Excerpt from techtimes.comMany of the technologies that are in use today such as the airplane and the internet were once ideas that became reality and it appears that this still goes true with the innovations of the future. Take for instance ...
Tag: astronomer (page 1 of 6)
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| The Antennae galaxies, shown in visible light in a Hubble image (upper image), were studied with ALMA, revealing extensive clouds of molecular gas (center right image). One cloud (bottom image) is incredibly dense and massive, yet apparently star free, suggesting it is the first example of a prenatal globular cluster ever identified. |
Excerpt from huffingtonpost.com
A dense cloud of gas 50 million light-years away has astronomers buzzing, and they're using all sorts of strange metaphors to get the rest of us to pay attention.
They've discovered what they think may be a globular cluster -- a big ball of up to one million stars -- on the verge of being born.
“This remarkable object looks like it was plucked straight out of the very early universe," Dr. Kelsey Johnson, an astronomer at the University of Virginia in Charlottesville and lead author on a paper about the research, said in a written statement. "To discover something that has all the characteristics of a globular cluster, yet has not begun making stars, is like finding a dinosaur egg that’s about to hatch.”
ALMA image of dense cores of molecular gas in the Antennae galaxies. The round yellow object near the center may be the first prenatal example of a globular cluster ever identified. It is surrounded by a giant molecular cloud.
Johnson and her colleagues spotted the bizarre object, which they call the "Firecracker," using the Atacama Large Millimeter/submillimeter Array (ALMA) in the Atacama desert in Chile. It's located inside a pair of interacting galaxies known to scientists as NGC 4038/NGC 4039, or The Antennae Galaxies.
The Firecracker has a mass that's 50 times that of our sun, and is under an enormous amount of pressure -- roughly 10,000 times greater than the average pressure in interstellar space. According to the researchers, this makes it a good candidate for collapsing into a globular cluster within the next million years.
What do other scientists make of the discovery? Dr. Alison Peck, ALMA scientist at the National Radio Astronomy Observatory, who was not involved in the new research, called it "important" and said she was "really excited to hear about these results."
She told The Huffington Post in an email:
"One of the things that we all yearn to understand is how our surroundings formed, how our galaxy and our solar system came to be. To do this, since we can’t actually watch things change over time, (it just takes too long), we need to find similar objects at different stages of development and compare them. What Dr. Johnson’s team have found here is an analog of an object that we look for in the very early universe, but they’ve found it so close by that we’ll be able to make extremely detailed observations and find out much more about the physical conditions in this exciting region."The research is set to be published in the Astrophysical Journal.
Excerpt from dailytimes.com.pk
The sun has unleashed its most powerful flare of the year causing radio blackouts throughout the Pacific region.
The enormous X-class solar flare peaked at 6:11pm ET yesterday from a sunspot called Active Region 2339 (AR2339).
Solar flares are powerful bursts of radiation that, when intense enough, can disturb the atmosphere in the layer where GPS and communications signals travel - and scientists say they could get more powerful in the future.
This latest flare is classified as an X2.7. X-class denotes the most intense flares, while the number provides more information about its strength.
Despite the recent radio blackouts, scientists say the flare is unlikely to cause any further major issues here on Earth.
‘Given the impulsive nature of this event, as well as the source location on the eastern limb of the sun, we are not expecting a radiation storm at Earth,’ scientists with the U.S. Space Weather Prediction Center (SWPC) in Boulder, Colorado.
‘We will be on the lookout for new imagery from the Nasa Soho [Solar and Heliospheric Observatory] mission to determine if there was an associated coronal mass ejection (CME) with this event,’ they added.
‘Given the same logic above, however, we do not expect there to be one that would impact Earth.’
Yesterday Kazunari Shibata, an astrophysicist from Kyoto University in Japan, said the sun has the potential to unleash a flare of such a magnitude that it would be larger than anything humans have ever seen.
At the Space Weather Workshop in Colorado, Shibata said ‘superflares,’ that contain energy 1,000 times larger than what we have seen could be on their way.
He said there is evidence of this happening every 800 to 5,000 years on Earth,
Scientists say such a solar ‘super-storm’ would pose a ‘catastrophic’ and ‘long-lasting’ threat to life on Earth.
A superflare would induce huge surges of electrical currents in the ground and in overhead transmission lines, causing widespread power outages and severely damaging critical electrical components.
The largest ever solar super-storm on record occurred in 1859 and is known as the Carrington Event, named after the English astronomer Richard Carrington who spotted the preceding solar flare.
