or bigger than Jupiter has a comet-like orbit, coming in very close to the star at very high speed, then moves very far out before falling back in again.
- How do you think about the answers? You can sign in to vote the answer.
- nineteenthlyLv 79 months ago
No. In other star systems there are often "hot Jupiters" near the stars, which are gaseous planets which orbit so close to their primaries that much of what would be rock on this planet is vapourised by the heat. There are some star systems like ours though.
- daniel gLv 79 months ago
We simply don't know for the vast distances to other solar systems.
What is known, is solar systems are quite random and unique in their beginnings, so generalizing based on our own system is being too narrow minded to be scientific fact.
- CarolOklaNolaLv 79 months ago
No. Many planetary systems have hot Jupiters amazingly close to the star. The planets in our Solar System have moved have moved. The terrestrial planets may be second generation planets.
- ElaineLv 79 months ago
So far it seems that each solar system is unique. Some stars have gas giants orbiting so close to their sun that they are given the name "Hot Jupiters". Then there are the "Hot Neptunes". Some stars appear to have only one or two planets. | 0.863304 | 3.230831 |
Now that NASA’s Institute for Advanced Concepts (NIAC) is back in business, I’m reminded that it was through NIAC studies that both Gerald Jackson and James Bickford introduced the possibility of harvesting antimatter rather than producing it in huge particle accelerators. The idea resonates at a time when the worldwide output of antimatter is measured in nanograms per year, and the overall cost pegged at something like $100 trillion per gram. Find natural antimatter sources in space and you can think about collecting the ten micrograms that might power a 100-ton payload for a one-year round trip mission to Jupiter. Contrast that with Juno’s pace!
That assumes, of course, that we can gather enough antimatter to test the concept and develop propulsion systems — doubtless hybrids at first — that begin to draw on antimatter’s power. Bickford (Draper Laboratory, Cambridge MA) became interested in near-Earth antimatter when he realized that the bombardment of the upper atmosphere of the Earth by high-energy galactic cosmic rays should result in ‘pair production,’ creating an elementary particle and its antiparticle.
A planetary magnetic field can hold such particles in place, producing a localized source of antiprotons. The detection of antimatter in this configuration has now been confirmed by a team of researchers using data from the Pamela satellite (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics). In fact, Pamela picks up thousands of times more antiprotons in a region called the South Atlantic Anomaly than would be expected from normal particle decays.
Image: A cross-sectional view of the Van Allen radiation belts, noting the point where the South Atlantic Anomaly occurs. Credit: Wikimedia Commons.
We could go so far as to talk about an ‘antimatter belt’ around the Earth, as the paper on this work explains:
Antiprotons are… created in pair production processes in reactions of energetic CRs [cosmic rays] with Earth’s exosphere. Some of the antiparticles produced in the innermost region of the magnetosphere are captured by the geomagnetic field allowing the formation of an antiproton radiation belt around the Earth. The particles accumulate until they are removed due to annihilation or ionization losses. The trapped particles are characterized by a narrow pitch angle distribution centered around 90 deg and drift along geomagnetic field lines belonging to the same McIlwain L-shell where they were produced. Due to magnetospheric transport processes, the antiproton population is expected to be distributed over a wide range of radial distances.
The McIlwain L-shell referred to above describes the magnetic field lines under investigation. As to the South Atlantic Anomaly, it is here that the inner Van Allen radiation belt approaches the Earth’s surface most closely, which creates a higher degree of flux of energetic particles in the region. It turns out to be quite a lively place, as this Wikipedia article on the matter makes clear:
The South Atlantic Anomaly is of great significance to astronomical satellites and other spacecraft that orbit the Earth at several hundred kilometers altitude; these orbits take satellites through the anomaly periodically, exposing them to several minutes of strong radiation, caused by the trapped protons in the inner Van Allen belt, each time. The International Space Station, orbiting with an inclination of 51.6°, requires extra shielding to deal with this problem. The Hubble Space Telescope does not take observations while passing through the SAA. Astronauts are also affected by this region which is said to be the cause of peculiar ‘shooting stars’ (phosphenes) seen in the visual field of astronauts. Passing through the South Atlantic Anomaly is thought to be the reason for the early failures of the Globalstar network’s satellites.
