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Home/News/A star turned into a black hole before Hubble’s very eyes Bye bye supernove When a massive star expends its fuel, its core collapses into a dense object and sends the rest of its gas outward in an event called a supernova. What’s left is mostly neutron stars or black holes. And now, Hubble seems to have seen a supernova blink out — suggesting it captured the moment when a black hole took over. While some supernova events are explosive and leave clouds of debris for thousands of years (aka nebula) like SN 1054, the star in question seems to have begun to explode and then had all its gas sucked right back into the black hole at the center. This can happen when the core collapse of the star is especially massive. Rather than exploding, the gas collapses directly into the core of the star. Only a few of these so called “massive fails” (yes, that’s what they’re calling them) have been spotted, so astronomers are cautious about the results. But this particular star, located in the galaxy NGC 6946, was bright enough to see from 22 million light years away and faded in an instant, suggesting a massive stellar-mass black hole was the driving culprit. Want to learn more about the most exotic objects in the universe? Download our FREE eBook, Exotic Objects: Black holes, Pulsars, and more! RELATED ARTICLESYOU MIGHT ALSO LIKE
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Cosmology & The Universe
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We’ve now seen farther, deeper and more clearly into space than ever before. The first image from the James Webb Space Telescope, released in a White House briefing on July 11, shows thousands of distant galaxies. The galaxies captured here lie behind a cluster of galaxies about 4.6 billion light-years away. The mass from those galaxies distorts spacetime in such a way that objects behind the cluster are magnified, giving astronomers a way to peer about 13 billion years into the early universe. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox Even with that celestial assist, other existing telescopes could never see so far. But the James Webb Space Telescope, also known as JWST, is incredibly large — at 6.5 meters across, its mirror is nearly three times wider than that of the Hubble Space Telescope. It also sees in the infrared wavelengths of light where distant galaxies appear. Those features give it an edge over previous observatories. “The James Webb Space Telescope allows us to see deeper into space than ever before, and in stunning clarity,” said Vice President Kamala Harris in the July 11 briefing. “It will enhance what we know about the origins of our universe, our solar system, and possibly life itself.” Although this first image represents the deepest view of the cosmos to date, “this is not a record that will stand for very long,” astronomer Klaus Pontoppidan of the Space Telescope Science Institute in Baltimore said in a June 29 news briefing. “Scientists will very quickly beat that record and go even deeper.” And this image is just the first. On July 12, astronomers plan to release first images of a stellar birthplace, a nebula surrounding a dying star, and a group of closely interacting galaxies, plus the first spectrum of an exoplanet’s light, a clue to its composition. All these images are a glimpse of what JWST will continue to reveal over its decade-plus planned mission. This first image has been a very long time coming. The telescope that would become JWST was first dreamed up in the 1980s, and the planning and construction suffered years of budget issues and delays (SN: 10/6/21). The telescope finally launched on December 25. It then had to unfold and assemble itself in space, travel to a gravitationally stable spot about 1.5 million kilometers from Earth, align its insectlike primary mirror made of 18 hexagonal segments and calibrate its science instruments (SN: 1/24/22). There were hundreds of possible points of failure in that process, but the telescope unfurled successfully and got to work. The James Webb Space Telescope (illustrated) spent months unfolding and calibrating its instruments after it launched on December 25. Adriana Manrique Gutierrez/CIL/GSFC/NASA In the months following, the telescope team released teasers of imagery from calibration, which already showed hundreds of distant, never-before-seen galaxies. But the images now being released are the first full-color pictures made from the data scientists will use to start unraveling mysteries of the universe. For the telescope team, the relief in finally seeing the first images was palpable. “It was like, ‘Oh my god, we made it!’” says image processor Alyssa Pagan, also of Space Telescope Science Institute. “It seems impossible. It’s like the impossible happened.” In light of the expected anticipation surrounding the first batch of images, the imaging team was sworn to secrecy. “I couldn’t even share it with my wife,” says Pontoppidan, leader of the team that produced the first color science images. “You’re looking at the deepest image of the universe yet, and you’re the only one who’s seen that,” he says. “It’s profoundly lonely.” Soon, though, the team of scientists, image processors and science writers was seeing something new every day for weeks as the telescope downloaded the first images. “It’s a crazy experience,” Pontoppidan says. “Once in a lifetime.” For Pagan, the timing is perfect. “It’s a very unifying thing,” she says. “The world is so polarized right now. I think it could use something that’s a little bit more universal and connecting. It’s a good perspective, to be reminded that we’re part of something so much greater and beautiful.” This story will be updated as more images are released.
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Cosmology & The Universe
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We care about your data, and we'd like to use cookies to give you a smooth browsing experience. Please agree and read more about our privacy policy.astronomyThe grainy image of a “super-Jupiter” is a sign of what’s to come as the telescope’s exoplanet observations ramp up.Behold the bright blob of planet HIP 65426 b, located nearly 400 light-years away. The star symbol overlays the location of the masked-out star that the planet orbits.Aarynn Carter (UCSC), the ERS 1386 teamAstronomers have revealed the first photograph of an exoplanet taken by NASA’s James Webb Space Telescope (JWST). The image shows the bright blob of a world seven times heavier than Jupiter that orbits a star nearly 400 light-years away. The groundbreaking result is the latest in a slew of early exoplanet findings from the telescope, and a test of technologies that will enable direct imaging of Earth-like planets by future space telescopes.
“It’s exhilarating,” said Aarynn Carter, an astronomer at the University of California, Santa Cruz, and part of the team that processed the image. “The result is, honestly, excellent.”
JWST, a telescope decades in the making that launched in December 2021 and now floats a million miles from Earth, became fully operational this summer. Already, it has observed distant galaxies at the dawn of the universe and taken exquisite views of Jupiter, among other early results. Astronomers say the telescope is also performing 10 times better than expected at observing exoplanets. The new image, described in an accompanying paper posted online last night, comes from a team led by the astrophysicist Sasha Hinkley at the University of Exeter in the United Kingdom. The researchers pointed JWST at the fast-spinning star HIP 65426, where a planet was already known to exist; the SPHERE instrument on the Very Large Telescope in Chile first photographed the planet in 2017. Hinkley’s team sought to test and characterize JWST’s ability to see the planet, called HIP 65426 b.
Astronomers have directly imaged about two dozen exoplanets, but JWST will greatly expand the capability by wielding its 6.5-meter-wide hexagonal mirror, outclassing any ground-based observatory. “It is a moment of promise,” said Bruce Macintosh, an astrophysicist and the incoming director of the University of California Observatories.
Hot Young Giant
To photograph HIP 65426 b, JWST blocked the light of its host star using a small mask known as a coronagraph. This revealed the orbiting planet, which is thousands of times fainter, like “a firefly around a searchlight,” said Hinkley.
HIP 65426 b orbits about 100 times farther from its star than Earth does the sun, taking 630 years to complete an orbit. This distance means it’s easier to see the planet against the glare of the star; that, coupled with the planet’s extreme heat and thus brightness — it has a scorching temperature of about 900 degrees Celsius, a fever left over from its formation just 14 million years ago — makes it a prime target for direct imaging. “It has a temperature similar to a candle flame,” said Beth Biller, an astronomer at the University of Edinburgh who co-led the team.
JWST’s size and sensitivity enabled it to collect more light from this planet than any previous observatory has obtained. (Its photo looks grainier than SPHERE’s only because JWST observes longer, infrared wavelengths.) This allowed Hinkley, Biller and their team to refine the estimate of the planet’s mass, which they peg at about seven Jupiter masses, less than SPHERE’s estimate of about 10. Their results also help nail down the planet’s radius, which is 1.4 times that of Jupiter. Simple models of planetary evolution can’t easily explain this world’s combination of properties; Carter noted that the precise new data will allow scientists to test models against each other and “tighten our understanding.”
HIP 65426 b’s surface features aren’t visible in the image, but Biller said it would “probably look banded” like Jupiter, with belts caused by variations in temperature and composition, and might have spots in its atmosphere caused by storms or vortices.
The giant planet is inhospitable to life as we know it, but it represents a class of large planets that scientists are eager to learn more about. Jupiter probably played a key role in sculpting our solar system, perhaps enabling life on Earth to take hold. “It’d be nice to know if that works in other solar systems,” said Macintosh.
The Webb telescope’s Near Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) each captured views of the planet HIP 65426 b at multiple infrared wavelengths, providing details that astronomers could use to infer the planet’s properties. The white stars mark the location of the host star HIP 65426, which has been subtracted using coronagraphs and image processing, while the bar shapes in the two NIRCam images are artifacts of the optics, not objects in the scene.NASA/ESA/CSA, A Carter (UCSC), the ERS 1386 team, and A. Pagan (STScI)Because JWST is so much more stable than expected, scientists say it should be able to photograph smaller exoplanets than anticipated — perhaps as small as a third of Jupiter’s mass. “We could image things like Neptune and Uranus that we’ve never directly imaged before,” said Emily Rickman, an astronomer at the Space Telescope Science Institute in Maryland, which operates JWST.
Now that JWST’s coronagraph has passed its road test, Hinkley thinks astronomers will be lining up to use it to take otherworldly photos. He expects to see “definitely dozens” by the end of the telescope’s lifetime. “I hope it’s more like hundreds.”
Peeking in Distant Skies
In addition to the exoplanet photo, Hinkley’s team will announce in the coming days that they have discovered an array of molecules in the atmosphere of a suspected brown dwarf — sometimes known as a “failed star” — orbiting a companion star. Almost 20 times heavier than Jupiter, the object has a mass just below the threshold where fusion could begin in its core.
Using an instrument on JWST that picks apart the light’s frequencies, a process called spectroscopy, the scientists found water, methane, carbon dioxide and sodium, all revealed at an unprecedented level of detail. They also detected smokelike clouds of silica in the candidate brown dwarf’s atmosphere, something hinted at before in such objects but never established. “In my mind this is the greatest spectrum ever obtained of a substellar companion,” said Hinkley. “We’ve never seen anything like it.” The discovery follows hot on an announcement from last week, when a different team of astronomers reported that they have used JWST to detect carbon dioxide in a giant exoplanet called WASP-39 b located 650 light-years from Earth — the first time the gas has ever been seen in an exoplanet. They also spotted a mystery molecule in the atmosphere. That same team is also studying two more giant worlds, with results expected in the coming months that will help piece together an almost complete picture of the atmospheric composition of gas giants like these. “That’s the power of James Webb,” said Jacob Bean, an astronomer at the University of Chicago and the team’s co-leader. The observations will also build up a “chemical inventory” that will show what JWST might detect in the skies of smaller rocky worlds more similar to Earth, said team leader Natalie Batalha, an astrophysicist at Santa Cruz. She said the team plans to “push JWST to its limits” in their upcoming gas giant observations, which will “tell us what we can do on terrestrial planets.”
Other teams are conducting the first JWST observations of TRAPPIST-1, a relatively nearby red dwarf star orbited by seven Earth-size rocky worlds. Several of these planets are in the star’s habitable zone, where conditions favoring liquid water and even life may be possible. While JWST cannot directly image the planets, spectroscopy will help identify the gases in their atmospheres — possibly even hints of gases that could signify biological activity. “What we really want is Earths,” said Macintosh.