This massive CME released about 1022 kJ of energy - the equivalent to 10 billion Hiroshima bombs exploding at the same time - and hurled around a trillion kilos of charged particles towards the Earth at speeds of up to 3000 km/s.
However, its impact on the human population was relatively benign as our electronic infrastructure at the time amounted to no more than about 124,000 miles (200,000 km) of telegraph lines.
Nasa has also released incredible footage showing the sun unleashing a huge lick of plasma that increased the star’s visible hemisphere by almost half.
The solar filament, which exploded on April 28 and 29, was suspended above the sun due to strong magnetic fields that pushed outwards.
Solar astronomers around the world had their eyes on this unusually large filament and kept track as it erupted.
Nasa’s animation involves images taken from the orbiting Solar and Heliospheric Observatory using its Large Angle Spectrometric Coronagraph.
The diameter of the animation is about 30 million miles (45 million km) at the distance of the sun, or half of the diameter of the orbit of Mercury.
The white circle in the centre of the round disk represents the size of the sun, which is being blocked by the telescope in order to see the fainter material around it.
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| Astronomers have discovered a baby blue galaxy that is the furthest away in distance and time - 13.1 billion years - that they’ve ever seen. Photo: Pascal Oesch and Ivelina Momcheva, NASA, European Space Agency via AP |
Excerpt from smh.com.au
A team of astronomers peering deep into the heavens have discovered the earliest, most distant galaxy yet, just 670 million years after the Big Bang.
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| Close-up of the blue galaxy |
"We're actually looking back through 95 per cent of all time to see this galaxy," said study co-author Garth Illingworth, an astronomer at the University of California, Santa Cruz.
"It's really a galaxy in its infancy ... when the universe was in its infancy."
Capturing an image from a far-off light source is like looking back in time. When we look at the sun, we're seeing a snapshot of what it looked like eight minutes ago.
The same principle applies for the light coming from the galaxy known as EGS-zs8-1. We are seeing this distant galaxy as it existed roughly 13.1 billion years ago.
EGS-zs8-1 is so far away that the light coming from it is exceedingly faint. And yet, compared with other distant galaxies, it is surprisingly active and bright, forming stars at roughly 80 times the rate the Milky Way does today.
This precocious little galaxy has built up the mass equivalent to about 8 billion suns, more than 15 per cent of the mass of the Milky Way, even though it appears to have been in existence for a mere fraction of the Milky Way's more than 13 billion years.
"If it was a galaxy near the Milky Way [today], it would be this vivid blue colour, just because it's forming so many stars," Illingworth said.
One of the many challenges with looking for such faint galaxies is that it's hard to tell if they're bright and far, or dim and near. Astronomers can usually figure out which it is by measuring how much that distant starlight gets stretched, "redshifted", from higher-energy light such as ultraviolet down to optical and then infrared wavelengths. The universe is expanding faster and faster, so the further away a galaxy is, the faster it's going, and the more stretched, or "redder", those wavelengths of light will be.
The astronomers studied the faint light from this galaxy using NASA's Hubble and Spitzer space telescopes. But EGS-zs8-1 seemed to be too bright to be coming from the vast distances that the Hubble data suggested.
To narrow in, they used the MOSFIRE infrared spectrograph at the Keck I telescope in Hawaii to search for a particularly reliable fingerprint of hydrogen in the starlight known as the Lyman-alpha line. This fingerprint lies in the ultraviolet part of the light spectrum, but has been shifted to redder, longer wavelengths over the vast distance between the galaxy and Earth.
It's a dependable line on which to base redshift (and distance) estimates, Illingworth said - and with that settled, the team could put constraints on the star mass, star formation rate and formation epoch of this galaxy.
The telltale Lyman-alpha line also reveals the process through which the universe's haze of neutral hydrogen cleared up, a period called the epoch of reionisation. As stars formed and galaxies grew, their ultraviolet radiation eventually ionised the hydrogen and ended the "dark ages" of the cosmos.
Early galaxies-such as EGS-zs8-1 - are "probably the source of ultraviolet radiation that ionised the whole universe", Illingworth said.
Scientists have looked for the Lyman-alpha line in other distant galaxies and come up empty, which might mean that their light was still being blocked by a haze of neutral hydrogen that had not been ionised yet.
But it's hard to say with just isolated examples, Illingworth pointed out. If scientists can survey many galaxies from different points in the universe's very early history, they can have a better sense of how reionisation may have progressed.
"We're trying to understand how many galaxies do have this line - and that gives us some measure of when the universe itself was reionised," Illingworth said.
