(THIS ARTICLE IS COURTESY OF CNN)
Scientists have discovered a ‘monster’ black hole that’s so big it shouldn’t exist
(CNN)Scientists have discovered a “monster black hole” so massive that, in theory, it shouldn’t exist.
(THIS ARTICLE IS COURTESY OF CNN)
(CNN)Scientists have discovered a “monster black hole” so massive that, in theory, it shouldn’t exist.
(THIS ARTICLE IS COURTESY OF TRIVIA GENIUS)
Picture this. You’re camping with your family and it’s a clear night. As you look up into the night sky, it feels like there are a thousand stars, and they’re bright enough to touch. You feel the impact of how small you are in the grand scheme of things. And then your mind wanders as you try to wrap your head around how big the universe is. If this question has been keeping you up at night, we have the answer.
There was a time when we couldn’t give you a hard figure. But as far back as 1920, astronomers have been sharing estimates on the size of the known universe. Before we dig into hard figures, best guesses, and even erroneous ones, we need to set some ground rules.
First, the universe is constantly expanding. Any measurements given today won’t be accurate in the future. Likewise, scientists and astronomers can give only measurements based on the observable or known universe. This references what can be seen through their telescope, whether on the ground or with a satellite. Much like the expanding universe factor, dimensions based on the observable universe can be limited.
In other words, based on current research, observations and mathematical equations, the experts can estimate the universe’s size within a fair degree of certainty. But the caveat will always apply that these figures are impacted by the universe’s growth rate and the limitation of the observable universe.
Slow down there! Another important note is that we aren’t measuring in miles or kilometers like we would the distance between New York and London. Instead, we use light-years when we’re discussing the distance between two bodies in space. Standard forms of measurement would be too impractical because, in space, celestial bodies are very far apart.
Speaking literally, a light-year describes the distance a beam of light can travel in one year. To help you quantify that and realize why light years are better than traditional Earth-distance measurements, one light0year is the equivalent of 6 trillion miles. If you got dizzy just hearing that, now you know why astronomers prefer light-years over miles or kilometers.
Initial size estimates of our universe began with measuring our galaxy, the Milky Way. In 1920 the American astronomer Harlow Shapley was one of the first experts who attempted to measure the Milky Way and came up with a diameter of 300,000 light-years. It turns out he was very wrong, as today most astronomers believe our Milky Way is somewhere between 100,000 and 150,000 light years in diameter.
For perspective, we know that the Milky Way isn’t the only galaxy in our universe — nor is it the biggest. Current counts estimate that there are at least 100 billion galaxies in the known universe and the largest discovered galaxy to date is IC 1101 with a diameter of 6 million light-years (although this figure is contested). So if our little corner of the universe is 100,000 light-years wide, and the biggest galaxy is around 6 million light-years in diameter, that can give you a hint that the known universe is quite large.
Current measurements place the observable universe at roughly 93 billion light-years in diameter. There are a variety of methods used to reach this figure, but popular options include measuring radio wavelengths, parallax measurements, main sequence fitting, and cepheid variables. Radio wavelengths are a great option within our solar system because astronomers can measure the time it takes for a radio wave to bounce off the surface of a planet or asteroid and translate that into an actual light-year reading. But for celestial bodies farther out in the universe, it’s not practical.
Beyond our solar system, parallax measurement is preferred as it relies on comparing distances to an object based on measurements from multiple angles. This method relies on telescopes and satellites to compute various distance readings over time and scientists to extrapolate accurate positions from the data. But beyond 100 light-years, even parallax measurement is inefficient.
At great distances, main sequence fitting and cepheid variables are the preferred measurement tools. Main sequence fitting relies on a basic understanding of a star’s brightness and color compared to its age to determine distance. Cepheid variables focus on the actual “twinkle” or pulsating factor to determine age and position.
If we haven’t given you a headache yet, it means that even though astronomers and experts have a great grasp on the general size of the universe, figures can change as our methods for analyzing data improve. And for the average Joe, just know that the universe is huge, and we’re in one little corner of it!
Astronomers have discovered the oldest cluster of galaxies ever seen, which dates to the early universe.
The discovery, which could help explain the shape of the modern cosmos, reveals 12 galaxies that existed in a clump 13 billion years ago — just about 700 million years after the Big Bang. We can see them now because they’re so far away in the expanding universe (13 billion light-years) that their starlight is only now reaching Earth. One of the galaxies, a mammoth named Himiko after a mythological Japanese queen, was discovered a decade ago by the same team.