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Cosmology & The Universe
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Eta Carinae, one of the most massive stars known - Image credit: NASA Our sky is blanketed in a sea of stellar ghosts; all potential phantoms that have been dead for millions of years and yet we don’t know it yet. That is what we will be discussing today. What happens to the largest of our stars, and how that influences the very makeup of the universe we reside in.We begin this journey by observing the Crab Nebula. Its beautiful colors extend outward into the dark void; a celestial tomb containing a violent event that occurred a millennia ago. You reach out and with the flick of your wrist, begin rewinding time and watch this beautiful nebulae begin to shrink. As the clock winds backwards, the colors of the nebula begin to change, and you notice that they are shrinking to a single point. As the calendar approaches July 5, 1054, the gaseous cloud brightens and settles onto a single point in the sky that is as bright as the full moon and is visible during the day. The brightness fades and eventually there lay a pinpoint of light; a star that we don’t see today. This star has died, however at this moment in time we wouldn’t have known that. To an observer before this date, this star appeared eternal, as all the other stars did. Yet, as we know from our privileged vantage point, this star is about to go supernova and birth one of the most spectacular nebulae that we observe today. The Crab Nebula; at its core is a long dead star… - Image credit: NASA, ESA, J. Hester and A. Loll (Arizona State University) Stellar ghosts is an apt way of describing many of the massive stars we see scattered throughout the universe. What many don’t realize is that when we look out deep into the universe, we are not only looking across vast distances, but we are peering back into time. One of the fundamental properties of the universe that we know quite well is that light travels at a finite speed: approximately 300,000,000 m/s (roughly 671,000,000 mph). This speed has been determined through many rigorous tests and physical proofs. In fact, understanding this fundamental constant is a key to much of what we know about the universe, especially in respect to both General Relativity and Quantum Mechanics. Despite this, knowing the speed of light is key to understanding what I mean by stellar ghosts. You see, information moves at the speed of light. We use the light from the stars to observe them and from this understand how they operate.A decent example of this time lag is our own sun. Our sun is roughly 8 light-minutes away. Meaning that the light we see from our star takes 8 minutes to make the journey from its surface to our eyes on earth. If our sun were to suddenly disappear right now, we wouldn’t know about it for 8 minutes; this doesn’t just include the light we see, but even its gravitational influence that is exerted on us. So if the sun vanished right now, we would continue in our orbital path about our now nonexistent star for 8 more minutes before the gravitational information reached us informing us that we are no longer gravitationally bound to it. This establishes our cosmic speed limit for how fast we can receive information, which means that everything we observe deep into the universe comes to us as it was an ‘x’ amount of years ago, where ‘x’ is its light distance from us. This means we observe a star that is 10 lightyears away from us as it was 10 years ago. If that star died right now, we wouldn’t know about it for another 10 years. Thus, we can define it as a “stellar ghost”; a star that is dead from its perspective at its location, but still alive and well at ours.As covered in a previous article of mine (Stars: A Day in the Life), the evolution of a star is complex and highly dynamic. Many factors play an important role in everything from determining if the star will even form in the first place, to the size and thus the lifetime of said star. In the previous article mentioned above, I cover the basics of stellar formation and the life of what we call main sequence stars, or rather stars that are very similar to our own sun. Whereas the formation process and life of a main sequence star and the stars we will be discussing are fairly similar, there are important differences in the way the stars we will be investigating die. Main sequence star deaths are interesting, but they hardly compare to the spacetime-bending ways that these larger stars terminate. Inward force of gravity versus the outward pressure of fusion within a star (hydrostatic equilibrium)Credit: NASA As mentioned above, when we were observing the long gone star that lay at the center of the Crab Nebula, there was a point in which this object glowed as bright as the full moon and could be seen during the day. What could cause something to become so bright that it would be comparable to our nearest celestial neighbor? Considering the Crab Nebula is 6,523 lightyears away, that meant that something that is roughly 485 million times farther away than our moon was shining as bright as the moon. This was because the star went supernova when it died, which is the fate of stars that are much larger than our sun. Stars larger than our sun will end up in two very extreme states upon its death: neutron stars and black holes. Both are worthy topics that could span weeks in an astrophysics course, but for us today, we will simply go over how these gravitational monsters form and what that means for us.star’s life is a story of near runaway fusion contained by the grip of its own gravitational presence. We call this hydrostatic equilibrium, in which the outward pressure from the fusing elements in the core of a star equals that of the inward gravitational pressure being applied due to the star’s mass. In the core of all stars, hydrogen is being fused into helium (at first). This hydrogen came from the nebula that the star was born from, that coalesced and collapsed, giving the star its first chance at life. Throughout the lifetime of the star, the hydrogen will be used up, and more and more helium “ash” will condense down in the center of the star. Eventually, the star will run out of hydrogen, and the fusion will briefly stop. This lack of outward pressure due to no fusion taking place temporarily allows gravity to win and it crushes the star downwards. As the star shrinks, the density, and thus the temperature in the core of the star increases. Eventually, it reaches a certain temperature and the helium ash begins to fuse. This is how all stars proceed throughout the main portion of its life and into the first stages of its death. However, this is where sun-sized stars and the massive stars we are discussing part ways. The core and subsequent layers of a dying star. Each layer has been left over from millions of years of fusing each subsequent element into the next one. This is a snapshot of a massive star about to erupt. - Image Credit: Rursus via Wikimedia Commons A star that is roughly near the size of our own sun will go through this process until it reaches carbon. Stars that are this size simply aren’t big enough to fuse carbon. Thus, when all the helium has been fused into oxygen and carbon (via two processes that are too complex to cover here), the star cannot “crush” the oxygen and carbon enough to start fusion, gravity wins and the star dies. But stars that have sufficiently more mass than our sun (about 7x the mass) can continue on past these elements and keep shining. They have enough mass to continue this “crush and fuse” process that is the dynamic interactions at the hearts of these celestial furnaces.These larger stars will continue their fusion process past carbon and oxygen, past silicon, all the way until they reach iron. Iron is the death note sung by these blazing behemoths, as when iron begins to fill their now dying core, the star is in its death throws. But these massive structures of energy do not go quietly into the night. They go out in the most spectacular of ways. When the last of the non-iron elements fuse in their cores, the star begins its decent into oblivion. The star comes crashing in upon itself as it has no way to stave off gravity’s relentless grip, crushing the subsequent layers of left over elements from its lifetime. This inward free-fall is met at a certain size with an impossible force to breach; a neutron degeneracy pressure that forces the star to rebound outwards. This massive amount of gravitational and kinetic energy races back out with a fury that illuminates the universe, outshining entire galaxies in an instant. This fury is the life-blood of the cosmos; the drum beats in the symphony galactic, as this intense energy allows for the fusion of elements heavier than iron, all the way to uranium. These new elements are blasted outwards by this amazing force, riding the waves of energy that casts them deep into the cosmos, seeding the universe with all the elements that we know of. Artistic impression of a star going supernova, casting its chemically enriched contents into the universe. These new elements are blasted outwards by this amazing force, riding the waves of energy that casts them deep into the cosmos, seeding the universe with all the elements that we know of. Credit: NASA/Swift/Skyworks Digital/Dana Berryto But what is left? What is there after this spectacular event? That all depends again on the mass of the star. As mentioned earlier, the two forms that a dead massive star takes are either a Neutron Star or a Black Hole. For a Neutron Star, the formation is quite complex. Essentially, the events that I described occurs, except after the supernovae all that is left is a ball of degenerate neutrons. Degenerate is simply a term we apply to a form that matter takes on when it is compressed to the limits allowed by physics. Something that is degenerate is intensely dense, and this holds very true for a neutron star. A number you may have heard tossed around is that a teaspoon of neutron star material would weigh roughly 10 million tons, and have an escape velocity (the speed needed to get away from its gravitational pull) at about .4c, or 40% the speed of light. Sometimes the neutron star is left spinning at incredible velocities, and we label these as pulsars; the name derived from how we detect them. A pulsar with its magnetic field lines illustrated. The beams emitting from the poles are what washes over our detectors as the dead star spins. - Image Credit: NASA These types of stars generate a LOT of radiation. Neutron stars have an enormous magnetic field. This field accelerates electrons in their stellar atmospheres to incredible velocities. These electrons follow the magnetic field lines of the neutron star to its poles, where they can release radio waves, X-Rays, and gamma rays (depending on what type of neutron star it is). Since this energy is being concentrated to the poles, it creates a sort of lighthouse effect with high energy beams acting like the beams of light out of a lighthouse. As the star rotates, these beams sweep around many times per second. If the Earth, and thus our observation equipment, happens to be oriented favorably with this pulsar, we will register these “pulses” of energy as the stars’ beams wash over us. For all the pulsars we know about, we are much too far away for these beams of energy to hurt us. But if we were close to one of these dead stars, this radiation washing over our planet continuously would spell certain extinction for life as we know it.What of the other form that a dead star takes; a black hole? How does this occur? If degenerate material is as far as we can crush matter, how does a black hole appear? Simply put, black holes are the result of an unimaginably large star and thus a truly massive amount of matter that is able to “break” this neutron degeneracy pressure upon collapse. The star essentially falls inward with such force that it breaches this seemingly physical limit, turning in upon itself and wrapping up spacetime into a point of infinite density; a singularity. This amazing event occurs when a star has roughly 18x the amount of mass that our sun has, and when it dies, it is truly the epitome of physics gone to the extreme. This “extra bit of mass” is what allows it to collapse this ball of degenerate neutrons and fall towards infinity. It is both terrifying and beautiful to think about; a point in spacetime that is not entirely understood by our physics, and yet something that we know exists. The truly remarkable thing about black holes is that it is like the universe working against us. The information we need to fully understand the processes within a black hole are locked behind a veil that we call the event horizon. This is the point of no return for a black hole, for which anything beyond this point in spacetime has no future paths that lead out of it. Nothing escapes at this distance from the collapsed star at its core, not even light, and thus no information ever leaves this boundary (at least not in a form we can use). The dark heart of this truly astounding object leaves a lot to be desired, and tempts us to cross into its realm in order to try and know the unknowable; to grasp the fruit from the tree of knowledge.Now it must be said, there is much in the way of research with black holes to this day. Physicists such as Professor Stephen Hawking, among others, have been working tirelessly on the theoretical physics behind how a black hole operates, attempting to solve the paradoxes that frequently appear when we try to utilize the best of our physics against them. There are many articles and papers on such research and their subsequent findings, so I will not dive into their intricacies for both wishing to preserve simplicity in understanding, and to also not take away from the amazing minds that are working these issues. Many suggest that the singularity is a mathematical curiosity that does not completely represent what physically happens. That the matter inside an event horizon can take on new and exotic forms. It is also worth noting that in General Relativity, anything with mass can collapse to a black hole, but we generally hold to a range of masses as creating a black hole with anything less than is in that mass range is beyond our understanding of how that could happen. But as someone who studies physics, I would be remiss to not mention that as of now, we are at an interesting cross section of ideas that deal very intimately with what is actually going on within these specters of gravity.All of this brings me back to a point that needs to be made. A fact that needs to be recognized. As I described the deaths of these massive stars, I touched on something that occurs. As the star is being ripped apart from its own energy and its contents being blown outwards into the universe, something called nucleosynthesis is occurring. This is the fusion of elements to create new elements. From hydrogen up to uranium. These new elements are being blasted outwards an incredible speeds, and thus all of these elements will eventually find their way into molecular clouds. Molecular clouds (Dark Nebulae) are the stellar nurseries of the cosmos. This is where stars begin. And from star formation, we get planetary formation. Planets coalescing out of the remaining molecular cloud the star formed out of. Within this accretion disk lay the fundamental elements necessary for planet formation and potential life. Credit: NASA/JPL-Caltech/T. Pyle (SSC) – February, 2005 As a star forms, a cloud of debris that is made up of the molecular cloud that birthed said star begins to spin around it. This cloud, as we now know, contains all those elements that were cooked up in our supernovae. The carbon, the oxygen, the silicates, the silver, the gold; all present in this cloud. This accretion disk about this new star is where planets form, coalescing out of this enriched environment. Balls of rock and ice colliding, accreting, being torn apart and then reformed as gravity works its diligent hands to mold these new worlds into islands of possibility. These planets are formed from those very same elements that were synthesized in that cataclysmic eruption. These new worlds contain the blueprints for life as we know it.Upon one of these worlds, a certain mixture of hydrogen and oxygen occurs. Within this mixture, certain carbon atoms form up to create replicating chains that follow a simple pattern. Perhaps after billions of years, these same elements that were thrust into the universe by that dying star finds itself giving life to something that can look up and appreciate the majesty that is the cosmos. Perhaps that something has the intelligence to realize that the carbon atom within it is the very same carbon atom that was created in a dying star, and that a supernovae occurred that allowed that carbon atom to find its way into the right part of the universe at the right time. The energy that was the last dying breath of a long dead star was the same energy that allowed life to take its first breath and gaze upon the stars. These stellar ghosts are our ancestors. They are gone in form, but yet remain within our chemical memory. They exist within us. We are supernova. We are star dust. We are descended from stellar ghosts…Source: Universe Today
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Cosmology & The Universe
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A constellation of tiny satellites could revolutionize the study of the most energetic explosion in the cosmos and help astronomers untangle the mysteries of colliding stellar remnants that produce powerful gravitational waves.
In 2016, a group of Eastern European astronomers and space enthusiasts met in Hungary's capital Budapest to discuss new ideas to do ground-breaking science. That is, to do ground-breaking science the Eastern European way: With tiny budgets and a lot of resourcefulness. Among these people were astronomers András Pál, a senior research fellow at Budapest's Konkoly Observatory, and Norbert Werner, at that time newly appointed as the head of the "Hot Universe" research group at Budapest's Eötvös Loránd University. In his late 30s and originally from the neighboring Slovakia, Werner had just returned to his native corner of the world after an eight-year stint at California's famed Stanford University.
Energized by the spirit of the place that in the early 2000s had given birth to cubesats, perhaps the space industry's most game-changing innovation of recent decades, Werner wanted to find out what type of big science one could do with these cheap, easy-to-build space gadgets.
Norbert Werner is a professor of theoretical physics and astrophysics at Masaryk University in Brno, the Czech Republic. Originally from Slovakia, Werner completed his PhD at Utrecht University in the Netherlands and subsequently worked for eight years at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University in California. He is an expert in high-energy astrophysics and studies the hottest phenomena in the universe, such as intergalactic gas around black holes and giant galactic clusters.
Elusive gamma ray bursts
For these Eastern Europeans, naturally skilled in the DIY approach to make up for their lack of financial resources, cubesats appeared like a gift from the heavens. For Werner, whose interests had for years focused on the hottest places and the highest-energy phenomena that occur in the universe, it didn't take long to realize that gamma-ray bursts may be just the thing he wanted to study with these new toys.
"Gamma-ray bursts are really bright and all you need is a relatively small detector to spot them," Werner told Space.com. "You don't need anything complicated, like a good attitude control system."
Gamma-ray bursts are the highest-energy explosions known to take place in the universe. Astronomers believe that only the Big Bang produced more energy than these mysterious flashes of super-energetic photons that come from distant galaxies. Accidentally discovered in the 1960s by American satellites keeping an eye on Russia's testing of nuclear weapons (which too produce the dangerous, penetrating gamma radiation), gamma-ray bursts had long puzzled astronomers. While some last a fraction of a second, others can brighten up the sky for several minutes.
It took until the 1990s for astronomers to find that short gamma-ray bursts are likely caused by collisions of neutron stars, super-dense remnants of giant stars that prior to their death were over ten times more massive than our sun. The long-lasting bursts, astronomers believe, occur when even larger stars explode into supernovas at the end of their lives and then turn into black holes. Both of these events emit jets of super energetic material that illuminate the surrounding universe like the beam of a flashlight. Satellites orbiting Earth only detect a gamma-ray burst when this flashlight is directed toward our part of the cosmos, but detecting a gamma-ray burst is not a rare event. Almost every day, one flashes briefly at our planet from somewhere in the universe. Many more are believed to take place throughout the cosmos that go undetected because the "flashlight" is not aimed at us.
But because gamma-ray bursts are so fleeting, astronomers don't always manage to locate their source. In fact, only about 30% of detected gamma-ray bursts get tracked to their origins, a problem Werner thought his cubesats could solve.
The aging fleet of gamma-ray burst watchers
The European Space Agency's Integral mission, which celebrated two decades in orbit in October last year, and NASA's nearly 15-year-old Fermi are the current flagship gamma-ray burst spotters. Optimized to detect super high energy gamma radiation, which is billions of times more energetic than what human eyes can see, these two spacecraft together detect the vast majority of gamma-ray bursts aimed at Earth. However, Werner said, they don't do a very good job finding the source of those flashes. Another NASA spacecraft, Swift, just a year and a half short of its 20th birthday, is equipped to find the source of gamma-ray bursts. Swift, however, only sees about one ninth of the sky. And since gamma-ray bursts are distributed evenly all over the universe, Swift only detects a small fraction of them.
"It misses 8 out of 9 gamma-ray bursts," said Werner. "We don't have a mission that would cover the full sky and also provide localization."
Astronomers want to know where gamma-ray bursts come from so that they can point other types of telescope toward those sources, and study the aftermath of the cataclysmic events that produced them.
Werner's and Pál's brainstorming soon moved beyond a single cubesat. They envisioned a whole constellation, which, they thought, could make up for the shortcomings of the existing, aging gamma-ray burst-detecting fleet.
A GPS for gamma-ray bursts
"It occurred to us that if you have a constellation of cubesats, then you can cover the whole sky," Werner said. "That's a big advantage compared to the big monolithic missions. The second advantage is that you can measure the difference in time between when the different cubesats detect the gamma-ray burst and you can triangulate the position of the gamma-ray burst on the sky."
By 2018, the two managed to persuade the Hungarian Academy of Sciences to fund a development of a new detector that would fit on a 1U cubesat, the smallest type of cubesat measuring only 3.9 by 3.9 by 3.9 inches (10 by 10 by 10 centimeters) in size. Other partners jumped on board including researchers from the Technical University of Košice in Werner's native Slovakia and scientists from Japan's Hiroshima University. In March 2021, the world's first gamma-ray burst-detecting cubesat, called GRBAlpha, shot off to space from the Baikonur Cosmodrome in Kazakhstan squeezed inside the fairing of Russia's Soyuz rocket together with a bunch of other small satellites including the debris removing experiment ELSA-D of the Japan-headquartered firm Astroscale.
The smallest astrophysical observatory in the world
Since then, GRBAlpha, which Werner refers to as "the smallest astrophysical satellite ever," has been orbiting Earth 340 miles (550 kilometers) above the planet's surface. The innovative detector bolted to the tiny satellite's surface has been exceeding the team's expectations from the start.
"The first burst was detected in August 2021," Werner said. "We were all really, really happy, because the actual detection of gamma-ray bursts was considered a bonus, not the main goal. The main goal was the in-flight demonstration of the detector, which contained new technology."
Since then, GRBAlpha has detected 22 gamma-ray bursts.