What we’re seeing in the new work is that the Van Allen belt is indeed confining antiparticles in ways that the earlier NIAC work suggested. The antiprotons eventually encounter normal matter in the Earth’s atmosphere and are annihilated, but new antiparticles continue to be produced. The question is whether there may be enough antimatter here for hybrid missions like Steven Howe’s antimatter sail, which uses tiny amounts of antimatter to induce fission in a uranium-infused sail. James Bickford, in his Phase II study at NIAC, talked about a collection scheme that could collect 25 nanograms per day, using a plasma magnet to create a magnetic scoop that could be deployed in an equatorial Earth orbit, one that would trap incoming antiprotons.
Antimatter trapped in Earth’s inner radiation belt offers us useful savings, if Bickford is right in thinking that space harvesting will prove five orders of magnitude more cost effective than antimatter creation here on Earth. I also noticed an interesting comment in his Phase II NIAC report: “Future enhanced systems would be able to collect from the GCR [galactic cosmic ray] flux en route to further supplement the fuel supply.” Obviously, exploiting antimatter trapped near the Earth and other Solar System worlds assumes a robust space-based infrastructure, but it may be one that will finally be able to bring antimatter propulsion into a new era of experimentation.
James Bickford’s Phase II report is titled “Extraction of Antiparticles Concentrated in Planetary Magnetic Fields” (online at the NIAC site). Back in 2007 I looked at this work in three connected posts, which may be useful in putting all this in context:
- Antimatter For Deep Space Propulsion
- Finding Antimatter in the Solar System
- Collecting Natural Antimatter
The Pamela work is found in Adriani et al., “The discovery of geomagnetically trapped cosmic ray antiprotons,” Astrophysical Journal Letters Vol. 37, No. 2, L29 (abstract / preprint). See also Gusev et al., “Antiparticle content in the magnetosphere,” Advances in Space Research, Volume 42, Issue 9, p. 1550-1555 (2008). Abstract available. | 0.899489 | 3.895341 |
Our Earth is encapsulated by an Electro-Magnetic field, known as a Torroidal (Torus) or Toric Field.
The centre of Earth’s Torus is anchored deep within the crystalline iron core of Earth (the ‘Heart’ of Earth, or ‘Earth Gateway’ or the Zero Point). Energy then emanates through Earth’s Torus in Fibonacci spiral formations around/through the Earth, returning once more into the Earth’s Heart.
In a holographic/fractal universe the Toric Field of Earth is akin to the Toric Field of the Atom, the Toric Field that surrounds the Human Heart, the Toric Field around our Sun (Heliosphere) and even on a much larger scale again the Toric Field around our entire Milky Way Galaxy.
The Magnetic component of Earth’s Torus gives Earth her magnetic north and south poles.
The Electrical component is measured in hz (hertz) and is referred to as ‘Earths Heartbeat’.
Collectively, the Electro-Magnetic Field creates the container of Earth’s atmosphere and protects all life on Earth by deflecting solar wind and protecting against harmful solar radiation. In addition, the Toric Field resonance is the container of the consciousness of the planet.
Earths Heartbeat – Schumann Resonance
The Earths electrical hz frequency heartbeat is referred to as the Earth’s ‘Schumann Resonance’.
In 1952-54, German physicist, engineer & mathematician – Winfried Otto Schumann predicted and attempted to measure the hz resonance of Earth – the hz wave resonance within the Earths cavity – from the Earths surface up to the the upper levels of the atmosphere, the ionosphere. Whilst it wasn’t until the early 1960s that accurate measurements could be calculated (due to the work of Balser and Wagner), none-the-less today the measurements are called ‘Schumann Resonance’ frequencies.
The Schumann Resonance – the electromagnetic wave frequency between Earths surface & the ionosphere – is generated and excited by lightning. On Earth today the Schumann Resonance is tracked my monitors placed by research stations around the world and the recorded hz frequencies at each station vary day to day (and vary according to their location).
The resting state of Earths Heartbeat is 7.83hz and scientists hypothesize that this resonant frequency has remained this way for thousands of year. This biologic frequency represents the threshold between our Theta-Alpha brainwaves and supports homeostasis of all life forms within Earths biosphere. When astronauts are in outer-space, spacecrafts now simulate the 7.83hz frequency, to support the healthy physical, emotional & mental states of space travellers.
Schumann Resonance is Increasing
For thousands of years, the Schumann resonance biologic heartbeat of Earth has been 7.83 hz, but since the 1960’s, the Schumann Resonance has been steadily on the rise.
