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Giant Comets May Pose a Danger…Someday
They have been the topic of many disaster movies, but could giant comets really pose a threat to Earth? Scientists say, yes…someday. These “fictional” space rocks could very well crash into our planet, leaving a massive amount of damage in their wake, but when this may take place is still undetermined.
A team of astronomers from the University of Buckingham and the Armagh Observatory (Bill Napier and Duncan Steel of the University of Buckingham and Mark Bailey and David Asher of Armagh) published a review of recent research they conducted…the results may shock you.
Apparently, hundreds of giant comets have been making their way (and continue to do so) into our solar system over the last couple of decades, meaning the risk of one landing here on Earth has increased.
These giant space rocks called, Centaurs, used to be spinning around the outer reaches of our solar system, but because they are now encountering the gravitational forces of the larger planets (Jupiter, Saturn, Uranus and Neptune) they are occasionally being deflected into the path of Earth.
How big are these Centaurs?
Centaurs are typically 30–60 miles (50–100 kilometers) across, but can run even larger — containing more mass than the entire population of our planet! Calculations done by scientists show that Centaurs will enter Earths orbit about once every 40,000–100,000 years.
Where do we sit on this timeline?
With all the data collected over the years and extensive research done into the past all indicate a Centaur may have collided with our planet around 30,000 years-ago. In addition, researchers are also led to believe one of these cruising space rocks may have wiped out the dinosaurs some 65 million years-ago.
In a comment made by Napier, he states;
“In the last three decades, we have invested a lot of effort in tracking and analyzing the risk of a collision between Earth and an asteroid. Our work suggests we need to look beyond our immediate neighborhood too and look out beyond the orbit of Jupiter to find Centaurs. If we are right, then these distant comets could be a serious hazard, and it’s time to understand them better.”
While most space rocks burn up in our atmosphere, leaving behind fragments that can range from dust-size to mighty chunks, a collision by a Centaur would have truly devastating affects.
Although the above picture is of Phoebe (Saturn’s 124 mile diameter moon (200 kilometers)) scientists feel it is likely to be a Centaur that was once captured by the planet’s gravitational pull. Until we can send spacecraft to specifically image these Centaurs, Phoebe is the best guess researchers have into what these giant space rocks look like — this pic was obtained by the Cassini space probe orbiting Saturn.
“NASA’s New Horizons spacecraft has been targeted to conduct an approach to a 28 mile-wide (45-kilometer) trans-Neptunian object at the end of 2018.”
Is Earth likely to experience a giant comet slamming into its surface? Scientists are watching and learning all they can about this potential hazard. The possibilities may be slim, but we must be ever vigilant in our pursuit of knowledge and what lies beyond the sight of our telescopes. | 0.920524 | 3.612759 |
Astronomy Picture of the Day
APOD: 2004 November 21 - Spiral Galaxies in Collision
Explanation: Billions of years from now, only one of these two galaxies will remain. Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas, lanes of dark dust, bursts of star formation, and streams of cast-away stars. Astronomers predict that NGC 2207, the larger galaxy on the left, will eventually incorporate IC 2163, the smaller galaxy on the right. In the most recent encounter that peaked 40 million years ago, the smaller galaxy is swinging around counter-clockwise, and is now slightly behind the larger galaxy. The space between stars is so vast that when galaxies collide, the stars in them usually do not collide.
APOD: 2004 June 12 - NGC 4676: When Mice Collide
Explanation: These two mighty galaxies are pulling each other apart. Known as "The Mice" because they have such long tails, each spiral galaxy has likely already passed through the other. They will probably collide again and again until they coalesce. The long tails are created by the relative difference between gravitational pulls on the near and far parts of each galaxy. Because the distances are so large, the cosmic interaction takes place in slow motion -- over hundreds of millions of years. NGC 4676 lies about 300 million light-years away toward the constellation of Coma Berenices and are likely members of the Coma Cluster of Galaxies. The above picture was taken with the Hubble Space Telescope's Advanced Camera for Surveys which is more sensitive and images a larger field than previous Hubble cameras. The camera's increased sensitivity has imaged, serendipitously, galaxies far in the distance scattered about the frame.
APOD: 2005 April 4 - NGC 1316: After Galaxies Collide
Explanation: How did this strange-looking galaxy form? Astronomers turn detectives when trying to figure out the cause of unusual jumbles of stars, gas, and dust like NGC 1316. A preliminary inspection indicates that NGC 1316 is an enormous elliptical galaxy that includes dark dust lanes usually found in a spiral. The above image taken by the Hubble Space Telescope shows details, however, that help in reconstructing the history of this gigantic jumble. Close inspection finds fewer low mass globular clusters of stars toward NGC 1316's center. Such an effect is expected in galaxies that have undergone collisions or merging with other galaxies in the past few billion years. After such collisions, many star clusters would be destroyed in the dense galactic center. The dark knots and lanes of dust indicate that one or more of the devoured galaxies were spiral galaxies. NGC 1316 spans about 60,000 light years and lies about 75 million light years away toward the constellation of the Furnace.
Authors & editors:
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: EUD at NASA / GSFC
& Michigan Tech. U. | 0.861977 | 3.356235 |
A deep look at the MUSE spectrograph on the Very Large Telescope showed cosmic reservoirs of atomic hydrogen around distant galaxies. The sensitivity of the instrument made it possible to directly survey the dim clouds of hydrogen glowing with Lyman-alpha emissions in the early Universe.
A deep observation in the MUSE spectrograph on the Very Large Telescope revealed cosmic reservoirs of atomic hydrogen around distant galaxies. The sensitivity of the instrument made it possible to directly survey the dim clouds of hydrogen, glowing with Lyman-alpha emissions in the early Universe. It turns out the night sky is ablaze!
Astronomers are used to the fact that the sky is different depending on the wavelength, but the degree of radiation observed by Lyman-alpha is really surprising. The whole sky glows from distant clouds of hydrogen - the first building block of the universe.
The HUDF area observed by the team otherwise seems to be a completely unremarkable area in the constellation Pec. Its detailed map was provided by the Hubble Space Telescope in 2004 after 270 hours of observation.
The HUDF survey showed that thousands of scattered galaxies are hidden in a dark sky region. Opportunities MUSE allowed to look even deeper. Detection of Lyman-alpha radiation is the first time astronomers have been able to see this type of gas from the shells of early galaxies. The composite image shows the emission in blue superimposed on the HUDF frame.
MUSE is an ultra-modern integral field spectrograph on the Very Large Telescope of the Paranal Observatory. At the moment of observing the sky, MUSE sees the distribution of wavelengths in the light striking every pixel on the detector. A review of all light spectra allows us to better understand the astrophysical processes of space.
There is still no clear understanding of what causes these distant clouds of hydrogen to release Lyman-alpha waves. Future research is expected to find the cause through more sensitive measurements. | 0.884161 | 3.954439 |
With all this talk about human colonies on Mars, why not dream a little bigger? Dr Stephen Kane and his team of researchers at San Francisco State University are looking about 14 lightyears away from our solar system for some potentially inhabitable real estate.
Wolf 1061, a star system not terribly far from our own, has an interesting planet called Wolf 1061c. While scientists have known about the exoplanet since 2015, Kane and his team discovered that it’s squarely within the habitable zone — the region in the solar system where the atmospheric conditions could support liquid water. That said, Kane said that if there’s any life on the planet, it must be living under hostile conditions — similar to those of Venus — since it’s on the inner edge of the habitable zone, relatively close to its star.
“The Wolf 1061 system is important because it is so close and that gives other opportunities to do follow-up studies to see if it does indeed have life,” Kane said, according to Sci News. His team’s findings will be published in the next issue of Astrophysical Journal, though a pre-print is available here.
Image credit: NASA
The analysis of Wolf 1061c’s atmosphere could serve as an important case study for scientists looking to determine which exoplanets can support life. But while folks like Kane are analysing whether or not exoplanets are possibly habitable, other groups, like Messaging Extraterrestrial Intelligence (METI) are searching for signs of more advanced extraterrestrial life. Doug Vakoch, president METI, told Gizmodo his team has observed Wolf 1061c from their optical SETI observatory in Panama on four separate occasions. Alas, no luck yet.
“I’m not holding my breath that we’ll ever find evidence of life on Wolf 1061c, but the fact that there’s a roughly Earth-like planet in the habitable zone of a star so close to our own solar system is a good omen as we continue our search for life on other planets,” Vakoch said.
“We’ll try [to observe Wolf 1061c] again later next month, when it’s visible there again, using a more advanced detector system developed by Ben Schuetz, Director of the Boquete Optical SETI Observatory,” he added.
METI will continue its search for life outside the solar system, regardless of what it does or does not find on Wolf 1061c. But this latest bit of research from Kane and his team makes the planet a much more appealing prospect for further study.
“If we transmitted a radio signal to this exoplanet today, we might get a reply back from tech-savvy aliens in the Wolf 1061 system as early as 2045 — a mere blink of the eye on astronomical timescales,” Vakoch said. | 0.814696 | 3.179844 |
Priyamvada Natarajan, a theoretical astrophysicist at Yale University, is excited to be working in physics and astronomy at a time she and others call the “golden age of cosmology.”
“The maturity of our theoretical understanding, the sophistication of our instruments and tools that allow us to get the data—spacecraft, detectors—and the advanced computing are all aligned at the moment,” Natarajan said this week during a talk at Town Hall Seattle.
Natarajan has done a lot of work on mapping dark matter and dark energy, on gravitational lensing, and on figuring out how supermassive black holes are formed. It’s the latter that has her excited for the launch of the James Webb Space Telescope. She’s been a leader in pushing the idea that supermassive black holes could be formed by the direct collapse of matter. The physics pencils out, and Webb will peer back and possibly find the most distant, and therefore the first, black holes, and perhaps validate her ideas.
“The fact that you can come up with an idea as a scientist, for me, that’s the privilege,” she said.
Natarajan is the author of Mapping the Heavens: The Radical Scientific Ideas That Reveal the Cosmos (Yale University Press, 2016). She said she wrote the book not only to help us understand new discoveries about black holes and dark matter, but also to demystify the process of science.
“I believe very strongly that the current rampant disbelief in science stems from the contingent nature, the provisionality of science.” Natarajan said. “It’s something that’s very hard for the public at large to understand.”
The plus side is that cosmology and astronomy have the potential to win converts.
“Unlike many other fields in science, the night sky belongs to all of us,” she said. “We have to just look up and it’s there; the glory and the awe of the night sky.”
We know a lot
Natarajan finds it interesting that we know so much about the universe, with pretty solid evidence for much of what has happened since the tiniest fraction of a second after the Big Bang.
“It still stuns me that with a cantaloupe-sized gelatinous thing in our skull we’ve been able to figure all of this out,” she laughed. Yet despite all we do know, she said there is still a lot of mystery about our peculiar universe.
“We happen to live in one in which the total energy content of the universe is dominated by two components that we don’t know what they are,” she said.
What we call them are dark matter, which makes up 24 percent of the universe, and dark energy, which makes up 71 percent. We and all the stuff we see are less than five percent. Though we don’t know what dark matter is, Natarajan said there is solid evidence that it is indeed out there.
“The idea came out of an empirical need to explain an observation,” she said. Oddly enough, one of her other research interests, black holes, were conceived in exactly the opposite fashion.
“Black holes were actually proposed as a mathematical entity,” she noted. “They were a mathematical solution to Einstein’s equations, and they eventually became real.”
A little history
Dark matter was first suggested by Fritz Zwicky in 1933. Vera Rubin and others looking at galaxies in the 1970s proposed it as the reason rapidly spinning galaxies don’t fly apart. Natarajan said more than 80 years of research has left little doubt.
“We have incontrovertible evidence from many independent lines of investigation for the existence of dark matter because of the effects it produces, although it has not been directly detected yet,” she said. “We don’t know the particle.”
“We can exquisitely map it at the moment, even though we can’t see it, because of the gravitational influence that it exerts,” she said. “The other way in which we can detect dark matter is the impact that matter has on the propagation of light in our universe.”
This is where her work on gravitational lensing fits in. Large galaxy clusters, with as many as a thousand galaxies, can act as a sort of gravitational lens on steroids. Such clusters would be held together by enormous amounts of dark matter. The relativity “pothole” created by the cluster could be strong enough to split a beam of light.
“You end up seeing multiple images of an object where in reality there is only one object,” Natarajan said, noting that this has been observed many times now. Interestingly, she points out that the physics of both Newton and of Einstein would predict the effect.
“You can apply both of these arguments to clusters and you infer the same amount of dark matter,” she said. “In my opinion that is really, really strong evidence, compelling evidence, because they’re completely different world views and they still converge. There’s no escaping the concept of dark matter.”
Search for the holy grail
Natarajan said this sort of research may help us get to the holy grail of physics: a quantum theory of gravity.
“The motivation is to look for gaps, look for disagreements, and look for anomalies where an observation is actually inconsistent with our theoretical expectation,” she said.
A couple of great examples of this came out of the 1800s. The orbit of Uranus didn’t agree with Newton’s Laws, so they did the math and figured another planet could cause the observed discrepancies. That led to the discovery of Neptune. At the same time, there were anomalies in Mercury’s orbit, which led to the proposal that another planet, called Vulcan, was the cause. Vulcan was never found, but years later general relativity explained the precession of Mercury’s orbit perfectly.
“In one case the theory remained intact and an anomaly refined our understanding,” Natarajan said. “In the other case it pointed the way to the existence of a more fundamental covering theory that was yet to come.”
We can’t wait for the next breakthroughs in this golden age of cosmology.
You can purchase Mapping the Heavens by clicking the book cover or title link above. Buying through Seattle Astronomy helps defray our costs of creating and serving these articles. Thank you! | 0.89286 | 3.568419 |
An international team of galactic investigators has put together the intense history of the Andromeda galaxy, which is now looking at the Milky Way as its next victim.
The study published in Nature is headed by a team from the Australian National University. Along with researchers from the University of Surrey, they investigated data from the Pan-Andromeda Archaeological Survey. It was discovered that, over the last few billion years, Andromeda has consumed many small galaxies, based on the proof found in huge streams of stars.
Extremely faint traces of tiny galaxies that were devoured by Andromeda almost 10 billion years ago were discovered by the team even earlier. The team now fears that the home galaxy could be the next in roughly 4 billion years.
Indications of this shocking history can be traced in stars that orbit Andromeda, with the team reviewing dense clusters of stars called globular clusters. This enabled them to recreate how smaller galaxies were drawn in by Andromeda.
The research collaboration involved institutions from New Zealand, Australia, the United Kingdom, Netherlands, Canada, Germany, and France.
Seeing two distinct meal times for Andromeda was quite surprising. The way the globular clusters move around Andromeda suggest that this galaxy had a large breakfast around 10 billion years ago, and a big lunch perhaps only a few billion years ago.
Dr Michelle Collins, Researcher, University of Surrey
Dr Collins continued, “The two accretion events have come from strikingly different directions, as the two globular cluster populations are orbiting at right angles to one another. This directionality may tell us something about the cosmic web within which Andromeda and the Milky Way are embedded, and gives us insight into the formation of our massive neighbour.” | 0.837448 | 3.378395 |
by Paul Roggemans, Carl Johannink and Takashi Sekiguchi
A short-lived activity enhancement of the Phi Serpentids (PSR#839) allowed to calculate a reliable reference orbit for the 2020 return of this minor shower. The meteors and orbit identification of the Phi Serpentids caused confusion with the κ Serpentids (KSE#027) meteor stream for which the reference orbits were established before the PSR shower was known. The sudden activity with several orbits registered in a short time lapse from a very compact radiant is very likely related to an unknown long periodic comet. Attention should be paid to the PSR shower in the future as more dust may move ahead of the unknown parent body that may be on its way to return. The similarity between the KSE and PSR orbits suggests that these are both dust components of the same parent body.
When a small compact cluster of radiants appeared on the daily CAMS report screen (http://cams.seti.org/FDL/), it was obvious that one of the minor showers in this region of the sky had suddenly flared up. Peter Jenniskens identified the minor shower φ Serpentids (PSR#839) with the recorded orbits. This was somehow confusing as most camera operators got the κ Serpentids (KSE#027) suggested as possible shower identification. The KSE shower has been listed as an established shower for years, while PSR#839 was detected during a survey of the CAMS orbits as available until 2016 (Jenniskens et al., 2018).
The reference orbits from the IAU working list (https://www.ta3.sk/IAUC22DB/MDC2007/Roje/roje_lista.php?corobic_roje=0&sort_roje=0) of meteor showers are listed in Table 1. The velocity is about identical and the radiant positions are close to each other. Figure 1 shows the situation as registered this year on April 15 by the CAMS networks. The insets compare the compact radiant for the Global Meteor Network with CAMS.
Table 1 – The reference orbits listed for the KSE#027 and PSR#839 as listed in the IAU working list of meteor showers.
et al. 2016
et al. 2018
|vg||45 km/s||45.0 km/s||46.7 km/s||46.3 km/s|
|a||ꝏ||41.7 AU||7.9 AU||ꝏ|
|q||0.45 AU||0.417 AU||0.489 AU||0.435 AU|
The status of the κ Serpentids (KSE#027) as an established shower raises some questions. Cook (1973) obtained his data from four graphically reduced meteors (McCrosky and Posen, 1961), with limited accuracy. The second reference orbit (Jacchia and Whipple, 1961) is based on a single orbit, a rather questionable criterium to define a reference orbit for a meteor shower. The third reference orbit has been obtained from the CAMS dataset 2010–2013. Looking at the 21 orbits on which the KSE reference orbit is based, some of these orbits fit better with the φ-Serpentids (PSR#839) reference orbit. When the 2016 reference orbit for the κ Serpentids (KSE#027) was calculated the φ-Serpentids (PSR#839) was not yet known. When we calculate the median values for all parameters of these 21 KSE-orbits, we find 242.7° as R.A. instead of the 240.2° listed in the IAU shower list. This orbit is remarkable similar to that of the φ-Serpentids (PSR#839). The only significant difference between both is the time of activity, reflected in the difference in the ascending node Ω.
It looks like we have a dispersed meteor shower with orbits that define the κ Serpentids (KSE#027) followed by a compact component known as the φ-Serpentids (PSR#839). The similarity of both orbits suggests both are somehow related, probably from the same parent body. May be this is an old dispersed shower (KSE#027) with a compact dust trail now observed as the φ-Serpentids (PSR#839) moving perhaps ahead of a parent comet that has still to be discovered? Future observations can learn us whether the enhanced activity in 2020 is just a lucky encounter with a dust concentration in the shower, or the beginning of a trail which will become more active year after year?
2 CAMS BeNeLux
April 14–15 had an almost complete clear night for the CAMS BeNeLux network. All the operational cameras were recording this night. The data of 63 cameras got collected within 24 hours when the next morning Peter Jenniskens reported that the CAMS Namibia network had recorded enhanced activity from a radiant in the top of the constellation Serpens. The next day, data of 73 cameras was available for analyses and yes, CAMS BeNeLux had also registered a few orbits of this meteor shower. The results for CAMS BeNeLux are listed in Table 2. The camera operators who were lucky to contribute to these orbits were: Koen Miskotte (CAMS 354, Ermelo, the Netherlands), Adriana and Paul Roggemans (RMS 3830, Mechelen, Belgium), Hervé Lamy (CAMS 394, Dourbes, Belgium), Luc Gobin (CAMS 390 and 808, Mechelen, Belgium), Guiseppe Canonaco (RMS 3815, Genk, Belgium) and Tioga Gulon (CAMS 3900, Nancy, France).
All CAMS BeNeLux and Namibia PSR orbits were recorded from a very compact radiant area in a short time interval within the range of 25.21° < λʘ < 25.39°, which corresponds to about as little as 4 hours in time. All CAMS networks together had a total of 14 PSR orbits this year. The mean orbit for the 2020 PSR orbits is listed in Table 5 and refers to a thusfar unknown long periodic comet according to Jenniskens (2020). The mean orbit obtained by the CAMS networks agrees very well with that obtained independently by the Global Meteor Network.
Table 2 – The three PSR orbits obtained by CAMS BeNeLux.
|αg||242.0 ± 0.2°||242.3 ± 0.0°||241.9 ± 0.2°|
|δg||+12.7 ± 0.3°||+14.1 ± 0.1°||+14.1 ± 0.2°|
|vg||42.8 ± 0.3 km/s||44.8 ± 0.1 km/s||46.6 ± 0.1 km/s|
|Hb||101.2 km||107.2 km||105.5 km|
|He||92.9 km||85.8 km||90.8 km|
|a||4.26 AU||14.7 AU||ꝏ|
|q||0.3908 AU||0.4308 AU||0.489 AU|
3 Global Meteor Network
We checked the results of the Global Meteor Network for the night 14–15 April (https://globalmeteornetwork.org/data/traj_summary_data/daily/traj_summary_20200414_solrange_025.0-026.0.txt). All the raw trajectory and orbit data are made available online after 24 hours. The GMN radiants can also be compared online (http://cams.seti.org/FDL/index-GMN.html). We found 9 candidates, six were identified by the analyzing software as PSR, three were classified as KSE. Some of the PSR orbits recorded by the Global Meteor Network appeared several hours later than those recorded by CAMS BeNeLux and CAMS Namibia. The orbit identification was checked with the similarity criterion DD of Drummond (1981) using the orbits given by Jenniskens (2016, 2018) as reference, listed in Table 1. The meteors and cameras involved are listed in Table 3.
The meteor of 01h35m02.2s fails to fit the PSR reference orbit, the meteors of 05h50m48.0s and 05h50m48.0s have a best fit with the KSE reference orbit but also fit the PSR orbit. The meteor of 05h43m49.5s is listed as best fit with PSR but also fits the KSE orbit.
The cameras marked with BE share a part of the same layers of the atmosphere with the cameras of the CAMS BeNeLux network. The PSR meteor on BE0003 at 23h29m23s was not found at any other CAMS station, but on two French RMS cameras of GMN. The PSR meteor on BE0003 at 0h45m18s (Figure 3) had no partner camera within the GMN. The PSR meteor on BE0001 and BE0002 at 03h17m54s (Figures 4 and 5) for some reason did not pass the Coincidence procedure of CAMS. This proves how valuable complementary CAMS and GMN really work.
Table 3 – The Global Meteor Network candidate orbits for PSR shower association. The records marked in yellow have better similarity with the KSE reference orbit.
When we calculate the mean orbit based on the 6 certain PSR meteors using the method of Jopek et al. (2006), we find a mean orbit which is in good agreement with the result obtained by Peter Jenniskens based on the CAMS data, see Table 5.
4 SonotaCo Network Japan
The SonotaCo camera network found 6 candidate orbits:
- A: 2020 April 11 18h30m27s UT maga = +1.0
- B: 2020 April 14 12h05m12s UT maga = –2.7
- C: 2020 April 14 12h14m55s UT maga = –0.1
- D: 2020 April 14 18h55m58s UT maga = +0.9
- E: 2020 April 15 15h05m31s UT maga = –1.7
- F: 2020 April 15 16h29m01s UT maga = +0.4
Table 4 – The orbits obtained by the SonotaCo Network.
Table 5 – Comparing the PSR orbits obtained by CAMS, by GMN and by SonotaCo Network.
|αg||242.4 ± 0.4°||242.3 ± 0.7°||240.2°|
|δg||+13.9 ± 0.3°||+14.1 ± 0.8°||+14.8°|
|vg||46.4 ± 0.5 km/s||44.5 ± 2.3 km/s||41.1 km/s|
|Hb||–||104.3 ± 2.1 km||97.1 km|
|He||–||90.7 ± 2.6 km||88.5 km|
|a||ꝏ||72 AU||13.9 AU|
|q||0.432 ± 0.007 AU||0.432 ± 0.02 AU||0.4 AU|
|e||1.011 ± 0.034||0.994 ± 0.08||0.9|
|ω||277.6 ± 1.2°||277.92 ± 4.9°||281.4°|
|Ω||25.24 ± 0.13°||25.395°||25.2°|
|i||69.7 ± 0.7°||68.3 ± 3.1°||60.4°|
The orbit of meteor B is very similar to the mean orbit obtained for the PSR#839 orbits by CAMS and GMN. The other orbits are more spread and all have a lower geocentric velocity vg. As mentioned above the first alert came from orbits recorded in about 4 hours time. All PSR orbits from the compact radiant were collected in less than 24 hours of time. The meteor at April 14 12h05m12s UT detected by the SonotaCo Network may be one of the earliest meteors of the compact PSR return. Some of the meteors detected by the SonotaCo Network may belong to the more dispersed component. This could explain the lower velocity vg, smaller eccentricity e and lower inclination i of the mean orbit.
5 The KSE#027 and PSR#839 confusion
Both KSE#027 and especially PSR#839 are poorly documented. No activity period is determined and while we got a reliable reference orbit for PSR#839 from a compact cluster of orbits, the reliability of the reference orbits for the obviously very dispersed κ Serpentid shower remains questionable. Two showers with nearby radiants, the same velocity and only 5° apart in solar longitude, how to identify these orbits correctly? Are both somehow related?
This confusing situation has been discussed before in a study by Masahiro Koseki (2019). Masahiro Koseki considers the positions of shower radiants in Sun centered ecliptic coordinates relative to the median value of the radiant position. By counting the number of radiants that occur within concentric circles and radiant density ratios in function of the time (solar longitude) the evidence for the existence of the shower can be evaluated. The study by Masahiro Koseki includes two other nearby minor showers, the April β Herculids (ABH#836) and the δ Herculids (DHE#841) with nearby radiants but significant higher geocentric velocities. The conclusion is that no clear concentration could be found for the κ Serpentid shower and the question then is how KSE got ranked as an established shower? The φ-Serpentids (PSR#839) displays a small but clear peak and its radiant position is close to that of KSE.
The available orbits may help to get a better picture of the situation. We have 1101924 orbits public available, 630341 combined for EDMOND and SonotaCo (2007–2019), 471583 for CAMS (2010–2016). We use the orbit given for KSE#027 by Jenniskens et al. (2016) as reference (Table 1) and for PSR#839 the orbit of Global Meteor Network as reference (see Table 5). These reference orbits are used to search for orbits that fulfil the D-criteria of Southworth and Hawkins (1963), Drummond (1981) and Jopek (1993) combined. We define five different classes with specific threshold levels of similarity:
- Low: DSH < 0.25 & DD < 0.105 & DH < 0.25;
- Medium low: DSH < 0.2 & DD < 0.08 & DH < 0.2;
- Medium high: DSH < 0.15 & DD < 0.06 & DH < 0.15;
- High: DSH < 0.1 & DD < 0.04 & DH < 0.1.
- Very high: DSH < 0.05 & DD < 0.02 & DH < 0.05.
Working with the discrimination criteria requires caution. The results indicate only a degree of similarity between the orbits. D-criteria provide no prove for any physical relationship between the meteoroids. D-criteria can be very misleading, especially if applied on short period orbits with small eccentricity. In case of the KSE and PSR which have long period orbits with high eccentricity and high inclination the use of D-criteria is justified. However, the method should be applied unbiased and we must be confident that the orbits are based on reliable velocities. Although the 2020 PSR activity suggests a very narrow concentrated shower, we cannot apriory exclude that more dispersed orbits are related to this shower. It should be understood that the low threshold class of similarity may be contaminated by sporadics that fulfil the criteria by pure chance. The purpose is to check if a shower concentration is confirmed by the high threshold classes with very similar orbits.
Table 6 – Number of low and high threshold KSE and PSR orbits per year.
We find 293 KSE and 196 PSR orbits that fulfil at least the low similarity class mentioned above. This may be misleading somehow because of the risk for false positives. Therefore, we also list the number of orbits that fulfil the high threshold criteria in Table 6. Considering the high threshold class, the PSR shower emerges much stronger than the KSE which remains absent in most years. The number of high threshold PSR orbits registered in 2020 exceeds all previous years.
The number of orbits per year depends mainly on the number of available data. Before 2011 only EDMOND and SonotaCo Network orbits are available, after 2016 only SonotaCo Network orbits. There is no indication for any periodicity. Looking at the number of orbits in each class of similarity threshold we see that the KSE orbits appear very scattered while the PSR shower shows a distinct concentration of orbits (Table 7).
Table 7 – Number of KSE and PSR orbits per similarity class.
The KSE orbits were detected in the time range 6.3° < λʘ < 33.5° for the low threshold, 16.8° < λʘ < 24.9° for the high threshold with not a single orbit fulfilling the very high threshold. For the PSR the time range was 12.8° < λʘ < 37.4° for the low threshold, 23.5° < λʘ < 27.0° for the very high threshold. These periods are a good indication for the activity periods of these showers. In a future case study, we may attempt to run an iterative search to locate orbit concentrations to determine independently new reference orbits.
We consider the radiant distribution in Sun centered ecliptic coordinates to mark each radiant either as KSE or as PSR with a different color according to the threshold class of similarity. In Figure 6 we see how complex the picture really is. KSE radiants appear mainly north and east from the PSR radiants, but a large number of the orbits fit the discrimination criteria for both shower reference orbits. This becomes better visible if we display only the radiants of orbits that fit the D-criteria for the KSE reference in Figure 7 and only those that match the PSR reference in Figure 8. We see the PSR orbits (circles in Figure 8) fit the criteria for the KSE reference (triangles in Figure 7) and not only for the low threshold class. We make the same presentation in another distribution with the inclination i against the length of perihelion Π in Figures 9, 10 and 11.
The KSE radiants appear very dispersed and only the PSR radiants show a very distinct concentration. There seems to be no objective way to distinguish KSE and PSR associations. In Figures 6, 7 and 8 we see a dispersed concentration (at left) and a more concentrated one a bit lower right of it. This looks like two showers, but when we take the D-criteria into account, it becomes obvious there is a lot of overlap with orbits that fit both shower associations. In Figures 9, 10 and 11 the radiants also appear very dispersed, the best KSE associations appear to have a slightly higher inclination and lower value for the length of perihelion Π than the best PSR orbits.
In Figures 12 and 13 we look at the velocity distribution in the Sun centered ecliptic coordinates. To reduce the number of false positives that may still be included in the low threshold class, we used the medium low class orbits. Here we see for both KSE and PSR associated radiants slower velocities for radiants in the western part (at left) and higher velocities in the eastern part (at right) towards the Apex. Note that both the dispersed KSE radiants and the concentrated PSR radiants appear in the same velocity range in both plots.
The same picture emerges in the plots of inclination i (°) against the length of perihelion П (°) (Figures 14 and 15). Here the dispersed KSE orbits appear at slightly higher inclination with a higher velocity while the PSR concentration is situated at a bit lower inclination but within the same velocity range as the KSE orbits.
The question arises if the reference orbit for KSE we took from Jenniskens et al. (2016) is a good reference, this orbit may have been derived from a mixture of KSE and PSR orbits, as the PSR shower was not yet known when the 2016 mean orbits were calculated. The similarity between both KSE and PSR orbits makes it difficult, if not impossible to distinguish both with any degree of certainty.
A sudden short-lived activity enhancement of the φ-Serpentids (PSR#839) shower resulted in a number of orbits from a very narrow radiant concentration registered within a short time interval. The identification from simple radiant positions and velocities of the meteors caused confusion with the nearby κ Serpentids (KSE#027), an established but nevertheless poorly documented meteor stream. Looking up PSR and KSE orbits in our database with 1101924 public available orbits, both showers display considerable overlapping. This confirms an earlier detailed study by Masahiro Koseki (2019). While the φ-Serpentids (PSR#839) appear to be a very distinct concentration of similar orbits, the question arises if the available KSE reference orbits are relevant as these may be partially based on PSR orbits and perhaps some other nearby sources as the shower was not known when the KSE reference orbits were derived.
If we consider the φ-Serpentids (PSR#839) as a distinct minor shower, the KSE orbits may be related to it as a very dispersed component of this shower. The recent enhanced activity from the compact radiant of the φ-Serpentids is likely related to an unknown long periodic comet and could be caused by dust moving ahead of its parent body, announcing its return. Both the φ-Serpentids (PSR#839) and κ Serpentids (KSE#027) are very likely related and may have a common origin. It is highly recommended to keep an eye on the the φ-Serpentids activity in the future and it is very disrable to make a dedicated case study to check if a better representative reference orbit can be found for the KSE component.
The authors wish to thank Peter Jenniskens for providing the information of CBET 4756. We thank Masahiro Koseki for his very valuable feedback and we thank Denis Vida for providing the scripts to plot the velocity distribution with a color gradient and to compute the average orbit according to the method of Jopek et al. (2006).
We used the data of the Global Meteor Network (https://globalmeteornetwork.org/data/) which is released under the CC BY 4.0 license (https://creativecommons.org/licenses/by/4.0/). We thank the SonotaCo Network members in Japan who have been observing every night for more than 10 years, making it possible to consult their orbits. We thank the camera operators of the CAMS (http://cams.seti.org/) networks (http://cams.seti.org/FDL/). And we thank the contributors to EDMOND (https://fmph.uniba.sk/microsites/daa/daa/veda-a-vyskum/meteory/edmond/), including: BOAM (Base des Observateurs Amateurs de Meteores, France), CEMeNt (Central European Meteor Network, cross-border network of Czech and Slovak amateur observers), CMN (Croatian Meteor Network or HrvatskaMeteorskaMreza, Croatia), FMA (Fachgruppe Meteorastronomie, Switzerland), HMN (HungarianMeteor Network or Magyar Hullocsillagok Egyesulet, Hungary), IMO VMN (IMO Video Meteor Network), MeteorsUA (Ukraine), IMTN (Italian amateur observers in Italian Meteor and TLE Network, Italy), NEMETODE (Network for Meteor Triangulation and Orbit Determination, United Kingdom), PFN (Polish Fireball Network or Pracownia Komet i Meteorow, PkiM, Poland), Stjerneskud (Danish all-sky fireball cameras network, Denmark), SVMN (Slovak Video Meteor Network, Slovakia), UKMON (UK Meteor Observation Network, United Kingdom).
The authors thank Peter Jenniskens, Masahiro Koseki and Denis Vida for the verification of this article and for their valuable comments and suggestions.
Cook A. F. (1973). “A Working List of Meteor Streams”. In, Curtis L. Hemenway, Peter M. Millman, and Allan F. Cook, editors, Evolutionary and Physical Properties of Meteoroids, Proceedings of IAU Colloq. 13, held in Albany, NY, 14-17 June 1971. National Aeronautics and Space Administration SP 319, 1973, pages 183–191.
Drummond J. D. (1981). “A test of comet and meteor shower associations”. Icarus, 45, 545–553.
Jacchia, Luigi G., Whipple, Fred L. (1961). “Precision Orbits of 413 Photographic Meteors”. Smithsonian Contributions to Astrophysics, 4, 97–129.
Jenniskens P., Nénon Q., Albers J., Gural P. S., Haberman B., Holman D., Morales R., Grigsby B. J., Samuels D. and Johannink C. (2016). “The established meteor showers as observed by CAMS”. Icarus, 266, 331–354.
Jenniskens P., Baggaley J., Crumpton I., Aldous P., Pokorny P., Janches D., Gural P. S., Samuels D., Albers J., Howell A., Johannink C., Breukers M., Odeh M., Moskovitz N., Collison J. and Ganjuag S. (2018). “A survey of southern hemisphere meteor showers”. Planetary Space Science, 154, 21–29.
Jenniskens P. (2020). “Phi Serpentid meteor shower”. CBET 4756.
Jopek T. J. (1993). “Remarks on the meteor orbital similarity D-criterion”. Icarus, 106, 603–607.
Jopek T. J., Rudawska R. and Pretka-Ziomek H. (2006). “Calculation of the mean orbit of a meteoroid stream”. Monthly Notices of the Royal Astronomical Society, 371, 1367–1372.
Koseki Masahiro (2019). “Legendary meteor showers: studies on Harvard photographic results”. WGN, Journal of the International Meteor Organization, 47, 139–150.
McCrosky R. E. and Posen A. (1961). “Orbital elements of photographic meteors”. Smithson. Contrib. Astrophys., 4, 15–84.
Southworth R. R. and Hawkins G. S. (1963). “Statistics of meteor streams”. Smithson. Contrib. Astrophys., 7, 261–286. | 0.846296 | 3.662893 |
A group of international scientists have recently discovered something that's vying for the title of biggest thing in the observable universe: a clustered ring of galaxies located about 7 billion light-years away. But the ring, detailed in the latest monthly notice of the Royal Astronomical Society, is so big that some cosmologists are saying it violates the basic theoretical principles governing the universe.
The proposed cluster isn't visible from Earth because it's so far away. It was revealed to cosmologists after they observed nine gamma-ray bursts, which are the result of super-massive stars collapsing into black holes.
The bursts offer brief clues about the location of other galaxies. In this case, the bursts are so close together and similar to one another that scientists think they must be a single feature. The team said there's a very low chance — one in 20,000 — that the arrangement appeared by random chance.
This discovery is the latest addition to a mix of galaxy clusters referred to as galaxy filaments — the great walls and massive threads that clothe the vast voids of space. These features are so inconceivably large that scientists don't know how they could possibly be formed.
If you were to travel from one end of the new cluster to the other at the speed of light, it would take more than 5.6 billion years. Lajos Balazs, contributor to the ring's discovery and a professor from the Konkoly Observatory in Budapest, said that if we could see the feature in the night sky, it would be 70 times bigger than the moon.
But the ring has stiff competition for the title of "biggest." A team of scientists found another enormous cluster back in 2013, a tapestry of galaxies estimated to be somewhere around 10 billion light years across.
"The ring is based on distinct observations, and the first cluster is based upon a humongous over-density of bursts," said Jon Hakkila, an astrophysics professor at the College of Charleston who contributed to the discoveries of both the giant ring and the great wall.
He thinks the great wall will end up taking the throne, but added there's still a lot of research to be done because the wall doesn't have a strong, distinct boundary.
Regardless, both of these features are problematic because they might contradict what is known as the Cosmological Principle.
To understand the principle, consider sand on a beach. If you look at small sections of the sand, there might be points that stick out, maybe a small pebble here or an abnormally large mound there. But when observed at a larger scale, the sand looks relatively uniform.
That's theoretically the same way that the space works. There's no special place in the universe — no center, no edge, no area where stars cluster more than another place. Each region is governed by the same physical laws of nature.
If you want a mind-blowing illustration of what that looks like, check out this 3-D map from the Sloan Digital Sky Survey:
The Cosmological Principle has been a bedrock concept for scientists studying stars over the past couple of centuries because, unlike many other fields of science, there isn't much opportunity for experimentation. There's only one sky and one set of stars to work with.
These massive galaxy filaments breaks the rules, though. They are way too big to obey physical laws of gravity, which have previously limited the size of cosmological features to, at most, 1.2 billion light years.
So do these massive discoveries put the basic tenants of cosmology in jeopardy? That's still up for debate.
In 2013, Robert Clowes of the University of Central Lancashire discovered what he said was a quasar group about 4 billion light-years across, the first feature that was too big to exist under physical law. But the feature, called the Huge Large Quasar Group, fell under intense scrutiny when researchers started to question the statistical validity of its existence. They argued that his group of galaxies was the result of randomness — not due to actual physical properties pulling them together.
"People say, 'Well did you find them there because you were looking for them?'" Hakilla said. "A lot of the cosmologists are hoping that this is just going to go away."
So far, Balazs said his team's discovery has received a somewhat icy response from their fellow cosmologists.
"The first reaction is that they don't believe it," Balazs said. "Some people believe that it's only some statistical something."
Balazs argued that the staggering size of the ring cluster may end up not contradicting the principles of science. Instead, he said it could unlock clues to the mystery of star formation, helping us with much broader questions about the evolution of the universe.
"There's always some wiggle room," Hakilla said. "Scientists always have to add some bells and whistles based on the observations. It's not like cosmology will be overthrown." | 0.827012 | 3.950048 |
If Orion changed to wearing suspenders, the constellation would never be the same again.
Step out the next clear night, in late December/early January in early evening, face southeast and look about halfway up.
Bursting forth from the dark of night is the glorious stars of Orion, one of the most recognized and celebrated constellations of the entire heavens.
Orion, the mythical Hunter, can be seen anywhere on Earth. The three conspicuous “belt stars” straddle the Celestial Equator. This imagined line encircles the sky midway from the North Celestial Pole, where the North Star resides right nearby, and the South Celestial Pole, seen Down Under. In other words, if you were on the ice of the North Polar Cap, right at the North Pole, the Celestial Equator exactly follows your horizon, and the North Star gleams almost exactly straight overhead. Orion’s northern half will be seen riding around the horizon as the 24 hours of night proceeds.
Likewise, in July when night covers Antarctica, from the South Pole you would see Orion’s southern half ride the horizon, upside down from what you are used to seeing from the United States.
The three belt stars of Orion are actually part of a loose stellar association, a wide-open star cluster with a common origin, moving in space in tandem. From left to right, the stars have Arabic names: Alnitak (“Girdle”), Alnilam (“Belt of Pearls”) and Mintaka (“Belt”).
These stars are at nearly the same distance from us (from left, 800, 1,000 and 900 light years). They are blue-white giant stars, each about 20 times the mass of the sun. They shine at +2nd magnitude (+6th is the usual lower limit of visibility to unaided eyes).
Look for Mintaka’s +7th magnitude companion star, with binoculars. Long-exposure photographs reveal that Alnitak is bathed in a faint cosmic cloud, or nebula, which includes the famous “Horsehead Nebula.” The cloud of black dust, superimposed on background nebula that is lit by star shine, its equine silhouette is unmistakable. Large backyard telescopes (10-inch aperture and bigger) can reveal it under very good sky conditions, and it is one my goals to catch this horsey!
Look also for an S-shaped line of stars that starts above Mintaka and sweeps down and ends between Alnilam and Alnitak. Binoculars are needed if moonlight is an issue.
A group of stars seem to hang below Alnitak and are known as Orion’s Sword. The middle “star” appears fuzzy in binoculars; this is the Great Nebula of Orion (also known as M42), breathtaking in even a small telescope. Stars are being formed within this nebula.
Other principal stars in Orion is the brilliant blue-white Rigel at lower right of the Belt and the fiery red-orange, brilliant Betelgeuse at upper left of the Belt. They mark corners of a huge, rough rectangle, with the Belt in the middle.
While we think of Orion as a mythical Hunter, thanks to the Greeks, the Belt Stars are referred to as the Saucepan (with the Sword stars) in Australia and New Zealand; as the Three Marys in Latin America; and as the Three Kings or Three Sisters in South Africa. The Bible refers to Orion in Job 9:9, Job 38:31 and Amos 5:8.
Last quarter Moon is on December 29.
Keep looking up!
Peter Becker is Managing Editor at The News Eagle in Hawley, PA. Notes are welcome at [email protected]. Please mention in what newspaper or web site you read this column. | 0.83207 | 3.703027 |
MADISON – Starting around 1950, a series of advances formed a clear and accepted picture of how individual stars are born, evolve and die. As they age, the changing patterns of color, light output, size and lifespan of stars are predictable. Every star like the sun will become a red giant, a planetary nebula and finally a white dwarf.
But half of all stars are in binaries – pairs of stars that orbit each other. Half of binary stars orbit so close that gravitational interaction significantly affects their evolution and demise. Today, scientists led by Robert Mathieu, a professor of astronomy at the University of Wisconsin-Madison, and his former student Natalie Gosnell confirmed one of the possible explanations for a common group of exceptions: the blue stragglers.
Blue stragglers look younger and brighter than their age would suggest – skirting, in other words, the clean, clear rules of stellar evolution. Since their discovery in 1953, blue stragglers have been begging for explanation. Had two stars collided to form a more massive star? Was a blue straggler “stealing” gas from a companion star?
In recent years, based on observations at the WIYN telescope at Kitt Peak, Arizona, Mathieu and his students have established that over three-quarters of blue stragglers, in fact, have stellar companions.
This week, in a paper in The Astrophysical Journal, Gosnell, Mathieu and colleagues identified the orbital partner that was parasitized by the blue straggler. The victim, they found, was a red giant that donated hydrogen gas for eons until it was eventually transformed into a white dwarf – the old, small, bright and dense remnant of a red giant.
The researchers used the Hubble Space Telescope to study the “colors” of far ultraviolet light coming from blue stragglers and their companions. At a distance of 5,500 light years, the blue straggler binary appears as a single point of light, but by analyzing the amount of ultraviolet light, the researchers saw the unmistakable signal of a white dwarf.
The study builds on a series of logical deductions. The stars being studied were identified as members of a binary pair because they periodically move closer to and further from Earth – the hallmark of an orbiting pair of stars. Their optical color and intensity marked them as blue stragglers. They are bright in the far ultraviolet, a trademark of a hot white dwarf. And finally, for the white dwarfs to still be hot and detectable, they can only be 300 million years old. “These blue stragglers were formed ‘yesterday,'” says Mathieu.
White dwarfs form when certain stars lose their outer atmospheres. The mass “must be going somewhere,” Gosnell says, “and that’s to the companion normal star, which is close enough to attract the mass through gravity. Therefore, the white dwarf is left over after adding mass to a star, which becomes the blue straggler.”
The study expands our understanding of a major area of stellar evolution. If half of all stars are in binaries, and half of the binaries are, like the blue straggler, close enough to have gravitational interaction, then “these stars are not just an afterthought, a contaminant to our neat picture,” Gosnell says. “We need to bring this 25 percent of all stars into the fold, so we can say we really understand how stars evolve.”
If scientists don’t know how the blue stragglers formed, they are in a poor position to understand how they will evolve and die, adds Gosnell, who is now a postdoctoral fellow at the University of Texas. “Of course, we still have a third of the blue stragglers to figure out. I think we also have some stellar collisions in there.”
“Our understanding of single-star evolution is one of the great intellectual achievements of the last century,” says Mathieu. “We began with points of light in the sky, and with the application of new instrumentation, the physics breakthroughs of the last century, and computers, we took those points of light and turned them into a narrative of star life.
“For the evolution of single stars like our sun, by and large, we got it right, from birth to death. Now we’re starting to do the same thing for the one-quarter of stars that are close-orbiting binaries. This work allows us to talk not about points of light, but about the evolution of galaxies, including our own Milky Way. That’s a big deal, and getting it right is an even bigger deal.” | 0.923869 | 3.965781 |
TESS (Transiting Exoplanet Survey Satellite), which is also referred to as the planet hunter, discovers the first earth-sized planet in a habitable zone.
Scientists from NASA confirmed the discovery by using the Spitzer Space Telescope, which is owned by them.
The earth-sized planet has been named as TOI 700 d.
TOI 700 d is one of only a number of earth-sized planets that have been discovered in a star’s habitable zone.
The habitable zone is what NASA defines as “the range of distances where conditions may be just right to allow the presence of liquid water on the surface.”
Paul Hertz, the director of the astrophysics division at NASA in Washington, released a statement about the discovery.
Paul said, “TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars. Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth.”
He added, “Discovering TOI 700 d is a key science finding for TESS.”
TESS found TOI 700 d, a new potentially habitable exoplanet the size of Earth, located about 100 light-years away.
According to NASA, TOI 700 is a small cool M dwarf star that is located around 100 light-years away in the southern constellation Dorado.
TOI 700 d is believed to be a rocky planet with water.
The planet orbits its sun every 10 days.
Talking about the new discovery, NASA said, “All of the planets are thought to be tidally locked to their star, which means they rotate once per orbit so that one side is constantly bathed in daylight.”
At first, the start was misclassified in the database of TESS as it was more similar to our sun.
But later, an error was identified and a team of scientists requested a follow-up observation with the Spitzer telescope.
They also sharpened their measurements by 56 percent and its size by 38 percent.
How Did We Find The Planet
TESS (Transiting Exoplanet Survey Satellite) is a satellite that finds exo-planets by using its tried-and-true technique when objects are transiting in front of their host stars. TESS and Spitzer Space Telescope were both used to find the planet, achieving its measurements and how it orbits the sun.
What is Tess
TESS (Transiting Exoplanet Survey Satellite) is NASA’s new planet-hunting space telescope. The satellite is the successor of the Kepler Space Telescope, which found around 2600 exoplanets. TESS (Transiting Exoplanet Survey Satellite) is capable of surveying 85 percent of the night sky, which is 400 times more than what Kepler could monitor. | 0.827045 | 3.562447 |
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As far as atoms and their electron shells were concerned, not only did this yield a better overall description, i. e. the atomic orbital model, but it also provided a new theoretical basis for chemistry
Some Related Sentences
far and atoms
Hence it is difficult to conceive of a packing of the atoms in this material in which the oxygen atoms are far from geometrical equivalence.
Because electrical forces ( the charge-excess ) are far more powerful than gravitation, the surface hydrogen atoms would shoot away from the sphere.
Specifically, after acknowledging the various popular theories in vogue at the time, of how atoms were reasoned to attach to each other, i. e. " hooked atoms ", " glued together by rest ", or " stuck together by conspiring motions ", Newton states that he would rather infer from their cohesion, that " particles attract one another by some force, which in immediate contact is exceedingly strong, at small distances performs the chemical operations, and reaches not far from the particles with any sensible effect.
Notice that alone the number has 10 billion zeros when written down in decimal notation, and is already by far larger than the number of atoms in the observable universe.