In the meantime, in 2020, Werner relocated yet again. This time to Brno, a city in the Czech Republic, yet another country from the central-eastern European post-communist cluster that is now part of the European Union. Barely 40 years old at that time, Werner was appointed a professor of theoretical physics and astrophysics at Brno's Masaryk University, and quickly won the support of the country's small-but-eager space sector to add the new detectors on another mission. Three times larger than GRBAlpha, the Czech Republic's VZLUSAT-2 has been orbiting Earth since January 2022, having scored 12 gamma-ray bursts since then. And thus, the foundation of Werner's and Pál's constellation came into being.
Decoding the mysteries of neutron stars
Werner's interest in gamma-ray bursts goes beyond tracking down their sources. In addition to these powerful flashes of light, colliding neutron stars (and possibly supernova explosions too) produce another fascinating phenomenon: Gravitational waves.
First predicted by the iconic physicist Albert Einstein in 1916, gravitational waves are ripples in spacetime that arise from the interplay of gravitational forces of two or more supermassive objects, such as neutron stars and black holes. Across the universe, these objects frequently get pulled into each other's sphere of gravitational influence and start orbiting each other. Gradually, they spiral closer and closer to each other and eventually collide, the collision producing a gravitational tsunami that can be detected from Earth by gravitational wave detectors such as the American LIGO (The Laser Interferometer Gravitational-Wave Observatory) and the European Gravitational Observatory Virgo.
Having made its first ground-breaking gravitational wave detection in 2015, LIGO is currently undergoing upgrades and will start its next observing run later this year.
"For these further runs of the gravitational wave detectors, we need a gamma-ray burst-monitoring system that will allow us to see whether these gravitational wave events do produce observable counterparts in gamma-ray bursts," Werner said. "Especially in the neutron star mergers, it is important to see whether there was a gamma-ray burst or not because only a small fraction of those jets that produce the gamma-ray burst should be aimed at us."
Apart from their limited ability to detect the sources of gamma-ray bursts, Swift, Integral and Fermi are all way past their originally planned lifetimes. Replacing them with new, large space telescopes would take years and cost hundreds of millions of dollars. In comparison, the constellation envisioned by Werner and Pál would come with a friendly price tag of only about 10 million dollars and could be up and running within less than three years, Werner said.
An international endeavor
Soon after their first discussion, Werner and Pál found out they weren't alone in recognizing the potential of cubesats for the detection of gamma-ray bursts.
An Italian project called HERMES (opens in new tab) won European Union funding in 2018 to build and launch a constellation of six gamma-ray burst-detecting 3U cubesats (three times larger than the tiny, pioneering GRBAlpha). The first of these spacecraft is expected to launch in the second half of 2024, Fabrizio Fiore, the HERMES project coordinator and astronomer at Italy's National Institute for Astrophysics, told Space.com in an email. Prior to that, the HERMES project team will fly a hosted payload on a cubesat built by the University of Melbourne, Australia, which is set for launch at the end of 2023.
"We hope to see first data at the end of this year or beginning of 2024," Fiore wrote.
The HERMES satellites are quite a bit more sophisticated than GRBAlpha, featuring a detector sensitive to gamma-rays but also the slightly less energetic X-rays. The satellites are also equipped with a set of high-tech sensors including GPS receivers and accelerometers that will be able to report the spacecraft's positions with an accuracy of a few meters. And since there will be six of these satellites (plus the hosted payload), astronomers will be able, for the first time, to use the minuscule time difference in the arrival of the gamma-ray burst at the individual satellites, to calculate the location of the burst's source.
"The temporal resolution is of about 300 nanoseconds," Fiore wrote. "That is three to seven times better than any instrument flown so far for gamma-ray burst science."
NASA is also working on a gamma-ray burst-detecting cubesat. The BurstCube (opens in new tab), twice as big as the HERMES satellites, is expected to launch by the end of 2023.
Werner and his colleagues, too, have a new satellite in the pipeline. GRBAlpha's somewhat larger and more complex successor GRBBeta has its ride to space booked on the debut flight of Europe's new Ariane 6 heavy-lift rocket, which is expected to take place by the end of this year.
"It seems that we all had this idea of a small satellite detecting these high-energy events in the sky at about the same time," said Werner. "Now we can all coordinate our efforts and build the constellation together. Most of these cubesats are built by small teams that have limited funding, but by working together, we can do it easier with the funding that we have."
Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook.
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Cosmology & The Universe
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Space September 23, 2022 / 6:36 AM / CBS/AFP First pictures of Milky Way’s black hole First images of Milky Way’s black hole released 02:13 Astronomers said Thursday they have spotted a hot bubble of gas spinning clockwise around the black hole at the center of our galaxy at "mind blowing" speeds. The detection of the bubble, which only survived for a few hours, is hoped to provide insight into how these invisible, insatiable, galactic monsters work.The supermassive black hole Sagittarius A* lurks in the middle of the Milky Way some 27,000 light years from Earth, and its immense pull gives our home galaxy its characteristic swirl.The first-ever image of Sagittarius A* was revealed in May by the Event Horizon Telescope Collaboration, which links radio dishes around the world aiming to detect light as it disappears into the maw of black holes. One of those dishes, the ALMA radio telescope in Chile's Andes mountains, picked up something "really puzzling" in the Sagittarius A* data, said Maciek Wielgus, an astrophysicist at Germany's Max Planck Institute for Radio Astronomy. This is the first image of Sagittarius A*, the supermassive black hole at the center of our galaxy. It was captured by the Event Horizon Telescope, an array which linked together eight existing radio observatories across the planet to form a single "Earth-sized" virtual telescope. Although we cannot see the event horizon itself, we can see light bent by the powerful gravity of the black hole. Event Horizon Telescope Collaboration Just minutes before ALMA's radio data collection began, the Chandra Space Telescope observed a "huge spike" in X-rays, Wielgus told AFP. This burst of energy, thought to be similar to solar flares on the sun, sent a hot bubble of gas swirling around the black hole, according to a new study published in the journal Astronomy and Astrophysics.The gas bubble, also known as a hot spot, had an orbit similar to Mercury's trip around the sun, the study's lead author Wielgus said.But while it takes Mercury 88 days to make that trip, the bubble did it in just 70 minutes. That means it traveled at around 30 percent of the speed of light."So it's an absolutely, ridiculously fast-spinning bubble," Wielgus said, calling it "mind blowing." The scientists were able to track the bubble through their data for around one and half hours -- it was unlikely to have survived more than a couple of orbits before being destroyed.Wielgus said the observation supported a theory known as MAD. "MAD like crazy, but also MAD like magnetically arrested discs," he said.The phenomenon is thought to happen when there is such a strong magnetic field at the mouth of a black hole that it stops material from being sucked inside.But the matter keeps piling up, building up to a "flux eruption", Wielgus said, which snaps the magnetic fields and causes a burst of energy.By learning how these magnetic fields work, scientists hope to build a model of the forces that control black holes, which remain shrouded in mystery.Magnetic fields could also help indicate how fast black holes spin -- which could be particularly interesting for Sagittarius A*.While Sagittarius A* is four million times the mass of our sun, it only shines with the power of about 100 suns, "which is extremely unimpressive for a supermassive black hole," Wielgus said. "It's the weakest supermassive black hole that we've seen in the universe -- we've only seen it because it is very close to us."But it is probably a good thing that our galaxy has a "starving black hole" at its center, Wielgus said."Living next to a quasar," which can shine with the power of billions of suns, "would be a terrible thing," he added.By definition, black holes cannot be directly observed because nothing, not even light, can escape the crushing inward force of their titanic gravity.But their presence can be indirectly detected by observing the effects of that gravity on the trajectories of nearby stars and by the radiation emitted across the electromagnetic spectrum by material heated to extreme temperatures as it's sucked into a rapidly rotating "accretion disk" and then into the hole itself.A major objective of the new James Webb Space Telescope is to help astronomers chart the formation and growth of such black holes in the aftermath of the Big Bang. In: Black Hole Thanks for reading CBS NEWS. Create your free account or log in for more features. Please enter email address to continue Please enter valid email address to continue
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Cosmology & The Universe
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Image source, NASA/ESA/CSAImage caption, SMACS 0723: The red arcs in the image are light from very early galaxies.The first full-colour image from the new James Webb Space Telescope has been released - and it's a record-breaker.The picture represents the "deepest ever" view of the Universe, containing the light from galaxies that has taken many billions of years to reach us.US President Joe Biden was shown the image during a White House briefing from the American space agency.Further debut pictures from James Webb are due to be released in a global presentation on Tuesday.The $10bn James Webb Space Telescope (JWST), launched on 25 December last year, is billed as the successor to the famous Hubble Space Telescope.It will make all sorts of observations of the sky, but has two overarching goals. One is to probe far-off planets to see if they might be habitable; the other is to take pictures of the very first stars to shine in the Universe more than 13.5 billion years ago.The image unveiled before President Biden showcases Webb's capabilities to pursue the second of these objectives.What you see is a cluster of galaxies in the Southern Hemisphere constellation of Volans known by the ungainly name of SMACS 0723.The cluster itself isn't actually that far away - only about four billion light-years in the distance. But the great mass of this cluster has bent and magnified the light of objects that are much, much further away.It's a gravitational effect; the astronomical equivalent of a zoom lens for a telescope.Webb, with its 6.5m-wide golden mirror and super-sensitive infrared instruments, has managed to detect in this picture the distorted shape of galaxies that existed a mere 600 million years after the Big Bang (the Universe is 13.8 billion years old).And it's even better than that. Scientists can tell from the quality of the data produced by Webb that the telescope is sensing space way beyond the most far-flung object in this image.As a consequence, it's possible this is even the deepest cosmic viewing field ever obtained.Hubble used to stare at the sky for weeks on end to produce this kind of result. Webb identified its super-deep objects after only a few hours of observations.Nasa and its international partners, the European and Canadian space agencies, will release further colour imagery from Webb on Tuesday.Media caption, Amber Straughn: Why the James Webb telescope sees in the infraredOne of the topics to be discussed will touch on that other overarching goal: the study of planets outside our Solar System.Webb has analysed the atmosphere of WASP-96 b, a giant planet located more than 1,000 light-years from Earth. It will tell us about the chemistry of that atmosphere.One day, it's hoped Webb might spy a planet that has gases in its air that are similar to those that shroud the Earth.Nasa scientists promise Webb will not disappoint."I have seen the first images and they are spectacular," deputy project scientist Dr Amber Straughn said of Tuesday's big release."They're amazing in themselves just as images. But the hints of the detailed science we're going to be able to do with them is what makes me so excited," she told BBC News.Dr Eric Smith, the programme scientist for the Webb project, said he thought the public had already grasped the significance of the new telescope."The design of Webb, the way Webb looks, I think, is in large part the reason the public is really fascinated by this mission. It looks like a spaceship from the future."Nasa is holding a webcast on Tuesday to showcase further imagery from the new telescope. There are many places where you can view this presentation, including on the European Space Agency's web TV channel. Programming starts at 14:45 BST, 15:45 CEST; 09:45 EDT. Other viewing possibilities include the Canadian Space Agency's YouTube channel; and on Nasa Live. BBC Two television will air a special programme on Webb - Super Telescope: Mission to the Edge of the Universe - on Thursday at 20:00 BST.
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Cosmology & The Universe
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A few of the deeper returning questions people engage with in conversations and discussions about cosmology relate to what happened before the big bang and what instigated the big bang in the first place; in other words, how does something come from nothing.
With these questions, we currently find ourselves at the edge of science, somewhere near the intersection of cosmology and philosophy.
In this article, professor Alastair Wilson shares his understanding of the matter and takes you on a fascinating journey. Please enjoy!
By Alastair Wilson, University of Birmingham
“The last star will slowly cool and fade away. With its passing, the universe will become once more a void, without light or life or meaning.” So warned the physicist Brian Cox in the recent BBC series Universe. The fading of that last star will only be the beginning of an infinitely long, dark epoch. All matter will eventually be consumed by monstrous black holes, which in their turn will evaporate away into the dimmest glimmers of light. Space will expand ever outwards until even that dim light becomes too spread out to interact. Activity will cease.
Or will it? Strangely enough, some cosmologists believe a previous, cold dark empty universe like the one which lies in our far future could have been the source of our very own Big Bang.
The first matter
But before we get to that, let’s take a look at how “material” – physical matter – first came about. If we are aiming to explain the origins of stable matter made of atoms or molecules, there was certainly none of that around at the Big Bang – nor for hundreds of thousands of years afterward. We do in fact have a pretty detailed understanding of how the first atoms formed out of simpler particles once conditions cooled down enough for complex matter to be stable, and how these atoms were later fused into heavier elements inside stars. But that understanding doesn’t address the question of whether something came from nothing.
So let’s think further back. The first long-lived matter particles of any kind were protons and neutrons, which together make up the atomic nucleus. These came into existence around one ten-thousandth of a second after the Big Bang. Before that point, there was really no material in any familiar sense of the word. But physics lets us keep on tracing the timeline backwards – to physical processes which predate any stable matter.
This takes us to the so-called “grand unified epoch”. By now, we are well into the realm of speculative physics, as we can’t produce enough energy in our experiments to probe the sort of processes that were going on at the time. But a plausible hypothesis is that the physical world was made up of a soup of short-lived elementary particles – including quarks, the building blocks of protons and neutrons. There was both matter and “antimatter” in roughly equal quantities: each type of matter particle, such as the quark, has an antimatter “mirror image” companion, which is near identical to itself, differing only in one aspect. However, matter and antimatter annihilate in a flash of energy when they meet, meaning these particles were constantly created and destroyed.
But how did these particles come to exist in the first place? Quantum field theory tells us that even a vacuum, supposedly corresponding to empty spacetime, is full of physical activity in the form of energy fluctuations. These fluctuations can give rise to particles popping out, only to be disappear shortly after. This may sound like a mathematical quirk rather than real physics, but such particles have been spotted in countless experiments.
The spacetime vacuum state is seething with particles constantly being created and destroyed, apparently “out of nothing”. But perhaps all this really tells us is that the quantum vacuum is (despite its name) a something rather than a nothing. The philosopher David Albert has memorably criticised accounts of the Big Bang which promise to get something from nothing in this way.
Suppose we ask: where did spacetime itself arise from? Then we can go on turning the clock yet further back, into the truly ancient “Planck epoch” – a period so early in the universe’s history that our best theories of physics break down. This era occurred only one ten-millionth of a trillionth of a trillionth of a trillionth of a second after the Big Bang. At this point, space and time themselves became subject to quantum fluctuations. Physicists ordinarily work separately with quantum mechanics, which rules the microworld of particles, and with general relativity, which applies on large, cosmic scales. But to truly understand the Planck epoch, we need a complete theory of quantum gravity, merging the two.
We still don’t have a perfect theory of quantum gravity, but there are attempts – like string theory and loop quantum gravity. In these attempts, ordinary space and time are typically seen as emergent, like the waves on the surface of a deep ocean. What we experience as space and time are the product of quantum processes operating at a deeper, microscopic level – processes that don’t make much sense to us as creatures rooted in the macroscopic world.