"One [galaxy] is interesting, but it's when you have 50 that you can really say something about what galaxies were really like then."
As astronomers push the limits of current telescopes and await the completion of NASA's James Webb Space Telescope, set for launch in 2018, scientists may soon find more of these galaxies even closer to the birth of the universe than this new record breaker.
"You don't get to be record holder very long in this business," Illingworth said, "which is good because ultimately we are trying to learn about the universe. So more is better."
Excerpt from huffingtonpost.comIntroductionWhy is it so hard to find ET? After 50 years of searching, the SETI project has so far found nothing. In the latest development, on April 14, 2015 Penn State researchers announced that after searching through...
An artist's impression of the planet HATS-6b, orbiting the star, HATS-6. (Supplied: ANU) Excerpt from abc.net.au A "puffy" new planet orbiting a small, cool star has been discovered 500 light years away from Earth, by a team of scientists c...
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The Hooker 100-inch reflecting telescope at the Mount Wilson Observatory, just outside Los Angeles. Edwin Hubble's chair, on an elevating platform, is visible at left. A view from this scope first told Hubble our galaxy isn't the only one. Courtesy of The Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, Calif. |
Excerpt from hnpr.org
The Hubble Space Telescope this week celebrates 25 years in Earth's orbit. In that time the telescope has studied distant galaxies, star nurseries, planets in our solar system and planets orbiting other stars.
But, even with all that, you could argue that the astronomer for whom the telescope is named made even more important discoveries — with far less sophisticated equipment.
A young Edwin Hubble at Mount Wilson's 100-inch telescope circa 1922, ready to make history.
Edwin Hubble Papers/Courtesy of Huntington Library, San Marino, Calif.
In the 1920s, Edwin Hubble was working with the 100-inch Hooker telescope on Mount Wilson, just outside Los Angeles. At the time, it was the largest telescope in the world.
On a chilly evening, I climb up to the dome of that telescope with operator Nik Arkimovich and ask him to show me where Hubble would sit when he was using the telescope. Arkimovich points to a platform near the top of the telescope frame.
"He's got an eyepiece with crosshairs on it," Arkimovich explains. The telescope has gears and motors that let it track a star as it moves across the sky. "He's got a paddle that allows him to make minor adjustments. And his job is to keep the star in the crosshairs for maybe eight hours."
"It's certainly much, much easier today," says John Mulchaey, acting director of the observatories at Carnegie Institution of Science. "Now we sit in control rooms. The telescopes operate brilliantly on their own, so we don't have to worry about tracking and things like this."
The headquarters of the Carnegie observatories is at the foot of Mount Wilson, in the city of Pasadena. It's where Hubble worked during the day.
A century's worth of plates are stored here in the basement. Mulchaey opens a large steel door and ushers me into a room filled with dozens of file cabinets.
"Why don't we go take a look at Hubble's famous Andromeda plates," Mulchaey suggests.
The plates are famous for a reason: They completely changed our view of the universe. Mulchaey points to a plate mounted on a light stand.
"This is a rare treat for you," he says. "This plate doesn't see the light of day very often."
This glass side of a photographic plate shows where Hubble marked novas. The red VAR! in the upper right corner marks his discovery of the first Cepheid variable star — a star that told him the Andromeda galaxy isn't part of our Milky Way.
Courtesy of the Carnegie Observatories
The plate shows the spiral shape of the Andromeda galaxy. Hubble was looking for exploding stars called novas in Andromeda. Hubble marked these on the plate with the letter "N."
"The really interesting thing here," Mulchaey says, "is there's one with the N crossed out in red — and he's changed the N to VAR with an exclamation point."
Hubble had realized that what he was seeing wasn't a nova. VAR stands for a type of star known as a Cepheid variable. It's a kind of star that allows you to make an accurate determination of how far away something is. This Cepheid variable showed that the Andromeda galaxy isn't a part of our galaxy.
At the time, most people thought the Milky Way was it — the only galaxy in existence.
"And what this really shows is that the universe is much, much bigger than anybody realizes," Mulchaey says.
It was another blow to our human conceit that we are the center of the universe.
Hubble went on to use the Mount Wilson telescope to show the universe was expanding, a discovery so astonishing that Hubble had a hard time believing it himself.
If Hubble could make such important discoveries with century-old equipment, it makes you wonder what he might have turned up if he'd had a chance to use the space telescope that bears his name.