By recording full sets of reflections at three different wavelengths ( far below, far above and in the middle of the absorption edge ) one can solve for the substructure of the anomalously diffracting atoms and thence the structure of the whole molecule.
However, a study of Dalton's own laboratory notebooks, discovered in the rooms of the Lit & Phil, concluded that so far from Dalton being led by his search for an explanation of the law of multiple proportions to the idea that chemical combination consists in the interaction of atoms of definite and characteristic weight, the idea of atoms arose in his mind as a purely physical concept, forced upon him by study of the physical properties of the atmosphere and other gases.
The low-energy antihydrogen atoms synthesized so far have had a relatively high temperature ( a few thousand kelvin ), thus hitting the walls of the experimental apparatus as a consequence and annihilating.
Today the value of N < sub > A </ sub > can be measured at very high accuracy by taking an extremely pure crystal ( in practice, often silicon ), measuring how far apart the atoms are spaced using X-ray diffraction or another method, and accurately measuring the density of the crystal.
Details of nuclear weapon design also affect neutron emission: the gun-type assembly Hiroshima bomb leaked far more neutrons than the implosion type 21 kt Nagasaki bomb because the light hydrogen nuclei ( protons ) predominating in the exploded TNT molecules ( surrounding the core of the Nagasaki bomb ) slowed down neutrons very efficiently while the heavier iron atoms in the steel nose forging of the Hiroshima bomb scattered neutrons without absorbing much neutron energy.
But if the atoms are far apart, any signal cannot reach the other atoms in time, and they might end up absorbing the same photon anyway and dissipating the energy to the environment.
The above three paragraphs rationalise, albeit very generally, the reactions of some common species, particularly atoms, but chemists have so far been unable to jump from such general considerations to quantitative models of reactivity.
This is very useful when teaching about a topic that is difficult to otherwise see, for example, atomic structure, because atoms are far too small to be studied easily without expensive and difficult to use scientific equipment.
The energy required to break a single bond is far less than that required to break all the bonds on an entire plane of atoms at once.
* Hyperpolarization ( physics ) is the selective polarization of nuclear spin in atoms far beyond normal thermal equilibrium
For all values of n relevant to counting the running times of algorithms implemented in practice ( i. e., n ≤ 2 < sup > 65536 </ sup >, which is far more than the atoms in the known universe ), the iterated logarithm with base 2 has a value no more than 5.
And even if these proposed experiments were successful, they would only trap several antihydrogen atoms for research purposes, far too few for weapons or spacecraft propulsion.
It also greatly reduces conduction, as there are far fewer collisions between adjacent gas molecules ( or between gas molecules and atoms of the core material ).
For instance, to measure temperatures in the nanokelvin range ( billionths of a kelvin ), scientists using optical lattice laser equipment to adiabatically cool atoms, turn off the entrapment lasers and simply measure how far the atoms drift over time to measure their temperature.
far and their
They, and the two large fans which I could dimly see as daylight filtered through their vents, down at the far end of the hall, could be turned on by a master switch situated inside the office.
They squatted on their heels with their heads bent far forward, their eyes only a few inches from the ground.
they are the most valuable of commodities -- and the most salable, for their demand far exceeds supply.
Such characters, with their low existence and often low morality, produce humorous effects in his novels and tales, as they did in the writing of Longstreet and Hooper and Harris, but it need not be added that he gives them far subtler and more intricate functions than they had in the earlier writers ; ;
There is, of course, nothing new about dystopias, for they belong to a literary tradition which, including also the closely related satiric utopias, stretches from at least as far back as the eighteenth century and Swift's Gulliver's Travels to the twentieth century and Zamiatin's We, Capek's War With The Newts, Huxley's Brave New World, E. M. Forster's `` The Machine Stops '', C. S. Lewis's That Hideous Strength, and Orwell's Nineteen Eighty-Four, and which in science fiction is represented before the present deluge as early as Wells's trilogy, The Time Machine, `` A Story Of The Days To Come '', and When The Sleeper Wakes, and as recently as Jack Williamson's `` With Folded Hands '' ( 1947 ), the classic story of men replaced by their own robots.
That fact is very clearly illustrated in the case of the many present-day intellectuals who were Communists or near-Communists in their youth and are now so extremely conservative ( or reactionary, as many would say ) that they can define no important political conviction that does not seem so far from even a centrist position as to make the distinction between Mr. Nixon and Mr. Khrushchev for them hardly worth noting.
These biographical analogies are obvious, and far too much time has been spent speculating on their possible implications.
Contrarily, Republican `` volunteers '' go their separate ways, and thus far have given no indication that they'd be willing to join forces under a single directorate, except in the most loose-knit fashion.
and it is still very far from certain how valid the party's claim is that in `` a growing number of kolkhozes '' the peasants are finding it more profitable, to surrender their private plots to the kolkhoz and to let the latter be turned into something increasingly like a state farm.
Though far from completion, these studies indicated beyond a doubt that savings would result which would be of unprecedented benefit to the railroads concerned, their investors, their customers, their users, and to the public at large.
The outlook for entertainment electronics in 1961 is certainly far from clear at present, but recent surveys have shown a desire on the part of consumers to step up their buying plans for durable goods.
The host of novel applications of electronics to medical problems is far more thrilling because of their implication in matters concerning our health and vitality.
This would, naturally, lengthen their courses far beyond the largely esthetic demands of interior designer's training.
I fought like a tigress but by the time I appealed my case to the Supreme Court ( 1937 ), Mr. Roosevelt and his `` henchmen '' had done their `` dirty work '' all too well, even going so far as to attempt to `` pack '' the highest tribunal in the land in order to defeat little me.
The adherence of many in the population to the Indian background in their pedigree, and emphasis upon the fact that their ancestors had never been slaves, becomes of prime interest in determining how far these elements promote the self-image of the intermediate status of the group in society.
Since they are all either rented or borrowed, the requested dates for their use have to be far in advance.
And perhaps an observer of the vases will not go too far in deducing that the outlook of their makers and users was basically stable and secure.
far and electron
The electron is by far the least massive of these particles at, with a negative electrical charge and a size that is too small to be measured using available techniques.
In order to gain higher resolution, the use of an electron beam with a far smaller wavelength is used in electron microscopes.
If electrons ' move ' about the electron cloud in strict paths the same way planets orbit the sun, then electrons would be required to do so at speeds which far exceed the speed of light.
The farther the electron jumps the shorter the wavelength of the photon emitted, meaning they emit different colors based on how far they jump.
Here " immediately " means that the final electron position is far from the surface on the atomic scale but still close to the solid on the macroscopic scale.
Complete removal of an electron from an atom can be a form of ionization, which is effectively moving the electron out to an orbital with an infinite principal quantum number, in effect so far away so as to have practically no more effect on the remaining atom ( ion ).
One advantage of the double probe is that neither electrode is ever very far above floating, so the theoretical uncertainties at large electron currents are avoided.
While X-ray and electron beams are by far the most widely used sources for external beam radiotherapy, a small number of centers operate experimental and pilot programs employing heavier particle beams, particularly proton sources.
Scanning electron microscope images, such as that in the taxobox, are far more illuminating than those taken in transmitted light.
For most resists, it is difficult to go below 25 nm lines and spaces, and a limit of 20 nm lines and spaces has been found .< ref name =" liddle "> In actuality, though, the range of secondary electron scattering is quite far, sometimes exceeding 100 nm, but becoming very significant below 30 nm.
Electrons, within an electron shell around an atom, tend to distribute themselves as far apart from each other, within the given shell, as they can ( due to each one being negatively charged ).
An atom in a Rydberg state has a valence electron in a large orbit far from the ion core ; in such an orbit the outermost electron feels an almost hydrogenic, Coulomb potential, U < sub > C </ sub > from a compact ion core consisting of a nucleus with Z protons and the lower electron shells filled with Z-1 electrons.
This is especially troublesome in the setting of electron crystallography, where that radiation damage is focused on far fewer atoms.
The inelastic mean free path ( IMFP ) is an index of how far an electron can travel through a solid before losing energy.
So far ( 2009 ), there is only one reliable evidence ( through hyperfine interaction structure in electron paramagnetic resonance ) for isolated sulfur defects in diamond.
Also, image contrast of microstructures at relatively low magnifications, e. g., < 500X, is far better with the LOM than with the scanning electron microscope ( SEM ), while transmission electron microscopes ( TEM ) generally cannot be utilized at magnifications below about 2000 to 3000X.
In addition, MINOS looks for the appearance of electron neutrinos in the far detector, and will either measure or set a limit on the oscillation probability of muon neutrinos into electron neutrinos. | 0.838486 | 3.46618 |
To understand and predict changes in the climate system, we need a more complete understanding of seasonal-to-century scale climate variability than can be obtained from the instrumental climate record alone. So, several decades ago, paleoclimatologists began constructing a blueprint of how Earth's temperature changed over the centuries before 1850 and the widespread use of thermometers.
Out of this initial work emerged a view of the past climate based on limited data from tree rings, historical documents, sediments, and other proxy data sources. Today, many more paleoclimate records are available from around the world, providing a much improved view of past changes in Earth's temperature.
A Perspective on Climate Change
From the paleoclimate perspective, climate change is normal and part of Earth's natural variability related to interactions among the atmosphere, ocean, and land as well as changes in the seasonal amount of solar radiation reaching Earth. The geologic record also includes a variety of evidence for large-scale climate changes. For example, warm-climate vegetation, dinosaurs, and corals living at high latitudes about 90–120 million years ago indicate globally warm conditions at that time.
A Perspective on Glacial Cycles
Paleoclimate data has also shown that glacial cycles, a pattern of ice ages and glacial retreats lasting thousands of years, dominated the climate of the past two million years. During the peak of the most recent glacial cycle—about 21,000 years ago—massive terrestrial ice sheets extended over large parts of North America and Europe, reaching as far south as New York, Chicago, and Stockholm. And, at that time, the global temperature was about 9°F colder than it is today.
Since the end of the last ice age over 10,000 years ago, the planet has undergone smaller changes in climate. Warming during medieval times and cooling during the “Little Ice Age” a few centuries ago dominated the last millennia.
A Perspective on Changes in the Atmosphere
Paleoclimatology also puts recent changes in the atmosphere and climate into perspective. For example, gas bubbles trapped in ice cores tell us that atmospheric carbon dioxide levels are now significantly higher than they have been over at least the last 800,000 years.
Prior to the Industrial Revolution, when humans began burning large amounts of fossil fuels, carbon dioxide levels varied between 180 to 280 parts per million across glacial and interglacial cycles. Today, in 2017, carbon dioxide levels have reached over 407 parts per million.
A Perspective on Global Temperature
Paleoclimate records from multiple proxies also indicate that global temperatures, which have risen with atmospheric carbon dioxide levels, are now higher than at any point in the last 1,500 years. Our planet has likely not been as warm as it is today since over 5,000 years, when changes in Earth’s orbit increased temperature in some parts of the world.
What is especially remarkable is that the long-term cooling trend that has existed over the past 5,000 or more years has reversed abruptly. And, global temperatures have risen from the coldest to near the warmest levels of our current interglacial period within the last century. | 0.819144 | 3.078915 |
The open star cluster NGC 1981 (mag 4.6) in Orion's sword will be well placed, high in the sky. It will reach its highest point in the sky at around midnight local time.
At a declination of -04°25', it is visible across much of the world; it can be seen at latitudes between 65°N and 74°S.
From Cambridge, it will be visible between 19:41 and 03:45. It will become accessible around 19:41, when it rises to an altitude of 17° above your south-eastern horizon. It will reach its highest point in the sky at 23:41, 43° above your southern horizon. It will become inaccessible around 03:45 when it sinks below 18° above your south-western horizon.
At magnitude 4.2, NGC1981 is tricky to make out with the naked eye except from a dark site, but is visible through a pair of binoculars or small telescope.
The position of NGC1981 is as follows:
|Object||Right Ascension||Declination||Constellation||Magnitude||Angular Size|
The coordinates above are given in J2000.0.
|The sky on 15 December 2018|
8 days old
All times shown in EST.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location. | 0.901567 | 3.141 |
Today, NASA's New Horizons spacecraft finally entered the Pluto system, zipping along at 31,000 miles per hour between Pluto and Charon. NASA got the signal from the craft at 7:49 a.m. At closest approach, it will be just 7,750 miles above the surface of Pluto and about 18,000 miles from Charon.
This has been a long, long time coming, and so NASA scientists and Pluto fans wait with great anticipation for the results of humanity's first up-close observations of the once-ninth planet. But don't expect a live feed from Pluto. In fact, this won't even be like the landing of Curiosity on Mars, when, after a few minutes of heart-wrenching silence, NASA got a confirmation of success. New Horzions' Pluto flyby will unfold at a much slower pace as data trickles back to Earth.
It may take months to get all the new pictures from Pluto and its moons, but we should see the first ones by Wednesday. Those pictures will reveal a world we've never seen so closely. Already, the New Horizons mission has returned stunning clues to the topography of both Pluto and Charon, hinting at ancient impacts, high cliffs, and histories of bombardment. The best is yet to come.
Here's what to expect from New Horizons this week:
NASA will received word that New Horizons was entering the Pluto system at 7:49 a.m. this morning. At around 9 p.m., it will receive word that the craft has cleared the system. In between, the craft will do nothing but collect data during its 12-hour recon window. There will be radio silence from New Horizons during that time. After 9 p.m., the team can begin breathing easy, and start collecting data from the craft's encounter...
As long as it survives —which it probably will. There's a small chance of a collision with debris near Pluto. The region was formed by collisions, and there may be some detritus left. However, Alan Stern, principal investigator for New Horizons, says he believes that the chance of that happening is about 1 in 10,000.
The New Horizons team doesn't want to waste a single second of precious Pluto time, which is why they're going to have to suffer through that 12-hour window of silence while the spacecraft makes its observations. The spacecraft was designed with as few moving parts as possible, so to downlink with the Deep Space Network and send information back to Earth, it needs to pivot around entirely.
It won't do that until the flyby is complete. Once the downlink begins, it will go on and on and on. At a rate of about 1 kb/s, New Horizons will spend months returning data to NASA. This data will be stored on two solid state hard drives with about 8 GB of storage space each. The downlink will take until November 2015.
NASA has scheduled a press conference for 3 PM Eastern on Wednesday, at which time it could officially release the first pictures from the Pluto flyby. We wouldn't be shocked if they leaked earlier, though.
There are two main imagers on board New Horizons. It has the Ralph instrument for observation of the surface. Ralph has seven total imagers: three in black and white, three in standard color, and another specifically to detect methane. There's also LORRI, which is intended for more distant observations and was used for many of the Pluto pictures you probably saw in the lead-up to the historic flyby.
Beyond that, there are a number of other instruments on board New Horizons to teach us a lot about Pluto. The Alice instrument, a companion to Ralph, is an ultraviolet spectrometer that will study the dwarf planet's atmosphere. REX, the Radio Science Experiment, will measure the atmospheric pressure and ionosphere density of Pluto, while also checking for any atmosphere that Charon may possess.
The Solar Wind at Pluto instrument will measure the interaction of Pluto's atmosphere with solar winds, while the Pluto Energetic Particle Spectrometer Science Investigation will hunt for ionization of particles resulting from these interactions. Finally, the Venetia Burney Student Dust Counter will measure the size and density of outer solar system particles, determining frequency of collision and other information.
The extended mission
The main mission through the Pluto system officially ends in January 2016, when the planet fades into the background as New Horizons continues its traverse through the Kuiper Belt. Funding permitting, the spacecraft will then be set up for an encounter with one of two candidate Kuiper Belt objects, expending most of its remaining fuel for the encounter. The calibration for this will take place in October or November of this year, meaning that a specific target must be selected by then.
While Pluto is approximately 1,500 miles in diameter (we'll know for sure in the next few weeks!), the target KBOs are closer to 31 miles in diameter—around the size of Pluto's moon Nix. While the object may be small, it could reveal a lot about the early solar system. The Kuiper Belt is a sort of debris yard from the formation of the solar system, filled with icy objects including other dwarf planets and dwarf planet candidates. Think of it as an icier asteroid belt, consisting of objects that migrated out from the second zone of the solar system among the gas and ice giants, and some objects that formed out in those reaches. The objects in the Kuiper Belt are some of the most ancient in our solar system. | 0.829602 | 3.08801 |
A team of scientists led by University of Texas, Austin, astronomer Ivan Ramirez have identified a star that they believe is one of many siblings our sun has floating around the Universe. Formed 4.5 billion years ago from the same large interstellar cloud that gave birth to our sun, it is 15% larger and lies 110 light-years away in the constellation Hercules. Though not visible with the unaided eye, HD 162826 that lies close to bright star Vega, can be easily viewed with low-power binoculars.
The team began its research by investigating 30 possible candidates that had been found by various groups around the world that are also on similar quests. In addition to performing a chemical analysis of each star, they also studied their respective orbits before coming to the conclusion that HD 162826 was the one that had been born from the same gas and dust system as our sun.
Coincidentally, McDonald Observatory astronomers in West Texas have been studying HD 162826 for over 15 years - While they had no clue it was related to our sun, they do know that it does not have any hot Jupiter-sized planets orbiting close to the star. This however does not rule out the possibility that HD 162826 hosts some earth-size planets that harbor alien life.
While the find is certainly exciting, the team, who plan to publish their study in the June 1st edition of the Astrophysical Journal, believes this is just the first of many siblings our sun has. Professor Ramirez theorizes that 4.5 billion years ago, the sun was part of a cluster of a thousand or perhaps even hundred thousand stars. The cluster has since broken away and scattered to various parts of the Milky Way and mingled with the billions of other stars - Some like the HD 162826 have remained relatively close, whilst others are much farther away.
Though they will probably never be able to locate them all, if enough of the siblings can be found, the research team's 'dynamics specialists' will be able to run each star's orbits backwards in time and locate the place where they intersect. This will help solve the age-old mystery of how and where the sun was 'born'. According to the scientist, finding out what part of the galaxy we came from, may provide them with some clues about how our planet became hospitable to life.
Ramirez also believes that this may be the best way to locate other planets that can harbor life. He says that when the stars were in a dense cluster, massive collisions may have knocked off planetary chunks, and caused asteroids to travel between solar systems and possibly bring along building blocks of life. If that is true, there may be a other few siblings that have earth-like planets orbiting around, complete with aliens!
Resources: dailymail.co.uk, sciencedaily.com, gizmag.com | 0.919909 | 3.658634 |
Two of the brightest objects in the night sky head towards a close encounter on Monday night. The sky show begins after local nightfall on the 21st when the waxing gibbous moon snuggles up to brilliant white Jupiter in the southeast. This closeness is of course just an illusion – they are in reality separate by hundreds of millions of kilometers.
Lunar conjunctions with planets are not that unusual, however they are rarely this close, says Raminder Singh Samra, a resident astronomer at the H.R. MacMillan Space Centre in Vancouver, Canada.
“Each month the Moon will pass by every planet in the night sky but they are usually a few degrees or few moons discs apart,” said Samra. ” This time we get to witness them passing within half a degree of each other – that’s less than the width of a finger held at arm’s length apart.”
If you miss this alignment, the next time Jupiter and the Moon will pass close to each other will be on March 17 but won’t appear to North Americans quite as close as this one. On August 2016 when the pair will appear even closer in North American skies.
Here are some of Samra’s observing tips…
Who can see event?
The cosmic encounter will be best seen throughout both of the American continents. The exact time the Moon appears closest to Jupiter will depend on location – 7 p.m. in the Pacific time zone, 8:30 p.m. Mountain, 10 p.m. Central, and 11:30 p.m. Eastern time. Some parts of South America will be in for a special treat as they will witness the Moon completely block out Jupiter in the sky.. for local observing times click onto the International Occultation Timing Association website (http://www.lunar-occultations.com/iota/planets/0122jupiter.htm).
What is happening?
Both the Moon and all the planets appear to follow the ecliptic line in the sky – the plane of the solar system through which all orbits are seen edge on from our line of sight here on Earth. The close proximity of the Moon to Jupiter in the sky however is just an optical illusion as they are actually very far apart. While the moon is on average 400,000 km from Earth, Jupiter sits 1700 times further away at about 680 million km.
What is most unusual about this event?
This extra close encounter affords a unique opportunity for keen observers to try and spot Jupiter during daytime- before local sunset. First step is to locate the Moon about halfway up the late afternoon southeast sky and then take binoculars to scan the sky just to its lower left. Special observing challenge will be to see how far before local sunset skywatchers can spot Jupiter in daylight.
How is it best seen?
The conjunction will be a very impressive sight for any observer regardless of location as long as there is a clear line of sight towards the southeast horizon. Even from large, light polluted cities, it promises to be easy to observe with nothing more than naked eyes. Train any sized optical aid on these worlds however, much more details can be glimpsed.
“For those who have a small telescope or a pair of binoculars the view will be greatly enhanced, as even with moderate power both the Moon and Jupiter will be visible at the same time,” adds Samra.
Update 20/1/2013 10 am EST : The story was originally published with errors on the actual distance separating the Moon and Jupiter and there is some confusion regarding this being the tightest conjunction until 2026. This claim appears to be the expectation for North Americans and is based on geocentric calculations (from the center of the Earth) which shows that on Oct.6, 2026 the two will be separated by only 0.17 degrees – as the conjunction would theoretically appear from the center of the Earth. But since we don’t skywatch from there, what an observer at the surface of our planet actually sees (ie. separation of the Moon from the planet in the sky) depends on their geographical location.
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like. | 0.888351 | 3.506957 |
Based on the observation data of the 13.7-meter millimeter wave telescope of Purple Mountain Observatory of CAS (PMO) and the FAST of National Astronomical Observatories of CAS (NAOC), and combined with the archive data of other wavebands, Dr. JinLong Xu from NAOC and other partners revealed that the first buried cluster in California is formed by dismemberment after being hit by another giant molecular cloud. The result was published on April.8 in the Astrophysical Journal Letters.
“Most of the stars in the universe form in the form of clusters, while the clusters are formed in the giant molecular cloud. After the parent molecular cloud is dispersed, the clusters visible in the optical band are left behind. In the early stage of evolution, the age of stars in clusters is very similar and they are almost formed at the same time, it requires a large number of gases to accumulate rapidly in the formation position of clusters,” said Dr. JinLong Xu.
In addition, the traditional model of astronomy suggested that the only reason for the formation of star clusters is the gravitational collapse of giant molecular clouds. But what event triggered the formation of star clusters? Especially in large-scale giant molecular clouds, more than one cluster can be formed, so how is the first cluster formed? And the formation of the first cluster will cause the formation of other stars and clusters in the whole giant molecular cloud like a spark, which are all the research topics of great concern in the astronomical field.
“The California giant molecular cloud is the largest in mass within 500 pc of our solar system, and it has similar shape and scale with the famous Orion A giant molecular cloud. However, at present, there is only one cluster (LKHα 101) and several B-type massive stars in California, and these B-type massive stars are also located in the cluster,” said Dr. JinLong Xu.
The team used the observation data of the PMO 13.7-meter millimeter wave telescope to observe the molecular spectrum of carbon monoxide (CO) at the cluster location, and found that a new fibrous giant cloud interacted with the California, and the cluster was located at the intersection of the two giant clouds.
At the same time, the research team used the FAST to observe the radio hydrogen (H) and carbon (c) RRLs in the HII region associated with the cluster, and ruled out the possibility that the cluster only overlaps with the cross position in the visual direction through the detected composite line system speed, so as to directly confirm that the first buried cluster in the California giant molecular cloud is dismembered after being hit by another giant cloud Form. The team concluded that the "kindling" of the first cluster in the giant molecular cloud may be caused by the impact of foreign gases. The results of this study will be used for reference in the study of the origin of clusters.
Figure. Upper: CO molecular gas distribution and cluster position; Below: the hydrogen (H) and carbon (c) RRLs from the FAST observation (Credit: Jinlong XU)
This paper can be accessed at https://doi.org/10.3847/2041-8213/ab830e
Address: 20A Datun Road, Chaoyang District, Beijing, China code: 100012
Tel: 010-64888708 E-mail: [email protected] | 0.870068 | 3.998068 |
Today’s nebula news is brought to you by the letter “O.”
—Picture courtesy NASA/JPL-Caltech
In a new infrared picture from NASA’s Spitzer Space Telescope, a nebula known as RCW 120 makes a brilliant green “O” against a starry patch of sky.
It may look like a portal to Hell ripped through the fabric of spacetime, but this nebula is actually a bubble of gas and dust that’s formed around an “O” type star, the most massive stellar giants known to exist.
O stars appear blue in visible light and are very hot: Surface temperatures can be higher than 73,340 degrees Fahrenheit (40,727 degrees Celsius).
Because they are so bulky, O stars live fast and die young. Their intense radiation lights up their stellar nurseries shortly after they’re born, and they blow themselves apart as supernovae just a few million years later.
Bubbles like this one are found encircling O stars across the galaxy. In fact, the smaller objects near the bottom right of this frame may be similar rings deeper in space.
RCW 120 has been known and photographed before. But the nebula, about 4,300 light-years away near the constellation Scorpius, can take on different features depending of the wavelengths of light captured to make an image.
In 2008 the European Southern Observatory used a combination of visible and submillimeter light to take this snap of RCW 120:
—Picture courtesy ESO/APEX/DSS2/ SuperCosmos/ Deharveng(LAM)/ Zavagno(LAM)
The image shows the bright O star glowing with all its might near the center of the ring.
The powerful star is emitting huge amounts of ultraviolet radiation, which is very visibly pushing surrounding material so violently that it’s stripping the electrons from hydrogen atoms.
The freshly charged—or ionized—hydrogen gas glows deep red inside the bubble, as seen by ESO’s LABOCA camera in Chile’s Atacama Desert.
As the gas expands, it creates a shock wave that’s sweeping up interstellar gas and dust. This colder material, seen in hazy blue, is collapsing into dense clumps that are in turn becoming the seeds for new stars.
Since the youngest of these cloud clumps are relatively cold, around -418 degrees Fahrenheit (-250 degrees Celsius), it takes ESO’s submillimeter vision to make them out.
More recently, in May 2010 the European Space Agency used its Herschel infrared space observatory to examine RCW 120.
Nestled in the star-forming shock wave, Herschel found an embryonic star that’s shaping up to be one of the biggest and brightest in our galaxy.
—Picture courtesy ESA/PACS/SPIRE/HOBYS Consortia
Seen as a brighter patch near the base of the blue ring, this stellar monster is already eight to ten times as massive as our sun—and it’s still growing.
The big baby star is surrounded by an additional 2,000 solar masses of material, which means it has enough “food” to eventually get as big as stars can be: 150 solar masses.
As with the Herschel image, the new Spitzer view is in infrared, albeit in slightly different parts of the infrared spectrum. That means the blue-colored O star doesn’t shine as bright, but the surrounding ring of material shows up like a green beacon.
Because of this effect, rings like this are pretty common in Spitzer observations—so common that NASA scientists haven’t been able to catalog them all. | 0.908807 | 3.798129 |
Researchers using the Murchison Widefield Array radio telescope have taken a new and significant step toward detecting a signal from the period in cosmic history when the first stars lit up the universe.
Around 12 billion years ago, the universe emerged from a great cosmic dark age as the first stars and galaxies lit up. With a new analysis of data collected by the Murchison Widefield Array (MWA) radio telescope, scientists are now closer than ever to detecting the ultra-faint signature of this turning point in cosmic history.
In a paper on the preprint site ArXiv and soon to be published in The Astrophysical Journal, researchers present the first analysis of data from a new configuration of the MWA designed specifically to look for the signal of neutral hydrogen, the gas that dominated the universe during the cosmic dark age. The analysis sets a new limit — the lowest limit yet — for the strength of the neutral hydrogen signal.
“We can say with confidence that if the neutral hydrogen signal was any stronger than the limit we set in the paper, then the telescope would have detected it,” said Jonathan Pober, an assistant professor of physics at Brown University and corresponding author on the new paper. “These findings can help us to further constrain the timing of when the cosmic dark ages ended and the first stars emerged.”
The research was led by Wenyang Li, who performed the work as a Ph.D. student at Brown. Li and Pober collaborated with an international group of researchers working with the MWA.
Despite its importance in cosmic history, little is known about the period when the first stars formed, which is known as the Epoch of Reionization (EoR). The first atoms that formed after the Big Bang were positively charged hydrogen ions — atoms whose electrons were stripped away by the energy of the infant universe. As the universe cooled and expanded, hydrogen atoms reunited with their electrons to form neutral hydrogen. And that’s just about all there was in the universe until about 12 billion years ago, when atoms started clumping together to form stars and galaxies. Light from those objects re-ionized the neutral hydrogen, causing it to largely disappear from interstellar space.
The goal of projects like the one happening at MWA is to locate the signal of neutral hydrogen from the dark ages and measure how it changed as the EoR unfolded. Doing so could reveal new and critical information about the first stars — the building blocks of the universe we see today. But catching any glimpse of that 12-billion-year-old signal is a difficult task that requires instruments with exquisite sensitivity.
When it began operating in 2013, the MWA was an array of 2,048 radio antennas arranged across the remote countryside of Western Australia. The antennas are bundled together into 128 “tiles,” whose signals are combined by a supercomputer called the Correlator. In 2016, the number of tiles was doubled to 256, and their configuration across the landscape was altered to improve their sensitivity to the neutral hydrogen signal. This new paper is the first analysis of data from the expanded array.
Neutral hydrogen emits radiation at a wavelength of 21 centimeters. As the universe has expanded over the past 12 billion years, the signal from the EoR is now stretched to about 2 meters, and that’s what MWA astronomers are looking for. The problem is there are myriad other sources that emit at the same wavelength — human-made sources like digital television as well as natural sources from within the Milky Way and from millions of other galaxies.
“All of these other sources are many orders of magnitude stronger than the signal we’re trying to detect,” Pober said. “Even an FM radio signal that’s reflected off an airplane that happens to be passing above the telescope is enough to contaminate the data.”
To home in on the signal, the researchers use a myriad of processing techniques to weed out those contaminants. At the same time, they account for the unique frequency responses of the telescope itself.
“If we look at different radio frequencies or wavelengths, the telescope behaves a little differently,” Pober said. “Correcting for the telescope response is absolutely critical for then doing the separation of astrophysical contaminants and the signal of interest.”
Those data analysis techniques combined with the expanded capacity of the telescope itself resulted in a new upper bound of the EoR signal strength. It’s the second consecutive best-limit-to-date analysis to be released by MWA and raises hope that the experiment will one day detect the elusive EoR signal.
“This analysis demonstrates that the phase two upgrade had a lot of its desired effects and that the new analysis techniques will improve future analyses,” Pober said. “The fact that MWA has now published back-to-back the two best limits on the signal gives momentum to the idea that this experiment and its approach has a lot of promise.”
The research was supported in part by the U.S. National Science Foundation (grant #1613040). The MWA receives support from the Australian government and acknowledges Wajarri Yamatji people as the traditional owners of the observatory site.
Original article here: https://www.brown.edu/news/2019-11-26/reionization | 0.867713 | 4.176464 |
NASA's New Horizons mission to the Pluto-Charon system has yet to mark its finest hours – a historic flyby that makes its closest approach to the binary planet and its moons Tuesday morning.
But even as the spacecraft puts the wraps on its final approach, data New Horizons has delivered within the past 48 hours "is a gift for the ages," says Alan Stern, a planetary scientist at the Southwest Research Institute in Boulder, Colo., and the mission's principal investigator.
The craft's approach is revealing "tremendous diversity between the two planets in the system and their moons," he said. "We're already seeing complex and nuanced surfaces that tell us of history for these two bodies that is probably beyond our wildest dreams."
In short, "the Pluto system is enchanting in its strangeness and alien beauty," Dr. Stern said during a briefing Monday.
It's as though "we're on the bridge of the Enterprise approaching some alien planet around Alpha Centauri 3 or whatever it is," said Paul Schenk, a planetary geologist at the Lunar and Planetary Institute in Houston and a member of the New Horizons science team. "It's like someone painted it for a 'Star Trek' episode."
Even seemingly mundane measurements, such as a new, more-accurate determination of Pluto's size – now pegged at 1,473 miles across, at the high end of estimates that have ranged from 1,429 miles to around 1,491 miles – carry import.
The new size, combined with long-established, precise measurements of Pluto's mass, yields a dwarf planet a bit less dense than previously estimated. That means its interior contains more ice, versus rock, than previously estimated. This change has implications – yet to be worked out – for the process that formed the binary-planet system as well as for the chemistry of the disk of dust, gas, and ice that encircled the sun and provided the building blocks for the planets ad their moons, Stern explained.
Bragging rights also come into play.
"The new measurement unambiguously settles the debate about the largest object in the Kuiper Belt," Stern said, referring to a region of the solar system extending more than 2 billion miles beyond Neptune. By some estimates, the region hosts trillions of comets as well as several hundred thousand objects larger than 60 miles across. It's also the region that gave birth to Pluto and the object that would collide with it to form Charon. Another Kuiper Belt inhabitant, Eris, had previously laid claim to the "largest" label at 1,445 miles across.
A larger Pluto also means that the lower layer of the atmosphere is shallower than previously thought, which will affect models that try to shed light on the atmosphere's structure and behavior.
Another early result involves nitrogen escaping from Pluto's tenuous atmosphere. New Horizons' instruments began to pick up the great escape five days ago, when the craft supposedly was too far away to see it, Stern said. It could mean that the nitrogen is fleeing the planet at a higher rate than models have suggested or that the mechanism responsible for triggering the loss is different than researchers have anticipated.
In addition, incoming data show that a hypothesized polar cap on Pluto is in fact an ice cap consisting of nitrogen and methane ices.
New Horizons also is revealing features on Pluto that are generating speculation, pending more detail from measurements taken at the closest approach.
For instance, images of Pluto released over the weekend show a surface that in many places hosted vast expanses of small, tightly packed dimple-like formations.
The features appear to be similar to those on Neptune's moon Triton, Dr. Schenk said. Triton – itself thought to be a Kuiper Belt object that Neptune captured – hosts a surface "that looks like a boiling pot of porridge, with cells of material popping up. They create a cellular pattern that looks like the skin of a cantaloupe."
There, researchers suspect that relatively buoyant rock or ice has risen from deeper in the crust to build the array of hills and depressions – similar in principle to salt domes that rise through surrounding rock to form low hills in southern Louisiana or southeastern Texas.
The science team hopes to get a closer look at some of these dimpled regions in images New Horizons takes during its closest approach Tuesday morning.
In addition, images so far show a relatively smooth surface over much of Pluto, suggesting that the surface could be relatively young, Schenk said.
Again, he cites Triton as a possible analog. The relative smoothness of much of Triton's surface suggests that it's less than 100 million years old. "On Triton, everything is very young," Schenk said.
It speaks to Triton as a captured Kuiper Belt object whose orbit around Neptune initially would have been elliptical, but over time became circular. The change in orbit would have heated Triton significantly, allowing fresh material to well up from depth and repave the surface, erasing any evidence of impact craters that would have accumulated over time.
On Pluto, "we're not seeing any large craters that would pop out and say: There's a big basin here," he says. "So we're beginning to think that maybe that it's a very young surface."
The source of internal heating required to provide material for repaving Pluto is unclear, Schenk acknowledges. Perhaps heat left over from the impact that formed Charon remained intense enough long enough to provide sources of fresh material for resurfacing Pluto.
"We still don't know," he says. "But we'll find that out."
[Correction: This article has been updated to correct the new measurements of Pluto's diameter.] | 0.887645 | 3.637671 |
Being able to say that life exists in other places, within or outside our Solar system, will fundamentally change our view on the role of humanity in the Universe. Is the Earth really unique as a cradle of life? We are in a position where we will find the answer in the next decades.
The enormous technological progress of the past decades has put us in a position to start examining the climate and the habitability of other worlds in detail. Within our own Solar System Mars and the icy moons of Jupiter and Saturn are particularly interesting through the (former) presence of liquid water. Studies of the physical and chemical boundaries, and hallmarks of habitability based upon studies of Earth and in the wider Solar System will enable extrapolation to exoplanets.
An important challenge will be to recognize and understand the chemical biomarkers on other worlds, where both climatological and geological circumstances and the biological processes may be significantly different. Future efforts will focus on in situ detection of biomarkers on planetary surfaces, as well as through remote sensing. The in situ search for biosignatures focuses primarily on biomolecules, organic compounds that life uses, and biominerals on and embedded in the surface, whereas remote sensing focuses on the detection of atmospheric markers that betray the presence of biological activity, such as oxygen and methane on Earth.
Very remarkable is current progress in research into exoplanets, planets around stars other than the Sun. Although the nearest stars are over a hundred thousand times more distant than Mars, scientists are getting ever better at not only finding new exoplanets, but also at characterizing their atmospheric properties (as well as the chemistry of planetary systems in formation).
The European Extremely Large Telescope (E-ELT) will play a central role in this effort. As a first step, the first-light instrument METIS (2024/25), which is being built under Dutch leadership, will examine the atmospheres of rocky exoplanets like the Earth for the first time. The next step is the development of the second-generation E-ELT instrument EPICS (2030/35), which can also detect biomarker gases. The Netherlands is playing a leading role here as well. Ultimately, a complete characterization of the atmospheres of terrestrial planets can only be realized with a specialized space telescope (2035+). All these technological developments will be realized in the framework of the European Space Agency (ESA), and of the European Southern Observatory (ESO).
The importance of collaboration with Dutch industry for this research path is evident and crucial. However, the benefits are equally important for this very industry. Ambitious explorative programs like the search for extraterrestrial life bring unique technological spin-offs, since the challenging specifications of their instrumentation lead to new technological developments. | 0.876189 | 3.722692 |
Scientists at NASA have discovered that a planet located near the star Proxima Centuri might be capable of harboring life and even of having vast oceans. Earlier studies had determined the planet, called Proxima B, to be uninhabitable.
Proxima Centuri is an M-type red dwarf star that is known to be far cooler than our sun. As such, the planet, located 4.2 light years away from Earth, had to be positioned very close to the star in order to have a chance of sustaining life. However, the problem is that red dwarf stars are known to be highly active.
In their early life, these stars tend to be very hot and bright. This would mean that Proxima B, even if it started out as habitable, would eventually get too hot to harbor any life. Powerful flare activity was also observed from the star, which points to the possibility that the atmosphere of Proxima B could have been stripped away.
However, a new study by NASA states that the planet still has the potential of being habitable. The study theorizes that Proxima B initially formed far away from the star and eventually moved closer to it. This would have let the planet escape the extremely hot temperatures of the dwarf star during its early phase.
The report also puts forward the possibility that the distant planet might have contained 10 times more water than Earth. As such, even if any radiation blast would have stripped away most of its water, the planet could still have enough liquid to sustain life.
The team also used custom software to ascertain the type of atmosphere and liquid content that the planet might have. The results came out very positive, indicating the presence of vast oceans.
“So if it has an atmosphere and has water, Prox b has a pretty good chance to be habitable. We also found that the ocean currents carried warm water from the dayside to the nightside, keeping parts of the nightside habitable even though they never see any light. And if the ocean is very salty, almost the entire planet could be covered by liquid, but with temperatures below the usual freezing point almost everywhere,” Universe Today quotes Anthony D. Del Genio, leader of the research group.
The study also points to a possibility that other rocky planets that orbit M-type red dwarf stars might also be habitable. And considering that these stars form about 70 percent of all known stars in the Milky Way, the chances of discovering a habitable planet have vastly increased.
Other habitable planets
In addition to Proxima B, several other planets have been identified by scientists as having the potential for sustaining life. The most interesting among them is a planet named Wolf 1061c from the Ophiuchus constellation.
Located about 13.8 light years away from our planet, Wolf 1061c is reportedly the next potentially habitable planet known to scientists after Proxima B. The planet has an estimated mass that is 4.3 times that of the Earth and takes 17.9 days to complete an orbit around its star.
Other nearby planets that look promising for scientists include Gliese 832c, Gliese 667Cc, and TRAPPIST-1d. These are however much farther away from us than Proxima B. As such, this planet still remains our best chance of finding a habitable planet. | 0.849642 | 3.786619 |
The Event Horizon Telescope (EHT), which uses a network of telescopes around the globe to turn the Earth into an enormous radio telescope, has taken the first direct image of a black hole. This image shows the large black hole in the centre of another galaxy called galaxy Messier 87, which is 55 million light years away.
About black hole
- Black holes are places in space so dense, with such immense gravity, that beyond a certain boundary called the “event horizon,” nothing—not even particles and electromagnetic radiation such as light—can escape from it.
- They form at the end of some stars’ lives. When stars, which are around twenty times bigger than the sun exhaust all the energy, they can collapse in on themselves forming a black hole.
- There are four types of black holes:
• In 1915, Black holes was predicted by Einstein’s theory of relativity – although Einstein himself was sceptical that they actually existed. Einstein said that though his equations on theory of gravity indicated that such objects were theoretically possible, but they “do not exist in physical reality.”
• In 1974, Hawking for the first time predicted the existence of Hawking radiation which are released by black holes.
About event horizon telescope
- Event horizon telescope consists of eight radio observatories around the world, including telescopes in Spain, the US and Antarctica
- In 2006, an international team of more than 200 researchers, led by Harvard University astronomers, launched the Event Horizon Telescope (EHT) project with a sole aim: to capture a direct shot of a black hole.
- Thirteen partner institutions worked together to create the EHT, using both pre-existing infrastructure and support from a variety of agencies. Key funding was provided by the US National Science Foundation (NSF), the EU’s European Research Council (ERC), and funding agencies in East Asia.
- The EHT observations use a technique called very-long-baseline interferometry (VLBI) which synchronises telescope facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope observing at a wavelength of 1.3 mm.
- VLBI allows the EHT to achieve an angular resolution of 20 micro-arcseconds — enough to read a newspaper in New York from a sidewalk café in Paris
- Observations at the different sites were coordinated using atomic clocks, called hydrogen masers, accurate to within one second every 100 million years. Researchers combined radio-wave data from each telescope, creating the image.
When observations were launched in 2017, the EHT had two primary targets.
- First was Sagittarius A*, the black hole at the centre of the Milky Way, which has a mass of about 4m suns.
- The second target, which yielded the image, was a supermassive black hole in the galaxy M87, into which the equivalent of 6 billion suns of light and matter has disappeared.
The image doesn’t show the black hole’s event horizon, but a shadow cast by the light around it due to the unstable orbits of photons around the central object. This helps to infer some infer some of the black hole’s properties
- The researchers were able to deduce the mass of the M87* at 6.5 billion times that of the Sun.
- EHT scientists also deduced the radius of the event horizon as 3.8 micro-arcseconds.
- Rotation of the black hole is in a clockwise direction, and that its spin points away from earth.
- The ring of light around the black hole looks a little lopsided.
Significance of Image
- Einstein’s Relativity is a real scientific law: Image of a black hole is the first direct proof of existence of black hole and proves that Einstein’s Relativity is a real scientific law.
- More precise knowledge about blackhole: The image doesn’t show the black hole’s event horizon, but it is enough to infer some of the black hole’s properties
- Accurate estimates for black hole masses: EHT observations were able to deduce the mass of the M87* at 6.5 billion times that of the Sun. Previous estimates — based on models as well as spectroscopic observations of the galaxy by the Hubble Space Telescope — ranged between 3.5 and 7.7 billion solar masses.
- Help in proving other theories: It would help in proving other theories such as the Big Bang theory, where the plot is similar
The Event Horizon Telescope’s first run prove that event horizons really exist. Astronomers now hope to carry out further observations of M87 to deduce the shape and depth of the shadow region more accurately. They are also hopeful to add more telescopes to the array that will allow for higher-resolution images. As well as M87, the EHT team is attempting to take the first image of Sagittarius A.
The experiment of EHT owes to international collaboration and use of interdisciplinary expertise. Future runs could help us to understand the basics of our universe more precisely and accurately. | 0.848764 | 3.949374 |
14 Crazy Facts About Earth You Never Learned in School
The planet is almost 40,000 kilometres around and 4.54 billion years old, and humans are still discovering some of the amazing secrets it’s hiding.
Stories about giant waves have been circulating among sailors for centuries, but skeptical scientists thought they were about as common as mermaids. Then, in 1995, an oil platform in the North Sea was hit by a big one during a huge storm, and it had the equipment on hand to determine that the wave had been a massive 84 feet tall. A few years later, a 95-foot wave was measured by a research vessel west of Scotland. Oceanographers realized that not only were these massive waves real, they were surprisingly common. According to the U.S. National Oceanic and Atmospheric Administration, rogue waves are more than twice the size of surrounding waves (often getting as big as 100 feet tall), come from surprising directions, and only happen in open seas.
If you think these facts about Earth are surprising, wait until you read about the strangest mysteries about planet Earth.
Underwater mountain range
Rogue waves aren't the only giant secret the oceans have been keeping—the longest mountain range in the world is actually underwater. It's called the Mid-Ocean Ridge, and it extends more than 64,000 kilometres, running down the middle of the Atlantic, east through the Indian Ocean, and back up through the Pacific, along the west coast of the Americas. (Compare that with the Andes, the longest continental mountain range, which is only 7,000 kilometres long!) The Mid-Ocean Ridge is a continuous string of underwater volcanoes lying along the meeting points of Earth's tectonic plate—as the plates drift apart, magma seeps up continuously, creating new crust.
These are the creepiest things you can find at the bottom of the ocean.
World's tallest mountain
Mount Everest in the Himalayas usually takes this honour, at more than 29,000 feet above sea level; but if we include mountains that aren't fully above sea level, Hawaii's Mauna Kea is the winner. Only 13,706 feet of it come up above the water, but if you calculate its height starting from its base at the bottom of the Pacific Ocean, Mauna Kea is 30,610 feet tall, beating Everest by about 1,640 feet. Where Everest was formed by the collision of two tectonic plates (and is still growing taller), Mauna Kea developed because of the volcanic activity that formed the Hawaiian Islands—it's dormant now, according to the Hawaii Center for Volcanology.
Ring of fire
Nine out of ten of the world's earthquakes and 75 per cent of its volcanoes occur as a result of tectonic activity in what's known as the Pacific Ring of Fire—a circle of volcanically and seismically active hot spots marking the meeting points of several plates that all encircle the large Pacific Plate. The tectonic plates are bumping into and sliding past, over, and under one another, resulting in eruptions and quakes. The circle is about 40,000 kilometres in circumference and is the cause of recent eruptions in Indonesia and the Philippines, as well as earthquakes in Mexico, Taiwan, and Alaska.
Don't miss these fascinating things captured by Google Earth.
It's one of the facts about Earth that all of its tectonic plates are shifting, but Australia's is moving so quickly that it requires updates to maps and GPS systems fairly regularly—it moved almost five feet between 1994 and 2016, according to National Geographic. Geologist Christopher Scotese at Northwestern University told BBC that in about 50 million years, Australia will be colliding with southeast Asia. In about 250 million years, the continents might all merge into a single super-continent again, like Pangaea.
Believe it or not, but these seven animals are deadlier than sharks.
Volcanic islands are pretty easy to identify, but some of the ways volcanic activity shaped the Earth in its infancy are not as easy to spot. It was only in the 1960s that geologists realized the 70-kilometre-wide depression in the ground in Yellowstone National Park is a volcanic caldera. Rather than a lava flow that formed a mountain, like Hawaii's Mauna Kea and Washington state's Mount St. Helens, eruptions at Yellowstone took the form of massive explosions that actually caused mountains and other topography to collapse. The volcano is still active, in fact—there's a chamber of liquid magma underneath it that fuels the park's geysers and hot springs like Old Faithful. But the last major eruption was about 630,000 years ago, and although there's not currently any good way to predict volcanic eruptions, scientists aren't too worried about another big one. In fact, Ilya Bindeman, a University of Oregon geochemist, told the Washington Post that Yellowstone may be "approaching the end of its evolution."
These are the most jaw-dropping trees around the world.
Ancient Wuda forest
About 300 million years ago—long before the Yellowstone volcano formed—an eruption in what is now China left a thick layer of ash on top of a swamp forest. The Permian-era plants and trees were all fossilized and preserved. The continents were, at the time, still all joined together as a single land mass; over the intervening millennia, they've drifted apart into their current positions and the vegetation and animal life on Earth have changed immeasurably. That's why when scientists discovered the fossilized forest a few years ago, they called it a Permian Pompeii—they can see just how the plants were arranged, and have found trees as big as 80 feet tall. (There weren't any conifers or flowering plants, though—all plants reproduced through spores, like ferns, which were abundant.) "It's marvelously preserved," University of Pennsylvania paleobotanist Hermann Pfefferkorn told Gizmodo's Jesus Diaz. "We can stand there and find a branch with the leaves attached, and then we find the next branch and the next branch and the next branch."
There's a river in the Peruvian Amazon where water temperatures can actually cook unlucky animals that fall into the water. Geophysicist Andrés Ruzo, whose Peruvian grandfather mentioned the boiling river to him when he was a child, kept searching for the mysterious site even though his professors told him it had to be a myth. When he found it, he worried that it had been caused by nearby oil and gas extraction, but determined that it was a natural feature: It's "a non-volcanic, geothermal feature flowing at anomalously high rates," he told National Geographic. Meaning it's just very hot water (getting up to about 93 degrees Celsius) coming from very deep below the Earth's surface quickly enough that it doesn't cool off before it comes out into the river.