In the Planck epoch, our ordinary understanding of space and time breaks down, so we can’t any longer rely on our ordinary understanding of cause and effect either. Despite this, all candidate theories of quantum gravity describe something physical that was going on in the Planck epoch – some quantum precursor of ordinary space and time. But where did that come from?
Even if causality no longer applies in any ordinary fashion, it might still be possible to explain one component of the Planck-epoch universe in terms of another. Unfortunately, by now even our best physics fails completely to provide answers. Until we make further progress towards a “theory of everything”, we won’t be able to give any definitive answer. The most we can say with confidence at this stage is that physics has so far found no confirmed instances of something arising from nothing.
Cycles from almost nothing
To truly answer the question of how something could arise from nothing, we would need to explain the quantum state of the entire universe at the beginning of the Planck epoch. All attempts to do this remain highly speculative. Some of them appeal to supernatural forces like a designer. But other candidate explanations remain within the realm of physics – such as a multiverse, which contains an infinite number of parallel universes, or cyclical models of the universe, being born and reborn again.
The 2020 Nobel Prize-winning physicist Roger Penrose has proposed one intriguing but controversial model for a cyclical universe dubbed “conformal cyclic cosmology”. Penrose was inspired by an interesting mathematical connection between a very hot, dense, small state of the universe – as it was at the Big Bang – and an extremely cold, empty, expanded state of the universe – as it will be in the far future. His radical theory to explain this correspondence is that those states become mathematically identical when taken to their limits. Paradoxical though it might seem, a total absence of matter might have managed to give rise to all the matter we see around us in our universe.
In this view, the Big Bang arises from an almost nothing. That’s what’s left over when all the matter in a universe has been consumed into black holes, which have in turn boiled away into photons – lost in a void. The whole universe thus arises from something that – viewed from another physical perspective – is as close as one can get to nothing at all. But that nothing is still a kind of something. It is still a physical universe, however empty.
How can the very same state be a cold, empty universe from one perspective and a hot dense universe from another? The answer lies in a complex mathematical procedure called “conformal rescaling”, a geometrical transformation that in effect alters the size of an object but leaves its shape unchanged.
Penrose showed how the cold empty state and the hot dense state could be related by such rescaling so that they match with respect to the shapes of their spacetimes – although not to their sizes. It is, admittedly, difficult to grasp how two objects can be identical in this way when they have different sizes – but Penrose argues size as a concept ceases to make sense in such extreme physical environments.
In conformal cyclic cosmology, the direction of explanation goes from old and cold to young and hot: the hot dense state exists because of the cold empty state. But this “because” is not the familiar one – of a cause followed in time by its effect. It is not only size that ceases to be relevant in these extreme states: time does too. The cold empty state and the hot dense state are in effect located on different timelines. The cold empty state would continue on forever from the perspective of an observer in its own temporal geometry, but the hot dense state it gives rise to effectively inhabits a new timeline all its own.
It may help to understand the hot dense state as produced from the cold empty state in some non-causal way. Perhaps we should say that the hot dense state emerges from, or is grounded in, or realized by the cold, empty state. These are distinctively metaphysical ideas that have been explored by philosophers of science extensively, especially in the context of quantum gravity where ordinary cause and effect seem to break down. At the limits of our knowledge, physics and philosophy become hard to disentangle.
Experimental evidence?
Conformal cyclic cosmology offers some detailed, albeit speculative, answers to the question of where our Big Bang came from. But even if Penrose’s vision is vindicated by the future progress of cosmology, we might think that we still wouldn’t have answered a deeper philosophical question – a question about where physical reality itself came from. How did the whole system of cycles come about? Then we finally end up with the pure question of why there is something rather than nothing – one of the biggest questions of metaphysics.
But our focus here is on explanations which remain within the realm of physics. There are three broad options to the deeper question of how the cycles began. It could have no physical explanation at all. Or there could be endlessly repeating cycles, each a universe in its own right, with the initial quantum state of each universe explained by some feature of the universe before. Or there could be one single cycle, and one single repeating universe, with the beginning of that cycle explained by some feature of its own end. The latter two approaches avoid the need for any uncaused events – and this gives them a distinctive appeal. Nothing would be left unexplained by physics.
Penrose envisages a sequence of endless new cycles for reasons partly linked to his own preferred interpretation of quantum theory. In quantum mechanics, a physical system exists in a superposition of many different states at the same time, and only “picks one” randomly, when we measure it. For Penrose, each cycle involves random quantum events turning out a different way – meaning each cycle will differ from those before and after it. This is actually good news for experimental physicists, because it might allow us to glimpse the old universe that gave rise to ours through faint traces, or anomalies, in the leftover radiation from the Big Bang seen by the Planck satellite.
Penrose and his collaborators believe they may have spotted these traces already, attributing patterns in the Planck data to radiation from supermassive black holes in the previous universe. However, their claimed observations have been challenged by other physicists and the jury remains out.
Endless new cycles are key to Penrose’s own vision. But there is a natural way to convert conformal cyclic cosmology from a multi-cycle to a one-cycle form. Then physical reality consists in a single cycling around through the Big Bang to a maximally empty state in the far future – and then around again to the very same Big Bang, giving rise to the very same universe all over again.
This latter possibility is consistent with another interpretation of quantum mechanics, dubbed the many-worlds interpretation. The many-worlds interpretation tells us that each time we measure a system that is in superposition, this measurement doesn’t randomly select a state. Instead, the measurement result we see is just one possibility – the one that plays out in our own universe. The other measurement results all play out in other universes in a multiverse, effectively cut off from our own. So no matter how small the chance of something occurring, if it has a non-zero chance then it occurs in some quantum parallel world. There are people just like you out there in other worlds who have won the lottery, or have been swept up into the clouds by a freak typhoon, or have spontaneously ignited, or have done all three simultaneously.
Some people believe such parallel universes may also be observable in cosmological data, as imprints caused by another universe colliding with ours.
Many-worlds quantum theory gives a new twist on conformal cyclic cosmology, though not one that Penrose agrees with. Our Big Bang might be the rebirth of one single quantum multiverse, containing infinitely many different universes all occurring together. Everything possible happens – then it happens again and again and again.
An ancient myth
For a philosopher of science, Penrose’s vision is fascinating. It opens up new possibilities for explaining the Big Bang, taking our explanations beyond ordinary cause and effect. It is therefore a great test case for exploring the different ways physics can explain our world. It deserves more attention from philosophers.
For a lover of myth, Penrose’s vision is beautiful. In Penrose’s preferred multi-cycle form, it promises endless new worlds born from the ashes of their ancestors. In its one-cycle form, it is a striking modern re-invocation of the ancient idea of the ouroboros, or world-serpent. In Norse mythology, the serpent Jörmungandr is a child of Loki, a clever trickster, and the giant Angrboda. Jörmungandr consumes its own tail, and the circle created sustains the balance of the world. But the ouroboros myth has been documented all over the world – including as far back as ancient Egypt.
The ouroboros of the one cyclic universe is majestic indeed. It contains within its belly our own universe, as well as every one of the weird and wonderful alternative possible universes allowed by quantum physics – and at the point where its head meets its tail, it is completely empty yet also coursing with energy at temperatures of a hundred thousand million billion trillion degrees Celsius. Even Loki, the shapeshifter, would be impressed.
Sources and further reading in Space & Exploration:
Putting the size of the universe into human perspective - (Universal-Sci)
Special lettuce grown in space will help future Mars-bound astronauts prevent bone loss - (Universal-Sci)
The story about Earendel: the farthest star ever observed - (Universal-Sci)
Why Jupiter's four largest moons are among the most interesting worlds of our solar system - (Universal-Sci)
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Cosmology & The Universe
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Fascinating time-lapse footage captures never-before-seen view of the fiery aftermath from a collision between two starsAftermath of an epic collision involving two stars has been captured in new wayThis shows it for first time in a millimetre range of radio frequency wavelengthsLight is from fiery explosion caused by merger of neutron star with another star Could help experts learn about effect these events have on space around them Published: 07:17 EDT, 4 August 2022 | Updated: 07:35 EDT, 4 August 2022 Fascinating time-lapse footage has captured a never-before-seen view of the fiery aftermath from a collision between two stars.For the first time, scientists recorded millimetre-wavelength light from the merger of at least one neutron star with another star, which left behind one of the most luminous afterglows on record.The light travelled some 6 to 9 billion light-years across the Universe and was picked up by the Atacama Large Millimeter/Submillimeter Array (ALMA) observatory in Chile.Led by Northwestern University and Radboud University in the Netherlands, the team also confirmed this flash as one of the most energetic short-duration gamma-ray bursts (GRBs) ever observed. The data could help scientists learn more about these extreme events, and the effect they have on the space around them. Stellar event: Fascinating time-lapse footage has captured a never-before-seen view of the fiery aftermath caused by the collision of two stars For the first time, scientists recorded millimetre-wavelength light from the merger of at least one neutron star with another star, which left behind one of the most luminous afterglows on record The light travelled some 6 to 9 billion light-years across the Universe and was picked up by the Atacama Large Millimeter/Submillimeter Array (ALMA) observatory in Chile. Pictured is an artist's impression of the merger between a neutron star and another starGamma-ray bursts are the most violent explosions in the universeGamma ray bursts (GRBs), energetic jets of gamma rays that come from black holes, can be created in two different ways – resulting in long or short GRBs.They are created from some of the most violent deaths in the Universe.Long GRBs last about a minute, and scientists think they are produced by supernovae: when the core of a massive star collapses to become a black hole. Short GRBs last a second and are produced when two neutron stars merge. 'This short gamma-ray burst was the first time we tried to observe such an event with ALMA,' said Northwestern's Wen-fai Fong, principal investigator of the ALMA program. 'Afterglows for short bursts are very difficult to come by, so it was spectacular to catch this event shining so brightly. ' Gamma-ray bursts are the most powerful known explosions in the Universe. In just 10 seconds, they can emit more energy than a star the size of our sun gives off in 10 billion years.Long GRBs last about a minute, and scientists think they are produced by supernovae: when the core of a massive star collapses to become a black hole. Short GRBs last a second and are usually produced when two neutron stars merge. They are also important because it is in explosions like these that elements heavier than iron are forged and ejected throughout space. 'These explosions take place in distant galaxies which means the light from them can be quite faint for our telescopes on Earth,' said astrophysicist Tanmoy Laskar, of Radboud University in the Netherlands.'Before ALMA, millimeter telescopes were not sensitive enough to detect these afterglows.'Located in the high-altitude Atacama Desert in Chile, the ALMA array comprises 66 radio telescopes, making it the largest radio telescope in the world. Laskar added: 'ALMA's unparalleled sensitivity allowed us to pinpoint the location of the GRB in that field with more precision, and it turned out to be in another faint galaxy, which is further away.'That, in turn, means that this short-duration gamma-ray burst is even more powerful than we first thought, making it one of the most luminous and energetic on record.' Gamma-ray bursts are the most powerful known explosions in the Universe In just 10 seconds, they can emit more energy than a star the size of our sun gives off in 10 billion years GRBs are also important because it is in explosions like these that elements heavier than iron are forged and ejected throughout space Located in the high-altitude Atacama Desert in Chile, the ALMA array comprises 66 radio telescopes, making it the largest radio telescope in the worldFong said: 'After many years observing these bursts, this surprising discovery opens up a new area of study, as it motivates us to observe many more of these with ALMA and other telescope arrays in the future.' Last year, a massive gamma-ray blast more than a billion light-years from Earth was revealed to be the largest explosion in the Universe ever detected and recorded by astronomers.The explosive event was the death of a star and the start of its transformation into a black hole, according to experts from the German Electron Synchrotron in Hamburg.This was a massive gamma-ray burst, made up of a combination of bright X-ray and gamma-ray flashes observed in the sky, emitted by distant extragalactic sources. It was detected by space-based Fermi and Swift telescopes, with support from the Earth-based High Energy Stereoscopic System (H.E.S.S) telescope in Namibia. The new research has been accepted into The Astrophysical Journal Letters, and is available on arXiv.WHAT DO WE KNOW ABOUT GAMMA RADIATION?Gamma rays are a form of electromagnetic radiation (EMR), similar to X-rays, that are emitted from the excited nucleus of an atom. All EMR takes the form of a stream of photons, massless particles each travelling in a wave-like pattern and moving at the speed of light. Each photon contains a certain amount - a package or bundle - of energy, and all EMR consists of these photons. Gamma-ray photons have the highest energy in the EMR spectrum and their waves have the shortest wavelength.Scientists measure the energy of photons in electron volts (ev). X-ray photons have energies in the range 100 ev to 100,000 ev (or 100 kev). Gamma-ray photons generally have energies greater than 100 kev. For comparison, the ultraviolet radiation that causes your skin to tan or burn has energy that falls in the range from a few electron volts to about 100 eV.The high energy of gamma rays mean they can pass through many kinds of materials, including human tissue. Very dense materials, such as lead, are commonly used as shielding to slow or stop gamma rays.Gamma radiation is released from many of the radioisotopes found in the natural radiation decay series of uranium, thorium and actinium.It also emitted by the naturally occurring radioisotopes potassium-40 and carbon-14. These are found in all rocks and soil and even in our food and water.Artificial sources of gamma radiation are produced in fission in nuclear reactors, high energy physics experiments, nuclear explosions and accidents.Huge bursts of gamma rays have been detected out in the universe and are though to come from black holes that form when stars explode or when two neutron stars collide. Advertisement
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Cosmology & The Universe
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Most people have heard that Einstein’s Special Theory of Relativity revolutionized our understanding of time. But most people still aren’t aware of quite how profound the consequences of Einstein’s block universe are, according to which our experience of the present as uniquely different from the past or the future, the very idea of time having a direction, of “passing”, is put into question, argues Michael Silberstein. “The objective world simply is; it does not happen.” - Hermann Weyl“I am a Tralfamadorian, seeing all time as you might see a stretch of the Rocky Mountains. All time is all time. It does not change. It does not lend itself to warnings or explanations. It simply is.” - Kurt VonnegutIf you explore YouTube, you will find hundreds of videos and recorded lectures that assert “time is an illusion” given Einstein’s relativity. But is this true? And what exactly do these people mean by “time” and “illusion”? Because these words have multiple meanings, we must ask. My goal here is to help the reader understand in exactly what sense Einstein (or anyone else) might justifiably assert that time is an illusion based on relativity. In so doing, I argue that there are essential features of our temporal experience, such as the passage of time, presence, and direction, that cannot be fully explained in the block universe picture given to us by relativity—our best physical theory of time. And whilst these essential features of time are not themselves illusory, there is a mystery about the status in which relativity theory leaves them.Presentism vs Eternalism I will begin with an analogy between the experience of watching a film and our everyday experience of time (Passage, Presence, and Direction). Go back to the days of film on celluloid. Imagine you are a child who has just watched their first such film and you ask your parent, “How does it work”? Your parent takes you back to the projection booth and to your amazement, the film you watched is just a series of photographic stills each framed in black and ordered in a certain sequence. You are deeply puzzled by how these static images connect with what you just experienced. The projectionist jumps in to show you how the trick is done. You learn the film is projected at a rate of 24 frames per second, helping to create the experience of temporal passage. The film reel advances one frame, pauses for a fraction of a second, projecting the image of each individual frame when it is between the lamp and the lens, to create the sense that frame alone is happening now, and then advances to the next frame, and so on. The projector has other mechanical tricks for making the short periods of darkness between still frames, flicker effects, and its own motion undetectable.From this, you gain an understanding of the mechanism by which a mere reel of film can be turned into an experience of a story unfolding in time. Mystery solved. You realize that the combination of the appropriately ordered frames moving through the projector creates the “illusion” that only the present moment (the single frame poised between lamp and lens) is real (exists) and that the present moment (a NOW-slice) keeps moving from past to future evolving into ever newer present moments until the end. I say “illusion”, because you now know that the movie experience of continuous temporal flow does not reflect the reality of a series of still frames moving through a projector.