Surprisingly, the other 11 galaxies aren’t clustered around the giant Himiko, the researchers wrote in a paper that will be published on Sept. 30 in The Astrophysical Journal and is available as a draft on the website arXiv. Instead, Himiko sits at the edge of the system, which the researchers call a “protocluster” because it’s so small and ancient compared to most of the clusters we can see in the universe..
“It is reasonable to find a protocluster near a massive object, such as Himiko. However, we’re surprised to see that Himiko was located not in the center of the protocluster but on the edge, 500 million light-years away from the center,” Masami Ouchi, a co-author of the paper and an astronomer at the National Astronomical Observatory of Japan and the University of Tokyo, said in a statement.
Understanding how galaxy clusters came to be turns out to be important for understanding the galaxies they contain. Most galaxies, including the Milky Way, show up in clumps with other galaxies, so the galaxies aren’t evenly distributed throughout the universe. And that clumping seems to affect their behavior, astronomers have said. Galaxies in high-density, clumped environments full of galaxies form stars in different ways than do galaxies in low-density environments empty of galaxies. And the impact of clumping seems to have changed over time, the researchers said.
In more recent times, the researchers wrote in the paper, “there is a clear trend that the star-formation activity of galaxies tends to be lower in high-density environment than low-density environment.”
So, clumped-up galaxies these days form stars less often than their more independent cousins do. It’s as if they’re aging faster in their clusters, the researchers wrote, becoming geriatric and giving up on making new stars.
But in the ancient universe, the trend seems to have been reversed. Galaxies in highly packed clusters formed stars faster, not slower, remaining young and spry compared with their cousins not in dense clusters.
Still, “protoclusters” like this one from the early eons of the universe are rarely found and are poorly understood, the researchers wrote. These clumps tend to be much smaller than modern examples, which can contain hundreds of galaxies.
The further back telescopes peer into time, the fewer proto-clusters turn up. It’s possible many of them are simply obscured by intergalactic dust. The astronomers hope, they wrote, that the new discovery will help flesh out the picture and explain how the state of things 13 billion years ago changed over time to produce that clustered universe we see today.
Originally published on Live Science.
So there you are, about to leap into a black hole. What could possibly await should — against all odds — you somehow survive? Where would you end up and what tantalizing tales would you be able to regale if you managed to clamor your way back?
The simple answer to all of these questions is, as Professor Richard Massey explains, “Who knows?” As a Royal Society research fellow at the Institute for Computational Cosmology at Durham University, Massey is fully aware that the mysteries of black holes run deep. “Falling through an event horizon is literally passing beyond the veil — once someone falls past it, nobody could ever send a message back,” he said. “They’d be ripped to pieces by the enormous gravity, so I doubt anyone falling through would get anywhere.”
If that sounds like a disappointing — and painful — answer, then it is to be expected. Ever since Albert Einstein’s general theory of relativity was considered to have predicted black holes by linking space-time with the action of gravity, it has been known that black holes result from the death of a massive star leaving behind a small, dense remnant core. Assuming this core has more than roughly three-times the mass of the sun, gravity would overwhelm to such a degree that it would fall in on itself into a single point, or singularity, understood to be the black hole’s infinitely dense core.
The resulting uninhabitable black hole would have such a powerful gravitational pull that not even light could avoid it. So, should you then find yourself at the event horizon — the point at which light and matter can only pass inward, as proposed by the German astronomer Karl Schwarzschild — there is no escape. According to Massey, tidal forces would reduce your body into strands of atoms (or ‘spaghettification’, as it is also known) and the object would eventually end up crushed at the singularity. The idea that you could pop out somewhere — perhaps at the other side — seems utterly fantastical.
Or is it? Over the years scientists have looked into the possibility that black holes could be wormholes to other galaxies. They may even be, as some have suggested, a path to another universe.
Such an idea has been floating around for some time: Einstein teamed up with Nathan Rosen to theorize bridges that connect two different points in space-time in 1935. But it gained some fresh ground in the 1980’s when physicist Kip Thorne — one of the world’s leading experts on the astrophysical implications of Einstein’s general theory of relativity — raised a discussion about whether objects could physically travel through them.
“Reading Kip Thorne’s popular book about wormholes is what first got me excited about physics as a child,” Massey said. But it doesn’t seem likely that wormholes exist.