Discover other natural wonders around the world you've never heard of.
At a site in Ethiopia where three tectonic plates meet up, there are less than eight inches of rain every year, and the average daily temperature is 34 degrees Celsius, the landscape looks like an amazing sight from another planet. The Danakil Depression is part of the East African Rift Valley which, like the Mid-Ocean Ridge underwater, is a spot where tectonic plates are separating, allowing magma to seep up toward the Earth's surface. Volcanic activity causes bubbling lava lakes, hot springs, and tiny geysers. Heated groundwater brings dissolved mineral salts to the surface, and when the water evaporates, multi-coloured fields of deposits are left behind.
These are the most remote places on Earth.
One of the most surprising facts about Earth scientists have found at the Danakil Depression—and in other areas with very hot hydrothermal vents, where chemical-rich fluid escapes to the Earth's surface—is that specialized organisms call them home. When this happens deep under the ocean, especially, where sunlight can't penetrate to allow photosynthesis, microbes use chemosynthetic processes to create organic matter out of hydrogen sulfide, methane, and other chemicals. Tubeworms and other animals that live near the vents often host these microbes on or in their bodies.
Largest single organism
Scientists have been surprised by other forms of life over the past few decades as well—particularly the Armillaria fungus, a mushroom that's proved to be a gigantic wonder. A scientist in Michigan found one in the early 1990s that turned out to weigh about 22,000 pounds and extend out 37 acres; when scientists started hunting competitively for more giant Armillaria, an Oregon sample was found that covered more than 2,400 acres. Researchers estimate its age at 8,650 years old. This particular fungus gets so big (and evades notice so effectively) because it grows root-like structures called rhizomorphs that extend underground for miles. It grows up into trees from below, and as a result, can kill large swaths of forest, biologist László Nagy, of the Hungarian Academy of Sciences, told The Atlantic. "You can basically see entire hills wiped out," he said.
Scientists are still trying to figure out these 13 moon mysteries.
Another example of life showing up where you least expect it is when living creatures fall from the sky in a storm—and yes, this really happens. "Frog and toad rains, fish rains, and coloured rains—most often red, yellow or black—are among the most common accounts of strange rain, reported since ancient times," Cynthia Barnett writes in her book, Rain: A Natural and Cultural History. Scientists believe that a waterspout or tornado picks up the animals, dust, or other items in one place, and they get blown by the storm to another location where they fall. John Knox, an atmospheric scientist at the University of Georgia, told Smithsonian Magazine that he's seen photographs that fell back to earth 322 kilometres from where they were picked up by tornadoes.
Dust can travel in the atmosphere even farther than photographs or frogs, and besides causing odd-coloured rain, can also make the sky look hazy and cause asthma attacks in vulnerable people. According to NASA's Earth Observatory, hundreds of millions of tons of desert dust blow across the Atlantic Ocean from Africa every year, adding to Caribbean beach sand and fertilizing the Amazonian soil. The dust might also disrupt hurricane formation by suppressing cloud formation.
Don't miss these 10 scientific mysteries we take for granted.
Dust isn't just coming from deserts on Earth either—scientists recently collected samples of dust in the upper atmosphere that travelled here with comets. By studying the chemical composition of the particles, they can tell that the dust is actually older than the solar system. "Our observations suggest that these exotic grains represent surviving pre-solar interstellar dust that formed the very building blocks of planets and stars," lead researcher Hope Ishii, from the University of Hawaii at Manoa, said in a statement. "If we have at our fingertips the starting materials of planet formation from 4.6 billion years ago, that is thrilling and makes possible a deeper understanding of the processes that formed and have since altered them."
Next, read on for the most baffling mysteries of the universe. | 0.855061 | 3.100859 |
In this VIS image, taken by the NASA - Mars Odyssey Orbiter on July 1st, 2013, and during its 51.217th orbit around the Red Planet, we can see a small portion of Palos Crater (on top of the frame) and a section of the approx. 180-Km-long (such as a little less than 112-miles-long) Channel known as Tinto Vallis. In fact, Palos Crater is breached in its Southern portion by Tinto Vallis (right in the middle of the picture), and the water transported along this sinuous Channel could have collected - at some point in the Geological History of Mars - into Palos Crater itself, so to form a Lake that, later, drained to the North.
If you think about it, we can speculate that the Sediments carried by the waters flowing inside Tinto Vallis, could have reasonably been deposited within Palos Crater, so that the many Layered Units that have recently been identified (in several pictures taken by the NASA - Mars Reconnaissance Orbiter) all along the Floor of Palos, could well be representing the fossilized remnants of the aforementioned Fluvial Sediments.
Latitude (centered): 3,249° South
Longitude (centered): 110,809° East
This frame (which is an Original Mars Odyssey Orbiter b/w frame published on the NASA - Planetary Photojournal with the ID n. PIA 17439) has been additionally processed, magnified, contrast enhanced, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. | 0.851421 | 3.401967 |
Kepler Gets an Extended Mission
The NASA Senior Review panel decisions are in. The panel assessed Kepler and several other astrophysics missions including Hubble Space Telescope, Chandra X-ray Observatory, Spitzer Space Telescope, XMM-Newton, Swift, Planck, Fermi Gamma Ray Telescope,and Suzaku. This is to evaluate the missions and decide if they should be renewed or approved for an extended mission. For Kepler, having launched in March 2009, the spacecraft is over 3 years old. The primary mission was to last 3.5 years with the goal to find and constrain the frequency of rocky planets and in particular Earth-sized planets in the habitable zone (the region around the star where liquid water could exist on a planet with an atmosphere similar to the Earth’s) of solar-type stars.
Kepler has been a spectacular success finding a treasure trove of over 2000 planet candidates in the first 16 months of data (Quarters 1-6), and revolutionized our understanding of planetary systems. But the Earth-sized planets are proving tricky because stars are much more variable than the Sun. This was unexpected,so instead of taking 3 years to confidently identify Earth-sized and smaller planets it will take 3 more years beyond the nominal mission. For NASA missions, you’re given the time you request when the mission gets selected to do your primary science goals and then can ask for additional funding for an extended mission. The Kepler spacecraft is in excellent health, with the only major failure being the loss of once of their science modules in Quarter 4. There is plenty of fuel to keep Kepler alive and pointed well beyond 2016, so Kepler team applied as did the other missions for funding to extend the mission another four years.
A NASA panel reviewed the mission, and the excellent news is that Kepler was approved for a 4 year extension! They also recommended to extend all of the missions it assessed which is excellent for the astronomy community. You can read the entire report here. Congratulations to the Kepler team for the success of their program and thanks for the excellent data that we’ve been finding planets and other interesting things in with Planet Hunters. This is great news! So this means Kepler will be running an additional 4 years – so a total of ~7 years of data. This means we can probe planets out at even further distances. This will be particularly interesting because we have been finding these very compact multiplanet systems (some having more several planets on orbits smaller than Mercury’s), so I’m curious to see how many multiplanet systems that have planets at distances beyond an 1 AU exist.
So what does this mean for Planet Hunters? First off it’s mean we’ll have plenty of light curves to look at for a long while with the potential to find even more interesting things and planets awaiting discovery. But what’s going to change come November, is the there is no proprietary data anymore. Currently the Kepler scientists have a first crack at the data before it is released to the rest of the scientific community and the public. Kepler is currently observing Quarter 13 but we have only up to Quarter 6 data. In Novemeber this all changes – they’ll be another big data release in July 28 (Quarters 7,8, and 9 will be released) and the next on October 28 (Quarters 10, 11, 12, and 13 will be released) . After that once the data comes off the Kepler spacecraft and is processed by the data processing algorithms the data will be released to the public and the Kepler team at the same time and we’ll be showing the light curves as fast as we can get them on the site.
This is a new era for the exoplanet community. I can’t wait for November, it’s going to be a great couple of years for Kepler and Planet Hunters if the past year has been any indication of the interesting science we’ll be able to do. In the meantime, there’s still lots of light curves to search through before the next data release and we’re starting to look for new planet candidates in those classifications from Quarters 3, 4, and 5 as well as take follow-up observations of our highest priority candidates (more on that in next the few blog posts). So keep those clicks coming. | 0.811542 | 3.274789 |
A Guide on Choosing the Best Telescope Eyepieces
The optical elements of eyepieces allow you to focus light collected by a telescope, so you can observe a sharp view of the object or area where the telescope is pointing. It may seem like a small link in the chain, but it has a large effect on your telescope's optical system, and finding suitable eyepieces will greatly enhance its potential.
With so many options to choose from, selecting the right set of eyepieces for you and your telescope can seem a little tricky. This guide offers some insight and explanations on different eyepiece types, specifications, and how it all ties together to optimize your astronomy and astrophotography sessions!
Focal Length and Magnification
The Focal Length is an important specification to consider when determining the magnification, also known as power, of an eyepiece and the telescope it's being used with. The following formula will help you determine the magnification based on your eyepiece and telescope's specifications:
- A 20 mm eyepiece on a 2000 mm telescope (2000/20) gives you 100 power (100x), this makes objects appear 100 times closer to you through the telescope than they appear to your unaided eye.
Field of View: Apparent and True
An eyepiece's Apparent Field of View (AFOV) is expressed in degrees (°). It is how much of the sky is seen edge-to-edge through the eyepiece alone. AFOV's range from narrow (25° - 30°) to an extra-wide angle (80° or more).
An eyepiece's true field of view is the angle of sky seen through the eyepiece when it's attached to the telescope. The true field can be calculated using the following formula:
True Field = Apparent Field / Magnification
For example, suppose you have an 8-inch Schmidt-Cassegrain telescope with a 2000 mm focal length and a 20 mm eyepiece with a 50° apparent field. The magnification would be 2000 mm / 20 mm = 100x. The true field would be 50\100, or 0.5° - about the same apparent diameter as the full moon.
Eye Relief and Corrective Lenses
Eye Relief refers to the distance between your eye and the eyepiece lens when the image is in focus. Eye relief is traditionally in proportion with focal length: The shorter the focal length, the shorter the eye relief. However, some of the more modern eyepiece designs provide long-eye relief regardless of focal length, which is especially beneficial to those who wear glasses. If you like to keep your glasses on while using a telescope, the eye relief of an eyepiece is an important specification to consider (we recommend looking at long-eye relief eyepieces).
2 mm - 4.9 mm Eyepieces
These provide very high magnifications and work best on long focal length refractors and Schmidt-Cassegrains. Unless you have very steady seeing conditions, this range more than likely will produce too much magnification for other telescope types.
5 mm - 6.9 mm Eyepieces
These make good planetary detail and double star eyepieces for long focal length telescopes and will work satisfactorily in shorter focal length telescopes with steady seeing conditions.
7 mm - 9.9 mm Eyepieces
Ideal high magnification eyepieces for shorter focal length telescopes and serve as good planetary, double star, and lunar detail units.
10 mm - 13.9 mm Eyepieces
Good to use across all focal lengths and offer great background darkening capabilities for studying planetary nebula, small galaxies, planetary details, and lunar details.
14 mm - 17.9 mm Eyepieces
A great mid-range magnification for all focal lengths and helps resolve globular clusters, galaxy details, and spot planetary nebulae.
18 mm - 24.9 mm Eyepieces
Works nicely on long focal length telescopes to show wide field and extended objects. Shorter focal length telescopes will enjoy great mid-range magnification of galaxy clusters and large open clusters.
25 mm - 30.9 mm Eyepieces
Longer focal lengths are good for large nebula and open clusters. Shorter focal lengths are great for large objects such as the Orion nebula, views of the full lunar disc, large open clusters, and more. It also makes for good "locator" eyepieces in all focal lengths.
31 mm - 39.9 mm Eyepieces
These are well suited for shorter focal length telescopes for extended views and large, starry fields.
40 mm Eyepieces
These are exclusively the domain of shorter focal length telescopes. This magnification range is superb for showing large, starry vistas as well as extended nebulae with star fields, etc.
How Exit Pupil Relates to Power
Exit pupil refers to the size of the bundle of light rays coming out of the eyepiece. Exit pupil size (in inches) can be calculated by:
In order for all the light rays to enter your pupil, the exit pupil must be smaller than the pupil of your eye. A young person's fully dark-adapted eyes may have 7 mm-wide pupils. As you age, the maximum pupil diameter decreases. For middle-aged adults, the practical maximum is closer to 5 mm.
At the other end of the scale, magnifications that yield an exit pupil in the range of 0.5 mm to 1.0 mm, empty magnification begins to set in, depending on the quality of your telescope and your eyes. In other words, this much magnification starts to degrade the image you see.
How Many Eyepieces Do I Really Need
Although there is no specific number of eyepieces you should own, with a few different telescope eyepieces, you have a better chance of hitting the optimal power for the particular object you are observing, given the sky conditions at the time. Usually, you'll want to start with low power (i.e., long eyepiece focal length, such as 25 mm or 30 mm) to get the object in the field of view of the telescope. Then you might want to try a slightly higher-power (shorter focal length, maybe 18 mm or 15 mm) eyepiece and see if the view looks any better. If it does, swap in an even higher-power eyepiece, etc., until you hit that "sweet spot" where image brightness, image scale, and the amount of visible detail combine to form the most pleasing view.
What about Barlow Lenses?
You can also choose a long focal length eyepiece with comfortable eye relief and use image amplifiers to increase power, such as a Barlow lens. A Barlow increases the effective focal length of an objective lens, increasing the magnification. The idea is that two eyepieces and a Barlow will give you the flexibility of magnification of four eyepieces, and will give higher magnifications with less powerful eyepieces.
Using different eyepieces can profoundly increase the versatility and functionality of any telescope.
Basic Tips to Follow When Shopping for Eyepieces
Consider the focal length of your telescope, or telescopes, to make sure the eyepiece will provide an appropriate magnification to suit your needs.
If you wear eyeglasses while using a telescope, pay attention to the eye relief specification of different eyepieces, as ample eye relief can improve comfort and ease-of-use while wearing corrective lenses.
Depending on your observing goals, consider the apparent field of view of your eyepiece choices.
If versatility is paramount, consider a zoom eyepiece or Barlow lens to increase the number of possible magnifications to use. | 0.869925 | 3.846463 |
There are stars that, after burning all their “fuel,” turn into so-called “white dwarfs” but project their outer layers outward before performing this transformation. This material, projected at very high speed, destroys nearby objects and also strongly damages the planets by removing the outer layers of the latter in addition to the atmospheres.
According to a study by researchers at the University of Warwick, published in Monthly Notices of the Royal Astronomical Society, the remaining nuclei of these planets can “survive” for a necessary time, from 100 million to a billion years, so that they can be detected by our telescopes.
This is not an absolute novelty: already in the early 90s, Alexander Wolszczan of Pennsylvania State University discovered one of these planets around a pulsar using a method to detect radio waves emitted by the star.
Researchers at the University of Warwick intend to improve this method to detect the magnetic field that forms between a white dwarf and a planetary nucleus in orbit around it. The magnetic field can, in fact, form a unipolar inductor circuit in which the remaining nucleus of the planet acts as a conductor thanks to the fact that inside the nucleus there are more than anything metallic compounds.
This is a real circuit whose radiations are emitted as radio waves that can be detected by terrestrial radio telescopes. Among other things, an effect of this kind has already been noted between Jupiter and one of his moons, Io.
According to Dimitri Veras, one of the authors of the study, “There is a weak point to detect these planetary nuclei: a nucleus too close to the white dwarf would be destroyed by tidal forces and a nucleus too far away would not be detectable. Also, if the magnetic field is too strong, it would push the core into the white dwarf, destroying it. Therefore, we should only look for planets around the white dwarf ones with weaker magnetic fields at a distance of about 3 solar rays, the distance Mercury-Sun.”
In any case, finding the only nucleus of a “naked” planet would represent a very important discovery that would help to discover the history of star systems as well as allowing you to take a look at the future history of our solar system and specifically of our planet which should not be very different. | 0.896092 | 3.788368 |
Scientists from the University of Cambridge have discovered a pair of incredibly massive holes punched through a trail of Milky Way galaxy stars — and they think big clumps of dark matter were responsible.
The globs of dark matter that did the deed are insanely large — about one million to 100 million times the mass of the sun — and yet are the smallest bits of dark matter scientists have detected yet, according to a new study uploaded to the arXiv repository and last updated Wednesday.
Don’t take that literally — dark matter, for those who might not know, has never been directly observed, even though it comprises about 85 percent of the known universe. The reason we know dark matter exists is because it’s the only way to explain some of the weird gravitational effects influencing big celestial bodies in the universe.
Moreover, it’s the only way to explain exactly how an otherwise elegant stellar stream in the Palomar 5 globular cluster — itself 5,000 times the mass of the sun and 30,000 light-years long — possesses a bunch of vacant splotches.
The results, submitted to the Monthly Notices of the Royal Astronomical Society, could be critical in helping scientists actually characterize dark matter. The research team ran some calculations based on the new data that suggests dark matter is more massive and slower moving than we previously imagined.
“While we do not yet understand what dark matter is formed of, we know that it is everywhere,” said Denis Erkal from Cambridge’s Institute of Astronomy, the paper’s lead author, in a news release. “It permeates the universe and acts as scaffolding around which astrophysical objects made of ordinary matter — such as galaxies — are assembled.”
A dark matter clump blasting through a stellar stream would presumably create a gap that’s proportional the mass of the dark matter itself. Based on this assumption, the researchers studied Palomar 5 and ran some simulations to determine the gaps in the trail of stars lined up with a theoretical fly-by of dark matter.
“If dark matter can exist in clumps smaller than the smallest dwarf galaxy, then it also tells us something about the nature of the particles which dark matter is made of – namely that it must be made of very massive particles,” said study coauthor Vasily Belokurov. “This would be a breakthrough in our understanding of dark matter.”
If the team can further validate this new technique for determining the effects of dark matter, it would be another way to discern where smaller clumps of the hidden stuff might be zipping around.
“It’s like putting dark matter goggles on and seeing thousands of dark clumps each more massive than a million suns whizzing around,” said Erkal. | 0.83764 | 4.037134 |
By James Maynard
Earth may have been the target of more asteroids and comets than once believed, based on a new computer simulation. These violent impacts may have boiled away oceans, sending vast quantities of water vapor into the atmosphere.
Astronomers have long known that collisions between minor bodies and planets occurred frequently in the early history of the solar system. This period is known as the Late Heavy Bombardment.
Southwest Research Institute researchers developed a computer simulation that models our planet during it first 500 million years. The virtual solar system was created using data taken of lunar and interplanetary craters. Erosion and other planetary processes have erased nearly all evidence on Earth of interplanetary impacts during the first half-billion years of our planet’s history. This required researchers to study cratering patterns left on other worlds, including Mars and Mercury, in addition to our planetary companion.
The battered surface of the Moon provides a glimpse into the violent history of the Earth during its formation, the Hadean Eon. This was the first era of the Earth’s formation, when the planet was still rapidly cooling, with a shallow crust. Researchers also examined the presence of minerals, believed to be brought from space, and their reactions with gold and other elements present in the crust of the Earth.
Recreation of the Hadean Eon suggested that in addition to a myriad of collisions with smaller objects, our planet was also likely struck by several large bodies. These may have provided enough energy to melt the surface of the young Earth, a process which could have been repeated many times, continually reforming the crust of the young planet. These tremendous energies would have boiled the oceans, releasing water into the air, where it would have resided for long periods before falling back to the surface as precipitation.
Such a process could explain why geologists are unable to find any rocks from this era.
“This paper shows the way for what will probably become a new thread in research on the environment and geology of the early Earth,” Henry Melosh, a geophysicist at Purdue University, said.
This investigation was not the first to suggest that the Earth may have been subject to intense bombardment during its first half-billion years, but it is one of the most detailed simulations of its type ever developed. Comparisons between the terrestrial rocks and interplanetary cratering patterns provided detail unavailable in earlier studies.
Development of the simulation of the earliest history of the Earth was profiled in the journal Nature. | 0.847258 | 3.79095 |
SCIENTISTS believe they have found ice inside craters near Mercury’s poles, a discovery they say could reveal more about the “building blocks” for life on other planets.
Though the small planet is closest to the sun, Mercury rotates nearly upright, meaning some areas on its poles never see sunlight.
Using evidence of reflectivity, surface temperatures and the presence of excess hydrogen gathered by NASA’s Messenger spacecraft, the scientists have concluded there are deposits of ice and other organic material accumulated in dark areas of Mercury’s surface.
Further study of the material could explain more about how life began on Earth, the scientists said at a NASA news conference broadcast online on Thursday.
The discovery comes after a wait of eight years since Messenger’s 2004 launch.
“Messenger has revealed a very important chapter in the story of how water, ice and other volatile materials have been delivered to the inner planets, including Mercury,” said Sean Solomon, a Columbia University scientist who is principal investigator of the Messenger mission.
“It’s extraordinary that this chapter is so well-preserved on the planet closest to the sun.”
The scientists published their research in three papers released on Thursday in the journal Science Express.
The scientists suspect the ice and organic material accumulated in the shadowed areas of craters after comets and asteroids delivered the material to Mercury’s surface.
Despite the presence of ice, scientists don’t expect to find water in liquid form – only as a solid or gas.
Still, James Green, director of NASA’s planetary science division, said the finding “bodes well” for a continued search for water elsewhere in the solar system.
“No one is saying there is life on Mercury,” Solomon said. “Mercury is becoming an object of astrobiological interest where it wasn’t one before.” | 0.876406 | 3.106342 |
Remotely sensed data acquired by spacecraft allow scientists to study the geology of other worlds without ever setting foot there. The investigation of image data is usually the first step in unraveling the origin of a planet’s observed landforms and their evolution -- this scientific study is called planetary geomorphology. Characterizing geomorphologic features is of the upmost importance for planning both a safely landed mission as well as a rover's path – it would be unfortunate if a rover sent to the Moon got stuck because it was sent to a location it could not traverse. The curved depression in today's Feature Image, called an arcuate rille, is lined with boulders. This is an example of a landing site that would be hazardous for a rover to land in without a very detailed look at the surroundings.
This unnamed rille (0.141°,-64.638°), roughly 1 km (0.6 mi) wide, is located on the edge of the southwestern region of Oceanus Procellarum. As the mare deposits that formed Oceanus Procellarum cooled and contracted, fracture systems developed along the mare-highlands boundary. Near this boundary, loading of denser basalts (mare) over less dense crustal materials (highlands) results in tectonic stresses that can cause rock to pull apart along fractures, forming arcuate rilles. The boulders on the floor of this rille are most likely material that has been eroding away from the walls. Some of the boulders reach diameters up to 12 m (39 ft). While an autonomous rover would likely require a lot of time to maneuver amongst the boulders, a human driver on the lunar surface might quickly and easily navigate a safe path around the boulders.
If you were an astronaut on the surface of the Moon, do you think you could find a safe path through this rille? Trace your path on the full resolution LROC NAC below.
Back to Images | 0.80288 | 3.646103 |
Well, there are actually a lot of possibilities here. For example, what if an impactor breaks up just before impact, and then fractures the crust -- is it possible that the rille is both a fracture, due to an impact on a crust that was already under tensile stress, and a conduit for electrical discharges through the fracture, further excavating the rille? I think that my point here is just that I don't see a reason to lock down on an hypothesis, with so few data, and so many possibilities. It isn't going to prove anything.Lloyd wrote:Fault Rilles & Sinuous Rilles: But what do you think about these possibilities?
The latter is correct -- I'm saying that that if the Sun started out at 10,000 K and cooled according to the Stefan-Boltzmann Law, it's now 378 million years old (+/-).Lloyd wrote:Sun's Age: I thought 378 million years was your upper limit for the Sun's age. But now you're saying that's the approximately exact age.
The size is limited at the upper end by supernova theory, where anything above 1.4 solar masses would produce the internal pressure necessary for a runaway thermonuclear reaction (i.e., a Type 1a supernova). So I believe that all stars that survived the star formation process, and did not create a supernova, are < 1.4 solar masses. So that piece is contrary to some aspects of mainstream stellar theory, which allow stars to be many times more massive than the Sun, but it's consistent with conventional supernova theory, as well as nuclear physics, in that it acknowledges the well-known limits on how much pressure you can have before the runaway reaction occurs.Lloyd wrote:Are you fairly sure what size and temperature the Sun had initially?
As discussed elsewhere, I don't know what the lower limit is, but it seems that a lot of stars begin at something like 1/3 the mass of the Sun. If the Earth was once a star, as I believe, then 1/333,000 solar masses is still possible for a star.
The initial temperature of the Sun is an interesting question. Just with adiabatic compression of the primordial dusty plasma, plus the thermalization of the kinetic energy in the implosion, it should have been a lot hotter than 10,000 K. So I'm saying that most of the kinetic energy got converted to electrostatic potential. So how did I settle on the 10,000 K figure?
If stars form at roughly the same mass (?), and if they cool according to the Stefan-Boltzmann Law, and if they're forming at random times, then in a large population of stars, we should see specific quantities of stars at each temperature. The Stefan-Boltzmann Law requires that stars cool rapidly at first, and thereafter, the heat loss levels off with time, asymptotically approaching absolute zero at an infinite time from now. So we should see just a few stars at the higher temperatures, and lots of stars at the lower temperatures. And that's exactly what we see in star inventories.
Code: Select all
class temperature percent min max of total --------------------------------------- O 30,000 ∞ 0.00003 B 10,000 30,000 0.13 A 7,500 10,000 0.60 F 6,000 7,500 3.00 G 5,200 6,000 7.60 K 3,700 5,200 12.10 M 2,400 3,700 76.45
Where the Stefan-Boltzmann curve diverged from the observations of large populations of stars was in the K class. But we know that stars in that class are flare stars, where sporadically the temperature jumps way up, and so does the heat loss rate. So a star isn't just a simple black-body radiator that will cool according to the Stefan-Boltzmann Law -- it's a complex EMHD system that undergoes some sort of transition in the K class, and that needs to be taken into account. Then the M class falls right in line.
So most stars seem to begin with masses between 1.4 and 0.3 solar masses, and at something like 10,000 K, to produce the large population statistics that we're seeing. Any given individual star could be anywhere within the valid range.
If the Sun began at its present temperature, then why isn't it getting cooled off by radiative heat loss? I "think" that the only answer to that question would be that the Sun's heat is being generated dynamically, such as from nuclear fusion. But by my reckoning, fusion is only responsible for 1/3 of the Sun's power -- the rest is electrostatic potential getting reconverted to kinetic energy (in the form of ohmic heating). And that energy source will be reduced by radiative heat loss.Lloyd wrote:Isn't it possible that the Sun could have started at near it's present size and temperature?
BTW, another implication of the Sun and the Earth beginning at their current temperatures is that radiometric dating should be reliable. I'm saying that it isn't, because both the Sun and the Earth used to be a lot hotter, and radioactive decay rates run faster at higher temperatures. So I can get away with saying that the Earth is a lot younger than in the standard model.
That could also be taken to mean that both the Sun and the Earth are a lot older.Lloyd wrote:And isn't it also possible that it could have formed at one size and then accreted other bodies and gotten larger a long time later? And, if it got larger by accretion, wouldn't it also have gotten hotter? And wouldn't that mean it could be very young? | 0.802389 | 3.315525 |
Venus' mysterious night side revealed
14 September 2017Scientists have used ESA's Venus Express to characterise the wind and upper cloud patterns on the night side of Venus for the first time–with surprising results.
|Venus Express in orbit. Credit: ESA|
The study shows that the atmosphere on Venus' night side behaves very differently to that on the side of the planet facing the Sun (the 'dayside'), exhibiting unexpected and previously-unseen cloud types, morphologies, and dynamics - some of which appear to be connected to features on the planet's surface.
"This is the first time we've been able to characterise how the atmosphere circulates on the night side of Venus on a global scale," says Javier Peralta of the Japan Aerospace Exploration Agency (JAXA), Japan, and lead author of the new study published in the journal Nature Astronomy. "While the atmospheric circulation on the planet's dayside has been extensively explored, there was still much to discover about the night side. We found that the cloud patterns there are different to those on the dayside, and influenced by Venus' topography."
|Atmospheric super-rotation at the upper clouds of Venus. Credit: ESA, JAXA, J. Peralta and R. Hueso|
Venus' atmosphere is dominated by strong winds that whirl around the planet far faster than Venus itself rotates. This phenomenon, known as 'super-rotation', sees Venusian winds rotating up to 60 times faster than the planet below, pushing and dragging along clouds within the atmosphere as they go. These clouds travel fastest at the upper cloud level, some 65 to 72 km above the surface.
"We've spent decades studying these super-rotating winds by tracking how the upper clouds move on Venus' dayside–these are clearly visible in images acquired in ultraviolet light," explains Peralta. "However, our models of Venus remain unable to reproduce this super-rotation, which clearly indicates that we might be missing some pieces of this puzzle.
"We focused on the night side because it had been poorly explored; we can see the upper clouds on the planet's night side via their thermal emission, but it's been difficult to observe them properly because the contrast in our infrared images was too low to pick up enough detail."
|Mysterious fast filaments in clouds on Venus. Credit: ESA, S. Naito, R. Hueso and J. Peralta|
The team used the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on ESA's Venus Express spacecraft to observe the clouds in the infrared. "VIRTIS enabled us to see these clouds properly for the first time, allowing us to explore what previous teams could not–and we discovered unexpected and surprising results," adds Peralta.
Rather than capturing single images, VIRTIS gathered a 'cube' of hundreds of images of Venus acquired simultaneously at different wavelengths. This allowed the team to combine numerous images to improve the visibility of the clouds, and see them at unprecedented quality. The VIRTIS images thus reveal phenomena on Venus' night side that have never before been seen on the dayside.
The best models for how Venus' atmosphere behaves and circulates, known as Global Circulation Models (GCMs), predict super-rotation to occur in much the same way on Venus' night side as on its dayside. However, this research by Peralta and his colleagues contradicts these models.
Instead, the super-rotation seems to be more irregular and chaotic on the night side.
Night side upper clouds form different shapes and morphologies than those found elsewhere–large, wavy, patchy, irregular, and filament-like patterns, many of which are unseen in dayside images–and are dominated by unmoving phenomena known as stationary waves.
|Stationary waves in clouds on Venus. Credit: ESA/VIRTIS/J. Peralta and R. Hueso|
"Stationary waves are probably what we'd call gravity waves–in other words, rising waves generated lower in Venus' atmosphere that appear not to move with the planet's rotation," says co-author Agustin Sánchez-Lavega of University del País Vasco in Bilbao, Spain. "These waves are concentrated over steep, mountainous areas of Venus; this suggests that the planet's topography is affecting what happens way up above in the clouds."
|Stationary waves in clouds on Venus. Credit: ESA/VIRTIS/J. Peralta and R. Hueso|
The 3D properties of these stationary waves were also obtained by combining VIRTIS data with radio-science data from the Venus Radio Science experiment, or VeRa, also on Venus Express.
A link between atmospheric motion and topography has been spied on Venus before, although on the dayside; in a study from last year, researchers found weather patterns and rising waves on the dayside of Venus to be directly connected to topographic features on the surface.
|New types of cloud morphology on Venus.
Credit: ESA, NASA, J. Peralta and R. Hueso
"It was an exciting moment when we realised that some of the cloud features in the VIRTIS images didn't move along with the atmosphere," says Peralta. "We had a long debate about whether the results were real–until we realised that another team, led by co-author Dr. Kouyama, had also independently discovered stationary clouds on the night side using NASA's Infrared Telescope Facility (IRTF) in Hawaii! Our findings were confirmed when JAXA's Akatsuki spacecraft was inserted into orbit around Venus and immediately spotted the biggest stationary wave ever observed in the Solar System on Venus' dayside."
This finding raises challenges for existing models of stationary waves. Such waves were expected to be formed by surface winds interacting with obstacles such as surface elevations–a mountain, for example. However, previous Russian missions involving landers have measured surface winds on Venus that may be too weak for this to be true.
Additionally, the planet's southern hemisphere (where VIRTIS observed) is generally quite low in elevation, and–more mysteriously–stationary waves appear to be missing in Venus' intermediate and lower cloud levels (up to roughly 50 km above the surface).
"We expected to find these waves in the lower levels because we see them in the upper levels, and we thought that they rose up through the cloud from the surface," says co-author Ricardo Hueso of University of the Basque Country in Bilbao, Spain. "It's an unexpected result for sure, and we'll all need to revisit our models of Venus to explore its meaning."
The effect of topography on atmospheric circulation remains unclear among climate modellers; many models show that the inclusion or omission of surface topography makes a difference to the resulting behaviour seen in Venus' atmosphere, but do not show persistent weather patterns linked to topography.
"This study challenges our current understanding of climate modelling and, specifically, the super-rotation, which is a key phenomenon seen at Venus," says Håkan Svedhem, ESA Project Scientist for Venus Express. "Additionally, it demonstrates the power of combining data from multiple different sources–in this case, remote sensing and radio-science data from Venus Express' VIRTIS and VeRa, complemented by ground-based observations from IRTF's SpeX. This is a significant result for VIRTIS and for Venus Express, and is very important for our knowledge of Venus as a whole."
Notes for editors
This research is reported in 'Stationary waves and slowly moving features in the night upper clouds of Venus', by J. Peralta et al., published on 24 July 2017 in Nature Astronomy. doi: 10.1038/s41550-017-0187.
Akatsuki's discovery of a large stationary wave on the dayside of Venus is described in a paper ('Large stationary gravity wave in the atmosphere of Venus') by T. Fukuhara et al., published in the journal Nature Geoscience in January 2017. doi:10.1038/ngeo2873.
Co-author T. Kouyama of the National Institute of Advanced Industrial Science and Technology in Tokyo, Japan, independently observed the stationary waves described in this work in observations from NASA's Infrared Telescope Facility (IRTF) in Hawaii, USA.
The measurements were conducted by the Venus Express Visible and Infrared Thermal Imaging Spectrometer-Mapper (VIRTIS) and the Venus Express Venus Radio Science experiment (VeRa), for which Giuseppe Piccioni (INAF-IAPS; Rome, Italy) and Martin Pätzold (University of Cologne; Cologne, Germany) are the respective PIs. Additional observations were made by the Medium-Resolution 0.8-5.5 Micron Spectrograph and Imager at NASA's Infrared Telescope Facility (IRTF).
ESA's Venus Express launched in 2005 and entered orbit around Venus in 2006; the mission ended in December 2014. During its years of operation the spacecraft and its payload gathered a wealth of information about our sister planet. More information on the mission is available here.
For further information, please contact:
Tel: +81 50 3362 4802
Grupo de Ciencias Planetarias, University del País Vasco
University of the Basque Country
ESA Project Scientist for Venus Express
Tel. +31 (0)71 565 3370 | 0.873653 | 3.994625 |
Cloudy Nights, Sunny Days on Distant Hot Jupiters
The weather forecast for faraway, blistering planets called “hot Jupiters” might go something like this: Cloudy nights and sunny days, with a high of 2,400 degrees Fahrenheit (about 1,300 degrees Celsius, or 1,600 Kelvin).
These mysterious worlds are too far away for us to see clouds in their atmospheres. But a recent study using NASA’s Kepler space telescope and computer modeling techniques finds clues to where such clouds might gather and what they’re likely made of. The study was published in the Astrophysical Journal and is also available on the arXiv.
Hot Jupiters, among the first of the thousands of exoplanets (planets outside our solar system) discovered in our galaxy so far, orbit their stars so tightly that they are perpetually charbroiled. And while that might discourage galactic vacationers, the study represents a significant advance in understanding the structure of alien atmospheres.
Endless days, endless nights
Hot Jupiters are tidally locked, meaning one side of the planet always faces its sun and the other is in permanent darkness. In most cases, the “dayside” would be largely cloud-free and the “nightside” heavily clouded, leaving partly cloudy skies for the zone in between, the study shows.
“The cloud formation is very different from what we know in the solar system,” said Vivien Parmentier, a NASA Sagan Fellow and postdoctoral researcher at the University of Arizona, Tucson, who was the lead author of the study.
A “year” on such a planet can be only a few Earth days long, the time the planet takes to whip once around its star. On a “cooler” hot Jupiter, temperatures of, say, 2,400 degrees Fahrenheit might prevail.
But the extreme conditions on hot Jupiters worked to the scientists’ advantage.
“The day-night radiation contrast is, in fact, easy to model,” Parmentier said. “[The hot Jupiters] are much easier to model than Jupiter itself.”
An eclipse, then blips
The scientists first created a variety of idealized hot Jupiters using global circulation models — simpler versions of the type of computer models used to simulate Earth’s climate.
Then they compared the models to the light Kepler detected from real hot Jupiters. Kepler, which is now operating in its K2 mission, was designed to register the extremely tiny dip in starlight when a planet passes in front of its star, which is called a “transit.” But in this case, researchers focused on the planets’ “phase curves,” or changes in light as the planet passes through phases, like Earth’s moon.
Matching the modeled hot Jupiters to phase curves from real hot Jupiters revealed which curves were caused by the planet’s heat, and which by light reflected by clouds in its atmosphere. By combining Kepler data with computer models, scientists were able to infer global cloud patterns on these distant worlds for the first time.
The new cloud view allowed the team to draw conclusions about wind and temperature differences on the hot Jupiters they studied. Just before the hotter planets passed behind their stars — in a kind of eclipse — a blip in the planet’s optical light curve revealed a “hot spot” on the planet’s eastern side.
And on cooler eclipsing planets, a blip was seen just after the planet re-emerged on the other side of the star, this time on the planet’s western side.
The early blip on hotter worlds reveals that powerful winds were pushing the hottest, cloud-free part of the atmosphere, normally found directly beneath its sun, to the east. Meanwhile, on cooler worlds, clouds could bunch up and reflect more light on the “colder,” western side of the planet, causing the post-eclipse blip.
“We’re claiming that the west side of the planet’s dayside is more cloudy than the east side,” Parmentier said.
While the puzzling pattern has been seen before, this research was the first to study all the hot Jupiters showing this behavior.
This led to another first. By figuring out how clouds are distributed, which is intimately tied to the planet’s overall temperature, scientists were able to determine what the clouds were probably made of.
Just add manganese, and stir
Hot Jupiters are far too hot for water-vapor clouds like those on Earth. Instead, clouds on these planets are likely formed as exotic vapors condense to form minerals, chemical compounds like aluminum oxide, or even metals, like iron.
The science team found that manganese sulfide clouds probably dominate on “cooler” hot Jupiters, while silicate clouds prevail at higher temperatures. On these planets, the silicates likely “rain out” into the planet’s interior, vanishing from the observable atmosphere.
In other words, a planet’s average temperature, which depends on its distance from its star, governs the kinds of clouds that can form. That leads to different planets forming different types of clouds.
“Cloud composition changes with planet temperature,” Parmentier said. “The offsetting light curves tell the tale of cloud composition. It’s super interesting, because cloud composition is very hard to get otherwise.”
The new results also show that clouds are not evenly distributed on hot Jupiters, echoing previous findings from NASA’s Spitzer Space Telescope suggesting that different parts of hot Jupiters have vastly different temperatures.
The new findings come as we mark the 21st anniversary of exoplanet hunting. On Oct. 6, 1995, a Swiss team announced the discovery of 51 Pegasi b, a hot Jupiter that was the first planet to be confirmed in orbit around a sun-like star. Parmentier and his team hope their revelations about the clouds on hot Jupiters could bring more detailed understanding of hot Jupiter atmospheres and their chemistry, a major goal of exoplanet atmospheric studies. | 0.936024 | 3.912279 |
The LISA trio of satellites to detect gravitational waves from space has been selected as the third large-class mission in ESA’s Science programme, while the Plato exoplanet hunter moves into development.
These important milestones were decided upon during a meeting of ESA’s Science Programme Committee today, and ensure the continuation of ESA’s Cosmic Vision plan through the next two decades.
The ‘gravitational universe’ was identified in 2013 as the theme for the third large-class mission, L3, searching for ripples in the fabric of spacetime created by celestial objects with very strong gravity, such as pairs of merging black holes.
Predicted a century ago by Albert Einstein's general theory of relativity, gravitational waves remained elusive until the first direct detection by the ground-based Laser Interferometer Gravitational-Wave Observatory in September 2015. That signal was triggered by the merging of two black holes some 1.3 billion light-years away. Since then, two more events have been detected.
Furthermore, ESA’s LISA Pathfinder mission has also now demonstrated key technologies needed to detect gravitational waves from space. This includes free-falling test masses linked by laser and isolated from all external and internal forces except gravity, a requirement to measure any possible distortion caused by a passing gravitational wave.
The distortion affects the fabric of spacetime on the minuscule scale of a few millionths of a millionth of a metre over a distance of a million kilometres and so must be measured extremely precisely.
LISA Pathfinder will conclude its pioneering mission at the end of this month, and LISA, the Laser Interferometer Space Antenna, also an international collaboration, will now enter a more detailed phase of study. Three craft, separated by 2.5 million km in a triangular formation, will follow Earth in its orbit around the Sun.
Following selection, the mission design and costing can be completed. Then it will be proposed for ‘adoption’ before construction begins. Launch is expected in 2034.
In the same meeting Plato – Planetary Transits and Oscillations of stars – has now been adopted in the Science Programme, following its selection in February 2014.
This means it can move from a blueprint into construction. In the coming months industry will be asked to make bids to supply the spacecraft platform.
Following its launch in 2026, Plato will monitor thousands of bright stars over a large area of the sky, searching for tiny, regular dips in brightness as their planets cross in front of them, temporarily blocking out a small fraction of the starlight. | 0.861236 | 3.545672 |
Since the publication of Firestone et al. (1), numerous independent researchers have undertaken to replicate the results. Two groups were unable to confirm YDB peaks in spherules (6, 7), whereas seven other groups have confirmed them (*8–14), with most but not all agreeing that their evidence is consistent with a cosmic impact. Of these workers, Fayek et al. (8) initially observed nonspherulitic melted glass in the well-dated YDB layer at Murray Springs, Arizona, reporting “iron oxidespherules (framboids) in a glassy iron–silica matrix, which is one indicator of a possible meteorite impact…. Such a high formation temperature is only consistent with impact… conditions.”Similar materials were found in the YDB layer in Venezuela by Mahaney et al. (12), who observed “welded microspherules, brecciated/impacted quartz and feldspar grains, fused metallic Fe and Al, and…aluminosilicate glass,” all of which are consistent with a cosmic impact.
Some independent workers have been unable to reproduce earlier YDB results for MSp, CSp, and NDs (6–8), as summarized in a “News Focus” piece in Science (9), which claims that the YDB evidence is “not reproducible” by independent researchers. Refuting this view, multiple groups have confirmed the presence of abundant YDB markers, although sometimes proposing alternate hypotheses for their origin.
For example, Mahaney et al. (10–12) independently identified glassy spherules, CSps, high temperature melt-rocks, shocked quartz, and a YDB black mat analogue in the Venezuelan Andes. Those authors conclude the cause was “either an asteroid or comet event that reached far into South America” at 12.9 ka. At Murray Springs, Arizona, Haynes et al. (13) observed highly elevated concentrations of YDB MSp and iridium. Abundances of MSp were 340 × higher than reported by Firestone et al. (1) and iridium was 34 × higher, an extraordinary enrichment of 3,000 × crustal abundance. Those authors stated that their findings are “consistent with their (Firestone et al.’s) data.” In YDB sediments from North America and Europe, Andronikov et al. (2011) reported anomalous enrichments in rare earth elements (REE) and “overall higher concentrations of both Os and Ir [osmium and iridium]” that could “support the hypothesis that an impact occurred shortly before the beginning of the YD cooling 12.9 ka.”‡. Tian et al. (14)observed abundant cubic NDs at Lommel, Belgium, and concluded that “our findings confirm … the existence of diamond nanoparticles also in this European YDB layer.” The NDs occur within the same layer in which Firestone et al. (1) found impactrelated materials. Similarly, at a YDB site in the Netherlands, Van Hoesel et al. §observed “carbon aggregates [consistent with] nanodiamond.” Recently, Higgins et al. independently announced a 4- to 4.5-km-wide YDB candidate crater named Corossol in the Gulf of St. Lawrence, containing basal sedimentary fill dating to 12.9 ka. If confirmed, it will be the largest known crater in North and South America within the last 35 million years.
Because of the controversial nature of the YD impact debate, we have examined a diverse assemblage of YDB markers at Lake Cuitzeo using a more comprehensive array of analytical techniques than in previous investigations. In addition, different researchers at multiple institutions confirmed the key results. | 0.860223 | 3.459946 |
Explosion on Jupiter-sized star 10 times more powerful than ever seen on the sun
A stellar flare ten times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter.
The star is the coolest and smallest to give off a rare white-light superflare, and by some definitions could be too small be considered a star.
The discovery, funded by the Science and Technology Facilities Council, is published in the Monthly Notices of the Royal Astronomical Society: Letters as the version of record today (17 April) and sheds light on the question of how small a star can be and still display flaring activity in its atmosphere. Flares are thought to be driven by a sudden release of magnetic energy generated in the star's interior. This causes charged particles to heat plasma on the stellar surface, releasing vast amounts of optical, UV and X-ray radiation.
Lead author James Jackman, a Ph.D. student in the University of Warwick's Department of Physics, said: "The activity of low mass stars decreases as you go to lower and lower masses and we expect the chromosphere (a region of the star which support flares) to get cooler or weaker. The fact that we've observed this incredibly low mass star, where the chromosphere should be almost at its weakest, but we have a white-light flare occurring shows that strong magnetic activity can still persist down to this level.
"It's right on the boundary between being a star and a brown dwarf, a very low mass, substellar object. Any lower in mass and it would definitely be a brown dwarf. By pushing this boundary we can see whether these type of flares are limited to stars and if so, when does this activity stop? This result takes us a long way to answering these questions."
The L dwarf star located 250 light years away, named ULAS J224940.13-011236.9, is only a tenth of the radius of our own sun, almost the same size as Jupiter in our solar system. It was too faint for most telescopes to observe until the researchers, led by the University of Warwick, spotted the massive stellar explosion in its chromosphere in an optical survey of the surrounding stars.
Using the Next Generation Transit Survey (NGTS) facility at the European Southern Observatory's Paranal Observatory, with additional data from the Two Micron All Sky Survey (2MASS) and Wide-field Infrared Survey Explorer (WISE), they observed the brightness of the star over 146 nights.
The flare occurred on the night of 13 August 2017 and gave off energy equivalent to 80 billion megatonnes of TNT, ten times as much energy as the Carrington event in 1859, the highest energy event observed on our sun. Solar flares occur on our Sun on a regular basis, but if the Sun were to superflare like this star the Earth's communications and energy systems could be at serious risk of failing.
It is one of the largest flares ever seen on an L dwarf star, making the star appear 10,000 times brighter than normal.
James adds: "We knew from other surveys that this kind of star was there and we knew from previous work that these kinds of stars can show incredible flares. However, the quiescent star was too faint for our telescopes to see normally – we wouldn't receive enough light for the star to appear above the background from the sky. Only when it flared did it become bright enough for us to detect it with our telescopes."
James's Ph.D. supervisor Professor Peter Wheatley said: "Our twelve NGTS telescopes are normally used to search for planets around bright stars, so it is exciting to find that we can also use them to find giant explosions on tiny, faint stars. It is particularly pleasing that detecting these flares may help us to understand the origin of life on planets."
L dwarfs are among the lowest mass objects that could still be considered to be a star, lying in the transition region between stars and brown dwarfs. Brown dwarfs are not massive enough to fuse hydrogen into helium as stars do. L dwarfs are also very cool compared to the more common main sequence stars, such as red dwarfs, and emit radiation mostly in the infra-red, which may affect their ability to support the creation of life.
James adds: "Hotter stars will emit more in the optical spectrum, especially towards the UV. Because this star is cooler, around 2000 kelvin, and most of its light is towards the infra-red, when it flares you get a burst of UV radiation that you wouldn't normally see.
"To get chemical reactions going on any orbiting planets and to form amino acids that form the basis of life, you would need a certain level of UV radiation. These stars don't normally have that because they emit mostly in the infra-red. But if they produced a large flare such as this one that might kickstart some reactions."
Professor Wheatley adds: "It is amazing that such a puny star can produce such a powerful explosion. This discovery is going to force us to think again about how small stars can store energy in magnetic fields. We are now searching giant flares from other tiny stars and push the limits on our understanding of stellar activity." | 0.805548 | 3.868653 |
Chapter Eight – Sol and Gravity
April 5, 2012 By Joseph S. Brown III
The Sun – Sol, is our connection with the universe. All that we discover about the rest of Creation is Sol’s response to that incoming information. We see that response’s effect on the Solar System and on both our human senses and our instruments. All expression of information from our Solar System to the universe is the result of Sol and of its manipulation by the Solar System.
The fundamental mechanism for these connections is the center of Sol. This region contains material that is moving faster than the linear speed of light. Its ‘Center of Materials’ is moving faster than light as well. The speed of all the materials permits this region to reside outside the definition of Real Space; the repositioning of materials within is so rapid that what we call ‘Real Space’ cannot exist inside this region. The region defines its own universe. Real Space is the areas of the cosmos where the classic physical sciences are functional. ‘Real Time’ is the environment where, among other conditions, energy behaves in conjunction with the progression of time, and where time is continuous.