___There is something special about the character of the present moment. This is what presumably lead Einstein to say that “there is something essential about the Now which is just outside the realm of science.”___If you are the kind of child Einstein was, you might wonder how the trick of time works in the actual world. Just like in a film, life is experienced as a temporal progression in which the present moment seems objectively distinguished as if a spotlight is shone upon it (Presence), that moment seems to objectively flow or pass (Passage) into the next moment, and that passage seems to have an objective direction moving from past to future (Direction). I will refer to these three features of temporal experience as PPD. Presence has two features because it denotes the experience that a certain event, such as Neil Armstrong placing his foot on the moon, is happening NOW (is real), but it also denotes the experience that there is something special about the character of the present moment. This is what presumably lead Einstein to say that “there is something essential about the Now which is just outside the realm of science.When I say that the Passage, Presence and Direction features of time are “objective” I mean that they are not in any way mind/brain dependent (i.e., these features of the world are primary properties like shape and not secondary properties like colour), nor are they dependent on one’s place in the universe. Moving away from individual experience for a moment, we also tend to assume that, continuing with the film analogy, everyone in the universe is watching the same film, i.e., everyone would agree on the ordering of events (still frames) into past, present, and future NOW-slices, just as the audience in the theatertheatre does. In other words, everyone will agree about which events are real, because the phrase “is real” just means exists NOW. And to say that various events exist NOW means those events are simultaneous (co-exist) with each other. Based on everyday experiences of the sort that film attempts to emulate, we tend to assume that only present events (those that exist NOW) are real, and not past or future events. This is a metaphysical view of time known as presentism. SUGGESTED READING Einstein and why the block universe is a mistake By DeanBuonomano But suppose you found out that reality is much more like the film strip laid out in the projector booth in front of the child, whence all the frames (i.e., past, present, and future events in the actual world) are all equally real. This is a metaphysical view of time known as eternalism, also known as the block universe. The irony, as we shall see, is that eternalism follows from special relativity precisely because there will be relativistic reference frames whose observers disagree about the temporal-ordering of events into past, present, and future. That is to say, there will be disagreements as to which events are simultaneous with which. There will be frames of reference (such as planets at great distances from Earth or a spaceship moving by Earth at a large fraction of the speed of light), whose observers will disagree about how to order events in the universe into NOW-slices. In the terms of the film analogy, in the actual world, not everyone is watching the same movie. Newton vs Einstein To see why let us take a short interlude into the physics and the metaphysics of time. In Newtonian mechanics, we have three dimensions (3D) of absolute space in which objects move as a function of absolute time, i.e., everyone is watching the same movie, no one anywhere in the universe will disagree about the temporal-order of events. In Newtonian mechanics everyone agrees on what exists instant by instant, so NOW-slices are the same for all observers. That means the proper time for an object, such as time as measured on each observer’s watch, is the absolute time.Given this equality between proper time and absolute time, the Newtonian model for the path of an object through space is a one-dimensional curve in 3D space where absolute time is the curve parameter. For example, if you are using Cartesian coordinates [x,y,z] to locate an object’s location or an event in space, an object’s path would be specified by the three functions [x(t),y(t),z(t)] where t is the time parameter. A NOW-slice of all the coexisting (simultaneously existing) objects and events at time to would be all the objects’ locations and events given by [xn(to),yn(to),zn(to)] for each object or event “n”. Of course, Newton was simply modelling his own everyday film-like experience of space and time. Newton just assumed his temporal experience contained no misperceptions and no false beliefs based on such misperceptions.In Einstein’s special relativity, Newton’s 3D space plus absolute time parameter t (3+1 model) is replaced by a 4-dimensional (4D) model where space and time are fused into what is called spacetime. Special relativity follows from: 1) the light postulate which says the speed of light is the same in every inertial reference frame, and 2) the relativity principle which says the laws of nature are the same in every reference frame. In special relativity, the worldlines for all objects can no longer be given as a set of parameterized curves in one 3D space because observers can disagree as to what objects and events coexist to uniquely establish a NOW-slice of 3D space. In special relativity, simultaneity is no longer absolute; it is relative to each observer. That means each observer has their own 3+1 film-like model for their own NOW-slices.___If there is an event such as the supernova explosion that is experienced by different observers, but they do not agree as to when that event happened, the event must just exist statically, timelessly, in order to be experientable from both these different spatiotemporal perspectives___Combining all of these different 3+1 models into a single self-consistent 4D model (called Minkowski spacetime) requires the addition of a time dimension with its own coordinate t. Events are now located by a set of four coordinates [x,y,z,t] in the 4D spacetime, rather than three coordinates in 3D absolute space with a particular value of the absolute proper time parameter. This means that the path of an object in special relativity is now a curve in 4D spacetime given by [x(T),y(T),z(T),t(T)], where T is the proper time for the object. The 3+1 model is one of coexisting objects moving in space as a function of time in accord with our film-like experience. The 4D model, on the other hand, represents objects in terms of their worldlines in 4D spacetime and it cannot be carved uniquely into 3D collections of coexisting objects and events.Accordingly, the life of observer A would be a curve in 4D spacetime that begins at birth and ends at death as parameterized by observer A’s age (their proper time). Obviously, no two events on that worldline are simultaneous for observer A (i.e., all such events are timelike—inside or on observer A’s lightcone). But according to observer B, observer A’s 16th birthday might coexist with a supernova explosion in a distant galaxy, while according to observer C, that same supernova explosion coexists with observer A’s 20th birthday. Thus, from observer B’s perspective, A’s 16th birthday party and the supernova explosion are simultaneous events. Whereas from observer C’s perspective, A's 20th birthday party and the supernova explosion are simultaneous events. And in spacetime, observer B and C are both right. Observers B and C might even meet up in the future and discover this very disagreement. SUGGESTED VIEWING Spacetime and the Structure of Reality With Carlo Rovelli If there is an event such as the supernova explosion that is experienced by different observers, but they do not agree as to when that event happened, the event must just exist statically, timelessly, in order to be experientable from both these different spatiotemporal perspectives. And while observer A’s 16th and 20th birthdays are not simultaneous events from any “ant’s-eye” reference frame perspective such as A, B, or C, from the 4D perspective they must both be equally real because there are frames of reference (B and C) with respect to which the supernova explosion is simultaneous with each respective birthday party. Everything said here applies to all events in spacetime. All of this constitutes a powerful argument for Eternalism. Simply put, there is no unique way to carve 4D spacetime into individual 3D distributions of coexisting objects and events in order to create the individual frames for an objective film shared by all. Given that the world is 4D spacetime and not Newton’s 3+1 model, we can reasonably say that our film-like experience of a 3+1 world is a misperception, and some of our beliefs based on that misperception are false. Some use the word “illusion” to denote this. We have seen that with spacetime, just as with the entire reel of film in the projection booth, as viewed by the child, all events (frames) are equally real. But unlike the reel of film in the projection booth, events (frames) in spacetime have no objective ordering into NOW-slices. The irony is that the latter fact is the reason for the former fact. It is because the structure of spacetime demands that there must be many individual films with different temporal orderings involving some of the same events, that all events are equally real.Think how strange this is. Within spacetime there is no ant’s-eye observer’s reference frame (such as A, B, or C) for whom A’s 16th and 20th birthdays are simultaneous events. Yet, when we look at the spacetime diagram of all this, as in the 4D perspective, one must grant the equal reality of A’s 16th and 20th birthdays. This is the case because it is the only way to explain how both observers B’s and C’s claims can be true.So, is time an illusion then? In a recent piece, Tim Maudlin grants that spacetime is a block world as I have defined it, but he does not think it warrants the word “illusion.” In his own words, “when it comes to the question of whether time is real or illusory, there is no way in which it [Minkowski spacetime] essentially differs from Newtonian physics.” Some philosophers go further and suggest that there is no discernable difference at all between the Presentism of Newtonian mechanics and the Eternalism of Einstein’s spacetime. We have already seen that such claims are false. Just think of time-dilation and length-contraction in relativity, wherein we learn that the elapsed time between events and the length of objects are frame-dependent. Regarding the very same events and objects, there will be observers on various reference frames who will disagree about these properties, and both will be right! This highly counter-intuitive state of affairs could not happen in Newton’s world. I would say all of this constitutes a pretty significant difference, and we are not done yet.You might ask, since Maudlin and I do not disagree about the facts thus far, only whether to call this state of affairs an “illusion”, do we disagree about anything else? Yes. I think that the block universe of spacetime lacks PPD, and Maudlin does not. I will explain my position first and then reply to his.So, why does the block universe of spacetime lack Presence, Passage, and Direction in a way that Newton’s model does not? As Maudlin himself notes, the Newtonian model assumes absolute/objective simultaneity relations and that time is “the succession of the global instants” from past to future. Unsurprisingly then, Newton’s physical model of time grounded in everyday experience is often associated with or interpreted in terms of Presentism. Presentism in full holds that: 1) Only the present is real; 2) Time comprises an “A-series”: there exists an objectively present moment, and that moment continuously and objectively vanishes and is replaced by a new one, as time moves in the direction of past to future, and 3) the “A-series” that is built into the structure the world is both necessary and sufficient to explain our experience of PPD. In other words, Presentism is the view of time the child has after watching the film and before going back to the projection booth. If Presentism is true, then the statement that “time is like a river” is not a terrible analogy. SUGGESTED READING Einstein didn't think time was an illusion By TimMaudlin Sometimes Presentism is characterized as the claim that there are objective tensed facts, i.e., facts about the pastness, presentness, or futurity of events. The A-series provides a dynamic theory of time because once an objective distinction between past, present, and future is granted, then it is the case that events must continually change with respect to their pastness, presentness, or futurity. Presentism is taken as the champion of our everyday experience of time.The point is that spacetime poses an even greater threat to Presentism than alluded to so far. The worry is that the Eternalism of spacetime seems not to contain anything like PPD as conceived by Presentism. That is, there is no universal and objective NOW-slice in spacetime, no explanation for the experience that the present moment is ontologically special (Presence), and there is no literal passage of NOW-slices (Passage) from past to future (Direction). Regarding Direction, there is no reference frame-independent fact about which of two space-separated events is the earlier one and which the later one. Thus, the block universe of 4D spacetime is not logically compatible with Presentism as defined.The Newtonian 3+1 model, viewed in terms of Presentism, has the resources to explain PPD because there is a physical analog for each. We experience Presence because only the objectively present moment is real, we experience Passage because the present moment literally passes away and becomes another moment, and we experience Direction because everyone in every reference frame agrees on how to carve the universe into NOW-slices.___Our temporal experience misleads us into thinking that Newtonian Presentism is true___Let’s return to the film analogy to see the point. Imagine the 4D block universe from the Big Bang to the heat death of the universe is like the entire film reel in the projection booth laid out from the beginning to the end of the movie. In the case of the film, we know what mechanism explains how we get from a series of still frames to a PPD-experience of the film. But what is the commensurate mechanism in the block universe of 4D spacetime? If the analogy between real spacetime and the film reel is a good one (in the sense that each event/frame are equally real, not in the sense of objective temporal-ordering), then why do we experience PPD? In other words, if objective PPD is not there in the universe, some would say our experience of objective PPD is an “illusion” and our belief in objective PPD is false. This is not to say that the subjective experience of PPD itself is an illusion-we really are having such experiences-PPD is not a hallucination or mirage. Given relativity, the experience of the present, the passage of time, and the direction of time, are an illusion in that what you perceive as a primary property given objectively in the external world is just not there in the physics.Some people claim that 4D spacetime is missing something physical or metaphysical that needs to be added to explain the experience of PPD. Others claim that the explanation for the experience of PPD must lie with cognitive neuroscience, thus making PPD secondary properties, like color. There are several philosophers, physicists, and cognitive scientists who argue that the brain must somehow generate the experience of PPD. But one need only contemplate this idea for a second or two to see the problem. Barring radical emergence, if physics is “frozen” in the block universe, then so are brains. The brain (i.e., the static 4D worldline of a brain in spacetime) cannot be the analogue of the film projector, because its states no more move or flow than anything else in spacetime. The ‘activities’ of the brain are themselves just more events “frozen” in the still-frames, therefore the brain is not like the film projector that brings PPD to the game ‘from the outside’. Falling back on the ‘dynamical activity’ of the brain just begs the question of how a brain in a block universe could generate, produce, or cause any conscious experience, but especially those involving PPD.Maudlin thinks that the spatiotemporal structure of relativity itself is sufficient to provide objective PPD and thus explain our experience of PPD. He says it is an objective fact that some events take place before a given event and others after. At least it’s an “objective” fact relative to each observer’s frame of reference. As he puts it, “But time does have a directionality, indicated by the asymmetric relation before/after.” All of this suggests that for Maudlin the experience of Passage and Direction are explained by the fact that for each reference frame events are ordered into a temporal succession of the right sort. Regarding timelike events, every observer in that reference frame will agree on the ordering of events into earlier-than or later-than, before and after, cause and effect, etc. So, there will be many local ‘HERE-NOWS, these ‘HERE-NOWS change in succession, and that is what Maudlin calls Passage and Direction. Back to the film analogy, each of these local reference frames is its own movie. He says, “But the present practice of physics, including Relativistic physics—takes a fundamental earlier/later distinction, and in that sense a ‘flow of time’ for granted.” For Maudlin this fundamental and irreducible earlier/later-than distinction, as given by events having the right temporal ordering or succession is all there is to Passage and Direction. He also thinks that succession grounds talk of earlier events causing or bringing about later events. As regards general relativity, Maudlin notes that cosmology is done from the perspective of the “cosmic time frame” wherein it is very reasonable and useful to take the Big Bang as the beginning of the universe and the heat death as the end of it. There is a sense then in which the cosmic time frame is like the same movie for all observers.But is Maudlin right that such succession, whether local or global, is sufficient to explain the experience of Presence, Passage, and Direction? I am not convinced. To see why, let us return to our film analogy. Is the carefully crafted ordering of the still-frames making up the film reel sufficient for succession? Clearly Maudlin must say no since one does not experience PPD until the film reel is subjected to the mechanism of the projector. I assume he would say that before the projector is engaged there is only spatial succession. Temporal succession as in PPD only happens after the projector is active. So again, what in the real world does the work of the projector in the reel world? Nothing I know of. I would say in this case what is true of the static reel of film is also true of the static events in spacetime. Merely having events ordered in intuitive ‘before/after’ relations is not sufficient for the experience of PPD. As regards causation, in the block universe of spacetime, talk of one event “producing” or “causing” another in the sense of bringing something into being that absolutely did not exist before, only makes sense from the “ant’s-eye” timelike perspective of an individual observer. Likewise, it is only from the ant’s-eye perspective that talk of PPD makes sense, that is, experience with ‘the projector running’. Finally, regarding Presence Maudlin says, “But so what? Nobody ever thought differently. The idea that ‘the now’ has a ‘special objective status’ in a way that ‘the here’ does not is already universally rejected.” As noted earlier, Einstein, speaking from his everyday perspective, begged to differ. Einstein worried that physics fails to explain the experience that the present moment is special (Presence). I agree, and I see nothing in Maudlin’s program that resolves this.PPD itself is no hallucination, but our temporal experience misleads us into thinking that Newtonian Presentism is true. However, if relativity is true and complete, then PPD is largely missing from our best theory of time. Maudlin is right that if special relativity did not have the metric structure it does and if the initial conditions at the Big Bang didn’t enable Einstein’s equations to yield a cosmic time frame, that the mystery of PPD would be much worse. But I have little faith that relativity alone has the resources to resolve the mystery of our experience of time.