Our Sun’s Heliosphere entered into the Photon Band/Belt of Alcyone, the brightest star in the Pleiades, in the 1960’s (highly charged region of space according to Dr Alexey Dmitriev) affecting the resonant frequency of all celestial bodies with the Suns Heliosphere cavity, including Earth. What comes to mind for me is the ‘swinging sixties’ – a shift in consciousness as people ‘broke-free’ of dogmas limiting their freedoms and rights
1987 marked the 25 year countdown to the end of the Mayan Calendar (and the year of the Harmonic Convergence) and was the year that Earth first entered the Photon Belt of Alcyone. It was from this time that the Schumann Resonance rose to 11 or even 12hz. Whilst these changes seem very very small (after all, the energy of colours are in the trillions of hertz), small changes in Earths Heartbeat create huge shifts in biological life on Earth. To begin with, Earth’s 12hz Schumann Resonance equates to an effective 16 hour day… so yes, time really is speeding up !
As I mentioned above, there are monitors around the world that record Schumann Resonance frequencies. One of the research bodies leading the way in understanding more about biological life and Schumann frequencies is the Global Coherenece Initiative (HeartMath) in cooperation with The Global Consciousness Project.
When reflecting on the Schumann Resonant frequencies over the last 12 months (2016-2017), there has been an upward trend in the resonances, with many stations around the world recording readings in the 40’s & even 50 hz frequencies. Whilst these readings have not been sustained and vary greatly between recording monitors, needless to say this continued rise is drawing attention of scientists and avid Earth Healers alike.
Of particular interest are the present ‘reversed poles’ in deep regions of the Earth under Southern Africa – the region is referred to as the ‘African Large Low Shear Velocity Province‘. The HeartMath readings of Schumann Resonate Frequencies in this region are off the scale… but that I feel is worth of a whole new article !
Earth’s Magnetic Pole Reversal
Earth’s electrical beat has an inverse relationship with Earths magnetic field – thus as the hz frequency of Earth increases, the Earth’s magnetic field is diminished. As the magnetics reach such a low threshold, Magnetic North & South become so weak and erratic (chaotic) that ultimately this leads to a full magnetic pole shift in Earth. Earth itself doesn’t flip (Geographic North & South stay the same), however the North & South Magnetics flip – meaning Magnetic North becomes Magnetic South and vice versa.
The diagram below from NASA displays the shift that occurs during a reversal. As you can see on the left, there is a Magnetic North & South of the Earths Toric Field. However, as the Earths Heartbeat hz increases, the Magnetics decrease and become ‘chaotic’, ultimately leading to a full shift where the Magnetic South is up and the Magnetic North is down (direction is based upon how ‘Earth’s globe’ is most commonly represented).
For thousands of years, ancient cultures from around the world hold within their story of Earth/humanity an understanding that this generation holds the key for the future. They talk about the ‘3 days of darkness’ (a full magnetic pole shift) a transition or birthing into a world where the Sun rises in the west as a new day (awakened consciousness) arises.
Has Earth’s Magnetic Poles Flipped before ?
Scientists/geologists look to the iron stores within the Earth to historically trace Earth’s cycles and her magnetic poles. It is known that Earth’s magnetic poles have flipped many many times before (see diagram below).
In the last 3.6 Million years there have been 9 full Magnetic Pole reversals, equating to approximately 400,000 years between each reversal. However, our last full Magnetic Pole reversal was over 780,000 years ago… thus based on the law of probability and looking at the data historically, we are well and truly overdue for a reversal.
What will trigger Magnetic Pole Reversal ?
As I have discussed, as the Earth’s Heartbeat hz increases, the magnetics of the Earth are diminished – which leads to a pole reversal. So the question is, what is causing the Earth’s Heartbeat hz to increase ?
There are so many factors involved in this complex question.. that it would be near to impossible to even attempt to try and cover everything in this short article. Rather, for simplicity, I have chosen to touch on the major catalysts and then more importantly look at the impact this will have upon biologic life.
Earth’s HeartBeat is gradually increasing due to:
- Solar Activity (& higher luminosity of the Heliosphere) activating Earths Toric field
- Photon Belt / Band of Alcyone activating Earths Toric Field
- Galactic Love Waves (through the Galactic Toric Field) activating Earths Toric field
- Humanities individual & collective ‘Activated Heart Coherence/Resonance‘ activating Earths Toric Field
- Celestial Alignments (eg Lunar & Solar Eclipses, Solstices, Equinoxes, Galactic Centre Conjuctions etc…).