Indeed, Thorne, who lent his expert advice to the production team for the Hollywood movie Interstellar, wrote: “We see no objects in our universe that could become wormholes as they age,” in his book “The Science of Interstellar” (W.W. Norton and Company, 2014). Thorne told Space.com that journeys through these theoretical tunnels would most likely remain science fiction, and there is certainly no firm evidence that a black hole could allow for such a passage.
But, the problem is that we can’t get up close to see for ourselves. Why, we can’t even take photographs of anything that takes place inside a black hole — if light cannot escape their immense gravity, then nothing can be snapped by a camera. As it stands, theory suggests that anything which goes beyond the event horizon is simply added to the black hole and, what’s more, because time distorts close to this boundary, this will appear to take place incredibly slowly, so answers won’t be quickly forthcoming.
“I think the standard story is that they lead to the end of time,” said Douglas Finkbeiner, professor of astronomy and physics at Harvard University. “An observer far away will not see their astronaut friend fall into the black hole. They’ll just get redder and fainter as they approach the event horizon [as a result of gravitational red shift]. But the friend falls right in, to a place beyond ‘forever.’ Whatever that means.”
Certainly, if black holes do lead to another part of a galaxy or another universe, there would need to be something opposite to them on the other side. Could this be a white hole — a theory put forward by Russian cosmologist Igor Novikov in 1964? Novikov proposed that a black hole links to a white hole that exists in the past. Unlike a black hole, a white hole will allow light and matter to leave, but light and matter will not be able to enter.
Scientists have continued to explore the potential connection between black and white holes. In their 2014 study published in the journal Physical Review D, physicists Carlo Rovelli and Hal M. Haggard claimed that “there is a classic metric satisfying the Einstein equations outside a finite space-time region where matter collapses into a black hole and then emerges from a while hole.” In other words, all of the material black holes have swallowed could be spewed out, and black holes may become white holes when they die.
Far from destroying the information that it absorbs, the collapse of a black hole would be halted. It would instead experience a quantum bounce, allowing information to escape. Should this be the case, it would shed some light on a proposal by former Cambridge University cosmologist and theoretical physicist Stephen Hawking who, in the 1970’s, explored the possibility that black holes emit particles and radiation — thermal heat — as a result of quantum fluctuations.
“Hawking said a black hole doesn’t last forever,” Finkbeiner said. Hawking calculated that the radiation would cause a black hole to lose energy, shrink and disappear, as described in his 1976 paper published in Physical Review D. Given his claims that the radiation emitted would be random and contain no information about what had fallen in, the black hole, upon its explosion, would erase loads of information.
This meant Hawking’s idea was at odds with quantum theory, which says information can’t be destroyed. Physics states information just becomes more difficult to find because, should it become lost, it becomes impossible to know the past or the future. Hawking’s idea led to the ‘black hole information paradox’ and it has long puzzled scientists. Some have said Hawking was simply wrong, and the man himself even declared he had made an error during a scientific conference in Dublin in 2004.
So, do we go back to the concept of black holes emitting preserved information and throwing it back out via a white hole? Maybe. In their 2013 study published in Physical Review Letters, Jorge Pullin at Louisiana State University and Rodolfo Gambini at the University of the Republic in Montevideo, Uruguay, applied loop quantum gravity to a black hole and found that gravity increased towards the core but reduced and plonked whatever was entering into another region of the universe. The results gave extra credence to the idea of black holes serving as a portal. In this study, singularity does not exist, and so it doesn’t form an impenetrable barrier that ends up crushing whatever it encounters. It also means that information doesn’t disappear.
Yet physicists Ahmed Almheiri, Donald Marolf, Joseph Polchinski and James Sully still believed Hawking could have been on to something. They worked on a theory that became known as the AMPS firewall, or the black hole firewall hypothesis. By their calculations, quantum mechanics could feasibly turn the event horizon into a giant wall of fire and anything coming into contact would burn in an instant. In that sense, black holes lead nowhere because nothing could ever get inside.
This, however, violates Einstein’s general theory of relativity. Someone crossing the event horizon shouldn’t actually feel any great hardship because an object would be in free fall and, based on the equivalence principle, that object — or person — would not feel the extreme effects of gravity. It could follow the laws of physics present elsewhere in the universe, but even if it didn’t go against Einstein’s principle it would undermine quantum field theory or suggest information can be lost.