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Cosmology & The Universe
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U.S. July 15, 2022 / 10:00 AM / CBS News Scientists detect "strange" radio signal in distant galaxy Scientists detect "strange" radio signal in distant galaxy which sounds like a heartbeat 01:54 Scientists have discovered a "strange and persistent" radio signal from a far-off galaxy that sounded like a heartbeat. Astronomers at the Massachusetts Institute of Technology and elsewhere detected the signal, which is classified as a fast radio burst, or FRB — but lasted much longer.A typical FRB, which is a strong burst of radio waves, lasts a few milliseconds. The new signal lasted up to three seconds – about 1,000 times longer than average, according to a news release. The astrophysical origins of FRBs are unknown.The signal repeated over .02 seconds in a clear pattern, almost like a heartbeat. "It was unusual," said Daniele Michilli, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research. "Not only was it very long, lasting about three seconds, but there were periodic peaks that were remarkably precise, emitting every fraction of a second — boom, boom, boom — like a heartbeat. This is the first time the signal itself is periodic." Astronomers detected a persistent radio signal from a far-off galaxy that appears to flash with surprising regularity. Named FRB 20191221A, this fast radio burst, or FRB, is currently the longest-lasting FRB, with the clearest periodic pattern, detected to date. Pictured is the large radio telescope CHIME that picked up the FRB. Photo courtesy of CHIME, with background edited by MIT News The signal came from a distant galaxy, several billion light-years from Earth. Researchers from MIT and McGill University in Canada, who published a study on the signal, have named it FRB 20191221A. It is currently the longest-lasting FRB with the clearest periodic pattern detected to date. The first FRB was discovered in 2007 and hundreds of similar radio flashes have been detected in space since. The Canadian Hydrogen Intensity Mapping Experiment, or CHIME, is an interferometric radio telescope that continuously observes the sky and is sensitive to fast radio bursts. Most FRBs are one-offs and last a few milliseconds before ending. But a signal that repeated every 16 days was recently discovered, although the signal was more random than periodic. But in December 2019, CHIME detected the periodic, heartbeat-like signal. Michilli was scanning the incoming data at the time. "There are not many things in the universe that emit strictly periodic signals," Michilli said. The source of the new FRB remains a mystery, but scientists think it could emanate from a radio pulsar or magnetar, which are neutron stars. These are dense, rapidly spinning collapsed cores of giant stars. "CHIME has now detected many FRBs with different properties," said Michilli. "We've seen some that live inside clouds that are very turbulent, while others look like they're in clean environments. From the properties of this new signal, we can say that around this source, there's a cloud of plasma that must be extremely turbulent."They hope to catch more bursts from FRB 20191221A. The detection could help them as they study the universe and neutron stars."This detection raises the question of what could cause this extreme signal that we've never seen before, and how can we use this signal to study the universe," said Michilli. "Future telescopes promise to discover thousands of FRBs a month, and at that point we may find many more of these periodic signals."More periodic signals from this source could be used as an astrophysical clock. "For instance, the frequency of the bursts, and how they change as the source moves away from Earth, could be used to measure the rate at which the universe is expanding," the press release reads. Caitlin O'Kane Caitlin O'Kane is a digital content producer covering trending stories for CBS News and its good news brand, The Uplift. Thanks for reading CBS NEWS. Create your free account or log in for more features. Please enter email address to continue Please enter valid email address to continue
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Cosmology & The Universe
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NASA's James Webb Space Telescope has captured never-before-seen details in a region of space known as Pandora's Cluster.
A new deep field image from the observatory displays three clusters of galaxies coming together to form a megacluster. The combined mass of those clusters creates a gravitational lens, allowing scientists to observe more distant galaxies in the early universe.
The cluster's central core has been previously studied in detail by the Hubble Space Telescope.
By using Webb and its powerful infrared instruments with a mosaic view of the region's multiple areas of lensing, astronomers aimed to achieve a balance of breadth and depth the agency said would open a new frontier in the study of cosmology and galaxy evolution.
The new view stitches Webb snapshots together in a panoramic image, displaying approximately 50,000 sources of near-infrared light.
Notably, the gravitational lensing distorts the appearance of the background galaxies, and the cluster lens is so massive that it warps the fabric of space itself.
To the lower right of the image, which has never been imaged by Hubble, the lensing core contains hundreds of distant lensed galaxies that appear like faint arced lines in the image.
"Pandora’s Cluster, as imaged by Webb, shows us a stronger, wider, deeper, better lens than we have ever seen before," Ivo Labbe, of the Swinburne University of Technology and co-principal investigator of the Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization (UNCOVER) program, said in a statement. "My first reaction to the image was that it was so beautiful, it looked like a galaxy formation simulation. We had to remind ourselves that this was real data, and we are working in a new era of astronomy now."
Labbe's team used the Near-Infrared Camera, or NIRCam, to capture the cluster, for a total of around 30 hours of observing time. The next step for the team will be to go through imaging data and select galaxies for follow-up observation with the Near-Infrared Spectrograph (NIRSpec).
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Cosmology & The Universe
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By Alexander MacKinnon - University of GlasgowA cold beer on a hot day or a whisky nightcap beside a coal fire. A well earned glass can loosen your thinking until you feel able to pierce the mysteries of life, death, love and identity. In moments like these, alcohol and the cosmic can seem intimately entwined. So perhaps it should come as no surprise that the universe is awash with alcohol. In the gas that occupies the space between the stars, the hard stuff is almost all-pervasive. What is it doing there? Is it time to send out some big rockets to start collecting it?The chemical elements around us reflect the history of the universe and the stars within it. Shortly after the Big Bang, protons were formed throughout the expanding, cooling universe. Protons are the nuclei of hydrogen atoms and building blocks for the nuclei of all the other elements.These have mostly been manufactured since the Big Bang through nuclear reactions in the hot dense cores of stars. Heavier elements such as lead or gold are only fabricated in rare massive stars or incredibly explosive events.Lighter ones such as carbon and oxygen are synthesised in the life cycles of very many ordinary stars – including our own sun eventually. Like hydrogen, they are among the most common in the universe. In the vast spaces between the stars, typically 88% of atoms are hydrogen, 10% are helium and the remaining 2% are chiefly carbon and oxygen.Which is great news for booze enthusiasts. Each molecule of ethanol, the alcohol that gives us so much pleasure, includes nine atoms: two carbon, one oxygen and six hydrogen. Hence the chemical symbol C₂H₆O. It’s as if the universe turned itself into a monumental distillery on purpose. Interstellar intoxicationThe spaces between stars are known as the interstellar medium. The famous Orion Nebula is perhaps the best known example. It is the closest region of star formation to Earth and visible to the naked eye – albeit still more than 1,300 light years away.Yet while we tend to focus on the colourful parts of nebulae like Orion where stars are emerging, this is not where the alcohol is coming from. Emerging stars produce intense ultraviolet radiation, which destroys nearby molecules and makes it harder for new substances to form.Instead you need to look to the parts of the interstellar medium that appear to astronomers as dark and cloudy, and only dimly illuminated by distant stars. The gas in these spaces is extremely cold, slightly less than -260℃, or about 10℃ above absolute zero. This makes it very sluggish.It is also fantastically widely dispersed. At sea level on Earth, by my calculations there are roughly 3x1025 molecules per cubic metre of air – that’s a three followed by 25 zeros, an enormously huge number. At passenger jet altitude, circa 36,000ft, the density of molecules is about a third of this value – say 1x1025. We would struggle to breathe outside the aircraft, but that’s still quite a lot of gas in absolute terms. Now compare this to the dark parts of the interstellar medium, where there are typically 100,000,000,000 particles per cubic metre, or 1x1011, and often much less than even that. These atoms seldom come close enough to interact. Yet when they do, they can form molecules less prone to being blown apart by further high-speed collisions than when the same thing happens on Earth.If an atom of carbon meets an atom of hydrogen, for instance, they can stick together as a molecule called methylidyne (chemical symbol CH). Methylidyne is highly reactive and so is quickly destroyed on Earth, but it is common in the interstellar medium.Simple molecules like these are more free to encounter other molecules and atoms and slowly build up more complex substances. Sometimes molecules will be destroyed by ultraviolet light from distant stars, but this light can also turn particles into slightly different versions of themselves called ions, thereby slowly expanding the range of molecules that can form.Soot and fire waterTo make a nine-atom molecule such as ethanol in these cool and tenuous conditions might still take an extremely long time – certainly much longer than the seven days you might ferment home brew in the attic, let alone the time it takes to walk to the liquor store.But there is help at hand from other simple organic molecules, which start sticking together to form grains of dust, something like soot. On the surfaces of these grains, chemical reactions take place much more rapidly because the molecules get held in proximity to them.It is therefore cool sooty regions, the potential stellar birthplaces of the future, that encourage complex molecules to appear more quickly. We can tell from the distinctive spectrum lines of different particles in these regions that there is water, carbon dioxide, methane and ammonia – but also plenty of ethanol.Now when I say plenty, you have to bear in mind the vastness of the universe. And we are still only talking about roughly one in every 10m atoms and molecules. Suppose you could travel through interstellar space holding a pint glass, scooping up only alcohol as you moved. To collect enough for a pint of beer you would have to travel about half a million light years – much further than the size of our Milky Way.In short, there are mind-bogglingly vast quantities of alcohol in outer space. But since it is dispersed over truly enormous distances, the drinks companies can rest easy. It will be a cold day on the sun before we figure out how to collect any of it, I’m sorry to say.Source: The Conversation
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Cosmology & The Universe
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A University of Hawaiʻi-led discovery of an immense bubble 820 million light years from Earth is believed to be a fossil-like remnant of the birth of the universe. Astronomer Brent Tully from the UH Institute for Astronomy and his team unexpectedly found the bubble within a web of galaxies. The entity has been given the name Hoʻoleilana, a term drawn from the Kumulipo, a Hawaiian creation chant evoking the origin of structure.
The new findings published in The Astrophysical Journal, mention these massive structures are predicted by the Big Bang theory, as the result of 3D ripples found in the material of the early universe, known as Baryon Acoustic Oscillations (BAO).
"We were not looking for it. It is so huge that it spills to the edges of the sector of the sky that we were analyzing," explained Tully. "As an enhancement in the density of galaxies it is a much stronger feature than expected. The very large diameter of one billion light years is beyond theoretical expectations. If its formation and evolution are in accordance with theory, this BAO is closer than anticipated, implying a high value for the expansion rate of the universe."
Astronomers located the bubble using data from Cosmicflows-4, which is to date, the largest compilation of precise distances to galaxies. Tully co-published the exceptional catalog in fall 2022. His team of researchers believe this may be the first time astronomers identified an individual structure associated with a BAO. The discovery could help bolster scientists' knowledge of the effects of galaxy evolution.
Enormous bubbles of matter
In the well-established Big Bang theory, during the first 400,000 years, the universe is a cauldron of hot plasma similar to the interior of the Sun. Within a plasma, electrons were separated from the atomic nuclei. During this period, regions with slightly higher density began to collapse under gravity, even as the intense bath of radiation attempted to push matter apart. This struggle between gravity and radiation made the plasma oscillate or ripple and spread outward.
The largest ripples in the early universe depended on the distance a sound wave could travel. Set by the speed of sound in the plasma, this distance was almost 500 million light years, and was fixed once the universe cooled and stopped being a plasma, leaving vast three-dimensional ripples. Throughout the eons, galaxies formed at the density peaks, in enormous bubble-like structures. Patterns in the distribution of galaxies, properly discerned, could reveal the properties of these ancient messengers.
"I am the cartographer of the group, and mapping Hoʻoleilana in three dimensions helps us understand its content and relationship with its surroundings," said researcher Daniel Pomarede of CEA Paris-Saclay University in France. "It was an amazing process to construct this map and see how the giant shell structure of Hoʻoleilana is composed of elements that were identified in the past as being themselves some of the largest structures of the universe."
This same team of researchers also identified the Laniākea Supercluster in 2014. That structure, which includes the Milky Way, is small in comparison. Stretching at a diameter of about 500 million light years, Laniākea extends to the near edge of this much larger bubble.
Uncovering a single BAO
Tully's team discovered that Hoʻoleilana had been noted in a 2016 research paper as the most prominent of several shell-like structures seen in the Sloan Digital Sky Survey. However, the earlier work did not reveal the full extent of the structure, and that team did not conclude they had found a BAO.
Using the Cosmicflows-4 catalog, the researchers were able to see a full spherical shell of galaxies, identify its center, and show that there is a statistical enhancement in the density of galaxies in all directions from that center. Hoʻoleilana encompasses many well-known structures previously found by astronomers, such as the Harvard/Smithsonian Great Wall containing the Coma Cluster, the Hercules Cluster and the Sloan Great Wall. The Boötes Supercluster resides at its center. The historic Boötes Void, a massive empty spherical region, lies inside Hoʻoleilana.
The implications of Hoʻoleilana
Tests with simulations have demonstrated that the shell structure identified as Hoʻoleilana has less than 1% probability of being a statistical accident. Hoʻoleilana has the properties of a theoretically anticipated baryon acoustic oscillation, including the prominence at its center of a rich supercluster, however it stands out stronger than expected. In detail, Hoʻoleilana is slightly larger than anticipated from the theory of the standard model of cosmology, and what has been found from prior statistical pair-wise studies of galaxy separations. The size is in accord with observations of the local expansion rate of the universe and of galaxy flows on large scales that also hint at subtle problems with the standard model.