- World events that open our Hearts and create Global Coherence within the Field.
The above factors, in combination with many others is increasings Earths HeartBeat hz and gradually decreasing the magnetic field, ultimately leading to a full magnetic polar shift… possibly any time soon !
What will happen during a Magnetic Pole Reversal ?
As the Earth’s Heartbeat hz increases and holds a synchronised, sustained and harmonic HeartBeat frequency around the Earth of 13.13 hz, this will be the critical point hz frequency that will lead to a full Earth’s Magnetic Pole reversal.
As the Earths Magnetics diminish and became erratic, it will then be humanity’s individual/collective Heart Toric fields (in combination with Galactic Toric Field) that will quantum leap ALL life forms into this next phase of evolution.
At the threshold of 13.13 hz, humanities primordial cells are resonated and pineal glands ‘ignite’ creating a cascade of quantum shifts in the body… from the Activation of DNA (all 64 DNA Lightcodes) through to the Attunement of DNA to a resonate frequency that now reflects a awakened level of 5D consciousness within the physical body.
Humanity’s individual/collective Heart Toric fields will then re-establish the new Electro-Magnetic HeartField of Earth, stablise her HeartBeat and support a ‘simulation’ of consciousness from an awakened level of 5D awareness. Refer to the diagram below:
Regarding the 13.13hz threshold, I will cover the reasons behind this in future articles. If you would like to receive my future articles, then please sign up to my FREE eNewsletter below.
When will Earth’s Magnetic Poles Reverse ?
When the next Magnetic Pole Reversal will be is anyone’s guess. Among scientists there is an understanding that a Pole Reversal in imminent, but theory’s cover wide ranges of time/conditions for a reversal. The reversal could easily happen tomorrow or possibly in hundreds of year time… and then once triggered it could possibly take just a few days to reverse with some schools of thought saying it could take at least a 1,000 years to reverse.
My feeling is, rather than get stuck on a date (a very human ‘mental’ thing to do according to a linear Gregorian Calender) – a better solution would be to hold within your heart a vision of a beautiful new world. To take responsibility for your life, your heart resonance, what you gift in service to the world and breath by breath live your life in service to this greater vision.
It is our individual & collective heart fields that will create this beautiful new world… and it is up to each and everyone of us what we do NOW that will make the difference in the future and determine the level of awakened consciousness that we leap into.
As world events take place over the days, weeks, months & years to come (coming to mind at this moment is the recent US Presidential election) and as Celestial Alignments are pushing you into new states of expansion, you have a choice in how you resonate and align with the collective heart field.
Rather than get caught in the divisive concept of ‘us’ & ‘them’… choose to live your life in compassionate understanding, in unified vision and in service of a vision greater than yourself to lift up the human spirit to new heights and awaken a beautiful new world that our hearts know is possible (thank you Charles Eisenstein).
From an esoteric view point, I believe that a full polar shift does not have to be an event of destruction, chaos, earthquakes, tsunami’s and the like (and I have deliberately avoided discussion of these scenarios in this article).
Take ownership of your Sacred Wealth through your Heart and live/work in harmonic alignment with the HEART of Creation in order to step into the Harmonically Wealthy FREEDOM of your Soul. From this place of awareness we can catalyse this pole reversal in highest good of the greater all and choose to make it a peaceful transition into a new story of our planet Earth. | 0.885623 | 3.571807 |
Launched on August 5, 2011, NASA’s Juno spacecraft will arrive at Jupiter in 2016 to study its magnetic field and atmosphere. Using its suite of science instruments Juno will peer inside the gas giant’s thick clouds, revealing hidden structures and powerful storms. To help people visualize what it means to see the invisible, JPL’s visual strategist Dan Goods created the exhibit above, titled Beneath the Surface. It’s an installation of lights, sound and fog effects that dramatically recreates what Juno will experience as it orbits Jupiter. By using their cell phone cameras, viewers can see lightning “storms” hidden beneath upper, opaque layers of “atmosphere”… in much the same way Juno will.
Goods explains: “Humans are only able to see a little, tiny sliver of what there is available in light. There’s gamma rays, microwaves, ultraviolet and infrared light also, and infrared is close enough to the visible part of the spectrum that cell phone cameras can pick it up. Cell phones normally produce more grainy photos at night because they don’t try to cut out the infrared light the way higher-end digital cameras do so in this case, the cell phone cameras are an advantage.” (Via the Pasadena Weekly.)