Step forward Hawking once more. In 2014, he published a study in which he eschewed the existence of an event horizon — meaning there is nothing there to burn — saying gravitational collapse would produce an ‘apparent horizon’ instead.
This horizon would suspend light rays trying to move away from the core of the black hole, and would persist for a “period of time.” In his rethinking, apparent horizons temporarily retain matter and energy before dissolving and releasing them later down the line. This explanation best fits with quantum theory — which says information can’t be destroyed — and, if it was ever proven, it suggests that anything could escape from a black hole.
Hawking went as far as saying black holes may not even exist. “Black holes should be redefined as metastable bound states of the gravitational field,” he wrote. There would be no singularity, and while the apparent field would move inwards due to gravity, it would never reach the center and be consolidated within a dense mass.
And yet anything which is emitted will not be in the form of the information swallowed. It would be impossible to figure out what went in by looking at what is coming out, which causes problems of its own — not least for, say, a human who found themselves in such an alarming position. They’d never feel the same again!
One thing’s for sure, this particular mystery is going to swallow up many more scientific hours for a long time to come. Rovelli and Francesca Vidotto recently suggested that a component of dark matter could be formed by remnants of evaporated black holes, and Hawking’s paper on black holes and ‘soft hair’ was released in 2018, and describes how zero-energy particles are left around the point of no return, the event horizon — an idea that suggests information is not lost but captured.
This flew in the face of the no-hair theorem which was expressed by physicist John Archibald Wheeler and worked on the basis that two black holes would be indistinguishable to an observer because none of the special particle physics pseudo-charges would be conserved. It’s an idea that has got scientists talking, but there is some way to go before it’s seen as the answer for where black holes lead. If only we could find a way to leap into one.
Many of the best-loved galaxies in the cosmos are remarkably large, close, massive, bright, or beautiful, often with an unusual or intriguing structure or history. However, it takes all kinds to make a universe — as demonstrated by this Hubble image of Messier 110.
Messier 110 may not look like much, but it is a fascinating near neighbor of our home galaxy, and an unusual example of its type. It is a member of the Local Group, a gathering of galaxies comprising the Milky Way and a number of the galaxies closest to it. Specifically, Messier 110 is one of the many satellite galaxies encircling the Andromeda galaxy, the nearest major galaxy to our own, and is classified as a dwarf elliptical galaxy, meaning that it has a smooth and almost featureless structure. Elliptical galaxies lack arms and notable pockets of star formation — both characteristic features of spiral galaxies. Dwarf elliptical are quite common in groups and clusters of galaxies, and are often satellites of larger galaxies.
Because they lack stellar nurseries and contain mostly old stars, elliptical galaxies are often considered “dead” when compared to their spiral relatives. However, astronomers have spotted signs of a population of young, blue stars at the center of Messier 110 — hinting that it may not be so “dead” after all.
Messier 110 is featured in Hubble’s Messier catalog, which includes some of the most fascinating celestial objects that can be observed from Earth’s Northern Hemisphere. See the NASA-processed image and other Messier objects in Hubble’s Messier Catalog.
M110 is an elliptical galaxy, which means that it has a smooth and nearly featureless structure. Elliptical galaxies do not have arms or regions of star formation. They are oftentimes considered “dead” compared to spiral galaxies, and the stars in elliptical galaxies are often older than those in other galaxies. However, there is evidence that a population of young blue stars exists at the center of M110. This small elliptical galaxy has approximately 10 billion stars, as well as at least eight globular clusters (the brightest of which can be seen with large telescopes).
This Hubble observation was taken in visible and near-infrared light with the Wide Field and Planetary Camera 2. The core of M110 is seen toward the lower right of the image, with the galaxy’s globular clusters and numerous stars shown as points of light throughout the frame. Also featured in this Hubble image are large clouds of gas and dust, seen as dark splotches (one large region is located near the middle of the image and another, smaller one appears above the galaxy’s core). Hubble took these observations of M110 to study the development of globular clusters located in the galaxy.
With a telescope, M110 is fairly easy to spot near the core of the much larger and brighter Andromeda galaxy. Smaller telescopes will only reveal a faint, diffuse patch of light, while larger telescopes will unveil an oval shape with a brighter core. The best time to view M110 is during November.
Astronomers have spotted hints of water raining in the atmosphere of a planet beyond the Solar System.