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A fast-spinning neutron star south of the constellation Leo is the most massive of its kind seen so far, according to new observations. The record-setting collapsed star, named PSR J0952-0607, weighs about 2.35 times as much as the sun, researchers report July 11 on arXiv.org. “That’s the heaviest well-measured neutron star that has been found to date,” says study coauthor Roger Romani, an astrophysicist at Stanford University. The previous record holder was a neutron star in the northern constellation Camelopardalis named PSR J0740+6620, which tipped the scales at about 2.08 times as massive as the sun. If a neutron star grows too massive, it collapses under its own weight and becomes a black hole. These measurements of hefty neutron stars are of interest because no one knows the exact mass boundary between neutron stars and black holes. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox That dividing line drives the quest to find the most massive neutron stars and determine just how massive they can be, Romani says. “It’s defining the boundary between the visible things in the universe and the stuff that is forever hidden from us inside of a black hole,” he says. “A neutron star that’s on the hairy edge of becoming a black hole — just about heavy enough to collapse — has at its center the very densest material that we can access in the entire visible universe.” PSR J0952-0607 is in the constellation Sextans, just south of Leo. It resides 20,000 light-years from Earth, far above the galaxy’s plane in the Milky Way’s halo. The neutron star emits a pulse of radio waves toward us each time it spins, so astronomers also classify the object as a pulsar. First reported in 2017, this pulsar spins every 1.41 milliseconds, faster than all but one other pulsar. That’s why Romani and his colleagues chose to study it — the fast spin led them to suspect that the pulsar might be unusually heavy. That’s because another star orbits the pulsar, and just as water spilling over a water wheel spins it up, gas falling from that companion onto the pulsar could have sped up its rotation while also boosting its mass. Observing the companion, Romani and his colleagues found that it whips around the pulsar quickly — at about 380 kilometers per second. Using the companion’s speed and its orbital period of about six and a half hours, the team calculated the pulsar’s mass to be more than twice the mass of the sun. That’s a lot heavier than the typical neutron star, which is only about 1.4 times as massive as the sun. “It’s a terrific study,” says Emmanuel Fonseca, a radio astronomer at West Virginia University in Morgantown who measured the mass of the previous record holder but was not involved in the new work. “It helps nuclear physicists actually constrain the nature of matter within these extreme environments.”
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By Pallab GhoshScience correspondent, La PalmaImage source, BBC News/Stelios ThoukididesImage caption, The collision of neutron stars is an opportunity to see what is inside these incredible objectsScientists have developed a new telescope to detect the collisions of dead suns known as neutron stars. The process is thought to create the heavy metals in the Universe including gold and platinum. The stars are made from a substance that is so heavy that a small teaspoon weighs four billion tonnes. I went to see this instrument high in the mountains that allows astronomers to effectively crack open a neutron star to see what is inside. I met Prof Danny Steeghs, of Warwick University, on the volcanic island of La Palma, Spain. The clouds spread like a white fleecy carpet below us.The telescope is on a mountain peak, home to a dozen instruments of all shapes and sizes, each studying different phenomena. They gleam in the late afternoon, straw-coloured sunlight scattered across the peak like white and silver sculptures.This latest addition allows scientists to see neutron stars "being smashed together and observe the rich material that comes out of this explosion," Danny, who leads the project, tells me.It was in this environment in space where heavy elements like gold and platinum began to be formed billions of years ago - material that ended up in stars and planets like ours.Image source, BBC News/Kevin ChurchImage caption, The new telescope looks like a battery of rocket launchersDanny's telescope system is more like artillery than art. As the twin domes open, they reveal two jet-black batteries of eight cylindrical telescopes bolted together. They look like menacing rocket launchers. Each battery covers every patch of sky above it by rapidly rotating vertically and horizontally.They are designed to be nimble. The light from colliding neutron stars is visible in the night sky for only a couple of days - it is a race against time to pin-point its location.A neutron star is a dead sun that has collapsed under its immense weight, crushing the atoms that once made it shine. They have such strong gravity that they are drawn to each other. Eventually they crash together and merge. Image source, BBC News/Stelios ThoukididesImage caption, Neutron Stars are suns that have collapsed under the weight of their own gravity, crushing the atoms that once made them shine.When that happens, it creates a flash of light and a powerful shockwave ripples across the Universe. It makes everything in the Universe wobble, including, imperceptibly, the atoms inside of us.The shockwave, called a gravitational wave, distorts space. When it is detected on Earth, Danny's telescope, called the gravitational-wave optical transient observer (GOTO), scrambles into action to find the exact location of the flash.All hands on deckAstronomers observed one of these collisions in 2017, but it was more by luck than design. Now, GOTO has been built in order to systematically search for then."When a really good detection comes along, it's all hands on deck to make the most of it," Danny tells me with his typical enthusiasm. "Speed is of the essence. We are looking for something very short-lived - there's not much time before they fade away". Image source, BBC News/Kevin ChurchImage caption, The telescope is located above the clouds so that it can get a clear view of the night skyThey want to locate flash in the sky within hours, or even minutes of the gravitational wave detection. The researchers take photographs of the sky and then digitally remove the stars, planets and galaxies that were there the previous night. Any spec of light that wasn't there before may be the colliding neutron stars. This normally takes days and weeks, but now it must be done in real time. It's a big task, done using computer software."You would think that these explosions are very energetic, very luminous, it should be easy - but we are having to search through a hundred million stars for the one object that we are interested in. We have to do this very rapidly because the object will disappear within two days," explains Danny's colleague, Dr Joe Lyman.Image source, BBC News/Kevin ChurchImage caption, The team work with other astronomers to study the collision in greater detail.Once the astronomers pinpoint the collision, they turn to larger, more powerful telescopes across the world. These probe the collision in much greater detail, and at different wavelengths.This process is "telling us about physics at the extreme," Dr Lyman explains.Gravitational waves - Ripples in the fabric of space-timeMedia caption, A visualisation shows the coalescence of two orbiting neutron starsGravitational waves are a prediction of the Theory of General RelativityIt took decades to develop the technology to directly detect themThey are ripples in the fabric of space-time generated by violent eventsAccelerating masses will produce waves that propagate at the speed of lightDetectable sources ought to include merging black holes and neutron starsLigo/Virgo fire lasers into long, L-shaped tunnels; the waves disturb the lightDetecting the waves opens up the Universe to completely new investigationsThe mountain peak brings the astronomers a little bit closer to the stars. With the telescope they have a new way to peer into the cosmos, says GOTO's instrumentation scientist, Dr Kendall Ackley.Traditional astronomy was about being lucky, she says. "Now we're not hoping for new discoveries anymore. Instead, we're being told where to find them, and getting to uncover, piece-by-piece what lies out there in the Universe."As the sun sets, Danny, Joe and Kendall begin setting up GOTO, in the red and amber glow before nightfall. As they begin their search for the violent collisions far away, they hope it will forever change our understanding of how the Universe came to be. Related Internet LinksThe BBC is not responsible for the content of external sites.
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Cosmology & The Universe
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The next generation of dark matter detectors has arrived. A massive new effort to detect the elusive substance has reported its first results. Following a time-honored tradition of dark matter hunters, the experiment, called LZ, didn’t find dark matter. But it has done that better than ever before, physicists report July 7 in a virtual webinar and a paper posted on LZ’s website. And with several additional years of data-taking planned from LZ and other experiments like it, physicists are hopeful they’ll finally get a glimpse of dark matter. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox “Dark matter remains one of the biggest mysteries in particle physics today,” LZ spokesperson Hugh Lippincott, a physicist at the University of California, Santa Barbara said during the webinar. LZ, or LUX-ZEPLIN, aims to discover the unidentified particles that are thought to make up most of the universe’s matter. Although no one has ever conclusively detected a particle of dark matter, its influence on the universe can be seen in the motions of stars and galaxies, and via other cosmic observations (SN: 7/24/18). Located about 1.5 kilometers underground at the Sanford Underground Research Facility in Lead, S.D., the detector is filled with 10 metric tons of liquid xenon. If dark matter particles crash into the nuclei of any of those xenon atoms, they would produce flashes of light that the detector would pick up. The LZ experiment is one of a new generation of bigger, badder dark matter detectors based on liquid xenon, which also includes XENONnT in Gran Sasso National Laboratory in Italy and PandaX-4T in the China Jinping Underground Laboratory. The experiments aim to detect a theorized type of dark matter called Weakly Interacting Massive Particles, or WIMPs (SN: 12/13/16). Scientists scaled up the search to allow for a better chance of spying the particles, with each detector containing multiple tons of liquid xenon. Using only about 60 days’ worth of data, LZ has already surpassed earlier efforts to pin down WIMPs (SN: 5/28/18). “It’s really impressive what they’ve been able to pull off; it’s a technological marvel,” says theoretical physicist Dan Hooper of Fermilab in Batavia, Ill, who was not involved with the study. Although LZ’s search came up empty, “the way something’s going to be discovered is when you have multiple years in a row of running,” says LZ collaborator Matthew Szydagis, a physicist at the University at Albany in New York. LZ is expected to run for about five years, and data from that extended period may provide physicists’ best chance to find the particles. Now that the detector has proven its potential, says LZ physicist Kevin Lesko of Lawrence Berkeley National Laboratory in California, “we’re excited about what we’re going to see.”
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Science & Astronomy An illustration of a meteor racing past a web of dark matter.
(Image credit: NASA/NSF/Ralf Kaehler/Ethan Nadler/SLAC National Accelerator Laboratory/Robert Lea) Meteor-hunting methods could be adapted to hunt for dark matter, the mysterious substance that makes up around 85% of the universe's matter but remains invisible, researchers propose in a new paper. Dark matter doesn't interact with electromagnetic radiation, meaning it doesn't absorb or emit light like ordinary matter; the universe contains five times more dark matter than ordinary matter. Thus far, astronomers have not been able to directly observe dark matter; they can only infer its presence through its gravitational influence, which prevents galaxies from ripping apart as they spin.Scientists aren't even sure if the particles that make up dark matter are massive or small; they just know it isn't made up of protons and neutrons like the matter on Earth. Related: In the hunt for dark matter, are axions our best bet?"One of the reasons dark matter is so hard to detect could be because the particles are so massive," John Beacom, a professor of physics and astronomy at The Ohio State University and co-author of the study, said in a statement (opens in new tab). "If the dark-matter mass is small, then the particles are common, but if the mass is large, the particles are rare."In the new paper, Beacom and his colleagues propose that if dark matter particles are massive, the same technology used to track meteors could detect dark matter as it passes through Earth's atmosphere. Currently, scientists look mostly for tiny dark-matter particles with small masses. The aim of the new research, the study authors said, is to widen that dark matter hunt by helping to characterize large-mass dark matter particles that might not be spotted with traditional detectors.When meteors pass through Earth's atmosphere, they leave a form of radiation called ionization deposits that, in turn, leave behind free electrons and charged atoms capable of conducting electricity. Electromagnetic waves released by meteor-tracking radar bounce off these free electrons, meaning that, in theory, they could do the same for electrons left by dark matter particles — in effect, turning Earth's atmosphere into a titanic dark-matter-particle detector. Considering this method has been used to track meteors for decades, Beacom said he's surprised these systems and the data they've gathered haven't been employed in the hunt for dark matter. The team's proposed dark matter hunting system could complement and improve upon current cosmological dark matter search techniques. "Current cosmology techniques are pretty sensitive, but they don't have a way to check their own work," Beacom said. "This is a totally new technique, so if scientists are unsure about what they've detected, a signal from cosmology could be checked in detail with the radar technique."The team's paper is posted to the preprint server arXiv.Follow us on Twitter @Spacedotcom and on Facebook. Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.
Robert Lea is a science journalist in the U.K. whose articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space, Newsweek and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University. Follow him on Twitter @sciencef1rst.
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Cosmology & The Universe
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Somewhere across the universe, a magnetic field shrieked.Two stars -- created by the same stellar nursery, yet birthed on opposite ends -- appear to have found each other. But when these stars aligned, there were no angels crooning or futures falling into place. There was a disruption. The magnetic field surrounding this sparkly duo crumpled, creaked and contorted, according to a paper to be published this week in The Astrophysical Journal.Even though the new study's researchers still aren't quite sure of the reason behind this strange phenomenon, the prevailing hypothesis is that as one of these star siblings moved closer to the other, "it shifted the dynamics of the cloud to twist its magnetic field," Erin Cox, an astrophysicist at Northwestern University and lead author of the paper, said in a statement.And beyond telling the beautiful story of a cosmic homecoming, the team's weird, magnetic anomaly details could lead to pretty massive discoveries down the road. Things like understanding exoplanet habitability, sunlike star behaviors and maybe even aid the search for extraterrestrial life. That's because decoding any and all secrets of binary star systems -- like the two under scrutiny for messing with their own stellar nursery's magnetic field -- potentially shed light on what planets in their vicinity might be like."Planet and star formation take place at the same time, and binary stars dynamically interact with each other," Cox said. "In our census of exoplanets, we know planets exist around these double stars, but we don't know much about how these planets differ from the ones that live around isolated stars."Earth lives around an isolated star -- the sun -- but could there be a sort of Earth that lives next to stellar twins? Alpha Centauri, for instance, is the closest star system to us, and it has two main stars that orbit within. Many experts believe this spot in the cosmos could be friendly to life, and some even plan on sending a hyperspeed space sail with imaging instruments over there one day, in hopes of finding such alien signs. Having information about binary star dynamics in advance of the ambitious trip could greatly help with the quest.The tale of the twisted fieldCox and fellow scientists stumbled upon the odd binary star siblings after following a hunch about a well-known star-forming cloud dubbed L483. Initially, looking at L483 wasn't anything special – it was a standard stellar nursery, about 100 times the size of our solar system, that spits out stellar material with extreme vigor and helps give rise to tons of iridescent stars. It even had a magnetic field that seemed rather normal, standing parallel to the hypersonic nursery jets as expected."At first, it matched what theory predicts," Cox said. "But theory can say one thing, and observations can say another." Sure enough, zooming into L483 told a wildly different tale. After using NASA's Stratospheric Observatory for Infrared Astronomy, or SOFIA, to take a closer look at L483, the team saw right off the bat that the magnetic field of this stellar nursery was not parallel to the outflows at all. Something strange was going on. Time to dig deeper.Later, upon invoking a powerful radio telescope called the Atacama Large Millimeter/submillimeter Array in Chile, or ALMA, the researchers revealed a finding arguably even more peculiar than the magnetic complication. Hiding right behind one of L483's newborn stars…there was another baby orb."There is newer work that suggests it's possible to have two stars form far away from each other, and then one star moves in closer to form a binary," Cox said. "We think that's what is happening here."However, Cox added, "we don't know why one star would move toward another one, but we think the moving star shifted the dynamics of the system to twist the magnetic field."Further observations unlocked a few other key findings about the binary star system, such as the fact they're still really young from our perspective, they're steadily forming and they're about the same distance apart as our sun is to Pluto. Eventually, Cox said, "with new instruments coming online to discover and probe new binary systems, we will be able to test these results with a statistical sample."