I had a chance to meet Dan Goods during a Tweetup event for the Juno launch at Kennedy Space Center. He’d brought a table that had magnetic elements set beneath a flat black surface, and by passing a handheld magnet over the table you could “detect” the different magnetic fields… in some cases rather strongly, even though they were all obviously invisible. It was an ingenious way that Juno’s abilities could be demonstrated in a “hands-on” manner.
Beneath the Surface takes that kind of demonstration to an entirely new level.
“I love to work with the world of things that are right in front of you but you just can’t see,” Goods said. “With Juno, there’s all this structure just under the surface of Jupiter, but humans can develop tools that help us understand things we’d never have seen before.”
The exhibit was installed at the Pasadena Museum of California Art until January 8. It will now travel to science museums around the country.
Juno’s primary goal is to improve our understanding of Jupiter’s formation and evolution. The spacecraft will spend a year investigating the planet’s origins, interior structure, deep atmosphere and magnetosphere. Juno’s study of Jupiter will help us to understand the history of our own solar system and provide new insight into how planetary systems form and develop in our galaxy and beyond.
Explore the Juno mission more at http://missionjuno.swri.edu/. | 0.894487 | 3.410081 |
Let’s put some light to the pictogram that appeared in Avebury Manor on July 15, 2008.
The pictogram is a clear depiction of our planetary system on 23-24 Dec 2012, two or three days after the End of the Long Count Calendar – December 21, 2012.
It is a clear selection of two groups:
One group consist of thin circles and depicts the orbits of Mercury, Venus, Earth, Mars and Pluto.
The other one with bold circles consists of Jupiter, Saturn, Uranus and Neptune.
“They” insist that we pay attention to two things:
First: the first anomaly is in Pluto’s orbit, which clearly depicts that this heavenly body will be influenced by the outer gravitation from some passing body, planet or comet.
Second: the second anomaly is split into two groups. Can this be understood as a separation of our solar system into two groups, as result of the extreme Sun’s activity in combination with some extreme powerful gravitation of a passing body or comet?
The message is perfectly clear – it’s our solar system on 23-24 Dec 2012.
All this would not be so significant if 7 days after, on 22 July an update didn’t appear.
And what was on it, says absolutely everything we need to know!
It indicates huge geological changes and movements in our solar system as a result of the Sun’s expansion in mass and strong gravitational pull from the outside.
Have a look at the update and see for yourself:
The mass of the Sun is bigger by more then 25% and the planets Mercury and Venus are completely burned.
Attention: The person who depicted this diagram had made an error in the orbits of the Earth and Mars. They are both put in the same orbit, and its only a technical error.
Let’s proceed with the analysis:
The Earth with its companion (if the dot in it represents the Moon) together with Mars are staying in their orbits but dangerously close to the Sun.
It does not take to be a genius what this CME activity and Sun’s close gravity pull mean for Earth’s balance, magnetic and geological Poles.
According to this, we are facing a new extinction of human kind!
This is enough, but let’s see what else reveals the update of the 15 July pictogram.
After a short analysis, it becomes clear that the second pictogram (the update of the first one) is not depicting our solar system on 23, 24 Dec 2012 (it was only used to bring our attention to this time frame of 2012) but 8 days before the End of the Long Count Calendar – 13 Dec 2012.
Everything becomes clear from this point…and there is no doubt anymore what they are trying to say.
From the left side we see the approaching of a huge object (number 10) that is probably Planet X which has a strong gravitation which is influencing Pluto’s orbit and then a New Moon and a Bright Comet from the right side.
Expansion of the Sun is obvious, together with the swallowing of its two closest planets. Mercury and Venus are completely burned by the Sun.
If this pictogram is correct, our solar system will never be the same!
What is not completely clear to me is the huge circle outside of the planetary orbits.
Mr. Harold Stryderight considers that they are depicting an expanded view of the lunar orbit.
With that, in the planetary depiction of the Earth there is a dot inside, and on the bold circle outside the planetary orbits a similar symbol is shown, there is a high possibility that it is the zoomed orbit of the Moon around the Earth through the year.
About the other smaller figures close to the huge bold circle I can not comment because I honestly don’t know what they are trying to say with them.
Maybe if everything stays as it is, and the Shadow Government does not implement NWO at least during the summer season, new input will come and people will surely decode them.
Also surely there is someone over there that probably has the answers but we have already received the basic download.
I’m not sure about this but it is not bad if we see the pictures and the analysis of Mr. Harold Stryderight.