The discovery is a rare glimpse of water molecules around a distant world that is not much bigger than Earth. Named K2-18 b, the planet is 34 parsecs (110 light-years) from Earth in the constellation Leo. Notably, it lies in the ‘habitable zone’ around its star — the distance at which liquid water could exist, making extraterrestrial life possible in its hydrogen-rich atmosphere.
“That’s the exciting thing about this planet,” says Björn Benneke, a planetary astronomer at the University of Montreal in Canada. He is the lead author of a paper describing the discovery that was posted on the arXiv preprint server on 10 September1.
A competing team of scientists reports their own analysis of the same planet on 11 September in Nature Astronomy2. That paper′s lead author, planetary astronomer Angelos Tsairas of the University College London (UCL), says that the finding is exciting because the planet is just twice the diameter of Earth, and because little is known about the atmospheres of such small worlds.
Astronomers have previously found water in the atmospheres of gas-giant exoplanets, but studying a distant planet’s atmosphere gets harder as the planet gets smaller. Scientists have been pushing the limits to try to scrutinize planets that are smaller than Neptune but larger than Earth — a category that turns out to be surprisingly common among the thousands of exoplanets found so far.
Benneke and his colleagues decided to look at K2-18 b because it falls in that range. They used the Hubble Space Telescope to watch as the planet passed in front of its star, temporarily dimming its light, on eight different occasions.
The scientists analysed how the color of the star’s light changed as it filtered through the planet’s atmosphere. They combined this with data from the Spitzer Space Telescope, which examines more wavelengths of light. The researchers concluded that they were seeing water vapor in the planet′s atmosphere as well as signs that that vapor was condensing into liquid water.
It is the first time astronomers have seen such a water cycle — changing from gas to liquid and back again — on a small, distant world.
The UCL team that authored the second paper analysed the Hubble data from Benneke’s group. The observations had been uploaded to a publicly accessible archive immediately after being collected.
The UCL researchers came up with three possible explanations for what they were seeing, any one of which is equally likely. In the first scenario, the planet has no clouds and 20–50% of its atmosphere is water. In the second and third scenarios, which involve different amounts of clouds and other molecules in the atmosphere, the planet’s atmosphere contains between 0.01% and 12.5% water.
But the presence of water alone doesn’t mean that a planet is a good place to look for life, a point illustrated by one of Earth’s closest neighbors, Venus. It’s an Earth-sized planet in the habitable zone of its star that once had water vapor in its atmosphere — but the Sun’s rays have stripped away much of that water, leaving its surface barren.
K2-18 b might be equally unpromising. “It is highly unlikely that this world is habitable in any way that we understand based on life as we know it,” says Hannah Wakeford, a planetary astronomer at the Space Telescope Science Institute in Baltimore, Maryland.
Still, finding water in the planet’s atmosphere is “extremely exciting”, says Neale Gibson, an astrophysicist at Trinity College Dublin, “and the fact that two teams find the same result is very encouraging”. Future observations, such as those that the James Webb Space Telescope will collect after its planned 2021 launch, should help pin down exactly what this distant world is like.
Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and Space Radio, and author of “Your Place in the Universe.” Sutter contributed this article to Space.com’s Expert Voices: Op-Ed & Insights.
In 2010, astronomers working with the Fermi Gamma-ray Space Telescope announced the discovery of two giant blobs. These blobs were centered on the core of the Milky Way galaxy, but they extended above and below the plane of our galactic home for over 25,000 light-years. Their origins are still a mystery, but however they got there, they are emitting copious amounts of high-energy radiation.
More recently, the Ice Cube array in Antarctica has reported 10 super-duper-high-energy neutrinos sourced from the bubbles, leading some astrophysicists to speculate that some crazy subatomic interactions are afoot. The end result: the Fermi Bubbles are even more mysterious than we thought.
It’s not easy to make big balls of hot gas. For starters, you need energy, and a lot of it. The kind of energy that can spread hot gas to a distance of over 25,000 light-years doesn’t come easily to a typical galaxy. However, the peculiar orientation of the Fermi Bubbles — extending evenly above and below our galactic center — is a strong clue that they might be tied our central super massive black hole, known as Sagittarius A*.
Perhaps millions of years ago, Sag A* (the more common name for our giant black hole, because who wants to keep typing or saying “Sagittarius” all the time?) ate a giant meal and got a bad case of indigestion, with the in-falling material heating up, twisting around in a complicated dance of electric and magnetic forces, and managing to escape the clutches of the event horizon before falling in. That material, energized beyond belief, raced away from the center of the galaxy, riding on jets of particles accelerated to nearly the speed of light. As they fled to safety, these particles spread and thinned out, but maintained their energetic state to the present day.