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| The James Webb Telescope |
Excerpt from space.com
A telescope will soon allow astronomers to probe the atmosphere of Earthlike exoplanets for signs of life. To prepare, astronomer Lisa Kaltenegger and her team are modeling the atmospheric fingerprints for hundreds of potential alien worlds. Here's how:
The James Webb Space Telescope, set to launch in 2018, will usher a new era in our search for life beyond Earth. With its 6.5-meter mirror, the long-awaited successor to Hubble will be large enough to detect potential biosignatures in the atmosphere of Earthlike planets orbiting nearby stars.
And we may soon find a treasure-trove of such worlds. The forthcoming exoplanet hunter TESS (Transiting Exoplanet Survey Satellite), set to launch in 2017, will scout the entire sky for planetary systems close to ours. (The current Kepler mission focuses on more distant stars, between 600 and 3,000 light-years from Earth.)
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| Astronomer Lisa Kaltenegger |
While TESS will allow for the brief detection of new planets, the larger James Webb will follow up on select candidates and provide clues about their atmospheric composition. But the work will be difficult and require a lot of telescope time.
"We're expecting to find thousands of new planets with TESS, so we'll need to select our best targets for follow-up study with the Webb telescope," says Lisa Kaltenegger, an astronomer at Cornell University and co-investigator on the TESS team.
To prepare, Kaltenegger and her team at Cornell's Institute for Pale Blue Dots are building a database of atmospheric fingerprints for hundreds of potential alien worlds. The models will then be used as "ID cards" to guide the study of exoplanet atmospheres with the Webb and other future large telescopes.
Kaltenegger described her approach in a talk for the NASA Astrobiology Institute's Director Seminar Series last December.
"For the first time in human history, we have the technology to find and characterize other worlds," she says. "And there's a lot to learn."
Detecting life from space
In its 1990 flyby of Earth, the Galileo spacecraft took a spectrum of sunlight filtered through our planet's atmosphere. In a 1993 paper in the journal Nature, astronomer Carl Sagan analyzed that data and found a large amount of oxygen together with methane — a telltale sign of life on Earth. These observations established a control experiment for the search of extraterrestrial life by modern spacecraft."The spectrum of a planet is like a chemical fingerprint," Kaltenegger says. "This gives us the key to explore alien worlds light years away."
Current telescopes have picked up the spectra of giant, Jupiter-like exoplanets. But the telescopes are not large enough to do so for smaller, Earth-like worlds. The James Webb telescope will be our first shot at studying the atmospheres of these potentially habitable worlds.
Some forthcoming ground-based telescopes — including the Giant Magellan Telescope (GMT), planned for completion in 2020, and the European Extremely Large Telescope (E-ELT), scheduled for first light in 2024 — may also be able to contribute to that task. [The Largest Telescopes on Earth: How They Compare]
And with the expected discovery by TESS of thousands of nearby exoplanets, the James Webb and other large telescopes will have plenty of potential targets to study. Another forthcoming planet hunter, the Planetary Transits and Oscillations of stars (PLATO), a planned European Space Agency mission scheduled for launch around 2022-2024, will contribute even more candidates.
However, observation time for follow-up studies will be costly and limited.
"It will take hundreds of hours of observation to see atmospheric signatures with the Webb telescope," Kaltenegger says. "So we'll have to pick our targets carefully."
Set to see its first light in 2021, The Giant Magellan Telescope will be the world’s largest telescope.
Getting a head start
To guide that process, Kaltenegger and her team are putting together a database of atmospheric fingerprints of potential alien worlds. "The models are tools that can teach us how to observe and help us prioritize targets," she says.To start, they have modeled the chemical fingerprint of Earth over geological time. Our planet's atmosphere has evolved over time, with different life forms producing and consuming various gases. These models may give astronomers some insight into a planet's evolutionary stage.
Other models take into consideration the effects of a host of factors on the chemical signatures — including water, clouds, atmospheric thickness, geological cycles, brightness of the parent star, and even the presence of different extremophiles.
"It's important to do this wide range of modeling right now," Kaltenegger said, "so we're not too startled if we detect something unexpected. A wide parameter space can allow us to figure out if we might have a combination of these environments."
She added: "It can also help us refine our modeling as fast as possible, and decide if more measurements are needed while the telescope is still in space. It's basically a stepping-stone, so we don't have to wait until we get our first measurements to understand what we are seeing. Still, we'll likely find things we never thought about in the first place."