However, this is a confirmation from the 1996 pictogram where it is clearly shown that from the Earth for the first time some kind of cosmic rays from the galactic center will become visible.
What effect they will have on our solar system and on the life forms that live here, we have already explained.
We still need more input, but even from this little that we got, its 80% clear what is coming in 2012…
Alignment that is very important for us and also was for the ancients is on 21 Dec 2012.
This pictogram depicts our Solar System on 23-24 Dec 2012.
Here is the link to Solar System Live:
Please type: 2012-12-24
Compare the pictogram of the 22 July 2008 and it becomes clear.
2012 Nexus Event – Unknown Form of Energy comes our way!
There are high indications that climate change will increase, to extreme, as we approach the point of the perfect alignment with the galactic center on 21 Dec 2012.
This will be a natural result from the exposure of the maxim gravitational pull which comes from Sgr A* and from the passing celestial body that is close to our solar system and which as presented in the crop data, will intercept in 2012 an area close to Pluto.
If the galactic core which is in the center of the flatten disk has gravitational power to hold stars and planetary systems distant to 50,000 light-years in each direction, you better believe that it has power to do much more.
The stellar disk of the Milky Way is around 100,000 light-years in diameter and to hold all this together and to maintain the spin it takes extreme power. As we stated before, this engine is the Super Massive Black Hole, and Hubble Telescope discovered that is the case also with most of galaxies. In fact they are starting to find them everywhere but … it’s a huge Space, everything is possible.
Anyway, it will soon become obvious that the climate is out of control and more and more “surprises” will start to appear.
Tornados, Cyclones, earthquakes, volcanoes, shifting in the planetary magnetic balance, tsunamis and you name it, will eventually lead to a Shift in the Magnetic polarity of the Earths energetic grid and finally to a Shift in Geological Poles.
It starts to become clear to more and more people what Pole Shift in the geological aspect means.
It means new Global Flood, tearing apart of tectonic plates, sinking parts of continents, rising of new land, deadly CMEs and etc.
Not to mention the Sun, which by “coincidence”, will go through Pole Shift again, which so far, as far as we know, it was doing every 11 years.
The last Pole Shift was in 2001 the next one is in 2012.
Interesting, the more you dig, more and more it’s coming back to you, and its saying: “What more do you want, are you stupid or something…”
In magnetism North rejects North, but attracts South and vice versa.
Imagine if the Sun comes as close as it is depicted in the pictogram, and switches its polarity, in the moment of the flip its magnetic pull will certainly interfere with our magnetic and geological Poles.
There are already drastic changes in the magnetism of the Poles and not to mention changes in the geological Poles. It’s all connected with planetary spinning, then on the outer influence of the Sun, then directly to Sgr A* and so on and on.
excerpt slightly edited for better readability from the original at : http://www.postkvantnost.com/gloabal_awareness.htm
Are Sedna and Nibiru both orbiting our dark star companion, and is ours a double solar system?
(Pictures have been reproduced or modified from Andy Lloyd’s web page.)
Andy Lloyd, author of “The Dark Star”, presents a fascinating new theory about our Sun’s binary or companion and the famed Niburu, based on the work of Zechariah Sitchin’s “The Twelfth Planet”. Lloyd believes that there is a failed star or sun circling our own with a cometary orbit beginning just outside the Kuiper Belt at 60 to 70 AU and stretching all the way out to the Inner Oort Cloud. Its orbital period is at least three sars or 10,800 years which is very close to what astronomers have given to Sedna’s orbit. It orbits more or less on the same plane as the Sun and in the same direction as our solar system planets.
Nibiru’s Size, The Home World, and the Dark Star or Binary in the Background
What is really unique about his theory is that this dark star has its own planets, the first five minor, the sixth an Earth-sized Homeworld, and the seventh the planet or object we call Nibiru. The Homeworld is much like Earth and is where our Annunaki “gods” live. Nibiru is largely uninhabitable and acts more as a ship or battle station. When the dark star is at perihelion(closest approach to our sun) at 60 to 70 AU, Nibiru’s orbit, which is at 60 AU from its parent, has a wide enough orbit to cut through our solar system, usually in the vicinity of Jupiter’s orbit, although this can vary. Nibiru’s orbital inclination is some 30 degrees to our solar plane or ecliptic.