Or perhaps a star wandered too close to Sag A* and was ripped to shreds, releasing all that potent gravitational energy in a single violent episode, leading to the formation of the bubbles. Or maybe it had nothing to do with Sag A* itself, but the multitude of stars in the core — perhaps dozens or hundreds of those densely packed stars went supernova at around the same time, ejecting these plumes of gas beyond the confines of the galactic more.
Or maybe none of the above.
No matter what, the bubbles are here, they’re big, and we don’t understand them.
Related: 8 Baffling Astronomy Mysteries
You can’t see the Fermi Bubbles with your naked eye. Despite their high temperatures, the gas inside them is incredibly thin, rendering them all but invisible. But something within them is capable of making the highest-energy kind of light there is: gamma rays, which is how the Fermi team spotted them.
We think that the gamma rays are produced within the bubbles by cosmic rays, which themselves are high-energy particles (do you get the overall “high energy” theme here?). Those particles, mostly electrons but probably some heavier fellas too, knock about, emitting the distinctive gamma rays.
But gamma rays aren’t the only things that high-energy particles can produce. Sometimes the cosmic rays interact with each other, perform some complicated subatomic dance of matter and energy, and release a neutrino, an almost-mass-less particle that only interacts with other particles via the weak nuclear force (which means it hardly ever interacts with normal matter at all).
The Ice Cube Observatory, situated at the geographic south pole, uses a cubic kilometer of pure Antarctic water ice as a neutrino detector: every once in a rare while, a high-energy neutrino passing through the ice interacts with a water molecule, setting up a domino-like chain reaction that leads to a shower of more familiar particles and a telltale flash of light.
Due to the nature of its detectors, Ice Cube isn’t the greatest when it comes to pinpointing the exact origin location for a neutrino. But to date, it has found 10 of these little ghosts coming from roughly the direction of the two Fermi Bubbles.
Is this coincidence, or conspiracy?
So something could be producing these extremely exotic neutrinos inside the Fermi Bubbles. Or not — it could just be a coincidence, and the neutrinos are really coming from some distant part of the universe behind the Bubbles.
What’s more, somehow the cosmic rays are producing all the gamma rays, though we’re not exactly sure how. Perhaps we might get lucky: maybe there’s a single set of interactions inside the Bubbles that produces both gamma rays and the right kind of neutrinos that can be detected by IceCube. That would be a big step up in explaining the physics of the Bubbles themselves, and give us a huge clue as to their origins.
Recently, a team of researchers pored through the available data, even adding results from the newly operational High Altitude Water Cherenkov detector (a super-awesome ground-based gamma ray telescope), and combined that information with various theoretical models for the Bubbles, searching for just the right combo.
In one possible scenario, protons inside the Bubbles occasionally slam into each other and produce pions, which are exotic particles that quickly decay into gamma rays. In another one, the flood of high-energy electrons in the Bubbles interacts with the ever-present radiation of the cosmic microwave background, boosting some lucky photons into the gamma regime. In a third, shock waves at the outer edges of the Bubbles use magnetic fields to drive local but lethargic particles to high velocities, which then begin emitting cosmic rays.
But try as they might, the authors of this study couldn’t find any of the scenarios (or any combination of these scenarios) to fit all the data. In short, we still don’t know what drives the gamma ray emission from the Bubbles, whether the Bubbles also produce neutrinos, or what made the Bubbles in the first place. But this is exactly how science is done: collecting data, ruling out hypotheses, and forging onward.
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Earth is the only planet in the universe known to harbor life, but new research suggests that some distant worlds could put the Blue Marble’s biodiversity to shame.
It’s not because these other, hypothetically habitable exoplanets are devoid of humans (though Earth’s biodiversity would definitely be looking better without us). Rather, a planet’s potential to harbor life could hinge on how well its oceans move nutrients around the world, University of Chicago geoscientist Stephanie Olson said today (Aug. 23) in a presentation at the Goldschmidt Geochemistry Congress in Barcelona.
“NASA’s search for life in the universe is focused on so-called Habitable Zoneplanets, which are worlds that have the potential for liquid water oceans,” Olson said in a statement about her research. “But not all oceans are equally hospitable — and some oceans will be better places to live than others due to their global circulation patterns.”