A new research center
The spectral database is one of the main projects undertaken at the Institute for Pale Blue Dots, a new interdisciplinary research center founded in 2014 by Kaltenegger. The official inauguration will be held on May 9, 2015."The crux of the institute is the characterization of rocky, Earth-like planets in the habitable zone of nearby stars," Kaltenergger said. "It's a very interdisciplinary effort with people from astronomy, geology, atmospheric modeling, and hopefully biology."
She added: "One of the goal is to better understand what makes a planet a life-friendly habitat, and how we can detect that from light years away. We're on the verge of discovering other pale blue dots. And with Sagan's legacy, Cornell University is a really great home for an institute like that."
A Type Ia supernova, SN1994D, is shown exploding in lower left corner of the image at the top of the page of the galaxy NGC 4526 taken by the Hubble Space Telescope. (High-Z Supernova Search Team, HST, NASA)Excerpt from dailygalaxy.com Cer...
Excerpt from huffingtonpost.com
No one really knows whether we're alone or if the universe is brimming with brainy extraterrestrials. But that hasn't stopped scientists from trying to figure out what form intelligent aliens might take.
And as University of Barcelona cosmologist Dr. Fergus Simpson argues in a new paper, most intelligent alien species would likely exceed 300 kilograms (661 pounds)--with the median body mass "similar to that of a polar bear."
If such a being had human proportions, Simpson told The Huffington Post in an email, it would be taller than Robert Wadlow, who at 8 feet, 11 inches is believed to have been the tallest human who ever lived.
Robert Wadlow (1918-1940), the tallest man who ever lived.Simpson's paper, which is posted on the online research repository arXiv.org, is chockablock with formidable-looking mathematical equations. But as he explained in the email, his starting point was to consider the relationship between the number of individuals in a population on Earth and the body mass of those individuals:
"Ants easily outnumber us because they are small. Our larger bodies require a much greater energy supply from the local resources, so it would be impossible for us to match the ant population. Now apply this concept to intelligent life across the universe. On average, we should expect physically larger species to have fewer individuals than the smaller species. And, just like with countries, we should expect to be in one of the bigger populations. In other words, we are much more likely to find ourselves to be the ants among intelligent species."
Or, as Newsweek explained Simpson's argument, there are probably more planets with relatively small animals than planets with relatively large animals. It makes sense to assume that Earth is in the former category, so we can assume that humans are probably among the smaller intelligent beings.
What do other scientists make of Simpson's paper?
“I think the average size calculation is reasonable,” Dr. Duncan Forgan, an astrobiologist at the University of St. Andrews in Scotland who wasn't involved in the research, told Newsweek.
But to Dr. Seth Shostak, senior astronomer at the SETI Institute in Mountain View, Calif., the argument is suspect.
"There is an assumption here that intelligence can come in all (reasonable) sizes, and does so with more or less equal likelihood," Shostak told The Huffington Post in an email. "That may be true, but on Earth bigger has not always been better, at least in the brains department. Dolphins have higher IQs than whales, and crows are smarter than eagles. Octopuses are cleverer than giant squids, and obviously we’re smarter than polar bears."
Ultimately, Shostak said, we can’t know whether "little green men are actually big green men" before we actually make contact.
Until then!
Excerpt from stgist.com
The sun, or the nearest star from Earth, was formed around 5 billion years after the Milky Way galaxy’s peak production of stars, a new research published in the Astrophysical Journal.
It’s like traveling back in time. Researchers from Texas A&M University in College Station, headed by astronomer Casey Papovich, were able to see the undepicted past of our own galaxy by observing similar regions located billions of light years away from us.
The “baby boom” happened around 10 billion years ago, the new study published in Astrophysical Journal revealed. At that time, the Milky Way galaxy was producing 30 times more stars than today. If so, then our solar system’s 4.6 billion years old Sun was formed more than 5 billion years after the production peak.
Sun’s late formation allowed the solar system we know today to produce planets with heavier elements. Scientists say elements heavier than hydrogen and helium became more abundant in “late to the game systems”, and the death of massive stars that were formed before the Sun had provided materials needed to form planets, including Earth and its complex life forms.
Scientists scanned through a collection of more than 24,000 galaxies, and took at least 2,000 snapshots of galaxies that closely resemble our own. The census has provided the most complete picture yet of how spiral galaxies similar to Milky Way form in the universe.
According to Mr. Papovich, the lead author of the study who also serves as an associate professor in the Department of Physics and Astronomy at A&M University in Texas, they know where to find traces by analyzing how galaxies like our own were formed.