Dark Star Approaches(red) with giant Nibiru, its 7th Planet
As Nibiru cuts through our solar system in retrograde motion to the other planets it performs its various duties such as displacing or replacing planets and causing general havoc in the process. Its passage is momentous but short taking only a few weeks or months at most, after which it dissapears from view. It is fiery red in color with a debris-filled tail, and circling it are a number of moons which it sometimes uses as weapons to pound other planets. Nibiru or its moons were responsible for such feats as the destruction of Maldek and other planets which are now asteroid belts; the craters or surface scars on the Moon or planets of our solar system, as well as their varying axial tilts and orbits; the sinking of Atlantis and Noah’s Flood; and God knows what else. It is the physical link or “ferry” between our solar system and the dark star system.
Nibiru’s Orbit(red) Cutting Through Our Solar System
Close up of Nibiru Cutting Through Our Solar System
Nibiru, the Winged(or Horned) Disc
Many believe that since Nibiru causes so much fear, chaos, and destruction, that it is a reptillian or satanic instrument of war. In fact, the Dark Star and its entire system of planets may be a counterfiet system to our own, and domininantly alien or reptilian. Is this the domain of Lucifer and his fallen angels -the “outer darkness” of which the Bible speaks of, with tiny Pluto acting as Guardian of the Gates to Hell?
Do we have a miniature version of Nibiru and the Dark Star within our very own planet? If our hollow earth can be likened to to a cosmos or solar system and its inner central sun to a star around which other objects (representing planets) revolve, then we have a similar model, only on a much smaller scale. See the Earth’s Inner Sun on this site.
Astronomer Alessandro Morbidelli at the Cote D’Azur Observatory postulates that our Dark Star may have an orbital period of as much as six sars or 21,600 years. He bases this on the Babylonian Great Year period of six sars mentioned by Roman chronologist Censorinus in the third century AD. This is close to the 25,920 year period that astronomer Pickering gave to his planet Q back in 1909. After every such period or revolution the Earth’s poles become equatorial causing great catastrophes.
Like Andy Lloyd, Morbidelli believes our Dark Star is presently past its perihelion(farthest distance from the Sun) and on its way back, but it has a long way to go. He too believes it is now located somewhere in the star-rich fields of Sagittarius where it is not so easy to observe.
Magnificent presentation by Pane “AstralWalker” Andov about the mega event that will take place at the end of year 2012 and beginning of the 2013. He explains that thousands of years ago from the galactic centre of the Milky Way, there was a powerful release of an enormous amount of energy, which like a huge, shining, circular wave is spreading across the galaxy from its centre to its edges.
The released energetic pulse is already affecting the whole galaxy including the little dot we call our solar system. Very soon it will reach us and hit us with full strength. He explains what kind of implications this spreading wave of energy will have on our solar system, especially to our star and our planet and how it will affect the DNA of life.
The way that Pane connects the dots makes it clear what our planet will face soon and what we as humans can do about it. He is also a contactee and delivers important messages which he backs up with scientific data. For the record, his DNA was changed when his biological body was only seven years old, enabling him to utilize abilities such telepathy, remote viewing, astral travel and to make contact.
He claims that from time to time numerous ET races communicate and deliver important messages to him as a result of alternations to his DNA in early childhood. One of those races is the positive race that is delivering the genuine crop circles, and they explained to him what the complex geometries mean. That’s how Pane was able to translate the complex geometric designs which contain the solution to the equation regarding what humanity is facing, when it’s going to happen and what can be done about it.
For more reference please visit his website:
Unless you read the ‘Lost Book Of Enki’ or the actual Sumerian texts, all you need to know starts here. The word Anunnaki is Sumerian for Hero. On Nibiru, all residents are known as ‘Hero’s’, just as we are ‘People’. There is most certainly a celestial body out there and it is definitely moving towards us. However, they will not show us due to a world wide panic and disaster… just as no telescope can see the lunar landing site, why? If it is there, where?
………. .:. ……….
My gratitude to the additional information provided by blog reader Phillip Lozano:
The lunar landing sites (there were six of them) have never been mysteries; their locations are well known, but the equipment left behind is simply too small and remote for Earth-based telescopes to see. You might as well ask why individual rocks aren’t easily visible on the moon’s surface.
However, the lunar landing sites were photographed back in 2009 by the Lunar Reconnaissance Orbiter, which orbits close enough to the moon’s surface to make out some detail from the landing sites: http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html | 0.915193 | 3.243829 |
Finding organic compounds on 67P’s surface is not actually particularly surprising. Organic compounds have been detected in material shed by comets before, and have been observed throughout interstellar space.