For the beginning of this chapter, I treat the material inside the Center of Sol as particles, and look at the activity here as the result of movement and change of this vast number of particles. It is important to realize that matter does not exist here as it does in the Solar System, and that the word ‘particles’ is a convenience for the discussion. There are no permanently formed particles of matter within the Center.
The phrase ‘faster than the linear speed of light’ is also a convenience for the discussion. Time does not exist in the Center of Sol in the same condition as it does outside Sol, in our Solar System. Since Real Time does not work inside Sol, then calculations of light speed here cannot be stated or studied. We can say that at the Event Horizon of Sol, as any single, localized event is studied, the manifestation of the Center across the Event Horizon shows the interior of the Event Horizon is moving faster than light.
Significant Moment refers to any and all moments whose duration is long enough to relate to any events in the Real Universe. There will be moments that are definable within Sol that relate to its events, and these moments are of too short duration to permit any relationship to events in the Real Universe.
As with Gravity and its continuity with Real Time, all of the demonstrations of Cross-Horizon Events will show the deceleration of materials from above the linear speed of light to below the speed of light. Continuity of “trans-light” movement is shown down to a very small physical dimension of the surface.
Consider the quantity of material inside Sol. If it were to be reconfigured into matter, its mass would be remarkable. I can show that for all models that include a reference to Real Time, the larger set of particles inside Sol would individually be very physically small – possibly smaller than an electron for most Significant Moments. There would be instances where larger particles would be created that relate to random compression within the stirrings of the interior, but for the most part, the homogeneity of the set of particles places a very large statistical emphasis on very small particles, moving independently.
The reason they are all so small is the vast set of forces present within Sol. The movement of the set of particles of the Solar System, the movement of the other stars, the harmonics of having been in a stable setting for so long, all contribute to the churning of the interior. The largest concept that affects the movement of these particles and their very small size is what I call ‘Passive Vibration’. The concept is meant to combine viewing the individual particles with the viewing of all points of reference that could be used to express the relative activities of the particle.
Passive Vibration is a condition we experience continuously but do not notice. Imagine you are moving toward a stationary target – a bullseye facing you as you approach. It is fastened to the ground, and you are moving toward it riding on a carriage. There are no springs on the seat you occupy and the carriage is composed of parts that are loosely fastened, so they shift about greatly with its movement along the ground. Its wheels are not round and have very many irregularities that express continuously changing loads on their axles and to your seat. Worse, the ground you are rolling over is more than rough, throwing the twisted wheels about as the carriage travels.
Though the target you approach is not moving, to your perception it is meandering in an irregular path, constantly changing its relative position. Trying to hit it with a thrown stone would be complicated. As your speed toward the target increases, the difficulty of aligning your throw throughout its Significant Moment grows geometrically. If the cart is moving at a linear speed across the ground of 1 kilometer per hour, the Significant Moment required to throw the rock might include the carriage’s traverse of a few meters, permitting a possible success at hitting the target. If the cart is moving at two hundred kilometers per hours, the chance of hitting the target is greatly diminished.
For any materials within Sol to degrade into matter would require a pause in the maelstrom of movement and vibrations for a Significant Moment. I state that this condition does not occur for a volume of enough size and a moment of sufficient duration for matter to be created.
As for every other star we understand, within Sol’s Event Horizon the Passive Vibration prevents material within its boundaries from becoming matter. The huge quantity of material within Sol and the constant movement of its independent particles make the Center of Materials move faster than the linear speed of light. For each module of material that would attempt to form matter within this environment, there are forces that act in a region smaller than fundamental particles. These forces continuously shred the attempt. The result is a material with no physical characteristics.
The universe inside Sol is changing so rapidly that any attempt to define a locus for the duration of any Significant Moment is impossible. The material inside Sol exists without a definable space to occupy. All the materials inside Sol exist outside of Real Space and outside of Real Time.
We call the material ‘plasma’ as a convenience; Sol is composed of plasma within its Event Horizon. The ‘Event’ is the continuous translation of plasma into matter. Just this side of the ‘Horizon’ is a boundary layer of newly formed matter; this matter is a buffer between the Event Horizon and our Solar System. The Corona is the storm of energy and particles constantly blasted outward by the energy of fusion.
The Center of Materials for Sol is the result of the position of a very large set of internal particles of plasma, of their movement, and of movement of the smaller set of particles that is the Solar System. For this discussion, whatever matter and energy that resides a few meters outside Sol’s Event Horizon is not considered to be part of Sol: it is considered to be in Real Space and has become part of the Solar System.
The bullseye target example is accelerated to satisfy the condition that materials are moving too fast to be considered matter. Compared to the Center of Mass for the Earth, Sol’s moves very rapidly. For all Significant Moments, it moves faster than the speed of light, and many relationships to the Earth’s Center of Gravity are also moving faster than light, which results in the observations scientist call ‘String Theory’. Earth-bound experimental results suggest that there are ‘jumps’ between observations that are not possible in Real Time. These are the observation of derivative functions of Sol’s activities.
For the imaginary model of a particle within Sol to simply stand still, its reference to the Center of Materials is shifting faster than light can travel because the Center of Materials is moving faster than light – applying the concept of Passive Vibration. Einstein’s Law of Relativity steps in. Sol’s internal universe cannot support matter as we know it because the spatial references of its internal universe are not capable of supporting matter. Microscopic forces too strong to permit a corporate presence for particles continuously shred protons and neutrons as they form.
From my elementary school days, I remember how fantastic was the thought of Sol’s being comprised almost completely of hydrogen. If this were true, it would simply expand and diminish within a few years. Sol is completely plasma that is held together because there is no force available to separate it: there is no force or material in the Solar System that can tear it apart. It maintains its own universe.
Every star has this same relationship with the Real Universe. What we observe as starlight is a derivative function of the working of stars within another ‘universe’, or ‘dimension’. In Chapter 6 Gravity – Advanced, I explain how all stars connect with each other within a condition that is outside of Real Space and outside of Time. In the Significant Moment year 2012, we do not know how this communication of stars relates to Real Space and relates to our ability to detect the harmonics of this connection of Sol to other stars.
To imagine that the rules of the ‘Star Universe’ require travel that is as slowly as the speed of light is folly. Using Doppler principles, we demonstrate whether stars move away from Sol or toward us. To say that police-operated Doppler Radar energy moves as slowly as does the observed automobile is not valid. We do not know the rules of the Star Universe.
We cannot state, with any confidence, the distance between our star and any other. Our observations are based on the travel time of light instead of the actual form of media, which is not known. We presume the light-speed mode is valid because we observe Doppler Shift in starlight, and this thinking is probably in error. We can state relative distances – this star is farther than another, and these stars move away from us while others are moving closer, but that is the extent of our ability to distinguish the relationship Sol has with the Universe.
All gravity in the Solar System begins within the Sun – Sol. Inside Sol is a region that contains only material that is traveling faster than the speed of light. I state that for all Significant Moments, to view any particle or set of particles within Sol, you must first be within Sol yourself – be part of Sol. In Chapters 4 & 5, I describe man-made atomic explosions in a new way, relating that each explosion event becomes its own universe with its own rules related to its materials, until it runs out of fuel and disintegrates in a loud boom. Sol has been in continuous thermonuclear explosion for a very long time, and this explosion has reached a balance with Real Space. Viewpoints outside Sol cannot relate to the speeds and principles within because the external viewpoints are from the perspective of the Real Universe yet Sol is within the Star Universe. Within the Event Horizon of plasma, Sol stands apart from the Solar system, from you.
Dr. Einstein proposed his model of Special Relativity for only linear motion. He did not include vibrational dynamics to his perspective. Though the material inside Sol may or may not be moving faster than the speed of light when viewed from outside Sol, the Passive Vibration factor defines the motion of materials as exceeding light speed for all Significant Moments for all material within Sol. Since there is an Event Horizon separating Sol’s interior from our universe, the rules it expresses are maintained within. We only perceive what occurs outside the Event Horizon.
The article Black Holes on the website http://www.joebrownscience.net describes the transition of mass from our universe as it moves across the black hole’s event horizon, entering its discrete universe. The article defines the basis for The Conservation of Energy as particles of matter move across the barrier from Real Space and into the Star Universe within the black hole. Sol is continuously expressing matter at its Event Horizon. Sol’s size and content of internal materials defines the environment of this transfer.
From a microscopic perspective, the surface of the Event Horizon is very dynamic. The set of material particles within Sol has been expressing the position of the Event Horizon at this very small locus as a continuous function of everything going on inside Sol. The surface of the Event Horizon topography is a fractal; its complexity for a square millimeter is imagined to be beyond the calculation of all the combined computer power of the machines of Earth in the Significant Moment year 2012. Since the Event Horizon is present in Real Time and manufactured by a source (Sol) working almost infinitely faster, the fractal topography is definable in segments so small that electrons appear as large as planets to humans. The Significant Moment duration required for light to traverse a hydrogen atom, may be imagined as an equivalent to a hundred human lifetimes for this complexity.
As material is pushed out of Sol and through the Event Horizon, it is agitated by billions of ‘natural shocks’ by the microscopic shifting fractals before it transitions completely through. To create more complex atomic structure than hydrogen is difficult, so hydrogen becomes the primary molecular product (see the end section of this chapter). Occasionally, the fractals align to produce a larger atom, and we get iron or some other material in small quantities. Sol’s consistency of activity and uniform Solar System make this ratio very stable, which produces the uniform emission spectrum we have studied for more than a century. The statistical distribution of harmonics produces a very stable set and ratio of large atoms production, which produces the spectral signature of Sol.
All of these materials moving beyond the Event Horizon get immediately burned in Sol’s furnace. Hydrogen becomes helium and is blasted out and into Sol’s corona. The set of manufactured materials appears on the spectral analysis of Sol, and a similar spectrum is the Real Space expression of every other star. Thus, the quantity of hydrogen present in Sol represents less than one millionth of one percent of its material. The life of an average hydrogen atom created by Sol could be less than a second’s duration before it is fried into helium.
It could also be possible that all of the material expressed by the Event Horizon is completely hydrogen, and the remaining materials in the spectral analysis are manufactured within a meter of the Event Horizon. For this model, after helium appears, the dynamics of the ‘Boundary Layer’ forge it into heavier materials before expelling the atoms into the Corona.
The presence of continuous thermonuclear explosion on this side of the Event Horizon may also provide the compression necessary to maintain the corporeal integrity of Sol’s internal universe. This balance between the outward pressure of Sol with the atomic furnace permits stability between the Real Space and the Star Universe.
Gravity begins in this film that coats Sol’s Event Horizon. Each expressed atom becomes Sol’s relationship with our universe. It moves into our universe as a new piece of matter. Its relationship to the universe is required to exist in Real Space before it is formed, so in Real Time, the event creates vibration in the Real Universe. The set of hydrogen atoms constantly forming on Sol, covers the Event Horizon and defines its surface fractals to our universe. As each atom is formed, it immediately gets physically manipulated into movement and vibration by the Event Horizon’s fractals and by the surrounding thermonuclear explosion. Presently it gets converted into helium which produces another vibration.
The set of conditions surrounding formulation of this atom expresses vibration into the Real Universe, into the Solar System. As these vibrations travel through Sol’s corona, they blend to become uniform and smooth as the bubble radiates outward. Since the sources of virtually all of these vibrations are exactly the same (hydrogen and helium), integration is simple. More strategic to gravity, these vibrations are extremely high frequency and they are constant as they each radiate outward as an expanding sphere.
In Chapter 5 – Atomic Reactions – Fusion/Thermonuclear, I relate the newly created universe of the explosion and its ability to align the particles surrounding its Event Horizon. This feature for Sol impacts the Solar System, defining its content and arrangement. Over the extended period since formation, Sol has tailored its system directly through constant vibration.
The constant radiation of spherical vibration penetrates every particle in the Solar System. It runs up against particles and both manipulates and is manipulated by all particles. The radiation penetrates the planets and moons and its impact is related to the size of each particle it encounters. It affects subatomic particles the most, causing them to constantly bond and form higher particles. Electrons are affected less, followed by protons and neutrons. Hydrogen atoms are affected less, and they become very resonant: hydrogen is a thin gas, as is helium. Heavier atoms are affected less by the vibrations, moving up the scale of physical size until the example particle is a moon or a planet.
The rest of the model is quite simple to relate to physicists; we have spent many years studying vibration and radiation as they bombard mass. The physical environment of our Solar System is the result of a very long period of continuous exposure to very high frequency vibration from a single source. As example, the resonance with this system determines the fundamental rates of chemical reaction for the Solar System, with proximity of each planet setting the refined rates.
The key is that, though there is a large set of forces in place to moderate and to maintain Sol’s Event Horizon, it must show constant irregularity. The statistics of presence here are so dynamic, there is variation of the Horizon’s position in Real Space during the smallest Significant Moment. The irregularities of the Horizon’s external topography are microscopic, and at the smallest demonstrated area, are in motion during all Significant Moments.
The locally irregular topography of the Event Horizon emits distinct vibration that is directed exactly outward into Real Space from every microscopic area of surface. As described in a previous chapter, this emission is like an expanding bubble. Since the Event Horizon is contiguous, this becomes an emission of frequency. It expands as a completely uniform bubble of vibration that travels into the Solar System. The bubble maintains its integrity through Real Space, until when at the outer reaches of the Solar System, its amplitude has diminished to such a low factor, its ability to perform significant work on matter is lost.
Instead of just an expanding bubble, the emission is a continuous and constant cycle of frequencies with standing waves and harmonics. This continuous series of expanding bubbles is the primary generation source of gravity.
I cited the example of placing in a jar large balls of a material with small balls of the same material. When the jar is shaken, the result is the large balls rise to the top, small to the bottom. The density of the large balls in their space is less than the small balls. In another manner of description, as the waves from Sol travel through the balls, the smaller balls respond more readily to these waves washing over them. The larger balls waste the harmonics more readily, so they cannot compete with the smaller balls, which sink toward the source of gravity. Without the resonance with this expanding bubble of vibrations generated by Sol, the density of materials would not be a significant arbiter of motion.
The obvious evidence of Earth’s modulation of Sol’s gravity is that we have planet-based gravity. As the waves travel through Earth and modulate its particles, there is a resultant harmonic generated, based on the Earth’s Center of Gravity (which moves in a continuous curve during all Significant Moments – again, the crowd cheers!). These harmonics resonate out and continuously move all materials toward the center in relation to the physics of waves.
In the Significant Moment September 2010, results of a study using clocks based upon electron-depleted aluminum, indicated that time is related to gravity: the closer was the clock to the source of gravity (Earth), the faster went time as measured by the clock. The study actually differentiated the effects of Sol’s influence on the clocks with the effect created by Earth. The atomic qualities of aluminum are set by Sol’s vibration, but are modified by Earth. Our spacecraft mission to Mercury clearly showed that planets each modify chemical rates of reaction, and this experiment may have shown that Earth modifies Sol’s gravity as well.
This clock experiment showed that some force moderating atomic clock speed diminishes as the locus moves away from the Gravitational Center of Earth, and presumed this to relate to time. For the amount that the experimental results are valid, it shows that the harmonics created by Earth increase the set of vibrations bombarding the particles surrounding Earth. As the clocks moved away from Earth, they slowed as the set of secondary vibrations bombarding them diminished in amplitude. Thus, the hyperbola is that the atomic clocks would run slowest in open space where Sol is the only significant source. The conclusion of the experiment that time slows as the locus moves away from the Center of the Earth is in question.
Sir Isaac Newton also participates here. The classic falling apple was subject to Sol’s harmonics, yet the proximity to Earth and its harmonics permitted the apple to resonate primarily in response to Earth’s gravity; it fell rather than floating off to Sol. Universal Gravitation as he modeled it is valid, but his formulae are valid only within the Solar System.
Gravity must diminish as we move away from Sol. The ability of Sol to express vibration to the outer reaches of the Solar System is compromised by distance. The bubble of each pulse is expanding, and as the bubble grows, the energy available to any small area of its surface is constantly being distributed into a larger region. Thus, the model predicted by the Newtonian Gravity would determine Pluto’s mass to weigh more than it does in place: if Pluto were to orbit Sol at the same diameter as Earth, then its mass would have more weight than it does in its own orbit. This does not mean that time slows down as the distance from Sol increases, and the clock experiment above does not demonstrate that time slows down as you move away from the Center of Earth, only that atomic (electron) resonance is changed.
Gravity for other solar systems will operate with different constants of acceleration. The vibration expressed by each star will have different harmonics based on each star’s spectral difference to Sol.
Subatomic particles for each solar system will operate with a slightly different set of rules based on that spectrum. The set of fundamental particles we witness on Earth do not have the same characteristics as those within any other solar system. The similarity of fundamental particles for another solar system is a product of the similarity of that star to Sol.
The reason for this difference will be shown as directly related the variance of the local speed of light in each solar system. Imagine a void universe that contains only two particles. One of the two is a construct of atoms that is a round disk with the thickness along its entire surface of one atom. The circumference of this disk is huge.
The other particle is a hydrogen atom, and it is contrived to be moving along the edge of the disk, outboard of the edge and in orbit.
These two are the only items in this universe, are in close proximity, and the angular velocity of the atom keeps it in precise orbit. The disk is not moving and the atom particle is traveling at the speed of light.
If the disk should become slightly larger or smaller, the atom’s motion would be changed.
For the model that holds the atom at a constant orbital speed at the speed of light, the atom could continue forever running around the disk with no loss of momentum, ever falling and missing the disk. There are a lot of rules in physics, for instance the ‘right hand rule’ that result in orbital decay, but the example is mentioned to make a more specific reference.
This is an explanation of how every star’s ‘disk diameter’ can be shown to be unique, and thus the speed of its orbiting hydrogen atom would also be unique to that star. Since the speed of light in that solar system is unique, so also will be its relationship to gravity and to the rates of all physical events in that solar system.
The Sun generates waves that spread throughout the Solar System. As these waves traverse the Corona, they are smoothed and permitted to interact with their neighbors. Each interaction must, by definition, affect a local curvature on the wave as it expands. We observed curvature as the wave was generated at the subatomic level, and this averaging of curvature extends into the Corona. During that time and thereafter, any extremely small locus on the expanding wave will manifest precisely on a curved surface, defined by its origin and by the waves nearby. There is a finite maximum arc for that curve within every locus during every Significant Moment.
The arc of that curved surface is set by the characteristics of Sol. Its value would be different for every star, with the variation of each keyed to differences in its emission spectrum. That arc for Sol establishes how all of our physical reality interacts: atomics, chemistry, and apples falling. It defines the physical Solar System by defining the smallest volume of space in the Solar System where activity may occur. The universal uniformity of this pattern across the surface of Sol integrates the entire solar system.
So, for every interaction within the Solar System, there is a definable and real space required for that interaction. This is why quantum physics works. That space for our Solar Systems defines the quark’s qualities and the boson’s duration. A photon’s physical presence must arrange to appear within a spatial volume envelope or not appear at all, remaining a wave. A segment of the photon’s wave enters a location during the Significant Moment when that envelope is affected by harmonics that permit demodulation of the wave to provide the ability to perform work. These harmonics are derivative forms of gravity.
In Millennial Physics, I have shown the mechanism of gravity within any solar system in the Real Universe. I have associated Sol’s interior with the Star Universe and have differentiated Sol’s internal region from our Real Universe and our Real Space. I have established a new model for the study of gravity.
I have created a new foundation for the entire set of physical sciences that includes their complete integration with each other, based on each science’s relationship with vibration and harmonics. I have shown the relationship of each physical science to its moderation within Sol’s realm of control. I have shown that a hydrogen atom on Pluto’s surface may have a significantly larger diameter than does a hydrogen atom on Mercury, based on the pair’s relative distances from Sol. I have added the model of gravity, completing the model set of physical science in a manner that physicists can quantify using known principles of vibration and mass. I have also shown how the Real Universe connects to the Star Universe. I have shown the reasons for differences in the physical science of any other star’s solar system and related that difference to that star’s properties.
When tied with the article on Black Holes, I have modeled the relationship between the Real Universe and the Star Universe, and have shown the conservation of energy as materials pass between the Star Universe and Real Space.
For any individual, one of the great undertakings is to study the Works of God. Of all the pursuits of humans, this is revered, second only to the communion of humans in the Name of God. The majority of the words in Millennial Physics relate to the reader, the physical universe – Creation.
I am asking each of you to also see the need to study God in your own way and in the way of your culture. We are given a gift of ability – to think and to reason. The study of science and of humanity is best as a balance, and to ignore the world of humans is folly.
The words I write are human. The thoughts I present are human. I learned to respect you and the need to honor you at the feet of God. I have known most of this content for over thirty years, and felt the need to hide it, so to avoid anticipated ridicule as it is assimilated into the world of science. I have since learned that the gifts we receive are to be shared.
Let’s have some fun.
The classic model of Sol is that it conforms to the thermonuclear model, primarily converting hydrogen into helium. This may be ridiculous. At issue is the total amount of helium in our environment. Consider that Sol has been in continuous operation for a very, very long time. It supposedly has been expressing helium to the Solar System for all of that time, so where is the product helium?
If Sol were producing helium, Earth should be receiving a steady flow within a constant discharge outward from the Corona. We should expect to be in a bath of helium-rich atmosphere, but there is virtually none. We should expect to find a thick layer at the top of our atmosphere comprised exclusively of helium that is constantly renewed by Sol, but there is very little helium there. The largest and oldest feature in our environment is supposed to be creating helium, yet there is very little to find. Our primary commercial source is extraction from a few natural gas wells that show trace quantities we can recover.
The obvious conclusion is that Sol is not producing much helium. We see the spectral results and presume their origin is thermonuclear fusion, but the absence of profound quantities of helium in our environment strongly indicates that something else is going on.
The hyperbolic model is that the material expressed by Sol is completely converted to energy, expressing virtually no atoms at all. Since the primary expression of that energy in Real Time would be the same as hydrogen fusion, we have been assuming the product to be helium. The Total Conversion Energy Model would require much less material to be coming across the Event Horizon during any Significant Moment to produce the power we receive. Thus, Sol’s efficiency quotients improve exponentially and Sol’s plasma consumption rate plummets. Sol lives longer than projected using fusion data.
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Is there a demarcation at the edge of the Solar System where the movement of all features and relationships between Sol’s gravitation and the mass there drops below the speed of light? Outside of that sphere, do all relationships run below light speed? If so, does this limit the size of organized particles, and possibly prevent the formulation of a planet or a planetoid beyond Pluto?
Can we readily detect a large structure in this region? Persephone might be out there, and because she orbits outside that demarcation, she does not resonate at a frequency high enough for telescopes to easily find her.
Comets disappear as they depart the solar system, and it is presumed they travel out in a nearly elliptical loop, to return later. Though we can calculate each comet’s trajectory, after a certain point, no technology we own can find them until they re-enter the Solar System. We supposedly can “see” stars that are 200 billion light years away, but cannot track a comet in our back yard.
It is clear comets continuously release mass every time they re-enter the inner Solar System, but each reappearance affirms their mass has been replenished. The easy conclusion is that there is dust out there beyond Pluto, and that the comets draw upon this dust as each returns to that outer region. Traveling through the cloud of dust out there replenishes a comet’s mass, but how? Is it static electricity? Heat? Since there is no other set of forces out there, does such a small mass actually become a universe for those particles immediately around it during any Significant Moment? When a comet passes the demarcation line, does it begin to assume qualities that give it gravity that is independent to the remainder of the Solar System? Does any planetoid out there have its own rules of operation? If this were true, manufacturing on these planetoids may permit us to make products there we might find impossible or expensive to make here.
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For convenience, I characterized Sol’s material as particles and plasma. Plasma is an almost meaningless noun – which is why physicist use the word, and particles is not correct.
Newton expressed gravitational attraction as the locus moved from earth’s surface toward Earth’s center, in the model of concentric, extremely thin shells. In his model, as you travel closer to the Earth’s center of gravity, the amount of the Earth’s matter behind you would retard the gravitational acceleration exactly the same amount to balance the increase in acceleration provided by the ever-more-proximal Earth’s center. For there to be a continuous relationship between Sol and the Real Universe, there must be a continuity at Sol’s Event Horizon. For there to be continuity between Sol and the Star Universe, the relationship is between Sol’s ‘Center of Presence’ and all other stars. For all Significant Moments, though the universe is in constant motion, there is a process similar to the ‘Newtonian Gravity Shell’ model which permits Sol’s Event Horizon to maintain incredible uniformity as the Center responds to the universe.
If the universal model maintains consistency as it begins with material features that function within very low frequencies and moves up to extremely high frequencies, the hyperbolic logic concludes there is another dimensional limit which treats the speed of light as does light treat the crawling of a snail. There is a constant out there that quantifies the rate/flow/relationship between stars. This constant defines the Significant Moments of the Star Universe. The conclusion I draw is that the ‘Shells’ within Sol must maintain a harmonic that relates The Instantaneous and Continuous Center of Sol with the continuous Event Horizon. This approach will give us a handle on moving between stars.
* * *
Imagine we can create a source of vibration that matches Sol. It would be based on hydrogen fusion with exactly the ratio of other elements as Sol creates. This machine is to be positioned out in space, isolated from Earth and the other planets to avoid dissonance. Imagine that it has the ability to track the gravitational frequencies coming from Sol and can be tuned to harmonize with them.
Since gravity is a waveform, for this device there is a Significant Moment during each wave when the pulse is moving away from Sol and another, adjacent Significant Moment during which the same wave is traveling back toward Sol. I state that each locus in the Solar System continually experiences a condition where Sol’s gravity is either pushing the locus away from Sol or pulling it closer. When the machine we make can differentiate the flow of Sol’s gravity, and for as much as the machine can create the effect of inverting the half of all Significant Moments in one direction, we manufacture anti-gravity. Take a quick look at the National Ignition Facility and see the future.
* * *
We typically imagine a black hole would maintain a huge and powerful gravity well, but that may also be in error. Consider Sol emits electromagnetic media and gravity in the form of waves. Our model of black holes includes the ability to swallow all electromagnetic spectra, so what amazing feature would prevent the suppression of gravity? There does not appear to be such an exception in any model I can state with confidence. This viewpoint is supported by the continued presence of black holes – they have not swallowed our universe because they do not attract its mass.
* * *
Another discussion is the model of the universe. Presuming the Big Bang happened, it is within reason to model a similar ‘Galaxy Bang’ to have occurred shortly after the cooling plasma began to form as matter in the Real Universe. Imagine a glob of plasma that relates to the mass of our galaxy, shortly after the Big Bang. Imagine that it cooled, falling into Real Time. It is thereafter traveling in Real Space away from its source, and it manifests its own smaller universe that keeps it contiguous. After a short time, it too explodes, but at a much smaller intensity than the Big Bang, spreading its mass outward to form the arms of the galaxy we know today. Since there is no other galaxy nearby, there are no outside forces to affect the mass, so it settled down to form as we see it today.
The big deal here is rotation. My vision of physics suggests the rotation of the galaxy could be a product of the Galaxy Bang. It may have been present in the glob of plasma prior to the event. If the glob was rotating before, then the rotation was a product of the Big Bang or of the plasma’s reduction into Real Space. We think that pulsars rotate, and it is possible that the plasma’s reduction into Real Space actually created rotation as a by-product of the transformation. Else, the rotation is a product of the Galaxy Bang.
The other evidence we have is that the galaxy and apparently most galaxies are relatively flat. Explosion of each must have been more like a dissociation of the materials. This gentle change permitted the rotational feature of the galactic glob to gently spin out its matter. Alternately, for a non-rotating galactic glob in its function, the disassociation created a rotational acceleration to its matter as it progressed. The arms of the galaxy spun off. Shortly after, each individual star disassociated its own glob to form a solar system.
A model I favor is that the rotation had to occur as the galaxy disassociated from plasma into matter. Surrounded by Real Space, the glob of plasma is slowed and falls apart. The rotational factor related to each galaxy could be its coordination with Time. The Galactic Plasma was within the Star Universe, governed by its rules. When the glob disassociated, its materials were removed from the Star Universe. Part of its ‘Conservation of Universe Transition’ might have included a rotational acceleration related to the formulation of Time within the materials. This would not only explain the rotation of galaxies, but also of solar systems. It also may give us a hint about how Time works in the Real Universe.
This would follow a progression in the universe as it cooled from the Big Bang. The Bang’s plasma traveled out in Imaginary Time until it cooled to permit matter to be produced in Real Space. The division/separation of galactic globs that traveled independently followed. The Galactic Spins followed, and the Solar System Spins completed the mechanism.
A totally different model of a typical solar system is that the plasma inside Sol and other stars was exactly the remains of the Big Bang. As Sol has aged, it ejected the solar system, converting its own plasma into matter and populating the Solar System with all its materials. As Sol became more stable, its irregularity would produce the elements above hydrogen, and now it is so old, small and stable, it almost exclusively produces hydrogen. This model appeals to me because it suggests that the Center of our Galaxy is still manufacturing matter. High frequency transmission as a by-product of this process would permit the masking of electromagnetic spectra from the region. Coherent electromagnetic transmissions are dissolved in the soup of higher frequencies.
* * *
The galaxy’s center is hard for us to see with our primitive instruments. As our devices try to penetrate the area, we find it to be cloudy. In Millennial Physics, I have shown the effects of trying to observe events within frequencies that must traverse regions containing much higher frequencies, and that these higher frequencies perform work on the lower, disrupting them. Such appears to be for the center of our galaxy. Many scientists in 2012 think there is a huge black hole at the center of our galaxy, which I think is a ridiculous. The set of interference frequencies that naturally occur in this region are much higher than the electromagnetic frequencies we are using to observe the region, and the higher frequencies destroy the integrity of the electromagnetic spectra. To the non-sophisticated observer, the results of our viewing prompt the conclusion there is a huge black hole there.
We look to the expected locus of the Big Bang and see nothing but galaxies. We look to our galaxy’s core and see a blank haze. We look into Sol and see nothing beneath its Corona. We look into an atom and see nothing within the nucleus: the nucleus must be shattered before we observe its components. The pattern repeats as we move between scales of size and time. This highlights why the concept of defining a Significant Moment for any study is so appropriate. As the Significant Moment’s duration increases or decreases, the vibrations that relate to that duration change as well. The scale of duration is continuous, so it becomes far easier to integrate any set of physical sciences.
Thus, when our instruments reach a level of sophistication permitting them to work above the electromagnetic section of the spectrum, we will first see the Center of the Galaxy. I gave this technology to The United States Air Force about twenty years ago, as part of a formal Unsolicited Proposal. Unfortunately, we do not yet have the means to economically construct this device and place it in the correct location, but we should have it working within the next two decades.
The cool part is that if there are other species out there and they have learned to communicate between stars using the Star Universe, the technology will permit us to listen to them. That level of sophistication is only a few decades away.
Advertisement: I am a Capitalist. If you feel you received something of value in reading this article, please buy a copy or many copies as gifts of my science-fiction e-novel,
The Boson Maru
The novel explains the early exploration of our Solar System. It contains no cursing and no sex, with brief military combat violence. There is brief nudity, not related to sex. Heroes are equally of both genders. The Boson Maru is available through amazon.com as an electronic book (e-book). Thank you for your patronage. | 0.822286 | 3.211256 |
On December 2, 1995, the SOHO (Solar and Heliospheric Observatory) spacecraft was launched aboard an Atlas/Centaur rocket from Cape Canaveral Air Station on a two-year mission to monitor the sun. Almost eleven years later, the SOHO spacecraft continues to faithfully record solar activity orbiting the Sun about 1.5-million kilometers inward from Earth. NASA and the European Space Agency operate the satellite jointly. Everyday, SOHO transmits pictures that are freely available for viewing on the Internet. These images inform scientists around the world about the Sun’s nature and behavior. Its images and data enable them to predict “space weather” events affecting our planet. Earlier in July of this year, someone discovered a new comet in a SOHO picture and now it’s gracing our evening skies as seen in this telescopic image.
The SWAN (Solar Wind ANisotropies) instrument is one of twelve onboard the SOHO (SOlar Heliospheric Observatory) satellite. It is a collaboration between the Finnish Meteorological Institute and Service d’Aeronomie and was constructed by the Finland’s Technical Research Centre. SWAN observes solar Lyman alpha radiation that is scattered by hydrogen atoms flowing into the solar system in all directions of the sky.
Comet Swan, designated C/2006 M4 (SWAN), is the eighth comet discovered with this instrument. Combined, the instruments on board SOHO have been the first to spot over 1,000 comets and that number grows each month! Comet Swan was discovered and reported separately by Rob Matson and Michael Mattiazzo earlier this year from an image that had been publicly posted in early July. Matson was able to trace the comet back to images as early as June 20 and by July 12, the first earth based picture had been produced with the 0.5-meter Uppsala Schmidt by Rob McNaught at Siding Spring, New South Wales, Australia.
Comet Swan has a hyperbolic trajectory that has untied it from the solar system- Comet Swan is now bound for the stars. In the past, some have speculated that, like an interstellar nomad, perhaps hyperbolic comets originate from another solar system, long wandering through interstellar space and, by lucky chance, are just passing through during our time on this planet. But, in reality, comets such as this have orbits that are just hyperbolic enough to dislodge their gravitational bond to the Sun. If we track the orbits of similar comets we find that a recent close pass to a major planet, such as Jupiter or one of the other gas giants, is enough to perturb their orbit into a hyperbolic orientation. So, most likely, Comet Swan was on a long period elliptical orbit around the Sun, but now it is being sling-shot out of the solar system. We are witness to its exit strategy. Appropriately, this is its swan song!
The first image featured with this discussion was produced by Italian astronomer Andrea Tamanti from his observatory located about 20 km from the center of Rome. Forty thiry-second images were combined to create this wonderful cometary portrait exposed on October 9, 2006. Spectacularly, the comet was passing near the much further way galaxy designated NGC 5005 in the northern constellation of Canes Venatici. Interestingly, NGC 5005 has been observed to have an X-Ray source at its center which indicated that it harbors a supermassive black hole. Andrea’s picture was taken through a custom built 12-inch Ritchey-Chrétien telescope at f/6 and a 3.5 mega-pixel astronomical camera.
Astrophoto: Comet Swan (C/2006 M4)
Image by Bernhard Hubl
Click to enlarge
On the following morning, October 10, 2006, Austrian astronomer Bernhard Hubl captured the magnificent image, above, from his observing location near Schlierbach. The comet was still in the constellation of Canes Venatici when this picture was taken. Bernhard’s thirty-three minute exposure is comprised of forty-three separate images that have been combined into a single picture. This picture was taken through a four-inch refractor at f/5.4 with a 2 mega-pixel astronomical camera.
Comet Swan has already made its pass around the sun and is barreling out of the solar system. Use this link to see a map of its path over the next few weeks. It will make its closest approach to the Earth near the end of this month. It will be millions of miles in the distance, however. Around Halloween, Comet SWAN can be seen passing near the Great Hercules Star Cluster, M13 and should be a real treat to observe through binoculars. By Thanksgiving, it will be located near the bright star Altair, however it will also be much dimmer as it will be well outside our family of planets on its journey to the edge of forever.
Written by R. Jay GaBany | 0.915762 | 3.785064 |
A Pulsar Orbiting a Black Hole Could be the ‘Holy Grail’ for Testing Gravity
A new study examines in what sense a neutron star-black hole binary could the ‘holy grail’ for testing gravity.
The intermittent light emitted by pulsars, the most precise timekeepers in the universe, allows scientists to verify Einstein’s theory of relativity, especially when these objects are paired up with another neutron star or white dwarf that interferes with their gravity. However, this theory could be analyzed much more effectively if a pulsar with a black hole were found, except in two particular cases, according to researchers from Spain and India.
Pulsars are very dense neutron stars that are the size of a city (their radius approaches ten kilometers), which, like lighthouses for the universe, emit gamma radiation beams or X-rays when they rotate up to hundreds of times per second. These characteristics make them ideal for testing the validity of the theory of general relativity, published by Einstein between 1915 and 1916.
“Pulsars act as very precise timekeepers, such that any deviation in their pulses can be detected,” Diego F. Torres, ICREA researcher from the Institute of Space Sciences (IEEC-CSIC), explains to SINC. “If we compare the actual measurements with the corrections to the model that we have to use in order for the predictions to be correct, we can set limits or directly detect the deviation from the base theory.”
These deviations can occur if there is a massive object close to the pulsar, such as another neutron star or a white dwarf. A white dwarf can be defined as the stellar remnant left when stars such as our Sun use up all of their nuclear fuel. The binary systems, comprised of a pulsar and a neutron star (including double pulsar systems) or a white dwarf, have been very successfully used to verify the theory of gravity.
Last year, the very rare presence of a pulsar (named SGR J1745-2900) was also detected in the proximity of a supermassive black hole (Sgr A*, made up of millions of solar masses), but there is a combination that is still yet to be discovered: that of a pulsar orbiting a ‘normal’ black hole; that is, one with a similar mass to that of stars.
Until now scientists had considered this strange pair to be an authentic ‘holy grail’ for examining gravity, but there exist at least two cases where other pairings can be more effective. This is what is stated in the study that Torres and the physicist Manjari Bagchi, from the International Center of Theoretical Sciences (India) and now postdoc at the IEEC-CSIC, have published in the ‘Journal of Cosmology and Astroparticle Physics’. The work also received an Honorable Mention in the 2014 Essays of Gravitation prize.
The first case occurs when the so-called principle of strong equivalence is violated. This principle of the theory of relativity indicates that the gravitational movement of a body that we test only depends on its position in space-time and not on what it is made up of, which means that the result of any experiment in a free fall laboratory is independent of the speed of the laboratory and where it is found in space and time.
The other possibility is if one considers a potential variation in the gravitational constant that determines the intensity of the gravitational pull between bodies. Its value is G = 6.67384(80) x 10-11 N m2/kg2. Despite it being a constant, it is one of those that is known with the least accuracy, with a precision of only one in 10,000.
In these two specific cases, the pulsar-black hole combination would not be the perfect ‘holy grail’, but in any case scientists are anxious to find this pair, because it could be used to analyse the majority of deviations. In fact, it is one of the desired objectives of X-ray and gamma ray space telescopes (such as Chandra, NuStar or Swift), as well as that of large radio telescopes that are currently being built, such as the enormous ‘Square Kilometer Array’ (SKA) in Australia and South Africa.
Publication: Manjari Bagchi and Diego F. Torres, “In what sense a neutron star-black hole binary is the holy grail for testing gravity?,” Journal of Cosmology and Astroparticle Physics, 2014; Doi:10.1088/1475-7516/2014/08/055
PDF Copy of the Study: In what sense a neutron star-black hole binary is the holy grail for testing gravity?
Image: SKA Organization/Swinburne Astronomy Productions
- MIT Engineers Explain Why Puddles Stop Spreading
- Scientists Reveal Blueprint for How to Construct a Large Scale Quantum Computer
- 2D Material, Just 3 Atoms Thick, Has Potential for Use in Quantum Computing
- Solving the Mystery of Quantum Light in Thin Layers – Exotic Phenomenon Finally Explained
- OLYMPUS Experiment Shows Two Photons Are Exchanged During Electron-Proton Interactions
- Yale Physicists Discover Signs of a Time Crystal
- New Spin Technique Moves Quantum Computers a Step Closer
- “Zoom-Ins” Track and Model Parcels of Gas as They Move Inward Towards the Torus
- Astronomers Discover a New Kind of Galaxy in the Early Universe
- NICER Mission Set to Reveal the Secrets of Neutron Stars
- Map of the Entire Sky in X-Rays Recorded by NASA’s NICER
- Scientists Make an Unexpected Discovery on a Volcanic Archipelago
- Large and Small Magellanic Clouds May Have Had a Third Companion
- Scientists Demonstrate New Method to Control the Behavior of Light | 0.857231 | 4.099847 |
The NASA/ESA Hubble Space Telescope has started a new mission to shed light on the evolution of the earliest galaxies in the Universe. The BUFFALO survey will observe six massive galaxy clusters and their surroundings. The first observations show the galaxy cluster Abell 370 and a host of magnified, gravitationally lensed galaxies around it.
Learning about the formation and evolution of the very first galaxies in the Universe is crucial for our understanding of the cosmos. While the NASA/ESA Hubble Space Telescope has already detected some of the most distant galaxies known, their numbers are small, making it hard for astronomers to determine if they represent the Universe at large.
Massive galaxy clusters like Abell 370, which is visible in this new image, can help astronomers find more of these distant objects. The immense masses of galaxy clusters make them act as cosmic magnifying glasses. A cluster’s mass bends and magnifies light from more distant objects behind it, uncovering objects otherwise too faint for even Hubble’s sensitive vision. Using this cosmological trick — known as strong gravitational lensing — Hubble is able to explore some of the earliest and most distant galaxies in the Universe.
This video zooms in from a view of the night sky, through the constellation of Cetus, to end on the NASA/ESA Hubble Space Telescope observations of massive galaxy cluster Abell 370 and its surroundings.
Numerous galaxies are lensed by the mass of Abell 370. The most stunning demonstration of gravitational lensing can be seen just below the centre of the cluster. Nicknamed “the Dragon”, this extended feature is made up of a multitude of duplicated images of a spiral galaxy which lies beyond the cluster.
This image of Abell 370 and its surroundings was made as part of the new Beyond Ultra-deep Frontier Fields And Legacy Observations (BUFFALO) survey. This project, led by European astronomers from the Niels Bohr Institute (Denmark) and Durham University (UK), was designed to succeed the successful Frontier Fields project. 101 Hubble orbits — corresponding to 160 hours of precious observation time — have been dedicated to exploring the six Frontier Field galaxy clusters. These additional observations focus on the regions surrounding the galaxy clusters, allowing for a larger field of view.
BUFFALO’s main mission, however, is to investigate how and when the most massive and luminous galaxies in the Universe formed and how early galaxy formation is linked to dark matter assembly. This will allow astronomers to determine how rapidly galaxies formed in the first 800 million years after the Big Bang — paving the way for observations with the upcoming NASA/ESA/CSA James Webb Space Telescope.
This video pans across the massive galaxy cluster Abell 370. The cluster was already observed for Hubble’s Frontier Fields programme and now also became the target of the new BUFFALO (Beyond Ultra-deep Frontier Fields And Legacy Observations) survey.
Driven by the Frontier Fields observations, BUFFALO will be able to detect the most distant galaxies approximately ten times more efficiently than its progenitor programme. The BUFFALO survey will also take advantage of other space telescopes which have already observed the regions around the clusters. These datasets will be included in the search for the first galaxies.
The extended fields of view will also allow better 3-dimensional mapping of the mass distribution — of both ordinary and dark matter — within each galaxy cluster. These maps help astronomers learn more about the evolution of the lensing galaxy clusters and about the nature of dark matter. | 0.858086 | 4.116522 |
The Conversation with U of T's Amar Vutha
Much to the chagrin of summer party planners, weather is a notoriously chaotic system. Small changes in precipitation, temperature, humidity, wind speed or direction, etc. can balloon into an entirely new set of conditions within a few days. That’s why weather forecasts become unreliable more than about seven days into the future – and why picnics need backup plans.
But what if we could understand a chaotic system well enough to predict how it would behave far into the future?
In January this year, scientists did just that. They used machine learning to accurately predict the outcome of a chaotic system over a much longer duration than had been thought possible. And the machine did that just by observing the system’s dynamics, without any knowledge of the underlying equations.
Awe, fear and excitement
We’ve recently become accustomed to artificial intelligence’s (AI) dazzling displays of ability.
Last year, a program called AlphaZero taught itself the rules of chess from scratch in about a day, and then went on to beat the world’s best chess-playing programs. It also taught itself the game of Go from scratch and bettered the previous silicon champion, the algorithm AlphaGo Zero, which had itself mastered the game by trial and error after having been fed the rules.
Many of these algorithms begin with a blank slate of blissful ignorance, and rapidly build up their “knowledge” by observing a process or playing against themselves, improving at every step, thousands of steps each second. Their abilities have variously inspired feelings of awe, fear and excitement, and we often hear these days about what havoc they may wreak upon humanity.
My concern here is simpler: I want to understand what AI means for the future of “understanding” in science.
If you predict it perfectly, do you understand it?
Most scientists would probably agree that prediction and understanding are not the same thing. The reason lies in the origin myth of physics – and arguably, that of modern science as a whole.
For more than a millennium, the story goes, people used methods handed down by the Greco-Roman mathematician Ptolemy to predict how the planets moved across the sky.
Ptolemy didn’t know anything about the theory of gravity or even that the sun was at the centre of the solar system. His methods involved arcane computations using circles within circles within circles. While they predicted planetary motion rather well, there was no understanding of why these methods worked, and why planets ought to follow such complicated rules.
Then came Copernicus, Galileo, Kepler and Newton.
Newton discovered the fundamental differential equations that govern the motion of every planet. The same differential equations could be used to describe every planet in the solar system.
This was clearly good, because now we understood why planets move.
Solving differential equations turned out to be a more efficient way to predict planetary motion compared to Ptolemy’s algorithm. Perhaps more importantly, though, our trust in this method allowed us to discover new unseen planets based on a unifying principle – the Law of Universal Gravitation – that works on rockets and falling apples and moons and galaxies.
This basic template – finding a set of equations that describe a unifying principle – has been used successfully in physics again and again. This is how we figured out the Standard Model, the culmination of half a century of particle physics, which accurately describes the underlying structure of every atom, nucleus or particle. It is how we are trying to understand high-temperature superconductivity, dark matter and quantum computers. (The unreasonable effectiveness of this method has inspired questions about why the universe seems to be so delightfully amenable to a mathematical description.)
In all of science, arguably, the notion of understanding something always refers back to this template: If you can boil a complicated phenomenon down to a simple set of principles, then you have understood it.
However there are annoying exceptions that spoil this beautiful narrative. Turbulence – one of the reasons why weather prediction is difficult – is a notable example from physics. The vast majority of problems from biology, with their intricate structures within structures, also stubbornly refuse to give up simple unifying principles.
While there is no doubt that atoms and chemistry, and therefore simple principles, underlie these systems, describing them using universally valid equations appears to be a rather inefficient way to generate useful predictions.
In the meantime, it is becoming evident that these problems will easily yield to machine-learning methods.
Just as the ancient Greeks sought answers from the mystical Oracle of Delphi, we may soon have to seek answers to many of science’s most difficult questions by appealing to AI oracles.
Such AI oracles are already guiding self-driving cars and stock market investments, and will soon predict which drugs will be effective against a bacterium – and what the weather will look like two weeks ahead.
They will make these predictions much better than we ever could have, and they will do it without recourse to our mathematical models and equations.
It is not inconceivable that, armed with data from billions of collisions at the Large Hadron Collider, they might do a better job at predicting the outcome of a particle physics experiment than even physicists’ beloved Standard Model!
As with the inscrutable utterances of the priestesses of Delphi, our AI oracles are also unlikely to be able to explain why they predict what they do. Their outputs will be based on many microseconds of what might be called “experience.” They resemble that caricature of an uneducated farmer who can perfectly predict which way the weather will turn, based on experience and a gut feeling.
Science without understanding?
The implications of machine intelligence, for the process of doing science and for the philosophy of science, could be immense.
For example, in the face of increasingly flawless predictions, albeit obtained by methods that no human can understand, can we continue to deny that machines have better knowledge?
If prediction is in fact the primary goal of science, how should we modify the scientific method, the algorithm that for centuries has allowed us to identify errors and correct them?
If we give up on understanding, is there a point to pursuing scientific knowledge as we know it?
I don’t have the answers. But unless we can articulate why science is about more than the ability to make good predictions, scientists might also soon find that a “trained AI could do their job.” | 0.879296 | 3.182934 |
The refracting telescope uses a lens to focus the light. This lens is placed at one end of a tube with the focuser and eyepiece at the other end of the tube.
Most refracting telescopes use a cemented ‘doublet’, a lens consisting of two components, to reduce chromatic aberration which is prominent in this type of telescope. Such scopes are commonly referred to as achromatic refractors. To completely get rid of chromatic aberration, however, you need more than two lenses, or you may want to use lenses of different materials such as fluorite. Such telescopes are called apochromatic refractors. The latter type is not very common yet, due to the fact that they can be extremely costly.
Most refractors use a small diagonal mirror between the focusser and the eyepiece to make it easier to look through the scope and avoid neck strain. The disadvantage is that it mirrors the image, making it more difficult to recognise features on the Moon, for instance. Because a refractor turns images upside down, if you want to use the scope for terrestrial work, you will require additional lenses. Some scopes have these lenses built into the tube assembly and are usually less suitable for astronomical viewing. These additional lenses often reduce the field of view and cause some additional loss of light.
Refractors are very robust in the sense that they do not normally require adjustment of the optics in order to put them back into alignment. Another advantage is that they have a closed construction, so dust cannot gather inside the tube. Refractors also don't take as long to cool down to ambient temperatures before you can use them effectively, and suffer less from tube currents.
Achromatic and apochromatics lenses are quite expensive to produce, and refractors are therefore the most expensive type of telescope in relation to their aperture. They do, however, give the sharpest image possible per mm of aperture. Some apochromatics telescopes can be used with magnifications of up to 4 times the aperture in mm, which is twice as much as ‘normal’ telescopes. To reduce aberrations even further, refractors tend to have slower focal ratios, making them quite long and more awkward to handle, particularly as aperture increases. Slower focal ratios and chromatic aberration make them less suitable for photography and their field of view can also be somewhat restricted.