One circulation pattern in particular — known as “upwelling” — may be key to fostering life in the seas, Olson said. Upwelling occurs when wind rushes along the ocean’s surface, creating currents that push deep, nutrient-rich water up toward the top of the sea, where photosynthetic plankton live. The plankton feed on these nutrients, allowing them to produce organic compounds that feed larger organisms, which in turn become meals for still-larger organisms, and so on up the food chain.
As members of the food chain die and decompose, their organic remains sink to the bottom of the sea, where they may get caught in another upwelling and feed the surface life again. Thanks to this efficient, underwater recycling system, biodiversity tends to thrive in upwelling areas on Earth (mainly near the coasts). The same is likely true on habitable exoplanets, Olson said, which means that planets with conditions that favor more ocean upwelling may also favor strong biodiversity.
To find out what sorts of conditions lead to productive upwelling, Olson and her colleagues used a NASA simulator called ROCKE-3D to test how atmospheric and geophysical factors contribute to ocean currents.
“We found that higher atmospheric density, slower rotation rates and the presence of continents all yield higher upwelling rates,” Olson said. “A further implication is that Earth might not be optimally habitable — and life elsewhere may enjoy a planet that is even more hospitable than our own.”
While these findings don’t have any direct applications to the 4,000 or so exoplanets that have been discovered so far, they could inform the way scientists look for habitable worlds in the future. Ideally, Olson said, future generations of telescopes will be built that better analyze features like atmospheric density and rotation rate, which could offer a quick glimpse into a world’s habitability. With tech like that, we should be able to find the space-octopus homeworld in no time.
Olson’s new study has yet to appear in a peer-reviewed journal.
Originally published on Live Science.
A robot deployed on one of the darkest asteroids in the solar system may now shed light on the origins of some of the oldest, rarest meteorites, a new study finds.
These findings suggest that this asteroid formed during a collision of two very different space rocks, the scientists said. The research also suggests that dust may float off this asteroid, possibly driven by electric fields.
In 2018, the Japanese spacecraft Hayabusa2 arrived at Ryugu, a 2,950-foot-wide (900 meters) near-Earth asteroid that is one of the darkest celestial bodies in the solar system. Its name, which means “dragon palace,” refers to a magical underwater castle in a Japanese folktale.
One reason scientists may want to learn more about Ryugu is because its orbit brings it close — potentially dangerously close — to Earth.
“Knowing the composition and geological structure of asteroids and comets is essential to [developing] mitigation strategies in the case of potential collision scenarios,” study lead author Ralf Jaumann, a planetary scientist at the Institute of Planetary Research in Berlin, told Space.com.
In addition, previous research suggested Ryugu may contain primordial material from the nebula that gave birth to the sun and its planets. Hayabusa2 is designed to return samples from the asteroid to shed light on the formation of the solar system.
To investigate Ryugu’s surface, Hayabusa2 deployed the Mobile Asteroid Surface Scout (MASCOT) lander. This shoebox-size robot took photos both as it dropped from the main Hayabusa2 spacecraft onto Ryugu and after it landed on the asteroid’s surface, where it operated for a little more than 17 hours before its batteries ran out.
“To have this small lander reaching the surface and providing detailed images of the surface was very exciting,” Jaumann said.
MASCOT found Ryugu was covered with two kinds of rocks and boulders — one dark with a cauliflower-like, crumbly surface and the other bright with smooth faces and sharp edges. Both types are nearly evenly distributed on the surface of the asteroid, suggesting Ryugu was a pile of rubble that coalesced after two parent bodies crashed into one another, “indicating a violent history of asteroid collision,” Jaumann said.
Close-up images of Ryugu’s dark, rough stones revealed they often seem to possess small, colored inclusions similar to those found in one of the most primitive and rare types of meteorites, known as carbonaceous chondrites.
“Carbonaceous material is the primordial material of the solar system, from which all planets and moons originate,” Jaumann said. “Thus, if we want to understand planetary formation, including the formation of Earth, we need to understand its building parts.” He said the new findings support long-standing speculation that carbonaceous chondrites come from C-type asteroids — dark-gray, carbon-rich space rocks such as Ryugu.
Unexpectedly, the MASCOT images of Ryugu showed no fine dust, which scientists had expected would accumulate on the asteroid’s surface due to micrometeoroid impacts and other forms of weathering. The mission’s predecessor, Hayabusa, found that another rubble-pile asteroid, Itokawa, also seemed dust-free.