But we have never before been able to measure them in-situ, and this is where Philae offers something new and exciting.
While the results are preliminary, with researchers still working on a more detailed analysis, they are a tantalising reminder of the role comets played in the origin of life on Earth.
A rough but rewarding ride
European Space Agency’s mission of landing on the surface of a comet – a dirty snowball left over from the solar system’s birth – is surely one of the greatest technological achievements in the history of mankind.
Unfortunately, Philae’s landing wasn’t quite as smooth as was hoped, and the lander bounced to a stop leaning against a rock, in a shadowy region of the comet’s surface.
The result – Philae currently receives too little sunlight to stay awake, and after a couple of days of frantic activity on the surface, has now gone into hibernation.
Hopefully, as the comet swings towards perihelion (its closest approach to the sun) next August, the amount of light Philae receives will increase and the lander will awake from its slumber – but we can’t know for sure.
For now, Philae’s work is done, and the baton has been passed to the teams who are now furiously studying the hard-earned data sent back to Earth before Philae fell asleep.
That data was squirted back to the Earth shortly before the lander entered sleep mode – and it is likely that exciting results will continue to appear over the next weeks and months.
The first such results have already been made public, with the scientists confirming the detection of organic molecules on the comet’s surface. Not much is currently known – the scientists are still trying to fully disentangle the story of what has been observed – but the result is a tantalising glimpse of what is to come.
Comets and the origin of life
The reason that these results are particularly exciting goes back to two of the great unanswered scientific questions:
- what was the origin of life?
- how common is it throughout the universe?
Current theories of planet formation suggest that the Earth should have formed dry – this close to the sun in the proto-planetary nebula that birthed our planet, temperatures would have been too high for water to freeze out.
As a result, Earth required hydration, and it is thought that comets such as 67P would have been one of the main sources of the Earth’s water, delivering it in countless comet collisions during the final stages of planet formation.
Beyond the question of the origin of water, though, the origin of complex chemistry, the precursor to life, has long puzzled scientists. Where did the chemical building blocks that make up life as we know it come from?
Were those compounds “cooked” in the early oceans, or in the vast tidal zones that fringed the continents following the formation of the moon?
Or did they come from beyond the Earth, delivered in the collisions that dominated the process of planet formation?
Organics from space and home
As time goes by, it is seeming ever more likely that the origin of complex organic compounds on Earth is two-fold. Some was almost certainly cooked on our planet’s surface, with the rest delivered by comets and asteroids, smashing into our planet.
It is in this context that the Philae observations are so exciting – further evidence that organic compounds are common in the universe.
The result is an important confirmation that such compounds must be abundant. To have detected them after just a “sniff” of the comet suggests that they’re everywhere on its surface.
And given that we know comets have crashed into the Earth in vast numbers throughout our planet’s history, we must have been repeatedly doused in the kind of compounds that are the direct precursors to life itself.
Interestingly, the idea that life could have been delivered to Earth by comets has another, more speculative side – a theory known as “panspermia”. What if life didn’t start on Earth at all, but rather began elsewhere, and was delivered to our planet by rocks (or snowballs) from space?
The idea isn’t actually as far-fetched as it sounds. Experiments have shown that bacteria can survive the kind of forces that would be experienced in the collision of a comet or asteroid on a planet such as Earth.
And we know that impacts can eject solid, complete rocks from the surfaces of planets intact – we have meteorites on Earth that were definitely ejected from Mars. Still other experiments show that bacteria can survive, dormant, in the vacuum of space.
Following all of these results, it is quite possible, and perhaps even likely, that life in our solar system has been scattered back and forth between the planets over the billions of years since the planets formed. So if we do find life on Mars, then perhaps it will share a common origin with life on Earth, thanks to the countless collisions that have wracked both planets since they formed.
Some scientists go further, though, noting that life could be carried in comets from one planetary system to another. We know that they carry a rich organic budget – as demonstrated by Philae’s latest exciting result – but what if they carry more than just the precursors to life? Perhaps comets are actually an inter-stellar delivery mechanism, by which youthful planets are seeded with life as they form.
The more extreme versions of panspermia remain both speculative and controversial. Despite this, it is becoming more apparent that comets are, at the very least, a prime source of the precursors to life. They delivered the water on which life thrives, as well as the compounds upon which it is built.
Without comets, it seems, we may well not be here. | 0.893269 | 3.848978 |
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