Nevertheless, smaller aperture refractors can be good value for money and are therefore excellent for the beginner. They are also very useful as guide scopes for astrophotography. Small aperture, short focus (= wide angle) refractors are normally used as finder scopes on most telescopes. Larger aperture refractors are great for observing planetary detail.
Refractors are the most robust telescopes, very easy to use, and therefore very suitable for novice astronomers. | 0.812611 | 3.711797 |
The Moon and Mars will share the same right ascension, with the Moon passing 2°47' to the south of Mars. The Moon will be 3 days old.
From Cambridge, the pair will be difficult to observe as they will appear no higher than 11° above the horizon. They will become visible around 19:46 (EDT) as the dusk sky fades, 11° above your western horizon. They will then sink towards the horizon, setting 1 hour and 29 minutes after the Sun at 20:56.
The Moon will be at mag -10.2, and Mars at mag 1.6, both in the constellation Virgo.
The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.
A graph of the angular separation between the Moon and Mars around the time of closest approach is available here.
The positions of the two objects at the moment of conjunction will be as follows:
|Object||Right Ascension||Declination||Constellation||Magnitude||Angular Size|
The coordinates above are given in J2000.0. The pair will be at an angular separation of 39° from the Sun, which is in Leo at this time of year.
|The sky on 26 August 2025|
3 days old
All times shown in EDT.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
|16 Apr 2025||– Mars at aphelion|
|30 Nov 2025||– Mars at apogee|
|09 Jan 2026||– Mars at solar conjunction|
|26 Mar 2026||– Mars at perihelion| | 0.898291 | 3.390669 |
2013 GSA Distinguished International Lecturer
Dr. Victor R. Baker
Download additional information
and the lecture program flyer.
Video from talk in Madrid, Spain.
Megafloods on Earth, Mars, and Beyond
For more than 40 years University of Arizona Regents’ Professor Victor R. Baker has been studying the most spectacular and immense flood phenomena are currently known to occur anywhere in the solar system. The immense megafloods of the last Ice Age created bizarre landscapes like the Channeled Scabland and altered the circulation of the oceans thereby changing Earth’s climate. More surprising was the discovery that much larger megafloods occurred billions of years ago on the planet Mars. The Martian megafloods formed temporary bodies of water on that planet, even generating a kind of ocean that facilitated environmental conditions on Mars that may have been like those of an ice age on Earth. These discoveries are showing that Mars, like Earth, had a long-term cycle of water circulation that produced a habitable planet, and these are exactly the kinds of processes to seek out in the newly initiated search for the other habitable planets of the universe.
Geological History of Water on an Earth-like Planet
Recent advances in astronomy hold the prospect for discovery of a great many Earth-like planets, rich in both water and possible habitats for life, thereby greatly expanding from the current sample of one. Nevertheless, until it proves possible to do geology for these numerous potential exo-Earths, we can greatly advance the geological science of Earth-like planets by study of Mars. The early geological histories of both Mars and Earth are closely tied to the role of water, extending from the nature of planetary accretion to the origin of a physically coupled atmosphere and ocean, the prospects for initiating plate tectonics, and historical records of punctuated greenhouse-to-icehouse climatic transitions. Recent discoveries from Mars missions reveal the extensive role of water in generating sedimentary rocks, active and relict glacial and periglacial features, aqueous weathering products (clay minerals and sulfates), alluvial fans and deltas, the extensive development of paleolakes, and even a probable, though transient ocean.
2013 Lecture Schedule:
- Monday, 6 May, Universidad Complutense de Madrid, SPAIN
- Tuesday 7 May, Centro de Astrobiologia, CSIC-INTA, Madrid, SPAIN
- Wednesday 8 May, Museum of Natural Sciences, Madrid, SPAIN
- Friday 10 May, Academia Lincei, Rome, ITALY
- Monday 13 May, Universita d'Annunzio, Chieti, ITALY
- Wednesday 15 May, Istanbul Technical University, TURKEY
- Thursday 16 May, Istanbul Technical University, TURKEY | 0.859421 | 3.399154 |
Researchers are using Google Earth, the New York Times/IHT reports, to look for evidence of giant tsunamis, signs that the Earth has been hit by comets or asteroids more regularly, and more recently, than people thought:
This year the group started using Google Earth, a free source of satellite images, to search around the globe for chevrons, which they interpret as evidence of past giant tsunamis. Scores of such sites have turned up in Australia, Africa, Europe and the United States, including the Hudson River Valley and Long Island.
Chevrons are huge deposits of sediment that were once on the bottom of the ocean; they are as big as tower blocks and shaped like chevrons, the tip indicating the direction from which the tsunami came.
I love the idea that academics use a tool like Google Earth to — possibly — puncture one of the greatest myths of the human era: that comets only come along once every 500,000 years.
Scientists in the working group say the evidence for such impacts during the last 10,000 years, known as the Holocene epoch, is strong enough to overturn current estimates of how often the Earth suffers a violent impact on the order of a 10-megaton explosion. Instead of once in 500,000 to one million years, as astronomers now calculate, catastrophic impacts could happen every few thousand years.
There are a couple of other quirks to this story. The working group of misfits is cross-disciplinary — there’s a specialist on the structural analysis of myth in there — but only formed when they bumped into each other at a conference. How more efficient it would have been had they been blogging; they might have found each other earlier. (Perhaps they met before the blogging age; there’s a piece on the subject here from 2000.)
The second quirk for me is that the mythologist (actually Bruce Masse calls himself an enviromental archaeologist) reckons he can pinpoint the exact date of the comet which created the Burckle Crater between Madagascar and Australia using local legends:
Masse analyzed 175 flood myths from around the world, and tried to relate them to known and accurately dated natural events like solar eclipses and volcanic eruptions. Among other evidence, he said, 14 flood myths specifically mention a full solar eclipse, which could have been the one that occurred in May 2807 B.C.
I love the idea of myths; I see them as a kind of early Internet, a way of dispersing knowledge using the most efficient tools (in those days, this meant stories and word of mouth.) We tend to think of myths as superstition and scare mongering, but in fact in many cases they are the few grains of wisdom that get passed on from generation to generation. They often get contorted in the telling, the original purpose — to warn — sometimes getting lost.
Like the Moken sea gypsies of the Andaman Sea, most of whom were spared the 2004 tsunami because they “knew from their tribal lore that this was a warning sign to flee to higher ground”, according to Reuters. On the Acehnese island of Simeulue, similar lore, dating back to the 1907 tsunami, tells islanders that “if the land is shaking and shoreline is drained abnormally, they have to go to very high land.” Only seven people out of 80,000 islanders died.
Based on this, the idea of trying to pin down the comets, the craters and the chevrons by exploring local myth makes a lot of sense. I like the idea that is being done alongside using something as modern, and as freely available, as Google Earth. I guess I’m just not happy about the implications for us current planet dwellers. | 0.833317 | 3.354848 |
My first year out of college, 22 years old and glimmering with hubris, I taught 9th-grade Earth Science. I’d last studied the subject myself in 8th grade, which made for a fun year, if “fun” can refer to wildly inaccurate lectures about glaciers.
When we arrived at the unit on astronomy—a topic I’d actually explored in college—I felt the exhausted, wild-eyed relief of a shipwrecked man crawling onto dry land. All right! Finally I could teach them something, not just spit back stuff I’d learned from their textbook like a mother bird offering regurgitated food. We began with the age-old debate of geocentrism vs. heliocentrism.
Geocentric models of the solar system put Earth at the center, with the sun and planets all orbiting around us. That’s how ancient Greeks saw the world.
The heliocentric model, meanwhile, places the sun at the center. At one point, the Catholic Church clung so tightly to the geocentric model that they put Galileo under house arrest for espousing heliocentrism. How dare he correctly propose that we’re not the center of the universe!
With my kids, I wanted to get past the historical scandals. I wanted to talk about data, predictions, and the nature of science.
Since antiquity, people have watched the planets. To the naked eye, they look just like stars, but with two differences. First, they don’t twinkle. And second, while the stars hold a fixed pattern from night to night, the planets drift. They wander across the sky, moving against the backdrop of stars. That’s what “planet” means, in fact—wanderer.
How did people explain this? Well, they imagined a universe with the Earth at the center, the stars in the distant background, and planets orbiting around us.
But this model had a problem. Each planet usually moves one direction, but sometimes it doubles back, reversing course for a few weeks, and then continuing on its original path. This is called retrograde motion, and it blew Greek minds. Why would planets do that?
Ptolemy had a solution. “The planets don’t orbit us in a simple fashion,” he said (though probably not in those precise words, and definitely not in English). “There are roller coaster loops in their orbits. That explains why they seem to move backwards.”
This theoretical invention helped, but the planets dance a very funny dance. To fully explain their motion, Ptolemy needed further tweaks. He proposed loops within loops. His model grew dauntingly complex. But it successfully predicted the motions of the planets, so for a thousand years, his book stood as the definitive text on planetary astronomy.
Enter Copernicus. He offered a much more elegant way to explain retrograde motion. It’s not that planets are orbiting us. It’s that we’re both orbiting the sun. Retrograde motion occurs because we’re orbiting at different speeds. Mars, for example, orbits the sun more slowly than we do. So when we’re at this point, Mars will seem to move one way.
But then, later in the year, we’re passing Mars, so it seems to move the other way.
And still later, as the orbits continue, Mars resumes its original direction in our sky.
Yes, Ptolemy’s geocentrism can predict the planets’ motion. But Copernicus’s heliocentrism has the same predictive power, and it’s far more elegant to boot. It’s what scientists call parsimonious.
I explained all this to my Earth Science class, pretty sure I was nailing it. “These kids will make great scientists, thanks to me!” I gloated mentally. Then Kenny—often the only one brave enough to speak up in that vacuum-quiet class—chimed in with a question.
“How did those old Greek people even know the planets existed?” (Kenny always had a way with words.) “They couldn’t see them, could they?”
“You… they… of course they could,” I said, blinking.
“Did those dudes have telescopes?” Kenny asked.
“No,” I said. “Planets are… you can just… see them. They look like stars, but they change position in the sky from night to night.”
“OHHHHHH!” the whole class exclaimed, and my heart sank. Here I was, contrasting theoretical frameworks to explain the movements of the planets, while my students didn’t even know that they’re visible from Earth. You don’t see much of a night sky growing up in Oakland.
In that awful moment, I realized I’d lost them. The whole class. I was like a general who’s been marching ahead with his nose in the air, and then looks up to realize that his army is nowhere in sight.
The problem wasn’t just that I relied too heavily on lecture, or that I launched into advanced material without checking my kids’ basic understandings. On a deeper level, I was applying the wrong model of the classroom. I was committing an error even graver than Ptolemy’s.
The class doesn’t revolve around me. Each student follows his own orbit around something that sheds a light far brighter than I do, and exerts a pull far greater: the content itself. As they trace their own elliptic paths around the material, their progress might appear to me like retrograde motion. But that doesn’t mean they’re caught in backwards loop-de-loops. It just means I’ve got to work to see the whole system through their eyes. A class isn’t teacher-centric. It’s truth-centric.
And for the first time in my teaching career, but certainly not the last, I realized that Galileo would be ashamed of me. | 0.886333 | 3.48295 |
The way gravity deforms volcanoes could help explain mysterious features seen in volcanoes on Mars, Earth and elsewhere, as well as potentially revealing risks that volcanoes pose to neighboring communities on Earth, a group of researchers says.
Gravity can make large volcanoes warp under their own weight in two ways: they can either spread outward on top of their "basement" of underlying rock or sag downward into that basement.
The way volcanoes deform strongly influences the stability of their structures, and when and how they erupt. To learn more about how gravity can change the shape of volcanoes, researchers built models simulating a range of deformation styles, from pure spreading to pure sagging.
The scientists developed models consisting of large containers in which the researchers placed silicone putty mimicking the pliable part of the Earth's uppermost layers. On top of that, the scientists placed sand and gypsum to reflect the more brittle layers of a volcano's basement. Finally, researchers poured more sand and gypsum on top to build cones representing volcanoes and waited about 10 to 60 minutes to let the cones deform their basements. For some models, the team added a thin silicone layer just below the cone's base, imitating certain weak basement materials, such as waterlogged rocks.
"I can certainly say it was good fun, if messy," said researcher Paul Byrne, a planetary geologist at the Carnegie Institution of Washington. "The gypsum powder we used to increase sand cohesion had a tendency to settle on everything in the lab, and the silicone gel was impossible to control once it was out of a container. I wrote off more than a few pairs of pants, shoes and lab coats during the experiments I conducted."
The researchers took digital photos as the models developed and used special software to measure, with exceptional detail, how the structures' surfaces deformed over time.
"Our experimental method is sufficiently straightforward that these experiments can be carried out in high school labs, which could encourage the next generation of earth and planetary scientists," Byrne told OurAmazingPlanet.
Spreading and sagging
The researchers saw that a range of volcano spreading and sagging evolved, depending on the rigidity and strength of a volcano's basement compared to the size of the volcano it supported. Spreading occurred when the basement was rigid, as appears to be the case with the volcanic island of La Réunion in the Indian Ocean, while sagging happened when a volcano and its basement deformed together, as is the case with Elysium Mons on Mars.
Sagging and spreading can also happen at the same time, when a volcano and its basement deform separately. These interactions may explain features seen at Olympus Mons on Mars and with volcanoes on Hawaii, the largest volcanoes on Mars and Earth, respectively. Such activity may explain puzzling terraces seen jutting a bit like steps out fromthese structures' mid-to-upper flanks.
"Our models can reproduce, and so help explain, the range of structural complexity seen on volcanoes across the solar system," Byrne said. "In particular, we are able to tie the various enigmatic structural features on the largest known volcano, Olympus Mons on Mars, into a single model, which is rewarding as I've been studying this volcano since 2005."
Olympus Mons is the largest volcano in the solar system, about 370 miles (600 km) in diameter, wide enough to cover the entire state of New Mexico, and 13.6 miles (22 km) high, nearly three times taller than Mount Everest. [50 Amazing Volcano Facts]
Such research could help assess the hazards that different volcanoes pose. For instance, "a volcano that's more likely to spread than sag is at greater risk of suffering landslides or a full-blown flank collapse, and vice versa for a sagging volcano," Byrne said. These studies could also reveal likely sagging- or spreading-influenced sites of eruptions.
Byrne added that his team could start to think "about other, smaller volcanoes on Earth and Mars, and not just some of the very largest, like [those in] Hawaii or the enormous Olympus Mons. Moreover, we can look to apply these results to yet other extraterrestrial volcanoes, such as the shield volcanoes on Venus, structures named for their resemblance to a warrior's shield laid on the ground.
"And we can apply the insights gained from our laboratory models to numerical models, and so begin to get a more detailed understanding of how gravity-driven volcano deformation works mechanically."
Byrne and his colleagues detailed their findings online Jan. 17 in the journal Geology. | 0.830061 | 3.547346 |
Since the beginning of human history, people have understood that the Sun is a central part of life as we know it. It’s importance to countless mythological and cosmological systems across the globe is a testament to this. But as our understand of it matured, we came to learn that the Sun was here long before us, and will be here long after we’re gone. Having formed roughly 4.6 bullion years ago, our Sun began its life roughly 40 million years before our Earth had formed.
Since then, the Sun has been in what is known as its Main Sequence, where nuclear fusion in its core causes it to emit energy and light, keeping us here on Earth nourished. This will last for another 4.5 – 5.5 billion years, at which point it will deplete its supply of hydrogen and helium and go through some serious changes. Assuming humanity is still alive and calls Earth home at this time, we may want to consider getting out the way!
The Birth of Our Sun:
The predominant theory on how our Sun and Solar System formed is known as Nebular Theory, which states that the Sun and all the planets began billions of years ago as a giant cloud of molecular gas and dust. Then, approximately 4.57 billion years ago, this cloud experienced gravitational collapse at its center, where anything from a passing star to a shock wave caused by a supernova triggered the process that led to our Sun’s birth.
Basically, this took place after pockets of dust and gas began to collect into denser regions. As these regions pulled in more and more matter, conservation of momentum caused them to begin rotating, while increasing pressure caused them to heat up. Most of the material ended up in a ball at the center while the rest of the matter was flattened out into a large disk that circled around it.
The ball at the center would eventually form the Sun, while the disk of material would form the planets. The Sun then spent the next 100,000 years as a collapsing protostar before temperature and pressures in the interior ignited fusion at its core. The Sun started as a T Tauri star – a wildly active star that blasted out an intense solar wind. And just a few million years later, it settled down into its current form.
For the past 4.57 billion years (give or take a day or two), the Sun has been in the Main Sequence of its life. This is characterized by the process where hydrogen fuel, under tremendous pressure and temperatures in its core, is converted into helium. In addition to changing the properties of its constituent matter, this process also produces a tremendous amount of energy. All told, every second, 600 million tons of matter are converted into neutrinos, solar radiation, and roughly 4 x 1027 Watts of energy.
Naturally, this process cannot last forever since it is dependent on the presence of matter which is being regularly consumed. As time goes on and more hydrogen is converted into helium, the core will continue to shrink, allowing the outer layers of the Sun to move closer to the center and experience a stronger gravitational force.
This will place more pressure on the core, which is resisted by a resulting increase in the rate at which fusion occurs. Basically, this means that as the Sun continues to expend hydrogen in its core, the fusion process speeds up and the output of the Sun increases. At present, this is leading to a 1% increase in luminosity every 100 million years, and a 30% increase over the course of the last 4.5 billion years.
Approximately 1.1 billion years from now, the Sun will be 10% brighter than it is today. This increase in luminosity will also mean an increase in heat energy, one which the Earth’s atmosphere will absorb. This will trigger a runaway greenhouse effect that is similar to what turned Venus into the terrible hothouse it is today.
In 3.5 billion years, the Sun will be 40% brighter than it is right now, which will cause the oceans to boil, the ice caps to permanently melt, and all water vapor in the atmosphere to be lost to space. Under these conditions, life as we know it will be unable to survive anywhere on the surface, and planet Earth will be fully transformed into another hot, dry world, just like Venus.
Red Giant Phase:
In 5.4 billion years from now, the Sun will enter what is known as the Red Giant phase of its evolution. This will begin once all hydrogen is exhausted in the core and the inert helium ash that has built up there becomes unstable and collapses under its own weight. This will cause the core to heat up and get denser, causing the Sun to grow in size.
It is calculated that the expanding Sun will grow large enough to encompass the orbit’s of Mercury, Venus, and maybe even Earth. Even if the Earth were to survive being consumed, its new proximity to the the intense heat of this red sun would scorch our planet and make it completely impossible for life to survive. However, astronomers have noted that as the Sun expands, the orbit of the planet’s is likely to change as well.
When the Sun reaches this late stage in its stellar evolution, it will lose a tremendous amount of mass through powerful stellar winds. Basically, as it grows, it loses mass, causing the planets to spiral outwards. So the question is, will the expanding Sun overtake the planets spiraling outwards, or will Earth (and maybe even Venus) escape its grasp?
K.-P Schroder and Robert Cannon Smith are two researchers who have addressed this very question. In a research paper entitled “Distant Future of the Sun and Earth Revisted” which appeared in the Monthly Notices of the Royal Astronomical Society, they ran the calculations with the most current models of stellar evolution.
According to Schroder and Smith, when the Sun becomes a red giant star in 7.59 billion years, it will start to lose mass quickly. By the time it reaches its largest radius, 256 times its current size, it will be down to only 67% of its current mass. When the Sun does begin to expand, it will do so quickly, sweeping through the inner Solar System in just 5 million years.
It will then enter its relatively brief (130 million year) helium-burning phase, at which point, it will expand past the orbit of Mercury, and then Venus. By the time it approaches the Earth, it will be losing 4.9 x 1020 tonnes of mass every year (8% the mass of the Earth).
But Will Earth Survive?:
Now this is where things become a bit of a “good news/bad news” situation. The bad news, according to Schroder and Smith, is that the Earth will NOT survive the Sun’s expansion. Even though the Earth could expand to an orbit 50% more distant than where it is today (1.5 AUs), it won’t get the chance. The expanding Sun will engulf the Earth just before it reaches the tip of the red giant phase, and the Sun would still have another 0.25 AU and 500,000 years to grow.
Once inside the Sun’s atmosphere, the Earth will collide with particles of gas. Its orbit will decay, and it will spiral inward. If the Earth were just a little further from the Sun right now, at 1.15 AU, it would be able to survive the expansion phase. If we could push our planet out to this distance, we’d also be in business. However, such talk is entirely speculative and in the realm of science fiction at the moment.
And now for the good news. Long before our Sun enters it’s Red Giant phase, its habitable zone (as we know it) will be gone. Astronomers estimate that this zone will expand past the Earth’s orbit in about a billion years. The heating Sun will evaporate the Earth’s oceans away, and then solar radiation will blast away the hydrogen from the water. The Earth will never have oceans again, and it will eventually become molten.
Yeah, that’s the good news… sort of. But the upside to this is that we can say with confidence that humanity will be compelled to leave the nest long before it is engulfed by the Sun. And given the fact that we are dealing with timelines that are far beyond anything we can truly deal with, we can’t even be sure that some other cataclysmic event won’t claim us sooner, or that we wont have moved far past our current evolutionary phase.
An interesting side benefit will be how the changing boundaries of our Sun’s habitable zone will change the Solar System as well. While Earth, at a mere 1.5 AUs, will no longer be within the Sun’s habitable zone, much of the outer Solar System will be. This new habitable zone will stretch from 49.4 AU to 71.4 AU – well into the Kuiper Belt – which means the formerly icy worlds will melt, and liquid water will be present beyond the orbit of Pluto.
Perhaps Eris will be our new homeworld, the dwarf planet of Pluto will be the new Venus, and Haumeau, Makemake, and the rest will be the outer “Solar System”. But what is perhaps most fascinating about all of this is how humans are even tempted to ask “will it still be here in the future” in the first place, especially when that future is billions of years from now.
Somehow, the subjects of what came before us, and what will be here when we’re gone, continue to fascinate us. And when dealing with things like our Sun, the Earth, and the known Universe, it becomes downright necessary. Our existence thus far has been a flash in the pan compared to the cosmos, and how long we will endure remains an open question.
We have written many interesting articles on the Sun here at Universe Today. Here’s What Color Is The Sun?, What Kind of Star is the Sun?, How Does The Sun Produce Energy?, and Could We Terraform the Sun?
For more information, check out NASA’s Solar System Guide. | 0.886059 | 3.601799 |
KELT is a photometric survey for transiting exoplanets. We take images (photometry) of tens of thousands of stars every night in an attempt to see planets outside our Solar System pass in front of (transit) the star that they are orbiting. Since the late 1980s, astronomers have discovered thousands of planets orbiting other stars - in the same way that the eight planets of our Solar System orbit the Sun. Some of these planets are what are known as “hot Jupiters.” These planets are as big as Jupiter, the largest planet in our Solar System, but orbit their parent star much closer than our Jupiter does: typically taking anywhere from 2 to 10 days to complete an orbit, instead of the 12 years Jupiter takes to go around the Sun. These hot Jupiters can sometimes pass in front of, or transit, their star from our perspective on Earth.
The diagram above shows what typically happens when a planet the size of Jupiter passes in front of its parent star. From Earth, it appears as though the star gets slightly dimmer for the several hours it takes the planet to cross in front of the star. For a hot Jupiter, the planet will block about 1% of the light from the star. The goal of a photometric transit survey like KELT was to identify these planets by looking for this tell-tale 1% dimming. Since there is only a 1 out of 10 chance that a hot Jupiter will transit its star, and since not every star is orbited by a hot Jupiter, KELT would need to look at tens of thousands of stars over the course of several years to find transiting planets.
Both KELT telescopes are fully robotic. Every night, each KELT telescope would check if the weather is good, and if it is starts observing a list of fields around the sky, one after another through the whole night. In each field, there would be between 50,000 and 200,000 stars that KELT can measure the brightness of.
The various KELT fields are displayed below. This is a busy map; here is a larger version if you prefer. In this figure, the KELT fields are indicated by yellow squares. The blue patches are where the TESS mission is observing stars, so the KELT-TESS overlap is in green. In addition, we see the Kepler and K2 fields outlines in blue, a model of the galactic plane in magenta, and a number of the KELT planet discoveries also labeled.
Our typical target stars have apparent visual magnitudes of 8 to 11. This means that these stars are 20 to 100 times fainter than can be seen with the naked eye. But in comparison, most other transit surveys look for planets around stars 100 to 500 times fainter than the naked eye limit. KELT is able to effectively survey brighter stars because we have a much wider field of view and a smaller telescopic aperture than other surveys. Planets transiting brighter stars are very scientifically valuable, because these are the systems that are the easiest to measure with large ground- and space-based telescopes.
Once we identified a star which shows a dip in brightness, there is still remain a great deal of follow-up work. Through a twist of physics, hot Jupiters are the same size (though not the same mass) as the smallest stars. This means that a small star orbiting and passing in front of a larger star will cause the same dip in brightness as a transiting hot Jupiter in the KELT data. In fact, because small stars are orbiting other stars are more common than hot Jupiters, most of the signals that KELT would identify were in fact double star systems. We separate the hot Jupiters from the double star systems with the help of our follow-up collaborators. Located all over the world, our follow-up team takes high-quality imaging and spectroscopic observations of our best planet candidates. By looking for flat-bottomed achromatic transits and small amplitude radial velocity orbits in these data, we were able to pick out which stars host actual planets.
In March 2020, the KELT transit search was concluded as the NASA TESS mission has revolutionized the discovery of transiting exoplanets. Both of the KELT telescopes remain operational for science outside of transit discovery. During its 14 year run of transit observations, KELT discovered 26 planets and produced dozens of papers.
What is an exoplanet?
An exoplanet (also called an extra-solar planet) is a planet orbiting a star outside of our solar system. So far, about 3700 exoplanets have been discovered using various methods.
What is a transiting exoplanet?
In some cases, an exoplanet's orbit around its host star happens to be aligned with our line of sight from Earth. In those cases, when the exoplanet passes in front of its parent star during its orbit, it blocks a small fraction of the star’s light, and we see a drop in the brightness of the star. That drop in brightness happens once each time the planet orbits. The larger the planet is, the deeper the drop in the brightness of the star will be.
What is so special about transiting exoplanets?
There are also other methods to discover exoplanets such as direct imaging, radial velocity and microlensing. The transit method is special because it can provide a precise measurement of the size of the exoplanet. Also, if a planet is found to be transiting, it can be later observed with larger telescopes to measure its atmosphere.
Why look for exoplanets?
We eventually want to know if there is life any where else in the universe, and looking for habitable planets orbiting other stars is one way to investigate that. We also want to learn how all kinds of planets are formed, and how they change over time. We are therefore trying to find as many exoplanets as we can, of all different types, to learn about the variety and diversity of exoplanets.
What is KELT?
The Kilodegree Extremely Little Telescope (or KELT) consists of two telescopes in the North and South hemispheres and its primary mission is to look for transiting exoplanets around bright stars.
Where is KELT?
KELT-North is located at Winer observatory in southeastern Arizona, and KELT-South is located at South African Astronomical Observatory in South Africa.
Who runs KELT?
There are many people involved in KELT, but primarily, it is run by a collaboration of astronomers from Ohio State University, Vanderbilt University, and Lehigh University.
How long had KELT been running?
KELT-North was installed at Winer observatory in 2004, and started operating in 2006, and KELT-South was deployed at Sutherland in 2009 and began operating the same year.
Why did the KELT transit survey conclude?
Since the beginning of the KELT survey we've seen exoplanet science grow tremendously, in particular with the launch of the Transiting Exoplanet Survey Satellite (TESS) in April 2018, which is able to find exoplanets on a much larger scale.
How did KELT work?
Each KELT telescope takes images of the sky automatically every night if the weather is good. The data is then transferred online to Ohio State and Vanderbilt for analysis and storage.
How many planets has KELT discovered so far?
As of March 2020, KELT has discovered 26 extra-solar planets. Among the planets discovered by KELT is the hottest planet ever discovered, KELT-9b.
What are the common features of KELT exoplanets?
All of the KELT planets are hot gas giants that are in a very close orbit around their parent star. The masses of these planets range from 0.2 to 27 times the mass of Jupiter, with orbital periods between 0.9 and 8 days.
For more details about physical properties of these planetary systems please see here.
Are any of the KELT planets a potential candidate for having life?
All of the KELT planets are very hot gas giants orbiting close to their parent stars. They would be very hostile to life and would be unlikely to be habitable. We are not searching for these planets to directly find life. Rather, we are trying to better understand how planets form and evolve, and develop techniques that can later be use to search for life on other planets.
This site is edited by Dan Burger, web application developer at Vanderbilt University. Dan has nearly a decade of experience in building websites and web applications for astronomy collaborations and has been managing the internal candidate selection pages for KELT-North and KELT-South since 2011. His work on visualizations for KELT-South led to the development of Filtergraph, a free web-based data visualization service used by several NASA space missions and hundreds of users worldwide.
This site was designed and developed by Troy Weston of 3twenty9 Design, LLC, a web and graphic design firm based in Bellefonte, PA.
After 14 years of observations, 17 years since the project conception, 26 planets discovered, and dozens of papers, the KELT transit search is ending. This transition has been long-expected, since the NASA TESS mission has revolutionized the discovery of transiting exoplanets. We will continue observations by both KELT telescopes for as long as practical, since there is so much more science to be done outside of transit discovery. Thank you to everyone who supported the KELT project!... Read More
We are honored to have received the Award of Distinction at the 25th Annual Communicator Awards from the Academy of Interactive and Visual Arts for this website, together with our web design partners at 3twenty9 Design, LLC.... Read More
(Phys.org)—An international team of astronomers reports the discovery of a new "hot Jupiter" exoplanet with a short orbital period of just three and a half days. The newly detected giant planet, designated KELT-20b, circles a rapidly rotating star known as HD 185603 (or KELT-20). The finding was presented in a paper published July 5 on arXiv.org.... Read More
Scientists have discovered a giant ringed gas planet which is likely caused by a mysterious stellar eclipse. The planet has 50 times mass of Jupiter and it is surrounded by a ring of dust. According to researchers from the University of Warwick, this planet is hurtling around a star more than 1000 light years away from Earth.... Read More | 0.910255 | 3.981632 |
Phases of the Moon
As the Moon orbits around the Earth, the half of the Moon that faces the Sun will be lit up. The different shapes of the lit portion of the Moon that can be seen from Earth are known as phases of the Moon. Each phase repeats itself every 29.5 days.
The same half of the Moon always faces the Earth, because of tidal locking. So the phases will always occur over the same half of the Moon's surface.
A phase is an angle of the moon to the earth so it appears differently every day.
The moon goes through 8 major phases.
- A new moon is when the Moon cannot be seen because we are looking at the unlit half of the Moon. The new moon phase occurs when the Moon is directly between the Earth and Sun. A solar eclipse can only happen at new moon.
- A waxing crescent moon is when the Moon looks like crescent and the crescent increases ("waxes") in size from one day to the next. This phase is usually only seen in the west.
- The first quarter moon (or a half moon) is when half of the lit portion of the Moon is visible after the waxing crescent phase. It comes a week after new moon.
- A waxing gibbous moon occurs when more than half of the lit portion of the Moon can be seen and the shape increases ("waxes") in size from one day to the next. The waxing gibbous phase occurs between the first quarter and full moon phases.
- A full moon is when we can see the entire lit portion of the Moon. The full moon phase occurs when the Moon is on the opposite side of the Earth from the Sun, called opposition. A lunar eclipse can only happen at full moon.
- A waning gibbous moon occurs when more than half of the lit portion of the Moon can be seen and the shape decreases ("wanes") in size from one day to the next. The waning gibbous phase occurs between the full moon and third quarter phases.
- The last quarter moon (or a half moon) is when half of the lit portion of the Moon is visible after the waning gibbous phase.
- A waning crescent moon is when the Moon looks like the crescent and the crescent decreases ("wanes") in size from one day to the next.
Super Pink MoonEdit
A supermoon or Super Pink Moon takes place when moon's orbit is at its closest to the Earth. Supermoon take place each year between March and May"On April 7 and 8, 'Super Pink Moon' Will Be the Biggest and Best of 2020". https://amazingfact.co/. 07-04-2020. Check date values in:
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|website= (help). As Moon is exceptionally close to Earth; full Moon appears up to 7% larger and 15% brighter than a typical full moon. Traditionally any full moon that occurred in April was called a pink moon because it marked the blooming of Moss pink a wildflower.
- However, a blue moon can also refer to the third full moon in a season with four full moons.
- Sinnott, Roger W., Donald W. Olson, and Richard Tresch Fienberg (May 1999). "What's a Blue Moon?". Sky & Telescope. Retrieved 2008-02-09.
The trendy definition of "blue Moon" as the second full Moon in a month is a mistake.Italic or bold markup not allowed in: | 0.839286 | 3.572629 |
Black holes are one of the most fascinating aspects of space. They have such an extreme gravitational pull that not even light can escape. They are so phenomenal that they are said to have the ability to alter entire galaxies.
Black holes are severely curved off that it can be considered pinched off from the rest of the universe. Within a black hole, the laws of physics as we know them no longer apply. Using Einstein’s theory of relativity, physicists such as Karl Schwarzschild theorized that any mass can become a black hole if it was compressed into a space small enough. Black holes were first predicted by Einstein in 1916, however, it was only until 1971 that the first black hole was physically discovered.
Whatever happens within the black hole will never be known since no signal comes from this area. As we know, black holes have an infinitely curved space-time and density. Therefore a black hole has three layers so to speak. The outer and inner event horizon and the singularity. The singularity is where most of the black hole’s mass is concentrated.
A common misconception about a black hole is that it sucks in everything like a vacuum cleaner. This is not the case. A black hole will only affect matter that comes across its outer edge known as the event horizon. The event horizon is a boundary surrounding the black hole and in this area, nothing can escape its gravitational pull. Anything that comes across here is ultimately there for good. How wide the event horizon is depends on the mass of the black hole.
Objects fall into black holes due to their extreme gravitational pull, just as objects fall while on earth due to the earth’s gravitational pull.
How are black holes created?
When a star with a core that is 2.8 times bigger than the sun’s mass dies and its core collapses, a stellar-mass black hole is formed. How does this happen? When the core of a star begins collapsing, its gravity progressively gets stronger, meaning its escape velocity gets higher and higher. For a neutron star, during its collapse, its velocity is half the speed of light. For a star that is 2.8 times the sun’s mass or bigger, its core keeps collapsing, its size begins to continuously drop and when it gets to approximately 18 kilometers, its escape velocity is equal to the speed of light. As we know, nothing travels faster than the speed of light, and at this size, nothing can escape this hole. Therefore whatever comes across the path of a black hole, will never come out.
That is the origin of a standard stellar-mass black hole, however, it has not been determined how supermassive black holes such as Sagittarius A* are formed. Some theories have suggested that supermassive black holes are formed after stellar mass black holes and intermediate mass black holes collide.
Black holes are such a hot topic for astronomers and physicists today that even years after their discovery, their properties are still debated and argued over.
Can the earth and the sun become black holes?
For an object to form a black hole, it needs to have 20 times the sun’s mass or more. The object’s mass has to be large enough that its gravity is able to overcome any external forces pushing for its collapse. The earth has a mass of approximately 6×1024 kilograms, that’s too light in comparison. The sun itself does not have enough mass for it to become a black hole.
Sizes of black holes
As mentioned before, black holes have different sizes and those discussed most often are stellar black holes. These black holes have a mass of approximately thrice the sun and can go up to a dozen times the size of the sun. When stellar masses absorb more matter, they become larger. Huge black holes can be found in the center of galaxies including one in our very own milky way. Its mass is said to be 4.3 million times the sun’s mass and is known as Sagittarius A*.
The smallest black hole ever observed was found in the binary system GRO J1655-40. This black hole is said to be 5.4 times the mass of the sun and with a radius of ten miles. It is thought that unlike stellar black holes and larger black holes, small black holes are formed after two neutron stars merge instead of the collapse of a dying star. The size of stellar black holes is dependent on the mass of the original dying star. Some scientists also believe that primordial black holes, which are microscopic black holes, were created during the Big Bang.
Intermediate black holes have been harder to find. These black holes are bigger than stellar black holes and smaller than supermassive black holes. The most recent intermediate black hole to be discovered was found by the Hubble Space Telescope. Although bigger than stellar black holes, they are said to have a mass between 100 and 100,000 solar masses. In comparison, supermassive black holes can be a billion times the sun’s mass.
Within our galaxy, we have a supermassive black hole named Sagittarius A*. It weighs approximately 4 million solar masses and its radius is 17 times more than that of the sun. This may sound big, however, if compared to other black holes in other galaxies, this is small. The biggest black hole ever discovered was found within the Abell 85 galaxy cluster. Within this cluster is the galaxy Holm 15A. The black hole is found at the center of this galaxy. Its mass has been said to be astonishingly 40 billion solar masses with a diameter the size of the entire solar system.
How astronomers find black holes
Simply because nothing can escape a black hole, not even light, it is not possible to see them. These ‘objects’ do not produce photons that would allow them to be observed as an ‘object’ that is why they are called black holes. Because of their dark nature, only a few of them have been found although astronomers and physicists speculate that they’re more even in our galaxy. Astronomers have found them by observing the behavior of stars around them.
When a star falls into a black hole, material from the star heats up within the black hole and releases x-rays which can be observed by astronomers. A star that gets too close to a black hole will get torn apart by the black hole’s forceful tides. As it gets destroyed, it emits light which is blasting out energy.
In 2019, astronomers made a historic announcement. They were able to capture the first image of a black hole. To be more specific, they were able to capture an image of a black hole’s event horizon. This image was captured through a collaboration of the Event Horizon Telescope. This black hole was discovered in the center of the galaxy M87.
How many black holes are in the universe?
Black holes are generally shrouded in mystery. There is a general agreement by astronomers that there should be tens of millions of them in our galaxy. This has been inferred based on the number of stars we have. Because they are so difficult to find, only dozens have been found.
Some of the closest black holes are; A0620-00(V616 Monocerotis), Cygnus X-1, V404 Cygni, GRO J0422+32, Cygnus X-3, GRO J1655-40, Sagittarius A*, 47 Tuc X9, XTE J1118+480, and GS2000+25.
The closest black hole is only 1000 light years away and it is HR 6819. It is also said to be the only black hole containing system that is visible to the naked eye. The Sagittarius A* is within our Milky Way and is 2500 light years away and is the closest supermassive black hole.
With technological advancement, more black holes will ultimately be found with some of them within our own galaxy.
What happens if an astronaut falls into a black hole?
The simple answer, they die. As we know by now, a black hole’s gravity is incredibly intense therefore, its tidal force is also extreme. If an astronaut fell into a black hole feet first, the force of gravity on their feet would be much stronger than the gravity on their head. Once you fall in, your feet would be pulled with such extreme force that you would stretch. This process is popularly referred to as spaghettification. This happens if they happened to fall just a few kilometers from the black hole. On the other hand, if an astronaut fell in from a further distance, their speed would be almost equal to that of the speed of light and they would die within milliseconds.
Some physicists have speculated that it might be possible to escape a black hole. These physicists speculate that there is a tunnel through space-time that connects black holes to one another. They are referred to as ‘wormholes’. This is a very wild theory that is yet to be substantiated.
Do black holes die?
Previously, it was assumed that black holes existed forever. Stephen Hawkins, however, debunked this theory. In the 1970s, Hawkins and fellow physicist Jacob Beckenstein proved that black holes emit radiation and during this emission, it carries away energy. Therefore, after a period of time, a black hole simply disappears. After calculations, physicists believe that it could take billions of years for a ‘black hole evaporation’ to occur.
A black hole evaporating is often troublesome to astronomers. This is because when an object falls into a black hole, the object’s information disappears permanently in the black hole. Then the black hole evaporation means it also permanently disappears. This poses a big problem for physicists whose equations are always expected to retain information.
Amazing facts about black holes
Black holes are such a fascination to physicists, astronomers, and laypeople alike that many fictional books and movies have been created about them. Here are a few amazing facts about them;
- Earlier, it was mentioned that black holes have the ability to alter entire galaxies but other scientific discoveries surmise that they could create entirely new universes. This controversial idea was birthed by Lee Smolin, a physicist based in Canada. He theorized that when a star falls into a black hole and is squeezed down to extreme density, it bounces back and expands again. Once that star expands, it creates a whole new universe. He says this is possible largely because the laws of space-time within a black hole are not as we know them and these conditions could eventually create a new universe.
- Black holes are also capable of generating more energy than the sun. When material falls into the event horizon, it begins orbiting at extremely high speeds due to the intense gravitational pull of the black hole. Due to the extreme pace of the material, it generates heat of up to billions of degrees Celsius. If you compare, a nuclear fusion turns 0.7% of mass into energy, while a black hole converts 10% of mass into energy.
- One of the most recent discoveries on black holes is the discovery that occasionally matter is expelled from the accretion disk and thrown into our galaxy at 32 million km/h. In the same respect, supermassive black holes have been known to release enough material that new stars are born. Further studies have also shown that supermassive black holes are able to control how many stars are in a specific galaxy.
- If an astronaut were to fall into a black hole wearing a watch, an observer would note that his clock would progressively run slower and ultimately stop moving. Space-time within a black hole is not what we know it. If we were to observe, it would take light much longer to reach us and that is why time would seem to stop.
- Black holes are constantly growing in size and density. Everything that gets in stays in including gas, liquid, or solid material. Physicists, however, believe that black holes do not grow beyond 10 billion solar masses. This is because, above this mass, it would damage their accretion disk.
There is so much to learn and to be discovered about black holes. Astronomers and astrophysicists are constantly learning and discovering and that in itself makes black holes an amazing phenomenon of space. | 0.890012 | 3.957246 |
[Version française sur le site de La Recherche]
Why do we want to go to Mars so badly? The first answer that comes to mind is: to look for alien life.
You might think that, being an astrobiologist, I am biased. And you are probably right: microbes matter to me more than rocks, and if you’re a geologist you’re probably yelling at your screen. But the search for life is usually at the top of mission objectives when it comes to Mars. Mars has not always been the dry, cold and desert planet it is today. Evidence suggests that, at some points in its history, it was surrounded by a denser atmosphere, had lakes, rivers and oceans, and was warmer. The large amounts of nutrient-rich volcanic rocks, together with atmospheric gas, likely provided all the elements needed to support microbial life forms as we know them.
That being said, the fact that a planet has everything it needs to sustain life does not mean that it sustains life. “Where there is water, there is life”, as you might have read quite a few times, is a naive affirmation based on what we observe in terrestrial environments. Put water in a bottle, as well as sugars and everything microorganisms need to thrive, close it, heat it enough to kill everything inside, and let it cool. As long as your bottle is closed, you will have an environment which is suitable for life but does not harbor it. That Mars used to be hospitable does not mean that it was inhabited.
It does not mean that it was not, either. In particular, it is quite possible that Mars was contaminated by terrestrial life. And I am not referring to the fact that we sometimes mess up when sterilizing rover drills; no, I am speaking about bacteria surfing rocks through space. Sounds surprising? Maybe. But large amounts of materials have been transferred from Earth to Mars, and vice-versa, after being expelled by asteroids or comets.
Throw a rock in gravel. Pebbles will be expelled from the impact, right? Throw it harder. Ejected pebbles will fly farther and faster. If you threw the rock so hard that the ejected pebbles flew away at 12 km/s (and were not destroyed by heat), they could leave Earth: 12 km/s happens to be just above what we call Earth’s escape velocity. Escape velocity is basically the speed you need to break free from gravity. In other words: if you go faster than a planet’s escape velocity, you can end up in space.
No offense, but I doubt that you could throw a rock hard enough to accelerate pebbles beyond Earth’s escape velocity. However, an asteroid impact can. Ejecta reaching escape velocity leave the planet and begin orbiting around the Sun, for hundreds of thousands or millions of years, until they either impact another celestial body or leave our planetary system. And asteroid impacts on Earth and Mars are quite common (on a geological time scale; no, no need to invest in an underground bunker).
Interestingly, evidence shows that life on Earth existed more than 3.5 billion years ago, and could have appeared there at a time when Mars was hospitable. This overlap could have favored microorganism survival after Earth-to-Mars contamination. Or… conversely. Yes. For various reasons, if Earth and Mars harbored the same density of life, Mars-to-Earth transfer would be more likely than Earth-to-Mars transfer. In particular, Mars’s escape velocity is lower than Earth’s: 5 km/s (and no, sorry, you still could not throw a rock into space from Mars; you might be able do it from one of its moons, though). Expelling a rock from Mars could be done more smoothly. At this point I can – maybe – tell you this without you calling a psychiatric hospital to check for missing patients: it is not impossible that life on Earth came from Mars.
That being said, being ejected from one planet by an asteroid impact, surfing an ejectum and crashing on another planet is quite a ride. Could bacteria – or more primitive forms of life – survive it?
The first issue is the pressure faced by rocks expelled by an asteroid impact. But shock recovery experiments (a fancy term for “putting bacteria in a bullet, firing the bullet, and looking whether bacteria are still alive”) show that some bacteria could survive a shock expelling a rock from Mars. Another issue is temperature, due to friction with the atmosphere when leaving a planet and entering a new one (if you quickly rub one of your hands against the other, you will quickly realize that friction creates heat). But rocks can be expelled from Mars without been excessively heated, and it has been assessed that billions of ejecta have travelled from Mars to Earth without being heated above 100°C, a fraction of which travelled for a time below the known lifespans of dormant bacteria. Then, there is the trip to space, which involves low temperatures, radiations, vacuum, and a few other things you would not enjoy being exposed to. But resistance of bacteria to space has been extensively studied in the past decades, in simulations on Earth but also on-board spacecraft, and it seems that some bacteria could survive the trip if sheltered inside a rock.
If Mars ever harbored microbial life, its natural transfer to Earth is a highly probable process. Consistently, structures found in Martian meteorites found on Earth are strongly suspected to be fossilized bacteria. The most suspicious ones are contained in the meteorite fragment ALH84001; 20 years after their discovery, the microfossil-looking shapes still lead to heated discussions within scientific communities. More heated than you would ever expect of conversations about a rock (except, maybe, if the rock was thrown at your face). If such structures were found in an ordinary rock, in an ordinary place, most biologists would conclude that they are fossilized microbes, and nobody would blame them for that. But as Carl Sagan said, “extraordinary claims require extraordinary evidence”, and we have no unquestionable evidence that those structures – or any structure found in Martian meteorites so far – come from bacteria that once lived on Mars. In spite of tantalizing clues and convictions of eminent scientists.
Another burning interrogation concerns the existence of current life on Mars. Life on the surface is unlikely given today’s harsh conditions there, but nothing excludes the possibility of underground microbes.
Has there been life on Mars? Does it come from Earth? Does life on Earth come from Mars? Is there life on present-day Mars? We will likely not come with any satisfying answer to those questions before humans walk on Mars’s red dust. | 0.818593 | 3.361161 |
Pics and video NASA has discovered a mini solar system of seven Earth-sized planets orbiting a small cool dwarf star, including three within the Goldilocks zone where liquid water is possible.
Last year, a telescope in Chile – dubbed the TRAPPIST aka the TRAnsiting Planets and PlanetesImals Small Telescope – spotted two planets orbiting an ultra-cool white dwarf star. This diminutive star has about eight per cent of the mass of our own Sun.
After refocusing the Spitzer and Hubble space telescopes on the dwarf system, the astroboffins identified seven distinct planets. Today they've gone public with their findings.
"The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star," said Michael Gillon, lead author of a paper detailing the discovery, and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium. "It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds."
Cool dwarf stars are more common than our own type of star, but they weren't considered good candidates for spotting exoplanets because they don't put out much visible light. They do, however, put out a lot of infrared light. This was perfect for Spitzer and enabled the telescope to measure the planets as they were passing in front of the star. The system has been named TRAPPIST-1 after the Chilean telescope.
Of the three planets in the system's habitable zone, the innermost, TRAPPIST 1e, is the closest in size to Earth and would get around the same level of sunlight from its dwarf as we do from our Sun. Planet 1f is slightly larger than Earth, has a nine-day orbit and gets about as much light as Mars, while Trappist 1g is the largest of the seven – about 113 per cent of the size of Earth.
How we measure up ... the seven Earth-ish-sized planets in the TRAPPIST system. Click to enlarge (Source: NASA)
All of the planets are very close to the dim star they orbit, which means they are tidally locked like our Moon and so have one side in permanent darkness. They should also be water-rich, since they would have formed much further away from their sun and then fallen inwards, Gillion said.
The embarrassment of riches around TRAPPIST-1, and the type of star itself, has raised hopes that there may be many more Earth-like planets in habitable zones than first thought, said Thomas Zurbuchen, associate administrator of the Science Mission Directorate at NASA headquarters.
"While only three of the planets are in the right zone for liquid water, you could also find liquid water on any of the seven, with the right atmospheric conditions," he said. "Finding a second Earth is not just a matter of if, but when."