The researchers suggested that some as-yet-unknown force removes dust from Ryugu’s surface. Electric fields on the asteroid might cause dust to float away, Jaumann said, or micrometeoroid impacts and seismic vibrations could be responsible.
The scientists detailed their findings online on Aug. 22 in the journal Science.
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A team of astrophysicists has just spawned 8 million unique universes inside a supercomputer and let them evolve from just tots to old geezers. Their goal? To nail down the role that an invisible substance called dark matter played in our universe’s life since the Big Bang and what it means for our fate.
After discovering that our universe is mostly composed of dark matter in the late 1960s, scientists have speculated on its role in the formation of galaxies and their ability to give birth to new stars over time.
According to the Big Bang theory, not long after the universe was born, an invisible and elusive substance physicists have dubbed dark matter began to clump together by the force of gravity into massive clouds called dark matter haloes. As the haloes grew in size, they attracted the sparse hydrogen gas permeating the universe to come together and form the stars and galaxies we see today. In this theory, dark matter acts as the backbone of galaxies, dictating how they form, merge and evolve over time.
To better understand how dark matter shaped this history of the universe, Peter Behroozi, an assistant professor of astronomy at the University of Arizona, and his team created his own universes using the school’s supercomputer. The computer’s 2,000 processors worked without pause over a span of three weeks to simulate more than 8 million unique universes. Each universe individually obeyed a unique set of rules to help researchers understand the relationship between dark matter and the evolution of galaxies.
“On the computer, we can create many different universes and compare them to the actual one, and that lets us infer which rules lead to the one we see,” Behroozi said in a statement.
While previous simulations have focused on modeling single galaxies or generating mock universes with limited parameters, the UniverseMachine is the first of its scope. The program continuously created millions of universes, each containing 12 million galaxies, and each allowed to evolve over nearly the entire history of the real universe from 400 million years after the Big Bang to the present day.
“The big question is, ‘How do galaxies form?’” said study researcher Risa Wechsler, a professor of physics and astrophysics at Stanford University. “The really cool thing about this study is that we can use all the data we have about galaxy evolution — the numbers of galaxies, how many stars they have and how they form those stars — and put that together into a comprehensive picture of the last 13 billion years of the universe.”
Creating a replica of our universe, or even of a galaxy, would require an inexplicable amount of computing power. So Behroozi and his colleagues narrowed their focus to two key properties of galaxies: their combined mass of stars and the rate at which they give birth to new ones.
“Simulating a single galaxy requires 10 to the 48th computing operations,” Behroozi explained, referring to an octillion operation, or a 1 followed by 48 zeros. “All computers on Earth combined could not do this in a hundred years. So to just simulate a single galaxy, let alone 12 million, we had to do this differently.”
As the computer program spawns new universes, it makes a guess on how a galaxy’s rate of star formation is related to its age, its past interactions with other galaxies and the amount of dark matter in its halo. It then compares each universe with real observations, fine-tuning the physical parameters with every iteration to better match reality. The end result is a universe nearly identical to our own.
According to Wechsler, their results showed that the rate at which galaxies give birth to stars is tightly connected to the mass of their dark matter haloes. Galaxies with dark matter halo masses most similar to our own Milky Way had the highest star-formation rates. She explained that star formation is stifled in more massive galaxies by an abundance of blackholes
Their observations also challenged long-held beliefs that dark matter stifled star formation in the early universe.
“As we go back earlier and earlier in the universe, we would expect the dark matter to be denser, and therefore the gas to be getting hotter and hotter. This is bad for star formation, so we had thought that many galaxies in the early universe should have stopped forming stars a long time ago,” Behroozi said. “But we found the opposite: Galaxies of a given size were more likely to form stars at a higher rate, contrary to the expectation.”
Now, the team plans to expand the Universe Machine to test more ways dark matter might affect the properties of galaxies, including how their shapes evolve, the mass of their black holes and how often their stars go supernova.
“For me, the most exciting thing is that we now have a model where we can start to ask all of these questions in a framework that works,” Wechsler said. “We have a model that is inexpensive enough computationally, that we can essentially calculate an entire universe in about a second. Then we can afford to do that millions of times and explore all of the parameter space.”
The research group published their results in the September issue of the journal Monthly Notices of the Royal Astronomical Society.
Originally published on Live Science.
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