Papovich said his team has provided a data that clearly show the rapid phase of growth around 9 to 10 billion years ago, or at least more than 5 billion years after our Sun formed. They also found the connection between the size of the galaxy, and the formation of stars.
Surprisingly, the robust collection of distant galaxies confirmed that stars formed inside the Milky Way, instead of forming in other smaller baby galaxies that later merged to join the system.
In separate studies, scientists were able to confirm that our own solar system is wetter than thought. Beyond Earth, celestial objects like Jupiter’s Galilean moons Europa and Ganymede, Saturn’s Enceladus, and even the dwarf planet Ceres in the asteroid belt, are hosting fluid slightly similar to Earth’s — and it is highly possible that the Sun’s late formation allowed this setup to exist.
Papovich who worked alongside Texas A&M postdoctoral researchers Vithal Tilvi and Ryan Quadri, were joined by at least two dozen astronomers from other countries. The research is published April 9th entitled “ZFOURGE/CANDELS: ON THE EVOLUTION OF M* GALAXY PROGENITORS FROM z = 3 TO 0.5*.” The research was funded by NASA
Excerpt from huffingtonpost.comNASA's top scientist predicts that we'll find signs of alien life by 2025, with even stronger evidence for extraterrestrials in the years that follow. "I think we're going to have strong indications of life beyond Ea...
Excerpt from wired.com
In 2007, A Dutch schoolteacher named Hanny var Arkel discovered a weird green glob of gas in space. Sifting through pictures of galaxies online, as part of the citizen science project Galaxy Zoo, she saw a cloud, seemingly glowing, sitting next to a galaxy. Intrigued, astronomers set out to find more of these objects, dubbed Hanny’s Voorwerp (“Hanny’s object” in Dutch). Now, again with the help of citizen scientists, they’ve found 19 more of them, using the Hubble space telescope to snap the eight haunting pictures in the gallery above.
Since var Arkel found the first of these objects, hundreds more volunteers have swarmed to help identify parts of the universe in the Galaxy Zoo gallery. To find this new set, a couple hundred volunteers went through nearly 16,000 pictures online (seven people went through all of them), clicking yes/no/maybe as to whether they saw a weird green blob. Astronomers followed up on the galaxies they identified using ground-based telescopes, and confirmed 19 new galaxies surrounded by green gas.
What causes these wispy tendrils of gas to glow? Lurking at the center of each of these galaxies is a supermassive black hole, millions to billions times as massive as the sun, with gravity so strong that even light can’t escape them. As nearby gas and dust swirls into the black hole, like water circling a drain, that material heats up, producing lots of radiation—including powerful ultraviolet. Beaming out from the galaxy, that ultraviolet radiation strikes nearby clouds of gas, left over from past collisions between galaxies. And it makes the clouds glow an eerie green. “A lot of these bizarre forms we’re seeing in the images arise because these galaxies either interacted with a companion or show evidence they merged with a smaller galaxy,” says William Keel, an astronomer at the University of Alabama, Tuscaloosa.
The eight in this gallery, captured with Hubble, are especially weird. That’s because the quasar, the black-hole engine that’s supposed to be churning out the ultraviolet radiation, is dim—too dim, in fact, to be illuminating the green gas. Apparently, the once-bright quasar has faded. But because that UV light takes hundreds of thousands of years to travel, it can continue to illuminate the gas long after its light source has died away.
That glowing gas can tell astronomers a lot about the quasar that brought it to light. “What I’m so excited about is the fact that we can use them to do archaeology,” says Gabriela Canalizo, an astronomer at the University of California, Riverside, who wasn’t part of the new research. Because the streaks of gas are so vast, stretching up to tens of thousands of light years, the way they glow reveals the history of the radiation coming from the quasar. As the quasar fades, so will the gas’s glow, with the regions of gas closer to the quasar dimming first. By analyzing how the glow dwindles with distance from the quasar, astronomers can determine how fast the quasar is fading. “This was something we’ve never been able to do,” Canalizo says.
Measuring how fast the quasar fades allows astronomers to figure out exactly what’s causing it to turn off in the first place. “What makes them dim is running out of material to eat,” Canalizo says. That could happen if the quasar is generating enough radiation to blow away all the gas and dust surrounding the black hole—the same gas and dust that feeds it. Without a steady diet, the quasar is powerless to produce radiation. Only if more gas happens to make its way toward the black hole can the quasar turn on again. The glowing gas can provide details of this process, and if other mechanisms are at play.
With more powerful telescopes, astronomers will likely find many more. Hanny’s Verwoort, it turns out, may not be that weird after all.
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