Next year, when the much-delayed James Webb telescope finally lifts off, it will have TRAPPIST-1 as one of its first targets. The enormous power of the telescope will enable astronomers to see into the atmospheres of the planets and look for evidence of oxygen, ozone and methane – considered possible signs of life – and will also calculate their temperatures.
Because the planets are so close together, if you were to stand on the surface of one, you'd see the other six looking as large or larger than our moon. NASA has designed a travel poster for the system just in case – but getting there to check out the view could take a while.
The system is located about 39 light years away from Earth, so we won’t be seeing a probe there in our lifetimes, even if the Starshot program is successful. Nikole Lewis, astronomer at the Space Telescope Science Institute, pointed out it would take 44 million years to get there at the speed of a standard jet aircraft.
In the meantime, there's always Proxima Centauri, around which there is an Earth-style planet in orbit. It is just 4.25 light years away, and is the first Starshot target. But getting people out that far is a "100 miracle project," Zurbuchen said. ® | 0.838629 | 3.714341 |
President Reagan’s 1988 National Space Policy directed that “all space sectors will seek to minimize the creation of space debris … consistent with mission requirements and cost effectiveness.” At that time, the NASA orbital debris program had already established procedures to minimize the possibility of growth in the debris population from future explosions of the U.S. Delta 2nd stage, and had approached the European Space Agency (ESA) concerning a similar problem with ESA’s Ariane upper stage. These were the events that began NASA’s involvement in establishing standards for mitigation of orbital debris on an international basis.
Political, legal, technical, and economic considerations had to contribute to any standards that were established. The political and legal issues are discussed in Chapter 11. The economic issues were considered by consulting with the manufacturers and operators of space hardware. For example, most upper-stage rockets either have the ability to deplete the excess fuel remaining after delivering their payload, or could have that ability with a simple modification. Consequently, implementation of the mitigation standard for a spacecraft and upper stages to deplete their on-board stored energy after mission operations began in the early 1980s, well before there were any written requirements. This single mitigation action greatly reduced the risk of accidental explosions for those who exercised it and lowered the growth rate of cataloged fragments resulting from rocket body explosions from 150 fragments per year between 1964 and 1984 to only 50 fragments per year for the next 20 years (see Figure 1.2).
Other mitigation standards, such as minimizing any debris intentionally released, also had minimal impact on mission costs and were quickly accepted by the community. However, by the early 1990s it was becoming increasingly obvious that for as long as any object was in orbit it would always be subject to the external energy source of kinetic energy. The kinetic energy involved in collisions between cataloged objects is much greater than most remaining internal energy and is therefore capable of producing even more fragments than explosions. Consequently, it was concluded that the increasing accumulation of orbital mass in the form of intact spacecraft and upper stages would inevitably lead to collisions between these objects and become the dominant source of future debris.1 While there was uncertainty in when collisions would become the dominant source of debris, there was concern that at some point in the near future the rate of growth in low Earth orbit (LEO) would become irreversible. This led to a mitigation standard for upper stages and payloads at the end of their mission to either maneuver
1 Interagency Group (Space) for the National Security Council, Report on Orbital Debris, Washington D.C., February 1989; D.J. Kessler, Orbital debris environment for spacecraft in low Earth orbit, Journal of Spacecraft and Rockets 28(3):347-251, 1991; J.P. Loftus, Jr., D.J. Kessler, and P.D. Anz-Meador, Management of the orbital debris environment, Acta Astronautica 26(7):477-486, 1992; D.J. Kessler and J.P. Loftus, Jr., Orbital debris as an energy management problem, Advances in Space Research 16(11):139-144, 1995.
to one of a set of defined disposal regions or maneuver to an orbit where atmospheric drag would remove the object within 25 years.
The rationale for 25 years rather than any other time period was that it was an acceptable compromise between the amount of fuel required to maneuver to a lower orbit, and the effectiveness of such a maneuver to the long-term environment, as a result of predictions by various orbital debris models. Models such as NASA’s LEGEND and the earlier EVOLVE have consistently predicted that there is only a small difference in the long-term environment between an object being removed immediately and 25 years later. Before ESA accepted the 25-year rule, ESA considered everything from zero years to 100 years for a post-mission lifetime, using the ESA MASTER’99 model. ESA concluded that “a 25-year post-mission lifetime is the shortest possible before propellant requirements start to become disproportionately high.”2
Finding: NASA’s current orbital debris programs are recognized both nationally and internationally as leaders in providing support for defining the environment and related impact hazards associated with orbital debris, and mitigation techniques to effectively minimize the hazards associated with the current and future orbital debris environment.
Finding: Most relevant federal agencies accept all or some of the components of NASA’s orbital debris mitigation and prevention guidelines.
There are two problems with the current post-mission disposal standards: (1) As described in Chapter 11, “Issues External to NASA,” not all of the spacecraft community are required to follow NASA’s standards, with at least one U.S. agency not even encouraging compliance with the 25-year rule.3 (2) Current model predictions conclude that even 90 percent compliance is insufficient to prevent future debris growth in LEO. These same models predicted the collision rates that are observed from the past four collisions between cataloged objects, as well as the amount of debris generated as a consequences of China’s anti-satellite test (Box 1.2 in Chapter 1) and the accidental Iridium–Cosmos collision (Box 9.1 in Chapter 9), providing additional evidence that the models are correct, and that mitigation alone is not sufficient. The possibility that current mitigation standards may not be adequate requires either more aggressive mitigation or the introduction of removal operations; however, the agency is not prepared for either.
The only study to determine what actions would result in a stable orbital debris environment concluded that the retrieval of pre-selected objects could do so, and would be significantly helped by compliance with the 25-year rule.4 A study by both NASA and ESA has identified some alternative techniques to remove objects.5 However, the largest activity was the “International Conference on Orbital Debris Removal” in Chantilly, Virginia, on December 8-10, 2009, sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). The conference identified many possibilities, but all required further technology development, most raised legal issues, and some introduced policy conflicts. A few might be more accurately described as enhanced or active mitigation. A report to DARPA after the conference included the observation that “any future debris removal strategy must be tested to ensure that it will work in the operating environment.”6 None of the removal or “enhanced mitigation” concepts have been fully tested or tried in the operating environment.
2 R. Walker, C. Martin, H. Stokes, J. Wilkinson, H. Sdunnus, S. Hauptmann, P.Beltrami, and H. Klinkrad, Executive summary, in Update of the ESA Space Debris Mitigation Handbook, Ref. QINETIQ/KI/SPACE/CR021539, European Space Agency, Paris, France, July 2002, available at www.esa.int/gsp/completed/execsum00_N06.pdf.
3 National Research Council, Summary of the Workshop to Identify Gaps and Possible Directions for NASA’s Micrometeoroid and Orbital Debris Programs, The National Academies Press, Washington, D.C., 2011.
4 J.-C. Liou, N.L. Johnson, and N.M. Hill, Controlling the growth of future LEO debris populations with active debris removal, Acta Astronautica 66(5-6):648-653, 2010.
5 H. Klinkrad and N.L. Johnson, “Sustainable Use of Space through Orbital Debris Control,” Paper AAS 10-016 presented at the 33rd Annual AAS Guidance and Control Conference, Breckenridge, Colo., February 6-10, 2010; also in Advances in the Astronautical Sciences 137:63-74, 2010.
6 D. Baiocchi and W. Welser IV, Confronting Space Debris, Strategies and Warnings from Comparable Examples including Deepwater Horizon, prepared for DARPA by RAND Corporation, Defense Advanced Research Projects Agency, Arlington, Va., 2010.
FIGURE 7.1 LDEF was returned to Earth using the space shuttle. The space shuttle also returned the Satellites Palapa and Weststar; however, these satellites were “cooperative” in that they were stable and designed to be handled by the space shuttle. Returning a possibly spinning satellite that was not designed to be handled is a more difficult problem, even more so without the capabilities of a crewed space shuttle. SOURCE: Courtesy of NASA-JSC.
Objects have been removed from orbit, such as the LDEF satellite shown in Figure 7.1, but these were planned and designed for easy removal using the space shuttle. Various concepts for removing debris are discussed in DARPA’s recently released “Catcher’s Mitt” Final Report,7 and include the use of nets and harpoons to capture large objects, and tethers, drag augmentation devices, and solar sails to remove the objects. Other potential removal solutions that have flown in orbit or been tested on the ground are electrodynamic and momentum tethers; drag augmentation devices; solar sails; ground-based and space-based lasers; and soft-catch collection media. Many show some promise; however, necessary safeguards must also be addressed and tested to ensure that any operation system does not contribute to the production of orbital debris through unintentional consequences.
Finding: Enhanced mitigation standards or removal of orbital debris are likely to be necessary to limit the growth in the orbital debris population. Although NASA’s orbital debris programs have identified the need for orbital debris removal, the necessary economic, technology, testing, political, or legal considerations have not been fully examined, nor has analysis been done to determine when such technology will be required.
7 W. Pulliam, Catcher’s Mitt Final Report, Tactical Technology Office, Defense Advanced Research Projects Agency, Arlington, Va. | 0.809725 | 3.193738 |
B-Mode Pattern Observed with the BICEP2 Telescope
Gravitational waves from inflation generate a faint but distinctive twisting pattern in the polarization of the cosmic microwave background, known as a "curl" or B-mode pattern. For the density fluctuations that generate most of the polarization of the CMB, this part of the primordial pattern is exactly zero. Shown here is the actual B-mode pattern observed with the BICEP2 telescope, which is consistent with the pattern predicted for primordial gravitational waves. The line segments show the polarization strength and orientation at different spots on the sky. The red and blue shading shows the degree of clockwise and anti-clockwise twisting of this B-mode pattern.
B-Mode Polarization Pattern Observed by BICEP2
The tiny temperature fluctuations of the cosmic microwave background (shown here as color) trace primordial density fluctuations in the early universe that seeded the later growth of galaxies. These fluctuations produce a pattern of polarization in the CMB that has no twisting to it. Gravitational waves from inflation are expected to produce much a fainter pattern that includes twisting ("B-mode") polarization, consistent with the pattern observed by BICEP2, which is shown here as black lines. The line segments show the polarization strength and orientation at different spots on the sky.
BICEP 2 Sunset
The sun sets behind BICEP2 (in the foreground) and the South Pole Telescope (in the background).
How Gravitational Waves Work (Infographic)
Moving masses generate waves of gravitational radiation that stretch and squeeze space-time. See how gravitational waves work in this Space.com infographic.
BICEP2 Electronics Testing
Graduate student Justus Brevik tests the BICEP2 readout electronics.
BICEP2 Focal Plane
The BICEP2 telescope’s focal plane consists of 512 superconducting microwave detectors, developed and produced at NASA’s Jet Propulsion Laboratory.
3D visualization of gravitational waves produced by two orbiting black holes.
Lack of Gravity Waves Puts Limits on Exotic Cosmology Theories
Artist's impression of gravitational waves from two orbiting black holes.
Cosmic Superstrings Might Sing in Gravity Waves
Cosmic superstring loops wiggle and oscillate, producing gravitational waves, then slowly shrink as they lose energy until they disappear.
LISA Gravity Wave Hunting Mission
The LISA mission was planned to be the first space-based mission to attempt the detection of gravitational waves. These are ripples in spacetime that are emitted by exotic objects such as black holes.
Cataclysmic events, such as this artist's rendition of a binary-star merger, are believed to create gravitational waves that cause ripples in space-time. | 0.812856 | 4.154816 |
NASA finds clear skies on exoplanet
In a display of interstellar teamwork, NASA’s Hubble, Spitzer and Kepler space telescopes have discovered clear skies and water vapor in the atmosphere of a Neptune-sized planet orbiting a star 120 light years from Earth. According to the space agency, this may not only provide insights into the formation of giant exoplanets, but also act as a new tool for detecting water on Earth-like planets orbiting other stars.
Astronomers like clear skies on Earth, because it makes it easier to look out of the atmosphere. They also like clear skies on other planets because it allows them to look in. Otherwise, they just end up looking at a load of cloud tops. In a very distant example of a nice day, astronomer found clear skies on HAT-P-11b; an exo-Neptune planet that orbits the orange dwarf star HAT-P-11 once every five days.
Located 120 light years distant in the constellation of Cygnus, HAT-P-11b is a hot world with a rocky core and gaseous atmosphere. According to NASA, this is the smallest planet on which any sort of molecules have been detected. Previously, molecules, including water vapor, have been detected in the atmospheres of Jupiter and super-Jupiter sized planets because of their size and less dense atmospheres. But HAT-P-11b is the smallest planet yet where water has been detected – nothing of its size has been within the range of current technology until now.
The technique used for peeking through the atmosphere is called transmission spectroscopy. This involves studying the light from the planet’s star as it passes through the planet’s atmosphere. Obviously, if that atmosphere is laden with clouds, the light won’t go through. Fortunately, HAT-P-11b’s atmosphere has clear skies in at least the higher altitudes. This clearness was demonstrated by the fact that the Hubble could detect the starlight.
Using the Hubble's Wide Field Camera 3, the team took spectroscope readings of the light passing through the planet’s atmosphere and compared it to that of the star. The differences would indicate the presence and nature of any molecules in the air around HAT-P-11b.
According to NASA, the team did detect water vapor, but water can be found in regions of cooler stars called “starspots,” which are analogous to sunspots. To eliminate the possibility that all they were seeing was water on HAT-P-11, the team used data from the Kepler and Spitzer telescopes. Since they can see in the infrared, they could determine the temperature of the star and concluded that any starspots present would be too hot for water, which would break down into its constituent atoms at too high a temperature.
NASA says that HAT-P-11b has an atmosphere of water vapor, hydrogen, and other gases yet to be determined, and that the data will be helpful in learning more about the diversity of giant exoplanets and their formation. NASA plans to continue working to detect clear skies and water vapor on smaller and smaller planets with the goal of ultimately finding water on an Earth-like exoplanet using the James Webb telescope, which launches in 2018.
"The work we are doing now is important for future studies of super-Earths and even smaller planets, because we want to be able to pick out in advance the planets with clear atmospheres that will let us detect molecules," says Heather Knutson of the California Institute of Technology in Pasadena. | 0.87075 | 3.773879 |
May 30, 2019 report
Ammonia detected on the surface of Pluto, hints at subterranean water
A team of researchers affiliated with several institutions in the U.S. and one in France has found evidence of ammonia on the surface of Pluto. In their paper published in the journal Science Advances, the group describes their finding and what it might have revealed about the dwarf planet.
New Horizons is an interplanetary space probe that was launched by NASA in 2006—its primary mission was to fly by Pluto to learn more about the distant dwarf planet. Its secondary mission was to study Kuiper belt objects. After launch, the probe flew close to Jupiter and then went into hibernation mode until it arrived at Pluto in 2015. The probe remained in the vicinity of Pluto until the end of 2016. In this new effort, the researchers have been studying data sent back from the probe during its Pluto flyby.
The researchers focused on a part of Pluto's surface known as Virgil Fossa—an area around a large crack in the surface. Prior research has suggested the crack was the result of volcanic activity. The researchers chose to focus on the site because its reddish-brown color hinted at the possible presence of ammonia on the surface—a rarity in planetary research. Ammonia does not last long on the surface of planetary bodies because it is easily broken down by cosmic rays and ultraviolet light. Data from New Horizons provided a near-infrared spectrum of the surface at a resolution of 2,700 meters per pixel, showing some water ice on the surface and some ammonia.
Ammonia on the surface of Pluto suggests the dwarf planet likely harbors liquid water beneath its surface due to cryovolcanism, in which water mixed with ammonia was either blasted or pushed from the crack onto the surrounding area. The spacing of the ice and ammonia suggested it might also have been pushed through several vents in the region. And because of ammonia's nature, it could not have been there very long in geological terms—perhaps as recently as a few million years. The researchers note that despite a surface temperature of -230°C, it is possible for Pluto to contain subsurface water because of internal heat generated by radioactive decay of its core.
© 2019 Science X Network | 0.83277 | 3.686469 |
"Such a system must have had a very troubled history", said Pierre Maxted, lead author of the paper that reports the study in this week's issue of Nature. "Its existence proves that the brown dwarf came out almost unaltered from an episode in which it was swallowed by a red giant."
The two objects, separated by less than 2/3 of the radius of the Sun or only a few thousandths of the distance between the Earth and the Sun, rotate around each other in about 2 hours. The brown dwarf moves on its orbit at the amazing speed of 800 000 km/h!
The two stars were not so close in their past. Only when the solar-like star that has now become a white dwarf was a red giant, did the separation between the two objects diminish drastically. During this fleeting moment, the giant engulfed its companion. The latter, feeling a large drag similar to trying to swim in a bath full of oil, spiralled in towards the core of the giant. The envelope of the giant was finally ejected, leaving a binary system in which the companion is in a close orbit around a white dwarf.
"Had the companion been less than 20 Jupiter masses, it would have evaporated during this phase", said Maxted."
The brown dwarf shouldn't rejoice too quickly to have escaped this doom, however. Einstein's General Theory of Relativity predicts that the separation between the two stars will slowly decrease.
"Thus, in about 1.4 billion years, the orbital period will have decreased to slightly more than one hour", said Ralf Napiwotzki, from the University of Hertfordshire (UK) and co-author of the study. "At that stage, the two objects will be so close that the white dwarf will work as a giant "vacuum cleaner", drawing gas off its companion, in a cosmic cannibal act."
The low mass companion to the white dwarf (named WD0137-349) was found using spectra taken with EMMI at ESO's New Technology Telescope at La Silla. The astronomers then used the UVES spectrograph on ESO's Very Large Telescope to record 20 spectra and so measure the period and the mass ratio.
: Brown dwarfs are 'failed stars' that have less than 75 Jupiter masses and are unable to sustain nuclear fusion in their core.
: White dwarfs are Earth-size, hot and extremely dense stars that represent the end products of the evolution of solar-like stars. During most of their life, such stars draw most of their energy from the transformation of hydrogen into helium. But at some moment, the hydrogen fuel will run out: this phase - still many billions of years into the future for the Sun - signals the beginning of profound, increasingly rapid changes in the star which will ultimately lead to its death. The star dramatically increases in radius, becoming a red giant. Later, it will expel huge quantity of gas and appear as a planetary nebula. Once the planetary nebula has dissolved, one is left with a white dwarf. | 0.932636 | 3.775348 |
– Three planets with sizes and temperatures similar to those of Venus and Earth, orbiting an ultra-cool dwarf star just 40 light-years from Earth, have been discovered by astronomers using the TRAPPIST telescope at ESO’s La Silla Observatory.
Astronomers led by Michaël Gillon of the University of Liège have focused their observations on star 2MASS J23062928-0502285, now also known as TRAPPIST-1.
They found that this dim and cool star faded slightly at regular intervals, indicating that several objects were passing between the star and the Earth. Detailed analysis showed that three planets are present around the star.
TRAPPIST-1 is an ultra-cool dwarf star — it is much cooler and redder than the Sun and barely larger than Jupiter. Despite being so close to the Earth, this star is too dim and too red to be seen with the naked eye or even visually with a large amateur telescope.
It lies in the constellation of Aquarius (The Water Carrier).
Follow-up observations with larger telescopes, including the HAWK-I instrument on ESO’s 8-metre Very Large Telescope in Chile, have shown that the planets orbiting TRAPPIST-1 have sizes very similar to that of Earth.
Two of the planets have orbital periods of about 1.5 days and 2.4 days respectively, and the third planet has a less well-determined orbital period in the range 4.5 to 73 days.
“With such short orbital periods, the planets are between 20 and 100 times closer to their star than the Earth to the Sun. The structure of this planetary system is much more similar in scale to the system of Jupiter’s moons than to that of the Solar System,” explains Michaël Gillon.
Although they orbit very close to their host dwarf star, the inner two planets only receive four times and twice, respectively, the amount of radiation received by the Earth, because their star is much fainter than the Sun.
That puts them closer to the star than the so-called habitable zone for this system, defined as having surface temperatures where liquid water can exist, although it is still possible that they possess potentially habitable regions on their surfaces.
The third, outer, planet’s orbit is not yet well known, but it probably receives less radiation than the Earth does, but maybe still enough to lie within the habitable zone.
NASA’s Hubble Space Telescope and K2, the Kepler spacecraft’s second mission, will be observing TRAPPIST-1 and its planets later this year.
The new results are published in the journal Nature. | 0.89737 | 3.785118 |
Loge was discovered on March 6, 2006 by Scott S. Sheppard, David C. Jewitt and Jan T. Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii.
Loge has a mean radius of 1.9 miles (3 kilometers), assuming an albedo (a measure of how reflective the surface is) of 0.04. It orbits Saturn at an inclination of about 167 degrees and an eccentricity of about 0.2. At a mean distance of 14.3 million miles (23.0 million kilometers) from Saturn, the moon takes about 1,311 Earth days to complete one orbit.
Loge is a member of the Norse group of moons. These "irregular" moons have retrograde orbits around Saturn -- traveling around in the opposite direction from the planet's rotation. Loge and the other Norse moons also have eccentric orbits, meaning they are more elongated than circular.
Like Saturn's other irregular moons, Loge is thought to be an object that was captured by Saturn's gravity, rather than having accreted from the dusty disk that surrounded the newly formed planet as the regular moons are thought to have done.
How Loge Got its Name
Originally called S/2006 S5, Loge was named for Logi, a god who was the personification of fire in Norse mythology. He beat the trickster god, Loki, in an eating contest when he consumed not only the same amount of meat as Loki, but also the bone and the trough which held the food | 0.827884 | 3.389183 |
Moon ♑ Capricorn
Moon phase on 18 January 2072 Monday is Waning Crescent, 27 days old Moon is in Capricorn.Share this page: twitter facebook linkedin
Previous main lunar phase is the Last Quarter before 6 days on 12 January 2072 at 09:54.
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 ∠9° of ♑ Capricorn tropical zodiac sector.
Lunar disc appears visually 8.7% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1787" and ∠1950".
Next Full Moon is the Snow Moon of February 2072 after 16 days on 4 February 2072 at 04:55.
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 27 days old. Earth's natural satellite is moving from the second to the final part of current synodic month. This is lunation 890 of Meeus index or 1843 from Brown series.
Length of current 890 lunation is 29 days, 18 hours and 48 minutes. It is 41 minutes shorter than next lunation 891 length.
Length of current synodic month is 6 hours and 4 minutes longer than the mean length of synodic month, but it is still 59 minutes shorter, compared to 21st century longest.
This New Moon true anomaly is ∠138.1°. At beginning of next synodic month true anomaly will be ∠166.3°. 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°).
11 days after point of perigee on 6 January 2072 at 17:46 in ♋ Cancer. The lunar orbit is getting wider, while the Moon is moving outward the Earth. It will keep this direction for the next 3 days, until it get to the point of next apogee on 21 January 2072 at 20:00 in ♒ Aquarius.
Moon is 401 116 km (249 242 mi) away from Earth on this date. Moon moves farther next 3 days until apogee, when Earth-Moon distance will reach 406 490 km (252 581 mi).
8 days after its ascending node on 10 January 2072 at 03:26 in ♍ Virgo, the Moon is following the northern part of its orbit for the next 5 days, until it will cross the ecliptic from North to South in descending node on 24 January 2072 at 10:50 in ♓ Pisces.
8 days after beginning of current draconic month in ♍ Virgo, the Moon is moving from the beginning to the first part of it.
At 00:05 on this date the Moon is meeting its South standstill point, when it will reach southern declination of ∠-18.436°. Next 13 days the lunar orbit will move in opposite northward direction to face North declination of ∠18.364° in its northern standstill point on 1 February 2072 at 09:58 in ♋ Cancer.
After 1 day on 20 January 2072 at 06:35 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 | 3.075619 |
An international scientific team on Wednesday announced a milestone in astrophysics - the first-ever photo of a black hole - using a global network of telescopes to gain insight into celestial objects with gravitational fields so strong no matter or light can escape.
The research was conducted by the Event Horizon Telescope (EHT) project, an international collaboration begun in 2012 to try to directly observe the immediate environment of a black hole using a global network of Earth-based telescopes. The announcement was made in simultaneous news conferences in Washington, Brussels, Santiago, Shanghai, Taipei and Tokyo.
The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides about 54 million light-years from Earth.
Black holes, phenomenally dense celestial entities, are extraordinarily difficult to observe despite their great mass. A black hole's event horizon is the point of no return beyond which anything - stars, planets, gas, dust and all forms of electromagnetic radiation - gets swallowed into oblivion.
In a historic feat by @EHTelescope & @NSF, a black hole image has been captured for the 1st time. Several of our missions observed the same black hole using different light wavelengths and collected data to understand the black hole's environment. Details: https://t.co/WOjLdY76vepic.twitter.com/4PhH1bfHxc- NASA (@NASA) April 10, 2019
"This is a huge day in astrophysics," said US National Science Foundation Director France Cordova. "We're seeing the unseeable."
The fact that black holes do not allow light to escape makes viewing them difficult. The scientists look for a ring of light - disrupted matter and radiation circling at tremendous speed at the edge of the event horizon - around a region of darkness representing the actual black hole. This is known as the black hole's shadow or silhouette.
The project's researchers obtained the first data in April 2017 using telescopes in the U.S. states of Arizona and Hawaii as well as in Mexico, Chile, Spain and Antarctica. Since then, telescopes in France and Greenland have been added to the global network. The global network of telescopes has essentially created a planet-sized observational dish. | 0.886487 | 3.442861 |
It happens to all lovers of astronomy sooner or later.
I once had a friend who was excited about an upcoming conjunction of Saturn and Venus. They were passing closer than the apparent diameter of the Full Moon in the dawn sky, and you could fit ‘em both in the same telescopic field of view. I invited said friend to stop by at 5 AM the next morning to check this out. I was excited to see this conjunction as well, but not for the same reasons.
Said friend was into astrology, and I’m sure that the conjunction held a deep significance in their world view. Sure, I could have easily told them that ‘astrology is bunk,’ and the skies care not for our terrestrial woes… or I could carefully help guide this ‘at risk friend’ towards the true wonders of the cosmos if they were willing to listen.
We bring this up because this weekend, the Sun enters the constellation Ophiuchus, one of 13 modern constellations that it can appear in from our Earthly vantage point.
If you’re born from November 30th to December 18th, you could consider yourself an “Ophiuchian,” or being born under the sign of Ophiuchus the Serpent Bearer. But I’ll leave it up to you to decide what they might be like.
You might remember how the “controversy” of the 13th sign made its news rounds a few years back. Hey, it was cool to at least see an obscure and hard to pronounce constellation trending on Twitter. Of course, this wasn’t news to space enthusiasts, and to modern astronomers, a ‘house’ is merely where you live, and a ‘sign’ is what you follow to get there.
The modern 88 constellations we use were formalized by the International Astronomical Union in 1922. Like political boundaries, they’re imaginary constructs we use to organize reality. Star patterns slowly change with time due to our solar system’s motion — and that of neighboring stars —about the galactic center.
Astrologers will, of course, counter that their craft follows a tropical scheme versus a sidereal cosmology. In the tropical system, ecliptic longitude 0 starts from the equinoctial point marking the beginning of spring in the northern hemisphere, and the zodiac is demarcated by 12 ‘houses’ 30 degrees on a side.
This neatly ignores the reality of our friend, the precession of the equinoxes. The Earth’s poles do a slow wobble like a top, taking about 26,000 years to make one turn. This means that in the sidereal scheme of things, our vantage point of the Sun’s position along the zodiac against the background stars if reference to our Gregorian calendar is slowly changing: live out a 72 year lifespan, and the constellations along the zodiac with respect to the Sun will have shifted about one degree due to precession.
Likewise, the direction of the North and South Pole is changing as well. Though Polaris makes a good pole star now, it’ll become increasingly less so as our north rotational pole begins to pull away from it after 2100 A.D. To the ancient Egyptians, Thuban (Alpha Draconis) was the pole star.
Astrology and astronomy also have an intimate and hoary history, as many astronomers up until the time of Kepler financed their astronomical studies by casting royal horoscopes. And we still use terms such as appulse, conjunction and occultation, which have roots in astrology.
But the science of astronomy has matured beyond considering whether Mercury in retrograde has any connection with earthly woes. Perhaps you feel that you’re unlucky in love and have a vast untapped potential… sure, me too. We all do, and that just speaks to the universal state of the human condition. Astrology was an early attempt by humanity to find a coherent narrative, a place in the cosmos.
But the rise of the Ophiuchians isn’t nigh. Astrology relented to astronomy because of the latter’s true predictive power. “Look here, in the sky,” said mathematician Urbain Le Verrier, “and you’ll spy a new planet tugging on Uranus,” and blam, Neptune was discovered. If the planets had any true influence on us, why didn’t astrologers manage to predict the same?
Combating woo such as astrology is never simple. In the internet era, we often find tribes of the like-minded folks polarized around electronic camp fires. For example, writing ‘astrology is woo’ for an esteemed audience of science-minded readers such as Universe Today will no doubt find a largely agreeable reception. We have on occasion, however, written the same for a general audience to a much more hostile reception. Often, it’s just a matter of being that lone but patient voice of rationalism in the woods that ultimately sinks in.
So, what’s the harm? Folks can believe whatever they want, and astrology’s no different, right? Well, the harm comes when people base life decisions on astrology. The harm comes when world leaders make critical decisions after consulting astrologers. Remember, Nancy and President Ronald Reagan conferred with astrologers for world affairs. It’s an irony of the modern age that, while writing a take down on astrology, there will likely be ads promoting astrology running right next to this very page. And while professional astronomers spend years in grad school, you can get a “PhD in Astrology” of dubious value online for a pittance. And nearly every general news site has a astrology page. Think of the space missions that could be launched if we threw as much money at exploration as we do at astrology as a society. Or perhaps astronomers should revert back to the dark side and resume casting horoscopes once again?
But to quote Spiderman, “with great power comes great responsibility,” and we promise to only use our astronomical powers for good.
What astronomers want you to know is that we’re not separate from the universe above us, and that the cosmos does indeed influence our everyday lives. And we’re not talking about finding your car keys or selling your house. We’re thinking big. The Sun energizes and drives the drama of life on Earth. The atoms that make you the unique individual that you are were forged in the hearts of stars. The ice that chills our drink may well have been delivered here via comet. And speaking of which, a comet headed our way could spell a very bad day for the Earth.
All of these are real things that astronomy tells us about our place in the cosmos, whether you’re an Ophiuchian or a Capricorn. To paraphrase Shakespeare, the heavens may (seem to) blaze forth for the death of princes, but the fault lies not in the heavens, but ourselves. Don’t forget that, as James Randi says, “you’re a member of a proud species,” one loves to look skyward, and ultimately knows when to discard fantasy for reality. | 0.899916 | 3.281446 |
1994: News breaks that astronomer Alex Wolszczan has confirmed that planets are orbiting pulsar PSR B1257+12. His research appears in Science the next day.
The groundbreaking discovery came on the heels of a disaster: Wolszczan's telescope broke. He was working in early 1990 at the Arecibo Observatory in Puerto Rico (famous for its roles in films like Contact and GoldenEye), when the 1,000-foot-wide radio telescope had to be shut down for repairs. Scientists couldn't aim the telescope's receiver at particular parts of the sky for about a month. But they could still look straight up and see what was there.
Wolszczan took the opportunity to scan the sky for pulsars: the dense, spinning corpses of stars that died as supernovae. As they rotate, they sweep the sky with a beam of radio energy, so from Earth they appear to wink on and off, or "pulse." Normally the pulses are so regular, you could use them to set the most accurate atomic clock on Earth.
Not so with PSR B1257+12. This wonky cosmic clock kept unreliable time, alternately speeding up and slowing down. Wolszczan immediately suspected the presence of planets. The gravitational tug of a planet would nudge the pulsar back and forth, changing — by a few milliseconds — the time its radiation takes to reach Earth.
Finding a planet around another star was a revolutionary discovery in itself, but finding one around a pulsar was even weirder. "You couldn't imagine a worse environment to put a planet around," astronomer Dale Frail of the National Radio Astronomy Observatory said in a phone interview. Pulsars are essentially rubble from the cataclysmic explosion of an old, massive star — an explosion that would have incinerated any planets the old star might have harbored.
Wolszczan now thinks the first star had a companion, and ate it. The two stars danced around their common center of mass for a few millenniums, until the larger one exploded. Most supernova explosions begin inside the star, but slightly off-center, sending it careening through space in its death throes. Wolszczan's pulsar either rammed right into its neighbor, or came close enough to rip it apart gravitationally.
"It was like stealing part of the star and leaving the scene of the crime very quickly," Wolszczan said. The stolen stellar mass formed a disk around the cooling pulsar, which eventually coalesced into planets.
Cold, dark and constantly bombarded with radiation, pulsar planets are not friendly places for life. But the implications for finding planets around normal stars were huge. "If even in this hostile environment you can form rocky bodies in orbit, by golly, Earths must be pretty common," said Alan Boss of the Carnegie Institute of Washington, one of the first theorists to consider how extrasolar planets might form.
Of course, the pulsar's funny behavior could also have been explained by an error in measuring its position. Arecibo is great for large surveys, but it's too big to pinpoint exactly where a star is located. To be certain, Wolszczan asked Frail to use the Very Large Array, a series of 27 radio telescopes in New Mexico (itself famous as a film location for 2010 and Independence Day, among others), to calculate the pulsar's position as accurately as possible.
While they crunched the numbers, they were almost scooped. A team of astronomers led by British astronomer Andrew Lyne announced in July 1991 that they had found a planet around a pulsar. The astronomical community was agog, the media buzzed, and Wolszczan calmly continued to process his data.
"I decided, all right, he did it, I'll do my story, we'll see what happens," he said. "It was too exciting to get frustrated and throw it away."
His efforts paid off in September 1991. "I sat down in front of my computer and ran the model for the data, and got the answer that was very astonishing," he said. "Beyond any doubt there were planets."
In a dramatic turn of events, Wolszczan and Lyne were asked to give back-to-back speeches at the American Astronomical Society meeting in January 1992.
Lyne went first and shocked the thousand assembled astronomers by admitting that he'd goofed. He made exactly the sort of positioning error Wolszczan had contacted Frail to avoid. Rather than detecting the motion of an extrasolar planet, Lyne had detected the motion of the Earth.
"Everyone sucked in their breath at the same time," Frail recalled. "There was this moving gasp through the audience. And then Alex had to stand up there and give his talk."
It took another two years to confirm that the planets were really there. Ultimately, Wolszczan found three of them, one with a mass of 4.3 Earths, one of 3.9 Earths, and one just twice the mass of the moon, the least-massive extrasolar planet found to date. If they were in our solar system, they would all fit within the orbit of Mercury.
"Then all hell broke loose," Wolszczan said. "Now it's a blooming field." With hundreds of planet-hunting astronomers and telescopes on Earth and in space, we're closer than ever to finding worlds like ours.
Image: Artist's conception depicts the pulsar planet system discovered by Alex Wolszczan. Radiation would probably cause the planets' night skies to light up with auroras similar to our northern lights. One such aurora is illustrated on the planet at the bottom of the picture. (NASA/Jet Propulsion Laboratory–Caltech)
This article first appeared on Wired.com April 21, 2009.
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- April 21, 1987: Feds OK Patents for New Life Forms | 0.889207 | 3.809976 |
To reach another star system, we need a method of propulsion other than current rocket technology. Alpha Centauri, the closest star to us, is about 4.4 light years away, or about 41 trillion kilometers (or a little under 26 trillion miles). With Voyager 1—the most distant spacecraft we have ever launched—traveling at about 17 kilometers per second (38,000 mph), it would take more than 76,000 years to reach Alpha Centauri (if it were going in the right direction, which it's not).
One of the most promising propulsion methods that could take us to the stars is photonic propulsion, or using a big laser to propel a small reflective spacecraft that has already been launched into orbit. This is how Stephen Hawking and Russian billionaire Yuri Milner hope to reach Alpha Centauri in our lifetimes as part of the Breakthrough Starshot initiative.
When light reflects off a surface, the photons bounce off and transfer a small amount of energy to the object. In the frictionless vacuum of space, a sustained blast from a laser could accelerate a spacecraft to very high velocities, as much as 20 percent of the speed of light, or about 100 million mph, according to Breakthrough Starshot. This would let us reach Alpha Centauri in just 20 years. The smaller the spacecraft, the easier this would be to accomplish.
Enter KickSat-2, a project led by researchers from Cornell University that is attempting to launch some of the smallest spacecraft ever built into orbit. The "chipsats," as they are called, are spacecraft about the size of a sticky note, consisting of little more than a few basic electronics soldered onto a tiny little board. As Maddie Stone points out for Gizmodo, these are the types of spacecraft that might work for long-range photonic propulsion to Alpha Centauri. And considering that Zachary Manchester and Mason Peck, KickSat's lead engineers, sit on the advisory committee for Breakthrough Starshot, an interstellar trip might just be the long-term goal of the project.
KickSat-1 launched back in April 2014, but unfortunately, none of the "Sprites" (what the KickSat team calls their chipsats) deployed from the primary satellite that housed them all, and the whole thing burned up in Earth's atmosphere about a month later. KickSat-2 is planned for launch later this year, possibly this summer, and it will unleash 100 Sprite chipsats around the ISS to test their communications and navigation systems. The little sats will then burn up upon reentering the atmosphere.
There is reason to have faith in the technology, as three chipsats were mounted to the outside of the ISS in 2011, and the hardware stood up to the high doses of radiation. According to Gizmodo, the Sprites have a mass of four grams, and Breakthrough Starshot hopes to ultimately use nanocrafts that are just one gram each to send to the stars.
It's a long way to Alpha Centauri, metaphorically as well as physically. Sending a probe there in our lifetimes is highly ambitious and will require a host of technological advances, most notably in developing new long-range communications systems. But if the KickSat-2 mission goes smoothly, we might be one tiny step closer. | 0.819912 | 3.893662 |
The explosive death of a massive starhas broken the record for longest-lived light show. Observations from NASA's Swiftsatellite have revealed a so-called gamma-rayburst for which the afterglow remained visible for more than 125 days.
When a starthat's 10 to 25 times as massive as the Sun checks out, it can release in a matter ofseconds the same amount of energy that the sun will radiate over its10-billion-year lifetime.
Onceejected, these GRBjets slam into nearby interstellar gas, and the resulting collision generatesan intense afterglow that can radiate brightly in X-raysand other wavelengths.
Dubbed GRB060729 for the date of its discovery, the long-lived gamma-ray burst resides inthe constellation Pictor. Swift'sX-ray telescope monitored the afterglow until it faded out, a phenomenonthat typically lasts for a week or two. But the afterglow from this burststarted off so bright and faded so slowly that the telescope monitored it formonths, into late November 2006. In addition to its unprecedented brightness,the long-lived GRBis much closer to Earth than manybursts, which allowed the telescope to pick up the glow for an extended period.
Unlikeother afterglows, the long-lived one showed little drop in brightness over the125 days of observation. The prolonged light output suggests anunderlying engine that pumped energy continuously to the burst.
"Itrequires a larger energy injection than what we normally see in bursts and mayrequire continuous energy input from the central engine," said study teamleader Dirk Grupe, an astronomer of Penn State University.
The centralengine could be a magnetar,a neutron star with a mega magneticfield, the scientists suggest. The magnetic field puts the brakes on themagnetar's rotation. The energy from this spin-down could get converted into magneticenergy that flows into the initial blast wave that triggered the GRBin the first place.
Grupe'scolleague Xiang-Yu Wang, also of Penn State, calculated that this magneticenergy could power an observed afterglow for months.
Theresearch will be published in an upcoming issue of The AstrophysicalJournal.
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Winds at 0.25c spotted leaving mysterious binary systems
Posted on: Jun 30, 2016
Two black holes in nearby galaxies have been observed devouring their companion stars at a rate exceeding classically understood limits, and in the process, kicking out matter into surrounding space at astonishing speeds of around a quarter the speed of light.
The researchers, from the University of Cambridge, used data from the European Space Agency’s (ESA) XMM-Newton space observatory to reveal for the first time strong winds gusting at very high speeds from two mysterious sources of x-ray radiation. The discovery, published in the journal Nature, confirms that these sources conceal a compact object pulling in matter at extraordinarily high rates.
When observing the Universe at x-ray wavelengths, the celestial sky is dominated by two types of astronomical objects: supermassive black holes, sitting at the centres of large galaxies and ferociously devouring the material around them, and binary systems, consisting of a stellar remnant – a white dwarf, neutron star or black hole – feeding on gas from a companion star.
In both cases, the gas forms a swirling disc around the compact and very dense central object. Friction in the disc causes the gas to heat up and emit light at different wavelengths, with a peak in x-rays.
But an intermediate class of objects was discovered in the 1980s and is still not well understood. Ten to a hundred times brighter than ordinary x-ray binaries, these sources are nevertheless too faint to be linked to supermassive black holes, and in any case, are usually found far from the centre of their host galaxy.
“We think these so-called ‘ultra-luminous x-ray sources’ are special binary systems, sucking up gas at a much higher rate than an ordinary x-ray binary,” said Dr Ciro Pinto from Cambridge’s Institute of Astronomy, the paper’s lead author. “Some of these sources host highly magnetised neutron stars, while others might conceal the long-sought-after intermediate-mass black holes, which have masses around one thousand times the mass of the Sun. But in the majority of cases, the reason for their extreme behaviour is still unclear.”
Pinto and his colleagues collected several days’ worth of observations of three ultra-luminous x-ray sources, all located in nearby galaxies located less than 22 million light-years from the Milky Way. The data was obtained over several years with the Reflection Grating Spectrometer on XMM-Newton, which allowed the researchers to identify subtle features in the spectrum of the x-rays from the sources.
In all three sources, the scientists were able to identify x-ray emission from gas in the outer portions of the disc surrounding the central compact object, slowly flowing towards it.
But two of the three sources – known as NGC 1313 X-1 and NGC 5408 X-1 – also show clear signs of x-rays being absorbed by gas that is streaming away from the central source at 70,000 kilometres per second – almost a quarter of the speed of light.
“This is the first time we’ve seen winds streaming away from ultra-luminous x-ray sources,” said Pinto. “And the very high speed of these outflows is telling us something about the nature of the compact objects in these sources, which are frantically devouring matter.”
While the hot gas is pulled inwards by the central object's gravity, it also shines brightly, and the pressure exerted by the radiation pushes it outwards. This is a balancing act: the greater the mass, the faster it draws the surrounding gas; but this also causes the gas to heat up faster, emitting more light and increasing the pressure that blows the gas away.
There is a theoretical limit to how much matter can be pulled in by an object of a given mass, known as the Eddington limit. The limit was first calculated for stars by astronomer Arthur Eddington, but it can also be applied to compact objects like black holes and neutron stars.
Eddington’s calculation refers to an ideal case in which both the matter being accreted onto the central object and the radiation being emitted by it do so equally in all directions.
But the sources studied by Pinto and his collaborators are potentially being fed through a disc which has been puffed up due to internal pressures arising from the incredible rates of material passing through it. These thick discs can naturally exceed the Eddington limit and can even trap the radiation in a cone, making these sources appear brighter when we look straight at them. As the thick disc moves material further from the black hole's gravitational grasp it also gives rise to very high-speed winds like the ones observed by the Cambridge researchers.
“By observing x-ray sources that are radiating beyond the Eddington limit, it is possible to study their accretion process in great detail, investigating by how much the limit can be exceeded and what exactly triggers the outflow of such powerful winds,” said Norbert Schartel, ESA XMM-Newton Project Scientist.
The nature of the compact objects hosted at the core of the two sources observed in this study is, however, still uncertain.
Based on the x-ray brightness, the scientists suspect that these mighty winds are driven from accretion flows onto either neutron stars or black holes, the latter with masses of several to a few dozen times that of the Sun.
To investigate further, the team is still scrutinising the data archive of XMM-Newton, searching for more sources of this type, and are also planning future observations, in x-rays as well as at optical and radio wavelengths.
“With a broader sample of sources and multi-wavelength observations, we hope to finally uncover the physical nature of these powerful, peculiar objects,” said Pinto. | 0.835676 | 4.057938 |
The moon equinox begins and
This time of year is when we Celebrate the beginning of spring on Wednesday, March 20, under a supermoon, the last in a series of three and the final supermoon of 2019. The moon, which will appear bigger and brighter because of the supermoon effect, rises just hours after the spring or vernal equinox, which occurs at 5:58 p.m. Eastern Daylight Time.
The moon rises at 6:48 p.m. EDT. To catch the full effect, look toward the east horizon around sunset when the moon is still hugging the horizon. The moon turns full at 9:43 p.m. EDT.
Bigger and brighter than a typical full moon, the term “supermoon” was coined in 1979 by astrologer Richard Nolle. It’s become an increasingly more popular and media-friendly term in the decades since then.
The full moon is also known as the worm moon: For millennia, people across the world, including Native Americans in the eastern and central USA, named the months after nature’s cues. According to the Old Farmers’ Almanac, each full moon has its own name.
The sun’s new angle during the equinox will change the length of your shadow, but conditions would have to be perfect for this to happen. For example, you’d have to be standing right at the equator when the clock strikes noon to avoid casting a shadow, according to Accuweather.
How to see the ‘super worm equinox moon,’
Some of the best spots to see the moon will be on higher ground, such as Parliament Hill in Hampstead Heath, Primrose Hill and Alexandra Palace.
Ancient people used to mark the changing seasons by following the lunar months, naming the months after the features associated with that season.
The last full moon of winter is therefore called the Worm Moon because this is the time of year when earthworms start to appear after the icy ground thaws.
A supermoon happens only when a full moon aligns with the point closest to the earth in the moon’s elliptical orbit, known as the perigee.
During this time, the moon will appear 14 per cent bigger and 30 per cent brighter than usual as it reaches its closes point to Earth.
The “Worm Moon” supermoon will light up the night sky when it appears in the early hours of Thursday morning.
Coinciding with the Spring Equinox, the supermoon will mark the end of winter and the beginning of some warmer weather to come.
A few months ago
Thursday’s celestial spectacular completes the hattrick of supermoons visible in our skies over winter, with January 21 2019 seeing a “super blood moon” and February 19 2019 a “super snow moon”. | 0.811169 | 3.346559 |
A NASA space telescope has captured the most detailed photos of the Sun ever taken.
The images reveal spots on the Sun’s surface that are filled with hot plasma* strands.
The images also show that the Sun’s atmosphere is much more complex than previously thought.
They were taken by the NASA High-Resolution Coronal Imager (Hi-C) space-based telescope.
Researchers from the University of Central Lancashire in the UK, and NASA’s Marshall Space Flight Centre then studied the photos.
They found that sections of the Sun’s atmosphere previously thought to be dark or empty are actually filled with strands of hot electrified plasma.
Each strand is said to be up to almost 1 million degrees Celsius and many hundreds of kilometres long.
Scientists don’t know what created the strands.
The telescope that captured the images was carried into space on a suborbital* rocket.
It then captured an image of the Sun every second before returning to Earth.
NASA’s Dr Amy Winebarger, the telescope’s principal investigator said: “These new Hi-C images give us a remarkable insight into the Sun’s atmosphere.
“Along with (other) ongoing missions, this fleet of space-based instruments in the near future will reveal the Sun’s dynamic* outer layer in a completely new light.”
Future research will now look into how the strands are formed and what their presence means.
They could also provide a better understanding about how the Sun relates to the Earth.
University researcher Tom Williams, who worked on the Hi-C project, said it was a fascinating discovery.
“This … could better inform our understanding of the flow of energy through the layers of the Sun and eventually down to Earth itself,” he said.
“This is so important if we are to model and predict the behaviour of our life-giving star.”
Robert Walsh, professor of solar physics at the university, added: “Until now, solar astronomers have effectively been viewing our closest star in ‘standard definition’.
“The exceptional quality of the data provided by the Hi-C telescope allows us to survey a patch of the Sun in ‘ultra-high definition’ for the first time.”
The study has been published in the Astrophysical Journal.
This story was first published on The Sun and is republished with permission.
- plasma: an electrically charged form of matter that is not liquid, solid or gas but that is most like gas
- suborbital: something that reaches outer space but doesn’t go so far from Earth that it begins to orbit
- dynamic: moving or changing
- What is different or new about these photos?
- Who or what took the photos?
- How big are the strands?
- How did the telescope get into space?
- What will future research look at?
LISTEN TO THIS STORY
1. Building scientific knowledge
Scientific research, such as the photographs taken by NASA of the Sun, help humans to continually build upon our scientific knowledge. As new research is done we can confirm or reject existing theories, make new conclusions and form questions for future research.
Make a flow chart with three boxes labelled Before, Now and Future. Carefully read through the article and add more detail to your flow chart by explaining what we thought about spots on the Sun before the Hi-C photos were taken, what we now know, and what scientists are hoping to find out in the future.
Time: allow 30 minutes to complete this activity
Curriculum Links: English; Science
The words “life-giving star” are used in the news story. Write a short paragraph to explain what is meant by this.
Time: allow 10 minutes to complete this activity
Curriculum Links: English; Science
Scan through the article and see if you can locate three words that you consider to be basic, or low level. Words we use all the time and they can be replaced by more sophisticated words, words like good and said are examples of overused words.
Once you have found them, see if you can up-level them. Think of synonyms you could use instead of these basic words, but make sure they still fit into the context of the article.
Re-read the article with your new words. Did it make it better? Why/Why not?
HAVE YOUR SAY: What thing in space would you like to see close up?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors. | 0.813336 | 3.656174 |
Neutrinos faster than light?
Published: 11 October 2011 (GMT+10)
Will relativity need revising?
Headlines were buzzing with reports that neutrinos have been clocked travelling faster than light, and even more with claims like “Einstein’s theory busted by new discovery”.1 But did neutrinos really break the light speed barrier, and are there implications for creation models?
Researchers at CERN (Switzerland) generated neutrinos (see box), ghostly neutral particles, and shot them through the earth to the Gran Sasso National Laboratory (LNGS) in Italy, travelling a straight line distance of 732 km. This was the CERN neutrinos to Gran Sasso (CNGS) experiment; also called Oscillation Project with Emulsion-tRacking Apparatus (OPERA). Its aim was to observe neutrino “oscillations” between the three varieties or ‘flavours’ (see box). In particular, this experiment generated the type called ‘muon-neutrinos’, and the experimenters hoped to observe them changing into ‘tau-neutrinos’.2
But what they observed was unexpected: the neutrinos apparently arrived at the detectors 60 nanoseconds faster than light,3,4 which implied that they travelled 0.0025% faster than light, or one part in 40,000.5 This is not supposed to be possible under Einsteinian relativity. Brian Cox, the TV presenter and physicist we responded to in Doom and gloom from the BBC, said:
“If it is confirmed it will be the most important discovery in physics in at least the past 100 years. It is a very big deal, it requires a complete rewriting of our understanding of the universe … it is such an extraordinary claim that it is difficult to believe.”6
This seems like too small a difference, but it was larger than their experimental uncertainties. The researchers seemed to be very careful with their analysis. One Ph.D. physicist in Australia, John Costella, had thought their statistical analysis was wrong, but then retracted and commended the statistical analysis.7
But Costella urged some caution:
“the OPERA result—if its estimates for systematic errors withstand scrutiny, and if it is subsequently confirmed in future experiments—would arguably be the most important discovery in physics in almost a century.” [Emphasis added]
The CNGS researchers themselves were likewise commendably cautious:
“Despite the large significance of the measurement reported here and the stability of the analysis, the potential great impact of the results motivates the continuation of our studies in order to investigate possible still unknown systematic effects that could explain the observed anomaly. We deliberately do not attempt any theoretical or phenomenological interpretation of the results.”
We see here an example of what the physicist and philosopher of science Thomas Kuhn discussed in his famous book The Structure of Scientific Revolutions: that normal science is usually conducted within a framework of assumptions or a paradigm. In this case, the paradigm is Einsteinian Special and General Theories of Relativity.
Real scientists don’t tend towards a naïve falsificationism as proposed by Popper, and immediately jettison a theory because of one anomalous result. This is actually a healthy dogmatism: while no theory of science is infallible, by the same token, no single experiment is either. One report cited several skeptical scientists:
“ ‘That’s possible, but it’s far more likely that there is an error in the data. If the CERN experiment proves to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV,’ Prof Jim Al-Khalili, professor of Physics at Surrey University said according to The Telegraph.
It’s the usual story: extraordinary claims require extraordinary evidence. The theories of relativity have passed all experimental tests and predicted very important results, so it would be unreasonable to abandon it on the say-so of one experiment.
Furthermore, previous measurements of neutrino speed suggest that neutrinos travel very close to the speed of light. For example, when supernova SN 1987A was observed, the neutrino speed was observed to agree to one part in 450 million.9 Even the small difference was attributed to matter impeding light while the ghostly neutrinos barely interacted with the matter. If the neutrinos had really been travelling as fast as the experiment showed, under the usual assumption that a light year of distance requires a year of travel (which is known to be questionable10), they would have arrived over four years earlier.11 However, the CNGS experiment generated neutrinos with about a thousand times the energy of the supernova neutrinos.12 Why only those neutrinos above a certain energy should be faster-than-light is a puzzle. But some theorists have invoked a hypothetical neutrino condensate that would enable certain neutrinos to have an effective velocity above c.13 Then again, other theorists have argued against superluminal neutrinos, according to an article published after most of this article was written:
In a terse, peremptory-sounding paper posted online on September 29, Andrew Cohen and Sheldon Glashow of Boston University calculate that any neutrinos traveling faster than light would radiate energy away, leaving a wake of slower particles analogous to the sonic boom of a supersonic fighter jet. Their findings cast doubt on the veracity of measurements recently announced at CERN that clocked neutrinos going a sliver faster than light.23
Would it disprove relativity?
As shown above, the jury is still out on the experiment. However, let’s assume that the experiment is confirmed and shown to be a real occurrence. What would it mean? Well, not as much as many people think. Actually, relativity prohibits particles from accelerating past the light barrier, because the energy required would be infinite. But there are theories of faster-than-light particles called tachyons (from Greek: ταχύς tachys = fast), that would be created in their faster-than-light state. Thus they are immune from this objection. Furthermore, it is impossible for tachyons to cross the light barrier from the other side, so that part of relativity is safe: this barrier stands. The objection to tachyons is rather that they would travel backwards in time, so they would possibly allow signals to be sent to the past. This would violate the principle of causality. But then, as Dr Costella explained in another paper, antiparticles are well known, and one formulation is that they are ordinary particles travelling back in time.14 Other theorists have proposed an explanation that doesn’t violate causality.15
But more mundanely, let’s remember what happened with Newton’s laws when they met relativity and quantum mechanics. They remain extremely useful for most purposes, so are still heavily invoked. But at high speeds and high gravity, we must use relativistic equations instead, and for very low masses, quantum mechanics is required. Further, the equations of relativity must collapse to correspond with Newtonian ones at ordinary speeds—after all, they clearly work very well. Similarly, quantum mechanical equations must likewise approach those of classical physics at ordinary masses (many times that of atoms).
Similarly, it is most likely that relativity equations will still prove useful, even if we must refine them where neutrinos are concerned, maybe due to some yet-to-be discovered physics. Similarly, the previous refinement of relativity by Moshe Carmeli for galactic distances16 leaves most applications at normal distance scales untouched.
Application for creationists?
There are a few things to learn from this. One of them does NOT seem to be a solution to the distant starlight problem: the tiny difference for high-energy neutrinos does not really help; fortunately there are other ideas.10 However, when some 1970s creationist scientists proposed that light travelled much faster than today, they were attacked for their alleged ignorance that nothing could go faster than light at its current speed.17 Now plenty of scientists have no problem in theory with tachyons, and some have proposed that light was much faster in the past to rescue the big bang from its horizon problem.18
A more important one is the grip of the paradigm: creationist arguments are often ruled out of court because they contradict the ruling paradigm of evolutionary materialism. But a major difference is that scientists are free to criticize relativity, and healthy debate is regarded as healthy even by those scientists who disagree with the CNGS paper. Conversely, dissenters against evolution are routinely fired or have their grades reduced. This was documented in the movie Expelled, and in Dr Jerry Bergman’s book Slaughter of the Dissidents.
One reason for the difference is that evolution is a belief system about origins, about history, which is not open to experimental testing, whereas the speed of neutrinos is open to experimental testing.
However, the major reason for the difference is that relativity makes no ethical demands of its followers, but if creation is true, that might imply that we are accountable to our Creator! This is what prominent evolutionists don’t want. Philosopher Thomas Nagel is more candid than most:
“I want atheism to be true and am made uneasy by the fact that some of the most intelligent and well informed people I know are religious believers. It isn’t just that I don’t believe in God and naturally, hope there is no God! I don’t want there to be a God; I don’t want the universe to be like that.”19
In conclusion, this result is fascinating science, but little to do with creationist science per se, except to illustrate how scientists really work, regardless of arcane definitions of science.
What are neutrinos?
Wolfgang Pauli first proposed this particle in 1930, to explain why beta decay seemed to violate physical laws. That is, when a neutron decayed into a proton and electron (beta particle), the decay seemed to violate the laws of conservation of momentum, angular momentum and energy. To solve this problem, Pauli proposed a tiny neutral particle that Enrico Fermi later named the “neutrino”, and this carried off the observed differences in these quantities. The neutrino has the symbol ν, the Greek letter nu.
However, these neutrinos proved most elusive. Because they interact only via the short-range ‘weak nuclear force’, ordinary matter is almost transparent to them. It wasn’t until 1956 that a neutrino was detected by a similar reaction in reverse: a neutrino (extremely rarely) reacting with a proton, producing a neutron and a positron. And it was another four decades before this work was rewarded with the 1995 Nobel Prize for Physics.
Actually, later standard models of particle physics say that the above particles were anti-neutrinos, because of the Law of Conservation of Lepton number, a lepton meaning a small particle.20 Both electrons and neutrinos have lepton number +1, while antimatter equivalents positron (anti-electron) and anti-neutrino have a lepton number of –1. So when an electron is generated (+1), as in beta decay and nuclear fission, an antineutrino must be produced (–1); while positive beta decay and nuclear fusion produce positrons (–1), so also emit neutrinos (+1), so that the overall lepton number (0) is unchanged. Or in the detection reaction, an anti-neutrino (–1) plus proton makes a neutron plus positron (–1).
Then other leptons besides electrons were discovered: the mu particle (muon μ) and tau particle (tauon τ)—heavier and very unstable versions of the electron. It turned out that they had their own antineutrino counterparts as well.
For a long time, standard models of particle physics argued that the neutrinos had precisely zero rest mass, so should travel at precisely the speed of light, c. This raised a problem for theories of the sun’s energy output: if nuclear fusion were the only source of power, then it was producing only a third of the number of neutrinos— the ‘Solar Neutrino Problem’. But it seemed to be solved by evidence that neutrinos can ‘oscillate’ between the three ‘flavours’: electron-neutrino, muon-neutrino and tau-neutrino.21 But this required that neutrinos have some mass, contrary to standard models. The most recent estimates of the combined mass of the three varieties is less than 0.28 eV (electron volts).22 To put this into perspective, an electron is two million times heavier with 0.511 MeV, while a proton is 1836 times more massive than an electron at 938 MeV
The OPERA experiment was actually designed to observe neutrino oscillation, as the name suggests. It generated beams of muon-neutrinos that were sent through the earth, and hoping that some would change into tau-neutrinos, which would then interact with a neutron and produce a proton plus tauon. This tauon would give a distinctive signal.
- Particles seen to travel faster than light, www.news.com.au, 23 September 2011. Return to text.
- CNGS – CERN neutrinos to Gran Sasso: On the track of particle ‘chameleons’, public.web.cern.ch, 2008. Return to text.
- Adam, T. et al., Measurement of the neutrino velocity with the OPERA detector in the CNGS beam, static.arxiv.org/pdf/1109.4897.pdf, accessed 29 September 2011. Return to text.
- A useful account comes from a NASA engineer, Laughlin B., Neutrinos and the Speed of Light — A Primer on the CERN Study, wired.com, 26 September 2011. Return to text.
- The time difference was (60.7 ± 6.9 (stat.) ± 7.4 (sys.)) ns, implying that the fractional difference between neutrino speed and light speed (v − c)/c = (2.48 ± 0.28 (stat.) ± 0.30 (sys.))×10−5 or 0.00248%. Return to text.
- Nair, D., Particles Faster-Than-Light: Most Embarrassing Claim of Modern Science Ever? ibtimes.com, 24 September 2011. Return to text.
- Costella, J.P., Why OPERA’s claim for faster-than-light neutrinos is not wrong, johncostella.wordpress.com/, 25 September 2011. Return to text.
- Nair, op. cit. Return to text.
- Adam et al., op. cit. provide the following references: Hirata, K. et al., Phys. Rev. Lett. 58:1490, 1987; Bionta, R.M. et al., Phys. Rev. Lett. 58:1494, 1987; Longo, M.J., Phys. Rev. D 36:3276, 1987. Return to text.
- Big bang advocates know full well that it is not, since they have their own Horizon Problem. See Creation Answers Book ch. 5: How can we see distant stars in a young universe? Return to text.
- SN 1987A is 168,000 light years away; 168,000 × 2.48×10−5= 4.2 years. Return to text.
- 17 GeV vs. 10 MeV. Return to text.
- Mann, R.B. and Sarkar, U., Superluminal neutrinos at the OPERA? arxiv.org/PS_cache/arxiv/pdf/1109/1109.5749v1.pdf, 27 September 2011: “It is natural to ask why neutrinos are different from other particles. One reason emerges from the observation that if neutrinos form condensates to explain the cosmological constant [ref.], background neutrino condensate dark energy can, in principle, affect the dynamics of the neutrinos compared to other particles. For example, a νµ with momentum p can collide with a condensate [anti-]νµ−νµ pair and bind with the [anti-]νµ. The liberated νµ, located at a distance x away from its condensate partner, will continue with momentum p due to momentum conservation. As this process is repeated, the net effect is that the νµ “hops” through the condensate at an effective speed greater than unity, resulting in a different maximum attainable velocity for the neutrinos. Since no other particles couple to the νµ, they do not experience this effect.” Return to text.
- Costella, J.P., Do OPERA’s tachyonic neutrinos make sense? johncostella.wordpress.com/, 27 September 2011. Return to text.
- Mann and Sarkar, op. cit.: We argue that the recent measurement of the neutrino velocity to be higher than the velocity of light could be due to violation of Lorentz invariance by the muon neutrinos. This result need not undermine special-relativistic foundational notions of causality. Return to text.
- Hartnett, J., A 5D spherically symmetric expanding universe is young, J. Creation 21(1):69–74, 2007; Has ‘dark matter’ really been proven? Clarifying the clamour of claims from colliding clusters, 8 September 2006. Return to text.
- There are problems, but this is not one of them. See for example Wieland, C., Speed of light slowing down after all? Famous physicist makes headlines, J. Creation 16(3):7–10, 2002; creation.com/cdk. Return to text.
- Albrecht, A. and Magueijo, J., Time varying speed of light as a solution to cosmological puzzles, Physical Review D (Particles, Fields, Gravitation, and Cosmology) 59(4):043516-1–043516-13, 1999; Magueijo, J., Faster Than The Speed of Light: The Story of a Scientific Speculation. Basic Books, 2003. They propose that light was 60 orders of magnitude faster in the very early stages of the big bang. Return to text.
- Nagel, T., The Last Word, Oxford University Press, New York, 1997, p. 130. Return to text.
- The word originally referred to a small coin. The ‘widow’s mite’ mentioned in Mark 12:42 would have been a lepton. See Cardno, S. and Wieland, C., Clouds, coins and creation: An airport encounter with professional scientist and creationist Dr Edmond Holroyd, Creation 20(1):22–23, 1997; creation.com/holroyd. Return to text.
- Lisle, J., ‘Missing’ neutrinos found! No longer an ‘age’ indicator, J. Creation 16(3):123–125, 2002; creation.com/neutrinos. Return to text.
- “Neutrinos are likely half as massive as previous estimates suggested”, sciencedaily.com, 12 July 2010. Return to text.
- Castelvecchi, D., Superluminal Neutrinos Would Wimp Out En Route, blogs.scientificamerican.com, 2 October 2011. Return to text. | 0.818642 | 3.819899 |
Moon ♉ Taurus
Moon phase on 28 October 2023 Saturday is Full Moon, 14 days old Moon is in Taurus.Share this page: twitter facebook linkedin
Moon rises at sunset and sets at sunrise. It is visible all night and it is high in the sky around midnight.
Moon is passing first ∠0° of ♉ Taurus tropical zodiac sector.
Lunar disc appears visually 0.3% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1925" and ∠1931".
The Full Moon this days is the Hunter of October 2023.
There is high Full Moon ocean tide on this date. Combined Sun and Moon gravitational tidal force working on Earth is strong, because of the Sun-Earth-Moon syzygy alignment.
The Moon is 14 days old. Earth's natural satellite is moving through the middle part of current synodic month. This is lunation 294 of Meeus index or 1247 from Brown series.
Length of current 294 lunation is 29 days, 15 hours and 32 minutes. It is 1 hour and 27 minutes longer than next lunation 295 length.
Length of current synodic month is 2 hours and 48 minutes longer than the mean length of synodic month, but it is still 4 hours and 15 minutes shorter, compared to 21st century longest.
This lunation true anomaly is ∠232.5°. At the beginning of next synodic month true anomaly will be ∠269.5°. 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°).
2 days after point of perigee on 26 October 2023 at 02:53 in ♓ Pisces. The lunar orbit is getting wider, while the Moon is moving outward the Earth. It will keep this direction for the next 9 days, until it get to the point of next apogee on 6 November 2023 at 21:49 in ♌ Leo.
Moon is 372 341 km (231 362 mi) away from Earth on this date. Moon moves farther next 9 days until apogee, when Earth-Moon distance will reach 404 569 km (251 388 mi).
Moon is in ascending node in ♈ Aries at 03:14 on this date, it crosses the ecliptic from South to North. Moon will follow the northern part of its orbit for the next 13 days to meet descending node on 11 November 2023 at 08:49 in ♎ Libra.
At 03:14 on this date the Moon is completing its previous draconic month and is entering the new one.
8 days after previous South standstill on 20 October 2023 at 09:19 in ♑ Capricorn, when Moon has reached southern declination of ∠-28.305°. Next 4 days the lunar orbit moves northward to face North declination of ∠28.288° in the next northern standstill on 2 November 2023 at 05:12 in ♋ Cancer.
The Moon is in Full Moon geocentric opposition with the Sun on this date and this alignment forms Sun-Earth-Moon syzygy. | 0.860247 | 3.044638 |
Astronomers that use the NASA/ESA Hubble Space Telescope have found an unexpected thin disc of a specific material that is circling a supermassive black hole in the center of the spiral galaxy NGC 3147. It is placed 130 million light-years away.
The presence of this black hole disc in a low-lighted active galaxy has surprised many astronomers. Black holes in particular types of galaxies, like NGC 3147 are thought to be starving because there is not sufficient gravitationally captured material that can feed them regularly. So we are talking about a thin disc that’s circling a black hole that’s starving, which is quite similar to the larger disks that are found in other galaxies. How is this now surprising?
This is a once-in-a-lifetime opportunity for us.
The disc from this material represents a once-in-a-lifetime opportunity to test Albert Einstein’s theories of relativity. The disc is so embedded in the gravitational field of the black hole that the light that comes from the gas disc is actually altered. According to astronomers, this is how astronomers can find out more about the dynamic processes that are close to a black hole. They said that they have never seen the effects of general and special relativity when it comes to the visible light. Everything is so much clearer now.
Hubble measured the disc. It roams around the black hole at more than 10% of the speed of light. At this kind of velocity, the gas seems to be brighter, and it is even more when it travels towards Earth. It dims when it speeds away from our planet to the next one. This is called relativistic beaming. The data found by Hubble also shows that the gas exists so deep in a gravitational field, that the light is actually struggling to escape. This is the reason why the light appears to be stretched to redder wavelengths. | 0.853295 | 3.705503 |
Seventy-two unusual cosmic events have astronomers scratching their heads.
Scientists conducting a survey for supernovas — the dramatic explosions that end the lives of massive stars — noticed 72 powerful flashes of light. The mysterious emissions were similar in brightness to supernovas, but they evolved much more rapidly, so their exact nature is unclear.
The 72 light sources appeared in the Dark Energy Survey Supernova Program (DES-SN), which uses a large camera on a 13-foot (4 meters) telescope at the Cerro Tololo Inter-American Observatory in the Chilean Andes. The DES-SN is designed to help probe the nature of dark energy by measuring the expansion of the universe. While surveying the sky, it captures images of changing, or transient, events, including supernova candidates, which scientists follow up on. [Supernova Photos: Great Images of Star Explosions]
“The DES-SN survey is there to help us understand dark energy, itself entirely unexplained,” lead author Miika Pursiainen, of the University of Southampton in England, said in a statement. “That survey then also reveals many more unexplained transients than seen before.”
Pursiainen presented the collection of 72 very bright, but quick events il ) at the European Week of Astronomy and Space Science conference in Liverpool, England. He and his collaborators are still trying to understand the unusual events.
At the end of a massive star’s life, after nuclear-fusion activities stop, heavy elements build up at the star’s core. Eventually, the core grows so heavy that the star implodes and its outer shell is blown off in a violent type II supernova. (Another famous kind of supernova, called type 1a, involves a stellar corpse known as a white dwarf siphoning material from a companion star until the dwarf passes a mass threshold, triggering a runaway nuclear reaction.)
The newly spotted phenomena have a similar maximum brightness to different types of supernovae, but they are visible for shorter timescales, ranging from a week to a month. In contrast, true supernovae can linger in the sky for several months. The 72 events are hot, with temperatures ranging from 18,000 to 54,000 degrees Fahrenheit (10,000 to 30,000 degrees Celsius), and they’re up to 9.3 billion miles (15 billion kilometers) wide.
Astronomers still aren’t certain how these unusual episodes occur. Some stars shed material before they explode as supernovas. In the most extreme cases, shrouds of that material could completely envelop exploding stars. Energy from the supernova could then heat the surrounding material to very high temperatures, and then astronomers may see only the illuminated envelope rather than the exploding star. This scenario may explain the newly observed 72 events, but confirming it requires further research, the study team members said.
The team said it plans to continue hunting for transients, then estimate how often they occur compared with more-routine supernovas.
“If nothing else, our work confirms that astrophysics and cosmology are still sciences with a lot of unanswered questions,” Pursiainen said. | 0.8587 | 4.017772 |
Astronomers spot enormous twin stars heading for a cataclysmic end
ESO astronomers havediscovered a pair of enormous stars, known as an overcontact binarysystem, that orbit so close to each other that a bridge of stellarmaterial has formed. Scientists predict that at some point, thestrange partnership will end in spectacular fashion, with the stellarbodies either merging to create a single titanic star, or in aviolent supernova, that would birth a binary black hole system.
Situated in theTarantula Nebula around 160,000 light-years distant from Earth, VFTS352 is unusual for a number of reasons. For one, the O-type stars that form the system are the most massive everdiscovered, boasting a combined mass the equivalent of 57 Suns, and asurface temperature of around 40,000 ºC (72,032 ºF), making it thehottest overcontact binary system ever discovered. But mostintriguingly, the stars are almost identical in size.
It has been observed inthe past that when O-type stars orbit close enough for a bridge toform, that one of the bodies is significantly larger than the other,resulting in the smaller body siphoning material off of itscompanion, essentially becoming a "vampire star." But inthe case of VFTS 352, the mass of both O-trype stars is incrediblysimilar, meaning that they share around30 percent of their mass in a roughly even manner, so far as we cantell from telescopic observations.
Based on previousobservations of similar binary systems, this stage in the life of thestellar twins is likely to be short-lived, at least in cosmic terms. In time, the close proximity of the stars may result in them mergingto form a single enormous stellar body. In this scenario, the vast,rapidly spinning star would most probably end its life in anenergetic explosion known as a long-duration gamma-ray burst.
The second possibility,predicated on a mixing of material between the two stars interiorsvia powerful tidal forces, would see the stellar bodies explode intwin supernovae, creating a binary system of black holes – anevolutionary path that would exist outside of standard stellarevolution predictions.
A paper on the findingshas been published online in the Astrophysical Journal.
Scroll down to see an animation of the binary system VFTS 352. | 0.898802 | 3.684867 |
A new radio wave technique makes what was otherwise invisible, visible.
As modern science steers humanity through the dark corridors of the cosmos, radio waves can serve as a guide for mapping some of our galaxy's darker spots, according to a technique developed by Farhad Zadeh, a professor of physics and astronomy at Northwestern University.
Zadeh has developed a technique utilizing radio waves to locate and identify dusty stars and clouds in our Milky Way galaxy. The use of radio waves allows for the identification of dark galactic features that would not be caught by other spectra, such as X-rays, infrared and optical light.
"The concept is very simple. You have a big bath of radiation from stars or galaxies and you just put a cold gas, cold cloud in it, just punch it through. So what happens is that when you look at it, you have less radiation coming when there is cold gas and you see more outside of it," Zadeh said.
Zadeh earned his doctorate in radio astronomy from Columbia University in 1986. He has been studying the distribution of radio emission in the nucleus region of our galaxy for about 20 years. He presented his findings on Jan. 8 at a meeting of the American Astronomical Society in Long Beach, Calif.
"[When] you do radio interferometry (a branch of radio astronomy) . it creates an artifact, and these artifacts have to be accounted for," Zadeh said. These artifacts show up on the image as dark, he said. "It is generally very obvious whenever you see a dark feature that it is an artifact of the image, an artifact of 'cleaning the image' itself as radio astronomers call it." An artifact is a product of image construction that does not actually exist in reality.
Doyal Harper, a professor in the Department of Astronomy and Astrophysics at the University of Chicago, explained the advantage of interferometry for radio astronomers. "[Interferometry] allows you to get much more detailed pictures . that can show the structure of often complex regions where this star formation is occurring."
After further inspecting these images, Zadeh realized that these dark features were not just artifacts. They were something else.
"In the last couple of years I've realized that actually there's something there, it's unusual," he said. After inspecting the images using different radio maps, Zadeh noticed that these dark features coincided almost exactly with very cold molecular clouds, like "a hand in a glove."
Zadeh described the discovery process as a slow one, but he found himself excited about having discovered something new. Eventually, he came to understand its significance. "You see something and say 'Oh well hmm, do we see more of these clouds?' And you just look more . you say 'oh wow look at this, and look at this, look at this.' I found six, seven different types of clouds, all showing the same structure."
What at first may have been a coincidence required further data collection in order to establish the hand in a glove correlation. Zadeh acquired more and more data before reaching two conclusions: the dark structures he observed were in fact real (that is, not mere artifacts) and that there were dense clouds of gas sitting in these dark, cold spots not visible in other spectra of electromagnetic radiation. Similarly, Zadeh more recently found an analogous relationship between such dark areas and dusty stars. As such, these dark clouds and stars are referred to as "radio dark" clouds and stars.
"Good scientists are always suspicious at first," Zadeh said, laughing. "And then when they get excited it's always good also."
Harper works mostly with the far infrared radition, which is between visible light and radio (in terms of wavelength) on the electromagnetic spectrum. However, one of his primary research interests is dense regions where young stars are forming, "exactly the kind of region that [can be] studied using this technique," Harper said.
We know where a lot of star-forming regions in our own galaxy are, but it's difficult to study them in great detail because of their great distance from Earth, Harper noted.
This technique, however, also opens doors for the study of space beyond our galaxy. "[This] also opens up the opportunity of isolating particular molecular clouds in distant galaxies, things that are much farther away than the star-forming regions in the Milky Way," Harper said.
Zadeh is also currently studying whether these dark features are in fact pointing toward a black hole -a dense body in space from which nothing can escape- and if the holes are pulling some of this galactic dust to it, in a sense "feeding" it.
Zadeh will be giving a public talk at 7 p.m. Feb. 8 at the Adler Planetarium on the black hole at the center of our galaxy, also known as Sagittarius A*. He stressed the importance of communication between the astronomical community and the general public, adding that he enjoyed opportunities to speak with so called "amateur astronomers."
"I love these public talks because you talk for an hour and people are really interested in the science but they're not professionals," Zadeh said. "They are people who are just interested in astronomy." | 0.844813 | 3.929818 |
How’s your bank account doing these days? If you’re feeling a bit panicked — or, you know, hyperventilating constantly — with second term’s tuition deadline just a few months away, you were probably thrilled about recent news from a galaxy far, far away.
Nope, we’re not talking about Star Wars. On October 16, 2017, astronomers from the Laser Interferometer Gravitational-Wave Observatory announced that they had detected the collision of two neutron stars 130 million light-years away in the galaxy NGC 4993.
More importantly, upon further analysis of the data, astronomers determined that the merger of these two neutron stars smashed particles together fast enough to create nearly 300 septillion kilograms of gold.
If someone were able to bring it all back to Earth, this amount of gold would be worth about 100 octillion dollars today. That’s $100,000,000,000,000,000,000,000,000,000.
Feeling desperate enough to try gold digging in galaxy NGC 4993?
We understand the temptation. NGC 4993 — with that much gold and a roll-off-the-tongue name, who wouldn’t want to make the trip? But please, don’t.
Although this detection of gravitational waves paves the way for a new age of gravitational-wave astronomy and new ways to find answers to our biggest cosmological questions, you’ll probably die trying to get to NGC 4993 on a student budget.
Let’s talk about what it would take to make the 130 million light year journey. Getting down to the nitty gritty of interstellar travel, we have a few options.
The most viable option for intergalactic gold retrieval would be the use of a solar sail. A solar sail works by absorbing the energy from photons emitted by sun or some other powerful radiation source. These sails can hypothetically harness the energy from solar winds to travel up to about ten per cent the speed of light or just over one million kilometres per hour.
In May 2010, the Japanese Aerospace Exploration Agency launched IKAROS, an interplanetary spaceship that has been bouncing around the solar system powered only by the power of the sun. In December 2010, IKAROS passed by Venus after only six and a half months of space travel.
In order make it all the way to NGC 4993, you would need a solar sail approximately 10 million times larger than IKAROS, which could cost upwards of 800 billion dollars to produce. In order to get this sail moving at high enough speeds, you could boost your solar sail with a giant laser powered by massive nuclear fusion generators.
Building these nuclear reactors would only cost about two trillion dollars — pretty cheap compared to your investment return on the retrieved gold. The last limiting factor that stands in the way of payday is time. At ten per cent the speed of light it would take about 2.6 billion years to make the trip.
If you somehow launch the most successful Kickstarter campaign in history and also manage to extend your lifetime to half the age of planet Earth, then congratulations, you can make it to NGC 4993 and can claim 300 septillion kilograms of gold for yourself.
Now it’s up to you to figure out how to bring it all back.
Gabriel Robinson-Leith is a first year engineering student with a passion for travel and the outdoors. | 0.884745 | 3.539136 |
Artist’s impression of the dust belts around Proxima Centauri
This artist’s video impression shows how the newly discovered belts of dust around the closest star to the Solar System, Proxima Centauri, may look. ALMA observations revealed the glow coming from cold dust in a region between one to four times as far from Proxima Centauri as the Earth is from the Sun. The data also hint at the presence of an even cooler outer dust belt and indicate the presence of an elaborate planetary system. These structures are similar to the much larger belts in the Solar System and are also expected to be made from particles of rock and ice that failed to form planets.
Note that this video is not to scale — to make Proxima b clearly visible it has been shown further from the star and larger than it is in reality.Credit:
About the Video
|Release date:||3 November 2017, 12:00|
|Frame rate:||30 fps| | 0.800104 | 3.156362 |
Scientists have processed 400 gigabytes of data a second as they tested data pipelines for the Square Kilometre Array (SKA) telescope.
Researchers from ICRAR in Perth, Oak Ridge National Laboratory in the US and Shanghai Astronomical Observatory in China used the world’s most powerful supercomputer–Summit–to process simulated observations of the early Universe ahead of the radio telescope being built in Western Australia and South Africa.
The data rate achieved was the equivalent of more than 1600 hours of standard definition YouTube videos every second.
Professor Andreas Wicenec, the director of Data Intensive Astronomy at the International Centre for Radio Astronomy Research (ICRAR), said it was the first time radio astronomy data has been processed on this scale.
“Until now, we had no idea if we could take an algorithm designed for processing data coming from today’s radio telescopes and apply it to something a thousand times bigger,” he said.
“Completing this test successfully tells us we’ll be able to deal with the data deluge of the SKA when it comes online in the next decade.
“But, the fact that we need the world’s biggest supercomputer to run this test successfully shows the SKA’s needs exist at the very edge of what today’s supercomputers are capable of delivering.”
The billion-dollar SKA is one of the world’s largest science projects, with the low frequency part of the telescope set to have more than 130,000 antennas in the project’s initial phase, generating around 550 gigabytes of data every second.
Summit is located at the US Department of Energy’s Oak Ridge National Laboratory in Tennessee.
It is the world’s most powerful scientific supercomputer, with a peak performance of 200,000 trillion calculations per second.
Oak Ridge National Laboratory software engineer and researcher Dr Ruonan Wang, a former ICRAR PhD student, said the huge volume of data used for the SKA test run meant the data had to be generated on the machine itself.
“We used a sophisticated software simulator written by scientists at the University of Oxford, and gave it a cosmological model and the array configuration of the telescope so it could generate data as it would come from the telescope observing the sky,” he said.
“Usually this simulator runs on just a single computer, generating only a small fraction of what the SKA would produce.
“So we used another piece of software written by ICRAR, called the Data Activated Flow Graph Engine (DALiuGE), to distribute one of these simulators to each of the 27,648 graphics processing units that make up Summit.
“We also used the Adaptable IO System (ADIOS), developed at the Oak Ridge National Laboratory, to resolve a bottleneck caused by trying to process so much data at the same time.”
The test run used a cosmological simulation of the early Universe at a time known as the Epoch of Reionisation, when the first stars and galaxies formed and became visible.
Professor Tao An of the Shanghai Astronomical Observatory said the data was first averaged down to a size 36 times smaller.
“The averaged data was then used to produce an image cube of a kind that can be analysed by astronomers,” he said.
“Finally, the image cube was sent to Perth, simulating the complete data flow from the telescope to the end-users.”
Construction of the SKA is expected to begin in 2021.
Dr Andreas Wicenec (ICRAR / The University of Western Australia)
Ph: +61 8 6488 7847 E:
Professor Peter Quinn (ICRAR / The University of Western Australia)
Ph: +61 8 6488 4553 E:
Pete Wheeler (Media Contact, ICRAR)
Ph: +61 423 982 018 E:
This part of information is sourced from https://www.eurekalert.org/pub_releases/2019-10/icfr-wfs102219.php | 0.822883 | 3.093227 |
The extreme altitude poses something of a problem in explaining the features: it is far higher than where typical clouds of frozen carbon dioxide and water are thought to be able to form in the atmosphere.
Indeed, the high altitude corresponds to the ionosphere, where the atmosphere directly interacts with the incoming solar wind of electrically charged atomic particles.
Speculation as to their cause has included exceptional atmospheric circumstances, auroral emissions, associations with local crustal anomalies, or a meteor impact, but so far it has not been possible to identify the root cause.
Unfortunately, the spacecraft orbiting Mars were not in the right position to see the 2012 plume visually, but scientists have now looked into plasma and solar wind measurements collected by Mars Express at the time.
They have found evidence for a large ‘coronal mass ejection’, or CME, from the Sun striking the martian atmosphere in the right place and at around the right time.
“Our plasma observations tell us that there was a space weather event large enough to impact Mars and increase the escape of plasma from the planet’s atmosphere,” says David Andrews of the Swedish Institute of Space Physics, and lead author of the paper reporting the Mars Express results.
“But we were not able to see any signatures in the ionosphere that we can categorically say were due to the presence of this plume.
“One problem is that the plume was seen at the day–night boundary, over a region of known strong crustal magnetic fields where we know the ionosphere is generally very disturbed, so searching for ‘extra’ signatures is rather challenging.”
To go further, the scientists have looked at the chances of these two relatively rare events – a large and fast CME colliding with Mars, and the mysterious plume – occurring at the same time.
They have been searching back through the archives for similar events, but they are rare.
For example, the Hubble Space Telescope observed a similar high plume in May 1997, and a CME was registered hitting Earth at the same time.
Although that CME was widely studied, there is no information from Mars orbiters to judge the scale of its impact at the Red Planet.
Similarly, CMEs have been detected at Mars without any associated plume being reported, although changes in distance and visibility of Mars from Earth makes it difficult to acquire good ground-based images at all times.
“The jury is still out as to what physics is at play here, but given the altitude of the plume, we think that plasma interactions must be important,” says David.
“One idea is that a fast-travelling CME causes a significant perturbation in the ionosphere resulting in dust and ice grains residing at high altitudes in the upper atmosphere being pushed around by the ionospheric plasma and magnetic fields, and then lofted to even higher altitudes by electrical charging.
“This could lead to a plume effect that is significant enough to be detected from Earth by astronomers.”
“A number of processes could be responsible, but if these plumes are indeed driven by space-weather disturbances, this adds an important angle to our understanding of how Mars may have lost much of its atmosphere in the past, changing from a warm, wet world and becoming the cold, dry, dusty place it is today,” says Dmitri Titov, Mars Express project scientist.
“The plume also emphasises the scientific potential for continuous monitoring of Mars by both orbiters and ground-based observatories. In particular, we are now going to use the webcam on Mars Express for more frequent coverage of the planet.”
Plasma observations during the Mars atmospheric “plume” event of March–April 2012”, by D. Andrews et al has been accepted for publication in the Journal of Geophysical Research.
The measurements were conducted by the Mars Express Analyzer for Space Plasmas and Energetic Atoms (ASPERA-3) plasma instrument suite and the Mars Advanced Radar for Sub-Surface and Ionospheric Sounding (MARSIS).
You have used up your free articles for this month. To continue reading click here to login or subscribe. | 0.879288 | 4.034927 |
“Paradox created by misinterpreting cosmological redshift as Doppleresque waveform decompression.”
Hubble ST: The Galactic Field
The ‘Accepted’ Explanation
When we look at very distant objects in space, the light that we see is always to some degree more “red” than it should be. That is to say, the wavelength of the light is longer than expected for the type of galaxy or quasar being observed.
A similar phenomenon occurs when a car drives by with its horn blaring.
As the car approaches us, the sound waves created by the horn are compressed due to the motion of the car coming toward us; i.e. the wavelengths of the sound waves are shorter and the frequency of the sound increases. But, as the car passes by, the waves decompress and the frequency of the sound drops to a lower pitch. The faster the car is traveling, the greater the effect.
The same principle is used in various Doppler Radar devices (though using microwaves instead of sound waves); to measure the radial velocity of storm systems; to find planets orbiting other stars; or to catch you exceeding the highway speed limit.
In space, when a star within our own galaxy (the Milky Way) is moving away from us, the wavelength of its light also decompresses, causing blue light to appear more green (moving toward the redder end of the spectrum). Yellow light becomes more orange. Red light drops into the infrared range.
Within our galaxy, there are examples of both blueshift (object approaching) and redshift (object receding), depending upon the motion of the observed stars relative to our own position. But, when viewing objects outside our galaxy, light waves are predominantly shifted from blue to red. This would seem to indicate that virtually every other galaxy in the universe is moving away from us. These observations ultimately gave rise to the notion of the expanding universe, an idea which then became responsible for initiating the concept of the Big Bang.
By measuring how “redshifted” the light from a distant galaxy is, a determination can be made about the speed at which the observed galaxy is receding from us. Edwin Hubble proposed that the distance to a faraway object is proportional to the speed at which it is receding from our position. In other words, the further away the observed object, the faster it’s moving away from us.
This created some problems initially, since some galaxies (based on “Hubble’s Law”) appeared to be flying away from us at velocities greater than the speed of light; i.e. faster than the universal “speed limit” will permit [strictly enforced]. That misperception was remedied by invoking a relativistic requirement for very distant objects; i.e. when matter is moving at a very rapid rate, the passage of time (for that object) moves relatively more slowly. Though this resolved the problem of galaxies appearing to travel even more quickly than light, it still leaves us with the unlikely conclusion that a few galaxies (very far away from us) seem to be moving at something close to 90% of the speed of light.
So, “dark energy” was theoretically proposed to be the driving force behind the incredibly-rapid, but logically-deducible, expansion of the universe.
An Alternative (Heretical) View
The simplest solution often being the best, let’s look at cosmological redshift in a completely different way.
In classical mechanics, when an object moves at a given velocity between one point and another, that object has momentum, which is the product of its speed and its mass. Since light has no mass, it is commonly believed that light must have no true momentum. However, if we accept that light does have a special kind of momentum, which we can call effective momentum, then we can see its waveforms in a whole new “light”.
When blue light (having a short wavelength) passes through our atmosphere, it scatters more than red light (with its longer wavelength) does. The blue light can be said to be more materially interactive. Similarly, when discussing light refraction, as through the medium of a prism, blue light bends more than red light. The shorter the wavelength of the light, the greater the refraction. In response to a source of strong gravity, shorter wavelength (bluer) light reacts more like a material particle, its trajectory being altered by the gravity source more than its longer wavelength (redder) cohorts; though, to the observer, the light will become bluer or redder depending upon whether the observer is standing closer to–or further away from–the gravity source.
If bluer light displays more mass-like properties (is more materially interactive), then it can also be considered to have a higher effective momentum even though it has no true mass.
If we take the next step and view cosmological redshift (the reddening of light over the vast intergalactic distances) as the result of light’s declining effective momentum, then we would not be required to accept that some galaxies are zipping away from us at speeds perilously close to that of light.
Though the speed of light remains constant, the energy density at the observed wavefront declines according to the inverse square law. Energy being equatable with mass, this leads to a degradation of light’s effective momentum along with a corresponding transformation of the waveform to a lower frequency / longer wavelength.
Light is supremely efficient. It always finds the shortest route in its journey between two points – which is often not a straight line, owing to the way that gravitational influences curve space and flex time. At the primary origin (source) of light’s emanation, its waveforms are a model of efficiency, being integrally dependent upon the energy output of the process that creates them. High energy reactions emit short (high density) waveforms; e.g. gamma rays or x-rays. Low energy reactions emit longer (lower density) waveforms; e.g. microwaves or radio waves.
As light travels over extreme distances, its energy density declines and its effective momentum falls, which leads to a naturally contingent change in the waveform’s signature. (Think Planckian locus.) And, because light never completely loses its momentum (unless it stops being light), wavelengths will gradually grow (and redden) until they eventually fall below perceptible limits.
Of course, taken to its logical end, this means that there actually was no “Big Bang” and that the universe is not expanding — though it may very well be oscillating.
But maybe we should leave that discussion for another time… | 0.85665 | 4.104029 |
ann14059 — Mededeling
ALMA Pinpoints Pluto to Help Guide New Horizons Spacecraft
6 augustus 2014
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) are making high-precision measurements of Pluto's location and orbit around the Sun to help NASA’s New Horizons spacecraft accurately home in on its target when it nears Pluto and its five known moons in July 2015.
Though observed for decades with telescopes here on Earth and in space, astronomers are still working out Pluto’s exact orbit around the Sun. This lingering uncertainty is due to Pluto’s great distance from the Sun (approximately 40 times farther out than the Earth) and the fact that we have been studying it for only about one-third of its orbit. The dwarf planet was discovered in 1930 and takes 248 years to complete one orbit around the Sun.
“With these limited observational data, our knowledge of Pluto’s position could be wrong by several thousand kilometres, which compromises our ability to calculate efficient targeting manoeuvres for the New Horizons spacecraft,” said Hal Weaver, the New Horizons project scientist and a member of the research staff at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, USA.
The New Horizons team made use of the ALMA positioning data, together with newly analysed visible light measurements stretching back nearly to Pluto's discovery, to determine how to perform the first such scheduled course correction for targeting in July.
To prepare for these important milestones, astronomers need to pinpoint Pluto’s position using the most distant and most stable reference points possible. Finding such a reference point to accurately calculate trajectories of such small objects at such great distances is very challenging. Normally, distant stars are used by optical telescopes since they change position only slightly over many years. For New Horizons, however, even more precise measurements were necessary to ensure its encounter with Pluto is as on-target as possible.
The most distant and most apparently stable objects in the Universe are quasars — very remote galaxies with brilliant nuclei. Quasars, however, can appear very dim to optical telescopes, making accurate measurements difficult. But, due to the supermassive black holes in their centres as well as emission from dust, they are bright at radio wavelengths, particularly the millimetre wavelengths that ALMA can see.
“The ALMA astrometry used a bright quasar named J1911-2006 with the goal to cut in half the uncertainty of Pluto's position,” said Ed Fomalont, an astronomer with the National Radio Astronomy Observatory in Charlottesville, Virginia, and currently assigned to ALMA’s Operations Support Facility in Chile.
ALMA was able to study Pluto and Charon by picking up the radio emission from their cold surfaces, which are at about -230 degrees Celsius.
The team first observed these two icy worlds in November 2013, and then three more times in 2014 — once in April and twice in July. Additional observations are scheduled for October 2014.
“We are very excited about the state-of-the-art capabilities that ALMA brings to bear to help us better target our historic exploration of the Pluto system,” said mission principal investigator Alan Stern of the Southwest Research Institute; Stern is based in Boulder, Colorado. “We thank the entire ALMA team for their support and for the beautiful data they are gathering for New Horizons.”
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
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Over de Mededeling | 0.870318 | 3.897157 |
Astronomy / Math and ScienceEdit
An apsis (Greek ἁψίς, gen. ἁψίδος), plural apsides (/ˈæpsɨdiːz/; Greek: ἁψίδες), is a point of least or greatest distance of a body in an elliptic orbit about a larger body. For a body orbiting the Sun the point of least distance is the perihelion (/ˌpɛrɨˈhiːliən/ and the point of greatest distance is the aphelion (/æpˈhiːliən/). For any satellite of Earth including the Moon the point of least distance is the perigee (/ˈpɛrɨdʒiː/) and greatest distance the apogee . More generally, the prefixes peri- (from περί (peri), meaning "near") and ap-, or apo-, (from ἀπ(ό) (ap(ó)), meaning "away from") can be added to center (of mass) giving pericenter and apocenter. The words periapsis and apoapsis (or apapsis) are also used for these.
A straight line connecting the pericenter and apocenter is the line of apsides. This is the major axis of the ellipse, its greatest diameter. For a two-body system the center of mass of the system lies on this line at one of the two foci of the ellipse. When one body is sufficiently larger than the other it may be taken to be at this focus. However whether or not this is the case, both bodies are in similar elliptical orbits each having one focus at the system's center of mass, with their respective lines of apsides being of length inversely proportional to their masses. Historically, in geocentric systems, apsides were measured from the center of the Earth. However in the case of the Moon, the center of mass of the Earth-Moon system or Earth-Moon barycenter, as the common focus of both the Moon's and Earth's orbits about each other, is about 74% of the way from Earth's center to its surface.
In orbital mechanics, the apsis technically refers to the distance measured between the centers of mass of the central and orbiting body. However, in the case of spacecraft, the family of terms are commonly used to describe the orbital altitude of the spacecraft from the surface of the central body (assuming a constant, standard reference radius). | 0.827644 | 3.937254 |
The crescent Moon with earthshine is an inspiring site in the night sky. Earthshine images that capture the beauty seen by eye or through a telescope are rare. The extreme range of light and glare from the lunar crescent make it difficult to capture, with a camera, what the eye sees. Conventional High Dynamic Range (HDR) techniques require many exposures and careful processing to give good results. A simple technique, day-lapse earthshine imaging, produces stunning images of the Moon. Earthshine detail, right up to the terminator, duplicates the view of the eye through a telescope. This is done using just two exposure settings.
Our eyes can see a larger range of light than the best cameras. HDR photography captures details in highlights and shadows. Multiple images taken at different exposures capture a scene’s full range of light. Post-processing merges the images to produce a single HDR image without over or under-exposure. A typical daylight terrestrial HDR image includes three exposures taken about a stop (2X) apart to capture details in shadows and highlights.
The Moon with earthshine is very challenging to the HDR photographer. The sunlit portion of the Moon is bright and can be captured well by a single camera exposure. The rest of the Moon is dimly lit by earthlight, sunlight reflected from the Earth to the near side of the Moon. Because the Moon has no atmosphere, the terminator dividing lunar day from night is sharp. The difference in light levels between the crescent and earthshine is 8 to 10 stops (1000X).
Taking just two exposures 8 to 10 stops apart and combining them into an HDR image doesn’t work well. The earthshine exposure above is spoiled near the terminator by glare from the badly overexposed crescent. A cropped HDR composite with the crescent exposure included (figure below) shows two problems: glare from the bright crescent and a shift in the apparent location of the terminator.
This shift in the apparent location of the terminator is due to the very low angle of the Sun near the terminator. This dimly lit area along the terminator is dark in the short crescent image exposure and overexposed in the earthshine image. This region is often painted out in earthshine images. The image looks better, but any detail in this part of the Moon is lost in a grey blur. Increasing the number of HDR exposures (8 or more are needed) can capture detail in this region of low angle sunlight. Many more exposures at different settings make this more difficult to shoot and process. Reduced contrast because of glare from the crescent is still a problem in HDR images with many exposures.
Other techniques used to improve image quality require even more exposures. Lucky image stacking combines the best of multiple images of a target to reduce noise and increase contrast. If we improve image quality by image stacking, many hundreds of images must be taken. Using a video camera speeds up the exposures at a cost. Video gives lower resolution images or requires even more images to stitch together into high resolution mosaics.
The earthshine photographer needs techniques that can capture the whole lunar disk, with high resolution, and require the fewest possible exposure settings for HDR. DSLR or mirrorless cameras with APS-C or larger sensors are a good match for capturing the full Moon in a single exposure with most telescopes.
A night’s rest provides an simple solution to the many exposures problem… The terminator advances about 12 degrees across the Moon’s face each day. We only have to add delay between exposures. With enough delay, the detail hidden by glare and terminator shift is revealed by the advancing terminator. A day or two wait between just two exposures is enough. With only one exposure setting needed per night, it’s easy to take extra images for lucky image stacking. Detail in the earthshine will always be softer and lower contrast than in the crescent because of the dim, diffuse lighting from the nearby earth. Craters, highlands, and maria in the earthshine area are visible right up to the terminator in day-lapse earthshine images. They closely match the beauty of this scene in a telescope eyepiece.
Some fine points require attention. The apparent size of the Moon changes slightly because of distance changes due to its elliptical orbit around the earth. The portion of the Moon that we can see changes slightly because of the tilt between Earth’s rotation and the Moon’s orbit. Libration changes our perspective because the Moon’s orbit is tilted with respect to its axis. A small change in the Moon’s size is easy to correct during alignment. Large perspective changes cannot easily be corrected. With only a day or two delay, they can be corrected by aligning and transforming the earthshine layer to match the crescent layer features along the terminator. Corrected, small size and perspective changes are too small to see in the final result. For a waxing crescent take the earthshine exposure on the first day, for a waning crescent take it on the day following your crescent exposure.
There are too many software tools for processing HDR images to give details for each. Adapt these suggestions from my processing workflow to your own tools.
If you stack multiple images to improve the image quality, you need to deal with atmospheric seeing. The Moon has about 1/2 degree of apparent size. Variations in atmospheric seeing result in mirage-like distortions across the Moon. This makes lucky image stacking more difficult for full-disk Moon images than for lunar close ups. Align images using a stacking tool that corrects for geometric distortion. I use Nebulosity's non-stellar automatic alignment, with 8 parameter affine transform, very successfully. Alignment is slower, but the results are worth the wait.
Three layers are needed for two exposure HDR image merging in a layer based editor like Photoshop. The background layer is black. Lunar detail and background stars are picked up from the top two layers.
The earthshine layer is next; masked to include only the lunar disk shown. On this layer, I select the overexposed crescent area, and clone color sampled from the earthshine region. This will insure the correct level of earthshine illumination in the terminator and crater shadows in the brightly lit crescent.
The top layer is the exposure for the sunlit lunar crescent shown below. The earthshine layer must now be translated, rotated, and scaled to align to features on the crescent terminator. The final HDR merging is done by setting the top crescent layer to "lighten only" merge. The final balance between crescent and earthshine illumination is achieved by adjusting each layers exposure individually.
The final result below captures with fidelity the appearance of the Moon in the eyepiece when the crescent image was made. This image was made with small, light equipment, an 89mm f14 telescope and a 16 megapixel mirrorless APS-C camera at prime focus. The earthshine layer was exposed for 2.5 sec at ISO 800 with 14 frames stacked. The crescent layer was exposed 2 days later for 1/15 sec at ISO 200 with 9 frames stacked.
Compare this day-lapse image with these exceptional images made using conventional HDR techniques: Jerry Lodriguss's two-day old waxing crescent Moon and Dylan O'Donnell's March 20, 2015 Astronomy Picture of the Day.
Try this day-lapse technique with your own images and tools. Problems from glare and camera limitations will be gone. You will soon be making great earthshine images that capture the beauty of the scene as you see it through the eyepiece.
A very thin crescent, only a day or so from the new Moon, is relatively dim and reduces the exposure difference between earthshine and the crescent. This makes it easier to produce a good image without the need for the day-lapse technique:
Mercury & the Moon with Earthshine
Here are some more examples of the day-lapse technique. The image below was awarded 2nd place for the Astronomical League 2017 OPT Solar System Imaging Award.
January Earthshine Crescent Moon
04 Crescent Moon with earthshine
23 Waning Crescent Moon with Earthshine
Other astrophotographers from around the world are now using the day-lapse technique as well. Here's an example from Roch Lévesque. If you post any of your day-laps images, tell me about them, and I'll include them here.
Content created: 2015-05-29 and last modified: 2017-10-03
By submitting a comment, you agree that: it may be included here in whole or part, attributed to you, and its content is subject to the site wide Creative Commons licensing. | 0.855356 | 3.629234 |
At least once a month we hear of a new exoplanet with a strange and amazing story. From the ‘Super-Saturn’ ringed world to Magnetic Fields to systems of three Earths, there is an abundance of planets and strange systems.
The latest weird discovery brings us to a star 1,500 light years away in the constellation Cygnus. The small-Mercury sized planet it hosts orbits in only 16 hours, bringing its surface temperature to over 1,800 degrees celsius. This amount of heat is enough to vapourize rock, and so the star is literally roasting the planet and blasting away its surface. The dust liberated from the planet is trailing behind it as it orbits, resulting in a comet-like trail.
Even though the planet is very small, the dust cloud from its vapourized surface is large enough to block out 1% of the host star’s light. This is the same as if a Jupiter-sized planet was orbiting in its place. Without the massive dust cloud its unlikely we would be able to find such a small planet.
The William Herschel Telescope’s ULTRACAM was used to study the dust cloud, which blocks a slightly larger fraction of the star’s blue light than red light. This is similar to the Earth’s atmosphere scattering blue light, causing a sunset to appear red. The exact color-dependence of the scattered dust can reveal the size of the grains, and even their composition. Determining the dust composition, as the astronomers hope to with future observations, will give us the composition of the planet’s surface, a first in exoplanet astronomy.
I’ve said it before, and it will ring true for years to come. This is the most exciting time for planetary scientists and astronomers, and centuries from now it will be remembered as the beginning of humanity’s understanding of planetary systems beyond our own. | 0.915831 | 3.43114 |
How unique is Earth?
Assuming that all worlds in space are unique in some way … just how unique is Earth? Are there other planets out there with similar compositions, oceans, maybe even living things? We still don’t know for sure, although a quickly-growing number of rocky exoplanets at least similar in size to Earth are being discovered. But now, a new study of white dwarf stars by researchers from the University of California, Los Angeles (UCLA) provides fresh evidence that planets like Earth are probably quite common in our galaxy, an exciting implication.
The peer-reviewed study, published on October 18, 2019, in the journal Science, suggests there are many rocky planets with similar geochemistry as Earth. Various telescopes were used, primarily the W.M. Keck Observatory in Hawaii.
According to Edward Young, a UCLA professor of geochemistry and cosmochemistry:
We have just raised the probability that many rocky planets are like the Earth, and there’s a very large number of rocky planets in the universe. We’re studying geochemistry in rocks from other stars, which is almost unheard of.
As Hilke Schlichting, a UCLA associate professor of astrophysics and planetary science, explained, determining the composition of rocky material so far away is not an easy task:
Learning the composition of planets outside our solar system is very difficult. We used the only method possible – a method we pioneered – to determine the geochemistry of rocks outside of the solar system.
Oxygen fugacity is a measure of rock oxidation that influences planetary structure and evolution. Most rocky bodies in the solar system formed at oxygen fugacities approximately five orders of magnitude higher than a hydrogen-rich gas of solar composition. It is unclear whether this oxidation of rocks in the solar system is typical among other planetary systems. We exploit the elemental abundances observed in six white dwarfs polluted by the accretion of rocky bodies to determine the fraction of oxidized iron in those extrasolar rocky bodies and therefore their oxygen fugacities. The results are consistent with the oxygen fugacities of Earth, Mars, and typical asteroids in the solar system, suggesting that at least some rocky exoplanets are geophysically and geochemically similar to Earth.
The researchers developed a unique method for analyzing the geochemistry of such worlds, without looking at the planets themselves. Instead, they studied the rocky debris left over from planets that were destroyed around white dwarf stars. They have analyzed the debris from six white dwarfs so far, and the results were intriguing. The closest white dwarf star studied is about 200 light-years from Earth and the farthest is 665 light-years away.
Normally, just hydrogen and helium would be found in a white dwarf star, but instead the researchers also found silicon, magnesium, carbon and oxygen. Such elements would come from rocky planets that used to orbit the stars. As Alexandra Doyle, a graduate student at UCLA who led the new study, explained:
If I were to just look at a white dwarf star, I would expect to see hydrogen and helium. But in these data, I also see other materials, such as silicon, magnesium, carbon and oxygen – material that accreted onto the white dwarfs from bodies that were orbiting them.
By observing these white dwarfs and the elements present in their atmosphere, we are observing the elements that are in the body that orbited the white dwarf. Observing a white dwarf is like doing an autopsy on the contents of what it has gobbled in its solar system.
Rocks in our solar system – from Earth, Mars and elsewhere – are similar in composition, with a lot of oxidized iron. The iron in the rocky material around the white dwarfs had been oxidized in a similar manner, according to Young:
We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. Oxygen steals electrons from iron, producing iron oxide rather than iron metal. We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. We studied how much the metal rusts.
All the chemistry that happens on the surface of the Earth can ultimately be traced back to the oxidation state of the planet. The fact that we have oceans and all the ingredients necessary for life can be traced back to the planet being oxidized as it is. The rocks control the chemistry.
So just how similar is the rocky debris around the white dwarfs to that of planets like Earth and Mars? Very, according to Doyle:
Very similar. They are Earth-like and Mars-like in terms of their oxidized iron. We’re finding that rocks are rocks everywhere, with very similar geophysics and geochemistry.
As Young also noted:
It’s always been a mystery why the rocks in our solar system are so oxidized. It’s not what you expect. A question was whether this would also be true around other stars. Our study says yes. That bodes really well for looking for Earth-like planets in the universe.
The evidence for oxidation in the rocky debris around the white dwarfs is tantalizing, since it points to similar geological processes on the planets that used to exist. As Schlichting said:
If extraterrestrial rocks have a similar quantity of oxidation as the Earth has, then you can conclude the planet has similar plate tectonics and similar potential for magnetic fields as the Earth, which are widely believed to be key ingredients for life. This study is a leap forward in being able to make these inferences for bodies outside our own solar system and indicates it’s very likely there are truly Earth analogs.
As Doyle added:
We can determine the geochemistry of these rocks mathematically and compare these calculations with rocks that we do have from Earth and Mars. Understanding the rocks is crucial because they reveal the geochemistry and geophysics of the planet.
This new study not only provides fascinating new details on how Earth-like planets may be quite common, it is also a great example of astrophysicists and geochemists working together, according to Young:
The result is we are doing real geochemistry on rocks from outside our solar system. Most astrophysicists wouldn’t think to do this, and most geochemists wouldn’t think to ever apply this to a white dwarf.
Bottom line: A new study from UCLA suggests that there are probably many rocky worlds in our galaxy that are similar in composition and geochemistry to Earth or Mars. | 0.848831 | 3.813537 |
The Unification Epicenter of True Lightworkers
by Ronald Regehr
"The moon is the Rosetta stone of the planets."
- Robert Jastrow First Chairman, NASA Lunar Exploration Committee
After hundreds of years of detailed observation and study, our closest companion in the vast universe, Earths moon, remains an enigma. Six moon landings and hundreds of experiments have resulted in more questions being asked than answered. Among them:
1. Moons Age: The moon is far older than previously expected. Maybe even older than the Earth or the Sun. The oldest age for the Earth is estimated to be 4.6 billion years old; moon rocks were dated at 5.3 billion years old, and the dust upon which they were resting was at least another billion years older.
2. Rocks Origin: The chemical composition of the dust upon which the rocks sat differed remarkably from the rocks themselves, contrary to accepted theories that the dust resulted from weathering and breakup of the rocks themselves. The rocks had to have come from somewhere else.
3. Heavier Elements on Surface: Normal planetary composition results in heavier elements in the core and lighter materials at the surface; not so with the moon. According to Wilson,
"The abundance of refractory elements like titanium in the surface areas is so pronounced that several geologists proposed the refractory compounds were brought to the moons surface in great quantity in some unknown way. They dont know how, but that it was done cannot be questioned."
4. Water Vapor: On March 7, 1971, lunar instruments placed by the astronauts recorded a vapor cloud of water passing across the surface of the moon. The cloud lasted 14 hours and covered an area of about 100 square miles.
5. Magnetic Rocks: Moon rocks were magnetized. This is odd because there is no magnetic field on the moon itself. This could not have originated from a "close call" with Earthsuch an encounter would have ripped the moon apart.
6. No Volcanoes: Some of the moons craters originated internally, yet there is no indication that the moon was ever hot enough to produce volcanic eruptions.
7. Moon Mascons: Mascons, which are large, dense, circular masses lying twenty to forty miles beneath the centers of the moons maria,
"are broad, disk-shaped objects that could be possibly some kind of artificial construction. For huge circular disks are not likely to be beneath each huge maria, centered like bulls-eyes in the middle of each, by coincidence or accident."
8. Seismic Activity: Hundreds of "moonquakes" are recorded each year that cannot be attributed to meteor strikes. In November, 1958, Soviet astronomer Nikolay A. Kozyrev of the Crimean Astrophysical Observatory photographed a gaseous eruption of the moon near the crater Alphonsus. He also detected a reddish glow that lasted for about an hour. In 1963, astronomers at the Lowell Observatory also saw reddish glows on the crests of ridges in the Aristarchus region. These observations have proved to be precisely identical and periodical, repeating themselves as the moon moves closer to the Earth. These are probably not natural phenomena.
9. Hollow Moon: The moons mean density is 3.34 gm/cm3 (3.34 times an equal volume of water) whereas the Earths is 5.5. What does this mean? In 1962, NASA scientist Dr. Gordon MacDonald stated,
"If the astronomical data are reduced, it is found that the data require that the interior of the moon is more like a hollow than a homogeneous sphere."
Nobel chemist Dr. Harold Urey suggested the moons reduced density is because of large areas inside the moon where is "simply a cavity."
MITs Dr. Sean C. Solomon wrote,
"the Lunar Orbiter experiments vastly improved our knowledge of the moons gravitational field... indicating the frightening possibility that the moon might be hollow."
In Carl Sagans treatise, Intelligent Life in the Universe, the famous astronomer stated, "A natural satellite cannot be a hollow object."
10. Moon Echoes: On November 20, 1969, the Apollo 12 crew jettisoned the lunar module ascent stage causing it to crash onto the moon. The LMs impact (about 40 miles from the Apollo 12 landing site) created an artificial moonquake with startling characteristicsthe moon reverberated like a bell for more than an hour.
This phenomenon was repeated with Apollo 13 (intentionally commanding the third stage to impact the moon), with even more startling results. Seismic instruments recorded that the reverberations lasted for three hours and twenty minutes and traveled to a depth of twenty-five miles, leading to the conclusion that the moon has an unusually lightor even nocore.
11. Unusual Metals: The moons crust is much harder than presumed. Remember the extreme difficulty the astronauts encountered when they tried to drill into the maria? Surprise! The maria is composed primarily illeminite, a mineral containing large amounts of titanium, the same metal used to fabricate the hulls of deep-diving submarines and the skin of the SR-71 "Blackbird". Uranium 236 and neptunium 237 (elements not found in nature on Earth) were discovered in lunar rocks, as were rustproof iron particles.
12. Moons Origin: Before the astronauts moon rocks conclusively disproved the theory, the moon was believed to have originated when a chunk of Earth broke off eons ago (who knows from where?). Another theory was that the moon was created from leftover "space dust" remaining after the Earth was created. Analysis of the composition of moon rocks disproved this theory also.
Another popular theory is that the moon was somehow "captured" by the Earths gravitational attraction. But no evidence exists to support this theory. Isaac Asimov, stated,
"Its too big to have been captured by the Earth. The chances of such a capture having been effected and the moon then having taken up nearly circular orbit around our Earth are too small to make such an eventuality credible."
13. Weird Orbit: Our moon is the only moon in the solar system that has a stationary, near-perfect circular orbit. Stranger still, the moons center of mass is about 6000 feet closer to the Earth than its geometric center (which should cause wobbling), but the moons bulge is on the far side of the moon, away from the Earth. "Something" had to put the moon in orbit with its precise altitude, course, and speed.
14. Moon Diameter: How does one explain the "coincidence" that the moon is just the right distance, coupled with just the right diameter, to completely cover the sun during an eclipse? Again, Isaac Asimov responds,
"There is no astronomical reason why the moon and the sun should fit so well. It is the sheerest of coincidences, and only the Earth among all the planets is blessed in this fashion."
15. Spaceship Moon: As outrageous as the Moon-Is-a-Spaceship Theory is, all of the above items are resolved if one assumes that the moon is a gigantic extraterrestrial craft, brought here eons ago by intelligent beings. This is the only theory that is supported by all of the data, and there are no data that contradict this theory.
Greek authors Aristotle and Plutarch, and Roman authors Apolllonius Rhodius and Ovid all wrote of a group of people called the Proselenes who lived in the central mountainous area of Greece called Arcadia. The Proselenes claimed title to this area because their forebears were there "before there was a moon in the heavens."
This claim is substantiated by symbols on the wall of the Courtyard of Kalasasaya, near the city of Tiahuanaco, Bolivia, which record that the moon came into orbit around the Earth between 11,500 and 13, 000 years ago, long before recorded history.
1. Ages of Flashes: Aristarchus, Plato, Eratosthenes, Biela, Rabbi Levi, and Posidonius all reported anomalous lights on the moon. NASA, one year before the first lunar landing, reported 570+ lights and flashes were observed on the moon from 1540 to 1967.
2. Operation Moon Blink: NASAs Operation Moon Blink detected 28 lunar events in a relatively short period of time.
3. Lunar Bridge: On July 29, 1953, John J. ONeill observed a 12-mile-long bridge straddling the crater Mare Crisium. In August, British astronomer Dr. H.P. Wilkens verified its presence,
"It looks artificial. Its almost incredible that such a thing could have been formed in the first instance, or if it was formed, could have lasted during the ages in which the moon has been in existence."
4. The Shard: The Shard, an obelisk-shaped object that towers 1½ miles from the Ukert area of the moons surface, was discovered by Orbiter 3 in 1968. Dr. Bruce Cornet, who studied the amazing photographs, stated,
"No known natural process can explain such a structure."
5. The Tower: One of the most curious features ever photographed on the Lunar surface (Lunar Orbiter photograph III-84M) is an amazing spire that rises more than 5 miles from the Sinus Medii region of the lunar surface.
6. The Obelisks: Lunar Orbiter II took several photographs in November 1966 that showed several obelisks, one of which was more than 150 feet tall.
". . . the spires were arranged in precisely the same was as the apices of the three great pyramids." | 0.855176 | 3.134735 |
Skygazers at northern latitudes are familiar with the W-shaped star pattern of Cassiopeia the Queen. This circumpolar constellation is visible year-round near the North Star. Tucked next to one leg of the W lies a modest 5th-magnitude star named HD 219134 that has been hiding a secret.
News release • July 30, 2015 • Christine Pulliam
Astronomers have now teased out that secret: a planet in a 3-day orbit that transits, or crosses in front of its star. At a distance of just 21 light-years, it is by far the closest transiting planet to Earth, which makes it ideal for follow-up studies. Moreover, it is the nearest rocky planet confirmed outside our solar system. Its host star is visible to the unaided eye from dark skies, meaning anyone with a good star map can see this record-breaking system.
«Most of the known planets are hundreds of light-years away. This one is practically a next-door neighbor,» said astronomer Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics (CfA).
«Its proximity makes HD 219134 ideal for future studies. The James Webb Space Telescope and future large ground-based observatories are sure to point at it and examine it in detail,» said lead author Ati Motalebi of the Geneva Observatory.
The newfound world, designated HD 219134b, was discovered using the HARPS-North instrument on the 3.6-meter Telescopio Nazionale Galileo in the Canary Islands. The CfA is a major partner with the Geneva Observatory on the HARPS-North Collaboration, which includes several other European partners.
HARPS-North detects planets using the radial velocity method, which allows astronomers to measure a planet’s mass. HD 219134b weighs 4.5 times the mass of Earth, making it a super-Earth.
With such a close orbit, researchers realized that there was good possibility the planet would transit its star. In April of this year they targeted the system with NASA’s Spitzer Space Telescope. At the appropriate time, the star dimmed slightly as the planet crossed the star’s face. Measuring the depth of the transit gave the planet’s size, which is 1.6 times Earth. As a result, the team can calculate the planet’s density, which works out to about 6 g/cm3. This shows that HD 219134b is a rocky world.
But wait, there’s more! The team detected three additional planets in the system using radial velocity data. A planet weighing at least 2.7 times Earth orbits the star once every 6.8 days. A Neptune-like planet with 9 times the mass of Earth circles in a 47-day orbit. And much further out, a hefty fourth world 62 times Earth’s mass orbits at a distance of 2.1 astronomical units (200 million miles) with a «year» of 1,190 days. Any of these planets might also transit the star, so the team plans to search for additional transits in the months ahead.
HD 219134 is an orange Type K star somewhat cooler, smaller and less massive than our Sun. Its key measurements have been pinned down very precisely, which thus allows a more precise determination of the properties of its accompanying planets.
This discovery came from the HARPS-North Rocky Planet Search, a dedicated survey examining about 50 nearby stars for signs of small planets. The team targeted nearby stars because those stars are brighter, which makes follow-up studies easier. In particular, additional observations might allow the detection and analysis of planetary atmospheres.
HD 219134 was one of the closest stars in the sample, so it was particularly lucky to find that it hosts a transiting planet. This system now holds the record for the nearest transiting exoplanet. As such, it likely will be a favorite for researchers for years to come.
- provided by CfA | 0.904015 | 3.711769 |
An antimatter probe to a nearby star? The idea holds enormous appeal, given the colossal energies obtained when normal matter annihilates in contact with its antimatter equivalent. But as we’ve seen through the years on Centauri Dreams, such energies are all but impossible to engineer. Antimatter production is infinitesimal, the by-product of accelerators designed with a much different agenda. Moreover, antimatter storage is hellishly difficult, so that maintaining large quantities in a stable condition requires multiple breakthroughs.
All of which is why I became interested in the work Gerald Jackson and Steve Howe were doing at Hbar Technologies. Howe, in fact, became a key source when I put together the original book from which this site grew. This was back in 2002-2003, and I was captivated with the idea of what could be called an ‘antimatter sail.’ The idea, now part of a new Kickstarter campaign being launched by Jackson and Howe, is to work with mere milligrams of antimatter, allowing antiprotons to be released from the spacecraft into a uranium-enriched, five-meter sail.
Reacting with the uranium, the antimatter produces fission fragments that create what could be considered a nuclear-stimulated ablation blowing off the carbon-fiber sail. As to the reaction itself, Jackson and Howe would use a sheet of depleted uranium U-238 with a carbon coating on its back side. Here’s how the result is described in the Kickstarter material now online:
When antiprotons… drift onto the front surface, their negative electrical charge allows them to act like an orbiting electron, but with different quantum numbers that allow the antiprotons to cascade down into the ground orbital state. At this point it annihilates with a proton or neutron in the nucleus. This annihilation event causes the depleted uranium nucleus to fission with a probability approaching 100%, most of the time yielding two back-to-back fission daughters.
Now we get into a serious kick for the spacecraft:
A fission daughter travelling away from the sail at a kinetic energy of 1 MeV/amu has a speed of approximately 13,800 km/sec, or 4.6% of the speed of light. The other fission daughter is absorbed by the sail, depositing its momentum into the sail and causing the sail (and the rest of the ship) to accelerate.
The concept relies, as Jackson said in a recent email, on using antimatter as a spark plug rather than as a fuel, converting the energy from proton-antiproton annihilations into propulsion.
Image: The original antimatter probe concept. Credit: Gerald Jackson/Hbar Technologies.
The current work grows out of a 2002 grant from NASA’s Institute for Advanced Concepts but the plan is to develop the idea far beyond the Kuiper Belt mission Jackson and Howe initially envisioned. Going interstellar would take not milligrams but tens of grams of antimatter, far beyond today’s infinitesimal production levels. In fact, while the Fermi National Accelerator laboratory has been able to produce no more than 2 nanograms of antimatter per year, even that is high compared to CERN’s output (the only current source), which is 100 times smaller.
Even so, interest in antimatter remains high because of its specific energy — two orders of magnitude larger than fusion and ten orders of magnitude larger than chemical reactions — making further research highly desirable. If the fission reaction the antimatter produces within the sail is viable, we will be able to demonstrate a way to harness those energies, with implications for deep space exploration and the possibility of interstellar journeys.
The original NIAC work led to a sail 5-meters in diameter, with a 15-micron thick carbon layer and a uranium coating 293 microns thick. Interestingly, the study showed that the sail had sufficient area to remove any need for active cooling of the surface. Indeed, the steady-state temperature of the sail would be 570𝆩 Celsius, below the melting point of uranium.
Image: A cloud of anti-hydrogen drifts towards the uranium-infused sail. CREDIT: Hbar Technologies, LLC/Elizabeth Lagana.
The work was based around a 10 kg instrument payload to be delivered to 250 AU within 10 years. Turning to interstellar possibilities, Breakthrough Starshot has been talking about reaching 20 percent of lightspeed with a beamed laser array pushing small sails. Jackson and Howe now seek roughly 5 percent of c, making for a mission of less than a century to reach Proxima Centauri, where we already know an interesting planet awaits.
But here’s a significant difference: Unlike Breakthrough Starshot’s flyby assumptions, the antimatter sail mission concept is built around decelerating and attaining orbit around the target star. In the absence of magsail braking against Proxima’s stellar wind, this would presumably also involve antimatter, braking with the same methods to allow for long-term scientific investigation, thus avoiding the observational challenges of a probe pushing past a small and probably tidally-locked planet at 20 percent of lightspeed.
Here’s how Jackson describes deceleration in his recent email:
Our project considers deceleration and orbit about the destination star a mission requirement. There are serious implications for spacecraft velocity when the requirement of deceleration at the destination is imposed. Either drag or some other mechanism needs to be invoked at the destination, or enough extra fuel must be accelerated in order to accomplish a comparable deceleration. Because the rocket equation equates probe velocity with mass utilization, a staged spacecraft architecture is envisioned wherein a more massive booster accelerates the spacecraft and a smaller second stage decelerates into the destination solar system.
The discovery of Proxima b, that interesting planet evidently in the habitable zone around the nearest star, continues to energize the interstellar community. The Kickstarter campaign, just underway and with a goal of $200,000, hopes to upgrade earlier antimatter sail ideas into the interstellar realm. Tomorrow I want to say a few more things about the antimatter sail and the issues the Kickstarter campaign will address as it expands the original work. | 0.854566 | 3.483457 |
NASA's newest Mars orbiter, MAVEN, has returned its first observations of the red planet's upper atmosphere, laying a promising foundation for answering a nagging question about the planet's environment: What happened to an atmosphere that supported a warm and wet planet some 4 billion years ago, only to become the dry, chilled desert that astronomers see today?
Although its science mission has yet to begin, the craft already has revealed clues with the first detailed measurements of the upper atmosphere's hydrogen, oxygen, and carbon, which back in the day would have appeared as water vapor and carbon dioxide – two potent gases for trapping heat near the surface.
This would have allowed liquid water to remain stable on the surface, providing potential habitats for microbial life.
Following its arrival at Mars Sept. 21, the craft also recorded the passage of a blast of energetic particles that erupted from the sun on Sept. 30 in an event known as a coronal-mass ejection, the most powerful solar storms that the sun generates. Such storms are thought to have played an important role in altering Mars' climate by depositing large amounts of energy in the upper atmosphere, splitting water and CO2 molecules and ejecting the hydrogen into space.
MAVEN, short for Mars Atmosphere and Volatile Evolution, is still in its shakedown phase. All instruments are working but are in need of final adjustments before they begin to take measurements in a coordinated fashion starting in November.
Still, during its first few weeks on orbit, MAVEN has given the science team its first look at the structure of the extended upper atmosphere and the distribution of the three key atoms, some of which are escaping, said Bruce Jakosky, a University of Colorado astrobiologist and the mission's lead scientist, during a briefing Tuesday.
In addition, “we're starting to see the processes that drive the escape,” he said. Those processes are likely to have been more intense in the past, when a younger sun was more active than it is today.
The team is seeing these clues to Mars' atmospheric history with unexpected clarity.
For instance, MAVEN's Imaging Ultraviolet Spectrograph recorded an extended, if tenuous, envelope of hydrogen atoms around Mars that extends as far as 21,000 miles from the planet – easy pickings for stripping, because the atom is so light and thus is less tightly bound by the planet's gravity than is oxygen or carbon.
While MAVEN showed that Mars holds the upper atmosphere's inventory of carbon and oxygen much closer to its gravitational vest, the craft also revealed an extended envelope of oxygen above the sunlit hemisphere. This so-called hot oxygen has been energized through photochemical reactions that the sun's light triggers. Some of this extended oxygen gets stripped from Mars, as well.
“The quality of the data is better than we were expecting,” said Justin Deighan, a researcher at the University of Colorado at Boulder and one of the MAVEN scientists working with the craft's Imaging Ultraviolet Spectrograph. “The ability to see that high-altitude oxygen – we were hoping for it, but we could never have guessed how good that picture would come out.”
Since oxygen comes from the breakup of water and carbon dioxide molecules, “we need to understand it for a complete story of atmospheric escape from Mars,” he said.
MAVEN also returned a map of the distribution of ozone in the lower atmosphere above the planet's south pole. It's a key piece of the puzzle, the researchers say, because ozone is vulnerable to water vapor and sunlight, which break up ozone molecules.
The relative abundance of ozone shows the team “where water is and is not present,” Dr. Deighan explained, and it reveals the chemical processes taking place in the lower atmosphere. Those processes are responsible for breaking water up into its constituent atoms – the initial step of hydrogen and oxygen – and carrying them into the upper atmosphere, where they can be carried off into space.
Making such measurements simultaneously with measurements of the upper atmosphere several times a day over the next year “will allow us to understand how Mars' atmosphere is being lost today and, by extension, how much has been lost over the history of the solar system," he adds. | 0.851942 | 3.946469 |
The Rosette Nebula is a cloud of gas and dust, about 130 light years in diameter, lying approximately 5000 light years from our Solar System, in the direction of the constellation of Monoceros. The mass of the nebula is estimated at 10 thousand Solar masses, even though it is just a small part of a much larger region of gas and dust spanning the entire constellation. The Rosette would appear as large as the full Moon, if it were visible to the eye, but it is so faint that visual observation is difficult, even with telescopes. The hot, bright stars in its center are easily visible, being point sources of light; but the diffuse light of the nebula requires photography with filters which block out all of the light of the night sky, save for wavelengths emitted by gases in the nebula, as they absorb the ultraviolet radiation pouring out of the stars which illuminate the nebula.
In the animation at the right (from images by Richard Crisp at apod050214 and narrowbandimaging.com), the H-alpha (Ha) radiation of neutral hydrogen atoms is used to bring out the primary detail in the nebula, while radiation by doubly ionized oxygen atoms and singly ionized sulfur atoms is used to establish a range of colors, for an "artistic" rendering of the nebula's supposed color. This color is completely false, since objects so faint, even if visible to our eyes, would appear to be only a pale gray, or greenish-gray; but makes the image far more interesting than if presented only in black and white (as can be seen by the alternation of the color image with the black-and-white Ha image).
The spectacular image below (MegaPrime Camera, Canada-France-Hawaii Telescope, apod030429) shows the hot, bright stars in the center of the cloud heating the gas surrounding them from 100 Kelvins to 10000 Kelvins (*see note below), increasing the pressure of the gas by more than a hundred times, and causing it to push against the surrounding clouds of gas, simultaneously eating away at them, and compressing them to small, dark compact regions which will become the next generation of stars. Most of the bright stars visible in the central cluster were formed over a period of a few million years, but some may have formed within the last few thousands of years, since star formation is still ongoing, in the region.
*Note: Although most of the gas pushing against the surrounding clouds has a temperature of 10 thousand Kelvins, observations with the Chandra X-ray observatory have revealed that in the central part of the nebula, collisional shock waves from stellar winds blowing in opposite directions (from exceptionally hot, young stars in the center of the cluster) have heated the gas to 6 million Kelvins. | 0.825259 | 4.04323 |
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Therefore, even though Enceladus is only Saturn's sixth-largest moon, it is amazingly active. Because of the success of the Cassini mission, scientists now know that geysers spew watery jets hundreds of kilometers out into Space, originating from what may well be a vast subsurface sea. These jets, which erupt from fissures in the little moon's icy shell, whisper a siren's song to bewitched astronomers. This is because the jets suggest that the icy moon may harbor a zone where life might have evolved. The jets dramatically spray water ice from numerous fissures near the south pole, that have been playfully termed "tiger stripes." The "tiger stripes" look like giant scratches made by a tiger's raking claws.
and here is another
So here you have two definitions of a blue moon but the one for a calendar blue moon does not describe the true meaning of a blue moon. Here's why:
The three little moons (Methone, Pallene, and Anthe) orbit at very similar distances from Saturn, and they have a dynamical relationship. Mimas disturbs the trio of little moons, and causes the orbit of Methone to vary by as much as 20 kilometers (12.4 miles). Mimas causes the orbit of Pallene to vary by a slightly smaller amount--but it has the greatest influence on the orbit of the moon Anthe.
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Earth's Moon is the largest and brightest object suspended in the darkness of the starry night sky. It is both lovely and enchanting, and it has, since ancient times, inspired curiosity and wonder in human beings who gaze up at the mysterious sky after the Sun has set. As such, Earth's Moon has long served as the inspiration for imaginative, wild and marvelous tales--it is the stuff of mythology and folklore. The "Man in the Moon" refers to several fantastic images of a human face that certain traditions see outlined in the gleaming disk of the full Moon. In November 2013, astronomers using data from the lunar-orbiting twins composing NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, announced that they have been acquiring new and fascinating insight into how this bewitching "face," etched on our Moon's disk, received its captivating and enchanting good looks!
The scientists also considered other possible sources of hydrogen from the little moon itself, such as a preexisting reservoir in the icy crustal shell or a global ocean. Subsequent analysis indicated that it was unlikely that the observed hydrogen was obtained during the formation of Enceladus or from other processes on the moon-world's surface or in the interior.
In September 2015, a team of astronomers released their study showing that they have detected regions on the far side of the Moon--called the lunar highlands--that may bear the scars of this ancient heavy bombardment. This vicious attack, conducted primarily by an invading army of small asteroids, smashed and shattered the lunar upper crust, leaving behind scarred regions that were as porous and fractured as they could be. The astronomers found that later impacts, crashing down onto the already heavily battered regions caused by earlier bombarding asteroids, had an opposite effect on these porous regions. Indeed, the later impacts actually sealed up the cracks and decreased porosity. | 0.818782 | 3.179597 |
The universe is simply so vast that it can be difficult to maintain a sense of scale.
Many galaxies we see through telescopes such as the NASA/ESA Hubble Space Telescope, the source of this beautiful image, look relatively similar spiraling arms, a glowing center, and a mixture of bright specks of star formation and dark ripples of cosmic dust weaving throughout.
This galaxy, a spiral galaxy named NGC 772, is no exception.
It actually has much in common with our home galaxy, the Milky Way.
Each boasts a few satellite galaxies, small galaxies that closely orbit and are gravitationally bound to their parent galaxies.
One of NGC 772’s spiral arms has been distorted and disrupted by one of these satellites (NGC 770 — not visible in the image here), leaving it elongated and asymmetrical.
However, the two are also different in a few key ways.
For one, NGC 772 is both a peculiar and an unbarred spiral galaxy; respectively, this means that it is somewhat odd in size, shape or composition, and that it lacks a central feature known as a bar, which we see in many galaxies throughout the cosmos including the Milky Way.
These bars are built of gas and stars, and are thought to funnel and transport material through the galactic core, possibly fueling and igniting various processes such as star formation | 0.879354 | 3.777393 |
1 / 3Dark Matter We experiment and observe to find out the different characteristics that makes up the universe. In order to do so, we must go over basic observation such as what it looks like, and how it interacts with other things around it, etc. These are the easy go-to questions before being able to experiment further. The planets have already been studied by astronomers and by taking a closer look, they were able to calculate their approximate speed and found the amount of time it takes for a specific planet to rotate around the sun. They were able to figure out the answer because they saw it. It was a difficult process yet it was easy because they watched it. How can you study something that is invisible or simply just… not there? Let’s start with the question, how do we know an object exists? In space, there are numerous categories that we can encounter like the milky way, a star, a gas cloud, and rocks. We can see them because of light. Lights reflects and bounces off things but not only light is involved, matter is also added and that’s what makes up the ‘things’ in this equation. The ‘normal’ matter, if I may say, have particles made of baryons which consist of protons, neutrons, and all things composed of them. You may be asking, what about oxygen? We can’t see it. How did we find out its there? It was discovered because of the way it gave life on earth. Oxygen is such a huge factor in this world that it’s impossible to not experiment on it. This is similar to dark matter. What exactly is dark matter? The exact answer is… we don’t exactly know but studies show, about 25% of this dark matter is in our universe. It cannot be seen or sensed directly. Why is that? Why can’t we see this dark entity? Simple, because dark matter is the epitome of darkness. It does not emit or absorb light in any way making it impossible for us to see. This matter doesn’t do much of interaction with its own kind, let alone normal matter and later it was figured dark matter only interacts through gravity. How does it work, then? It starts back form 1933 when a Swiss astronomer, Fritz Zwicky, was in the zone of studying clusters of galaxies called the Coma cluster. He was calculating the mass of the galaxy based on its brightness and orbital speed only to find out these clusters were moving at a much faster rate than they should be. These galaxies orbit one another and gravity holds them together. The faster galaxies spin, the more gravitational attraction they need to keep them from letting go and because more gravity meant adding more mass, Zwicky wondered where the other mass was coming from. He discovered there may be something more than what he could see, more than meets the eye. Dark matter is responsible for the movement of objects spiraling a galaxy, the invisible halo. As ridiculous, as it sounds, we know more about what dark matter isn’t than what it really is. Chances are, this whole thing could be wrong but let’s not ruin it until we know more about it. Right off the bat, we can conclude that dark matter is not a star. As I’ve mentioned above, this matter does not care for any light. It is not a cloud of normal matter because it’s not 2 / 3baryonic matter. Antimatter can be crossed out of the list because it produces gamma rays, which dark matter does not. It’s also not a form of a black hole because black holes bend light. To conclude, dark matter is still a big mystery to us all. Even coming up with theory of it being dark could be wrong and little did we know, nothing was really there. This matter cannot be seen yet the things we can see only make a fraction of 5% in the entire universe. It really tells you how much more there is out there. Soon enough, newer things will be discovered and it could be another dark category adding to the invisible duo, dark matter and dark energy. | 0.802937 | 3.532432 |
Venus highest and brightest as evening star
If you doubt that February offers our best evening sky of the year, then consider the evidence. The unrivalled constellation of Orion stands astride the meridian at 21:00 GMT tonight, and two hours earlier by February’s end. Around him are arrayed some of the brightest stars in the night sky, including Sirius, the brightest, and Capella, the sixth brightest which shines yellowish in Auriga near the zenith. This month also sees Venus, always the brightest planet, reach its greatest brilliancy and stand at its highest as an evening star.
By our map times, a little later in the evening, Orion has progressed into the south-south-west and Sirius, nipping at his heel as the Dog Star in Canis Major, stands lower down on the meridian. All stars twinkle as their light, from effectively a single point in space, is refracted by turbulence in the Earth’s atmosphere, but Sirius’ multi-hued scintillation is most noticeable simply because it is so bright. On the whole, planets do not twinkle since their light comes from a small disk and not a point.
I mentioned two months ago how Sirius, Betelgeuse at Orion’s shoulder and Procyon, the Lesser Dog Star to the east of Betelgeuse, form a near-perfect equilateral triangle we dub the Winter Triangle. Another larger but less regular asterism, the Winter Hexagon, can be constructed around Betelgeuse. Its sides connect Capella, Aldebaran in Taurus, Rigel at Orion’s knee, Sirius, Procyon and Castor and Pollux in Gemini, the latter pair considered jointly as one vertex of the hexagon.
Aldebaran, found by extending the line of Orion’s Belt up and to the right, just avoids being hidden (occulted) by the Moon on the 5th. At about 22:20 GMT, the northern edge of the Moon slides just 5 arcminutes, or one sixth of the Moon’s diameter, below and left of the star. Earlier that evening, the Moon occults several stars of V-shaped Hyades cluster which, together with Aldebaran, form the Bull’s face.
Sunrise/sunset times for Edinburgh change from 08:07/16:46 on the 1st to 07:06/17:45 on the 28th. The Moon is at first quarter on the 4th and lies to the west of Regulus in Leo when full just after midnight on the night of the 10th/11th. It is then blanketed by the southern part of the Earth’s outer shadow in a penumbral lunar eclipse. The event lasts from 22:34 until 02:53 with an obvious dimming of the upper part of the Moon’s disk apparent near mid-eclipse at 00:33. This time, the Moon misses the central dark umbra of the shadow where all direct sunlight is blocked by the Earth, but only by 160 km or 5% of its diameter.
Following last quarter on the 18th, the Moon is new on the 26th when the narrow track of an annular solar eclipse crosses the south Atlantic from Chile and Argentina to southern Africa. Observers along the track see the Moon’s ink-black disk surrounded by a dazzling ring of sunlight while neighbouring regions, but not Europe, enjoy a partial eclipse of the Sun.
Venus, below and to the right of the crescent Moon as the month begins, stands at it’s highest in the south-west at sunset on the 11th and 12th and blazes at magnitude -4.6, reaching its greatest brilliancy on the 17th. It stands further above-and to the right of the slim impressively-earthlit Moon again on the 28th.
Viewed through a telescope, Venus’ dazzling crescent swells in diameter from 31 to 47 arcseconds and the illuminated portion of the disk shrinks from 40% to 17%. Indeed, steadily-held binoculars should be enough to glimpse its shape. This month its distance falls from 81 million to 53 million km as it begins to swing around its orbit to pass around the Sun’s near side late in March.
Mars stands above and to the left of Venus but is fainter and dimming further from magnitude 1.1 to 1.3 during February. It appears closest to Venus, 5.4°, on the 2nd but the gap between them grows to 12° by the 28th as they track eastwards and northwards through Pisces. Both set before our map times at present but our charts pick them up at midmonth as they pass below-left of Algenib, the star at the bottom-left corner of the Square of Pegasus.
Mars shrinks below 5 arcseconds in diameter this month so few surface details are visible telescopically. This is certainly not the case with Jupiter, whose intricately-detailed cloud-banded disk swells from 39 to 42 arcseconds. We do need to wait, though, for two hours beyond our map times for Jupiter to rise in the east and until the pre-dawn hours for it to stand at its highest in the south. Second only to Venus, it shines at magnitude -2.1 to -2.3 and lies almost 4° due north of Virgo’s leading star Spica where it appears stationary on the 6th when its motion switches from easterly to westerly. Look for the two below-left of the Moon on the 15th and to the right of the Moon on the 16th.
Saturn is a morning object, low down in the south-east after its rises for Edinburgh at 05:25 on the 1st and by 03:48 on the 28th. At magnitude 0.6 to 0.5, it stands on the Ophiuchus-Sagittarius border where it is below-right of the waning Moon on the 21st. It is a pity that telescopic views are hindered by its low altitude because Saturn’s disk, 16 arcseconds wide, is set within wide-open rings which measure 16 by 36 arcseconds and have their northern face tipped 27° towards the Earth. Mercury remains too deep in our south-eastern morning twilight to be seen this month. | 0.815927 | 3.573727 |
“The Milky Way and other galaxies in the universe harbor many young star clusters and associations that each contain hundreds to thousands of hot, massive, young stars known as O and B stars. The star cluster Cygnus OB2 contains more than 60 O-type stars and about a thousand B-type stars. Deep observations with NASA’s Chandra X-ray Observatory have been used to detect the X-ray emission from the hot outer atmospheres, or coronas, of young stars in the cluster and to probe how these fascinating star factories form and evolve. About 1,700 X-ray sources were detected, including about 1,450 thought to be stars in the cluster. In this image, X-rays from Chandra (blue) have been combined with infrared data from NASA’s Spitzer Space Telescope (red) and optical data from the Isaac Newton Telescope (orange).
Young stars ranging in age from one million to seven million years were found. The infrared data indicates that a very low fraction of the stars have circumstellar disks of dust and gas. Even fewer disks were found close to the massive OB stars, betraying the corrosive power of their intense radiation that leads to early destruction of their disks. There is also evidence that the older population of stars has lost its most massive members because of supernova explosions. Finally, a total mass of about 30,000 times the mass of the sun is derived for Cygnus OB2, similar to that of the most massive star forming regions in our Galaxy. This means that Cygnus OB2, located only about 5,000 light years from Earth, is the closest massive star cluster.
NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.”
Image credit: (NASA Marshall Space Flight Center, Chandra, 11/07/12) X-ray: NASA/CXC/SAO/J.Drake et al, Optical: Univ. of Hertfordshire/INT/IPHAS, Infrared: NASA/JPL-Caltech; Text credit: Harvard-Smithsonian Center for Astrophysics | 0.866367 | 3.719187 |
At first, it was just another bright, fuzzy speck in the sky. But it may turn out to be something much more exciting: the second known object to hurtle through our solar system after leaving another system.
Astronomers will need a lot more observations before they can be confident giving the comet that title, but early data about the object seems promising. That would make the comet, currently known as Comet C/2019 Q4 (Borisov) after the person who first spotted it, the first traveling successor to the interstellar object 'Oumuamua, which was discovered in October 2017.
"Based on the available observations, the orbit solution for this object has converged to the hyperbolic elements shown below, which would indicate an interstellar origin," read the Minor Planet Electronic Circular about the object.
Such a statement is issued on behalf of the International Astronomical Union by the Smithsonian Astrophysical Observatory when observers have registered enough data about an object to begin calculating its path through space.
The vast majority of asteroids and comets that astronomers have tracked to date follow an elliptical orbit: oval or egg-shaped or nearly circular. These objects spend eons looping through the solar system, perhaps kicked around a bit after straying too close to a planet and getting tugged off course. They were made in our solar system and remain trapped here, pacing around the sun's mass.
But as the Minor Planet Electronic Circular noted, for C/2019 Q4, the data so far suggest that its path is a hyperbola, with the object arcing in from beyond our solar system and destined to leave the neighborhood again soon. That's a trajectory scientists have so far seen only from 'Oumuamua, although estimates suggest that these visitors should charge through our solar system fairly regularly. (A few months ago, scientists suggested a meteorite that hit Earth in 2014 may also have been interstellar.)
A Ukrainian skywatcher named Gennady Borisov made the first sighting of C/2019 Q4, on Aug. 30, and caught sight of it again two days later. Since then, six other astronomers have filed observations to the Minor Planet Center's data hub, which houses the Minor Planet Electronic Circular. The data cover Aug. 30 to Sept. 8.
Here's an image of the possible interstellar comet, taken by G. Borisov, who discovered it. (HT @TM_Eubanks) pic.twitter.com/gK22iSfR43September 11, 2019
Astronomers hope that those sightings will soon have plenty of company. "Further observations are clearly very desirable, as all currently available observations have been obtained at small solar elongations and low elevations," the circular continued.
And there should be plenty of opportunities for observers to gather more data about C/2019 Q4. The search may need to pause for a month or so because of the object's proximity to the sun, but Borisov spotted the comet early enough in its journey that astronomers should be able to study it for at least a year, according to the circular. That's in stark contrast to 'Oumuamua, which was already waving goodbye to our solar system when scientists spotted it.
Comet C/2019 Q4, in contrast, is the kind of interstellar candidate that the European Space Agency (ESA) hopes to study via a mission called Comet Interceptor in just a few years. That mission consists of a trio of spacecraft that ESA wants to send to an Oort Cloud object or an interstellar object, depending on what observations are available as planning progresses.
According to a statement from ESA, C/2019 Q4 is a couple miles (a few kilometers) across and will pass closest to the sun, about 186 million miles (300 million km) away from the sun, in early December. That's about twice the average distance between Earth and the sun.
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Scientists Detect a Black Hole Swallowing a Neutron Star
Scientists, including from The Australian National University (ANU), say they have detected a black hole swallowing a neutron star for the first time. Neutron stars and black holes are the super-dense remains of dead stars.
On Wednesday 14 August 2019, gravitational-wave discovery machines in the United States and Italy detected ripples in space and time from a cataclysmic event that happened about 8,550 million trillion kilometers away from Earth.
Professor Susan Scott, from the ANU Research School of Physics, said the achievement completed the team’s trifecta of observations on their original wish list, which included the merger of two black holes and the collision of two neutron stars.
Professor Scott, leader of the General Relativity Theory and Data Analysis Group at ANU and a Chief Investigator with the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), said:
“About 900 million years ago, this black hole ate a very dense star, known as a neutron star, like Pac-man — possibly snuffing out the star instantly.
“The ANU SkyMapper Telescope responded to the detection alert and scanned the entire likely region of space where the event occurred, but we’ve not found any visual confirmation.”
Scientists are still analyzing the data to confirm the exact size of the two objects, but initial findings indicate the very strong likelihood of a black hole enveloping a neutron star. The final results are expected to be published in Scientific Journals. Professor Scott said:
“Scientists have never detected a black hole smaller than five solar masses or a neutron star larger than about 2.5 times the mass of our Sun.
“Based on this experience, we’re very confident that we’ve just detected a black hole gobbling up a neutron star.
“However, there is the slight but intriguing possibility that the swallowed object was a very light black hole – much lighter than any other black hole we know about in the Universe. That would be a truly awesome consolation prize.”
ANU plays a lead role in Australia’s partnership with the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), which is the most sensitive scientific instrument ever built and comprises twin detectors in the U.S.
The European Gravitational Observatory has a gravitational-wave detector in Italy called Virgo.
Provided by: Australian National University[Note: Materials may be edited for content and length.]
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Courtesy of Vision Times : | 0.825033 | 3.525548 |
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