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Cosmology & The Universe
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The Tarantula Nebula gets its name from its appearance, which is similar to that of a burrowing tarantula’s hole covered in spider silk. Image: NASA, ESA, CSA, and STScIThe latest wonder from the Webb Space Telescope is a new look at the Tarantula Nebula, a swirling mass of infantile and yet-to-be conceived stars. What looks like spider silk surrounds a hollowed-out center, where material has been blasted away by radiation, according to a NASA release. OffEnglishA nebula is a massive cloud of dust occupying the interstellar medium that could be the cradle of life for new stars, and the Tarantula Nebula gets its particular name for its resemblance to a tarantula’s burrow, covered in webbing.“The spectacular Webb images of the Tarantula Nebula give us an amazing new view into the largest stellar nursery in the local Universe, revealing stars in the earliest stages of their formation in the dense knots of gas and dust around the central cluster,” says Chris Evans, Webb project scientist for ESA.The Tarantula Nebula is located 161,000 light-years away from us Earthlings in the Large Magellanic Cloud, one of the Milky Way’s neighbors. Webb scientists were able to capture the nebula in all its glory using the telescope’s suite of infrared instruments, with the main view from the Near-Infrared Camera. According to NASA, the sparkling blue stars located right of center are responsible for the central cavity, as radiation emitted by the cluster of stars has hollowed out the area via intense stellar winds. The surrounding areas are incredibly dense and have formed pillars that are birthing young stars called “protostars.” Webb’s Mid-infrared Instrument, or MIRI, was able to see through the interstellar dust, since the longer wavelengths MIRI captures are able to penetrate the clouds of particulate matter. Scientists are excited to learn more about the Tarantula Nebula, especially because it shares a similar chemical composition to that of the “cosmic noon,” a time when the universe was only a few billion years old. By observing the Tarantula Nebula, astronomers can, in a way, peer into the universe’s past.
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Cosmology & The Universe
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As the universe evolves, scientists expect large cosmic structures to grow at a certain rate: dense regions such as galaxy clusters would grow denser, while the void of space would grow emptier.
But University of Michigan researchers have discovered that the rate at which these large structures grow is slower than predicted by Einstein's Theory of General Relativity.
They also showed that as dark energy accelerates the universe's global expansion, the suppression of the cosmic structure growth that the researchers see in their data is even more prominent than what the theory predicts. Their results are published in Physical Review Letters.
Galaxies are threaded throughout our universe like a giant cosmic spider web. Their distribution is not random. Instead, they tend to cluster together. In fact, the whole cosmic web started out as tiny clumps of matter in the early universe, which gradually grew into individual galaxies, and eventually galaxy clusters and filaments.
"Throughout the cosmic time, an initially small clump of mass attracts and accumulates more and more matter from its local region through gravitational interaction. As the region becomes denser and denser, it eventually collapses under its own gravity," said Minh Nguyen, lead author of the study and postdoctoral research fellow in the U-M Department of Physics.
"So as they collapse, the clumps grow denser. That is what we mean by growth. It's like a fabric loom where one-, two- and three-dimensional collapses look like a sheet, a filament and a node. The reality is a mixture of all three cases, and you have galaxies living along the filaments while galaxy clusters -- groups of thousands of galaxies, the most massive objects in our universe bounded by gravity -- sit at the nodes."
The universe is not only made of matter. It also likely contains a mysterious component called dark energy. Dark energy accelerates the expansion of the universe on a global scale. As dark energy accelerates the expansion of the universe, it has the opposite effect on large structures.
"If gravity acts like an amplifier enhancing matter perturbations to grow into large-scale structure, then dark energy acts like an attenuator damping these perturbations and slowing the growth of structure," Nguyen said. "By examining how cosmic structure has been clustering and growing, we can try to understand the nature of gravity and dark energy."
Nguyen, U-M physics professor Dragan Huterer and U-M graduate student Yuewei Wen examined the temporal growth of large-scale structure throughout cosmic time using several cosmological probes.
First, the team used what's called the cosmic microwave background. The cosmic microwave background, or CMB, is composed of photons emitted just after the Big Bang. These photons provide a snapshot of the very early universe. As the photons travel to our telescopes, their path can become distorted, or gravitationally lensed, by large-scale structure along the way. Examining them, the researchers can infer how structure and matter between us and the cosmic microwave background are distributed.
Nguyen and colleagues took advantage of a similar phenomenon with weak gravitational lensing of galaxy shapes. Light from background galaxies is distorted through gravitational interactions with foreground matter and galaxies. The cosmologists then decode these distortions to determine how the intervening matter is distributed.
"Crucially, as the CMB and background galaxies are located at different distances from us and our telescopes, galaxy weak gravitational lensing typically probes matter distributions at a later time compared to what is probed by CMB weak gravitational lensing," Nguyen said.
To track the growth of structure to an even later time, the researchers further used motions of galaxies in the local universe. As galaxies fall into the gravity wells of the underlying cosmic structures, their motions directly track structure growth.
"The difference in these growth rates that we have potentially discovered becomes more prominent as we approach the present day," Nguyen said. "These different probes individually and collectively indicate a growth suppression. Either we are missing some systematic errors in each of these probes, or we are missing some new, late-time physics in our standard model."
The findings potentially address the so-called S8 tension in cosmology. S8 is a parameter that describes the growth of structure. The tension arises when scientists use two different methods to determine the value of S8, and they do not agree. The first method, using photons from the cosmic microwave background, indicates a higher S8 value than the value inferred from galaxy weak gravitational lensing and galaxy clustering measurements.
Neither of these probes measures the growth of structure today. Instead, they probe structure at earlier times, then extrapolate those measurements to present time, assuming the standard model. Cosmic microwave background probes structure in the early universe, while galaxy weak gravitational lensing and clustering probe structure in the late universe.
The researchers' findings of a late-time suppression of growth would bring the two S8 values into perfect agreement, according to Nguyen.
"We were surprised with the high statistical significance of the anomalous growth suppression," Huterer said. "Honestly, I feel like the universe is trying to tell us something. It is now the job of us cosmologists to interpret these findings.
"We would like to further strengthen the statistical evidence for the growth suppression. We would also like to understand the answer to the more difficult question of why structures grow slower than expected in the standard model with dark matter and dark energy. The cause of this effect may be due to novel properties of dark energy and dark matter, or some other extension of General Relativity and the standard model that we have not yet thought of."
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Register now for FREE unlimited access to Reuters.comGREENBELT, Md., July 12 (Reuters) - Following a U.S. presidential sneak peek of a galaxy-studded photo from the deep cosmos, NASA officials on Tuesday drew back the curtain to a larger display of luminous images captured by the largest and most powerful observatory ever launched to space.The first full-color, high-resolution pictures from the James Webb Space Telescope, designed to peer farther than before with greater clarity to the dawn of the universe, were hailed by NASA as milestone marking a new era of astronomical exploration.Nearly two decades in the making and built under contract for NASA by aerospace giant Northrop Grumman Corp , the $9 billion infrared telescope was launched on Dec. 25, 2021. It reached its destination in solar orbit nearly 1 million miles from Earth a month later.Register now for FREE unlimited access to Reuters.comWith Webb now finely tuned after months spent remotely aligning its mirrors and calibrating its instruments, scientists will embark on a competitively selected agenda exploring the evolution of galaxies, life cycle of stars, atmospheres of distant exoplanets, and moons of our outer solar system.Whoops and hollers from a sprightly "cheer team" welcomed some 300 scientists, telescope engineers, politicians and senior officials from NASA and its international partners into a packed and lively auditorium at the agency's Goddard Space Flight Center in Maryland for the big reveal."I didn't know I was coming to a pep rally today," NASA Administrator James Nelson said from the stage, enthusing that Webb's "every image is a discovery."The event was simultaneously broadcast to watch parties of astronomy enthusiasts around the world, from Bhopal, India, to Vancouver, British Columbia.The first batch of photos, which took weeks to render from raw data collected by Webb, were selected by NASA to show off the telescope's capabilities and foreshadow the science missions ahead.The crowning debut image, previewed on Monday by U.S. President Biden at the White House but displayed with greater fanfare on Tuesday, was a "deep field" photo of a distant galaxy cluster, SMACS 0723, revealing the most detailed glimpse of the early universe recorded to date.Among the four other Webb subjects getting their closeups on Tuesday were two enormous clouds of gas and dust blasted into space by stellar explosions to form incubators for new stars - the Carina Nebula and the Southern Ring Nebula, each thousands of light years away from Earth.The collection also included fresh images of another galaxy cluster known as Stephan's Quintet, first discovered in 1877, which encompasses several galaxies NASA described as "locked in a cosmic dance of repeated close encounters."The "Cosmic Cliffs" of the Carina Nebula is seen in an image divided horizontally by an undulating line between a cloudscape forming a nebula along the bottom portion and a comparatively clear upper portion, with data from NASA's James Webb Space Telescope, a revolutionary apparatus designed to peer through the cosmos to the dawn of the universe and released July 12, 2022. Speckled across both portions is a starfield, showing innumerable stars of many sizes. NASA, ESA, CSA, STScI, Webb ERO Production Team/Handout via REUTERSApart from the imagery, NASA presented Webb's first spectrographic analysis of a Jupiter-sized exoplanet more than 1,100 light years away - revealing the molecular signatures of filtered light passing through its atmosphere, including the presence of water vapor.BIGGER, STRONGER THAN HUBBLEBuilt to view its subjects chiefly in the infrared spectrum, Webb is about 100 times more sensitive than its 30-year-old predecessor, the Hubble Space Telescope, which operates mainly at optical and ultraviolet wavelengths.The much larger light-collecting surface of Webb's primary mirror - an array of 18 hexagonal segments of gold-coated beryllium metal - enables it to observe objects at greater distances, thus further back in time, than any other telescope. Its infrared optics allows Webb's observations to penetrate clouds of dust and gas that obscure light in the visible spectrum.All five of Webb's introductory targets were previously known to scientists, but NASA officials said Webb's imagery captures its subjects in an entirely new light, literally.The mid-infrared image of Southern Ring Nebula, for instance, clearly showed that the dying stellar object at its center was a binary system, or pair of stars closely orbiting one another. The new photos of the Carina Nebula exposed contours of its massive gas clouds that had never been seen before.The SMACS 0723 image Biden first released on Monday showed a 4.6 billion-year-old galaxy cluster whose combined mass acts as a "gravitational lens," distorting space to greatly magnify the light coming from more distant galaxies behind it.At least one of the faint, older galaxies appearing in the "background" of the photo - a composite of images of different wavelengths of light - dates back about 13.1 billion years.That makes it less than 800 million years younger than the Big Bang, the theoretical flashpoint that set the expansion of the known universe in motion some 13.8 billion years ago.The bejeweled-like composite photo, according to NASA, offers the "most detailed view of the early universe" as well as the "deepest and sharpest infrared image of the distant cosmos" yet taken.Underscoring the vastness of the cosmos, the thousands of galaxies appearing in the SMACS 0723 image were captured in a tiny patch of the sky roughly the size of a grain of sand held at arm's length by someone standing on Earth, NASA said.The Webb telescope is an international collaboration led by NASA in partnership with the European and Canadian space agencies.Register now for FREE unlimited access to Reuters.comReporting by Joey Roulette in Greenbelt, Md.; Writing and additional reporting by Steve Gorman in Los Angeles; Editing by Raju Gopalakrishnan, Nick Zieminski and Richard ChangOur Standards: The Thomson Reuters Trust Principles.
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Cosmology & The Universe
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This weekend saw the launch of the European Space Agency (ESA)’s Euclid mission: a space telescope which aims to uncover the mysteries of dark matter and dark energy. The 2.2 ton spacecraft with its 1.2 meter telescope was carried into space by a SpaceX Falcon 9 rocket and is now on its way to its orbit around the sun.
The mission had originally been slated to launch using a Russian Soyuz rocket from Europe’s spaceport in French Guiana, but following Russia’s invasion of Ukraine cooperation between ESA and Russia was halted. So instead, the telescope launched from Cape Canaveral Space Force Station in Florida, lifting off at 12:11AM ET on Saturday July 1st.
The telescope is headed for an orbit called L2, the second Lagrange point, which is the same orbit used by the James Webb Space Telescope and other space telescopes. This orbit offers high stability which is particularly important for a mission like Euclid which aims to collect extremely detailed observations of the universe.
Euclid should arrive at L2 within four weeks, then conduct two months of preparations before beginning science observations around the beginning of October.
Euclid will perform both wide and deep surveys of the universe, stitching together images to create a map of the universe to help learn about two mysterious concepts: dark matter, which makes up around 27 percent of everything which exists, and dark energy, which accounts for around 68 percent of the universe. Every atom, molecule, and piece of matter that we can observe makes up the tiny remaining 5 percent known as ordinary or baryonic matter.
The telescope is headed for the same orbit used by the James Webb Space Telescope
We know that dark matter and dark energy must exist because of the movements of galaxies and the way that the universe expands. However, they are extremely difficult to study because dark matter does not interact with light and dark energy is an unknown form of energy. So to find evidence of them, we need to look on a very large scale.
“If you want to do cosmology and observe the cosmos as a whole, you need to take a big survey,” explained Giuseppe Racca, Euclid Project Manager at ESA in a press briefing. “And Euclid is specially designed with a very wide angle telescope to cover most of the universe that can be observed in a very short time.”
The Euclid telescope will survey 36 percent of the sky over its six year mission, and to observe an area that large the telescope has a very wide field of view. This refers to the amount of the sky which can be observed through the telescope, and in Euclid’s case the field of view is 2.5 times the size of the moon.
Compare that to, say, the Hubble Space Telescope, which has a field of view that is just 1/12th the size of the moon. Hubble can image objects like galaxies or nebulae in great detail, but it would take Hubble around 1,000 years to survey a comparable area of the sky to Euclid.
We know that dark matter and dark energy must exist because of the movements of galaxies and the way that the universe expands
And if you’re wondering why Euclid will only be surveying just over a third of the sky, it’s because it is impossible to see distant galaxies in other areas of the sky, because these distant objects are blocked by closer stars and dust within our own galaxy.
Euclid will have two instruments: the VISible instrument or VIS, which operates in the visible light wavelength, and the Near-Infrared Spectrometer and Photometer or NISP, which operates in the near-infrared. Having both these wavelengths covered allows researchers to see galaxies which are redshifted, meaning that because they are moving away from us the light coming from them is shifted toward the red end of the spectrum.
By combining observations from both instruments, Euclid observations can be used to create a 3D map showing the distribution of the visible matter in the universe.
But dark matter isn’t visible — that’s why it’s so hard to study. It can’t be observed directly, but its presence can be inferred by looking at the distribution of the matter we can see.
“Dark energy and dark matter reveal themselves by the very subtle changes they make to the appearance of objects in the visible universe,” René Laureijs, Euclid Project Scientist, explained.
The two main methods for studying dark energy and dark matter used by Euclid will be weak lensing and galaxy clustering. Using two methods for examining the same thing allows the researchers to check their results against each other, hopefully resulting in more accurate findings.
Gravitational lensing is an effect in which the gravity of very large objects like galaxies or galaxy clusters warps spacetime, acting like a magnifying glass and changing the light coming from distant objects behind the foreground object.
By seeing how strong this lensing effect is, scientists can calculate the mass of the foreground object — and they can compare this calculated mass to the mass of the visible matter in the foreground galaxy. If there’s a large difference between the calculated and observed masses, that suggests the presence of large amounts of dark matter in the foreground.
The other effect, galaxy clustering, refers to how galaxies are distributed in three dimensions across the universe. As the universe expands, galaxies are moving away from us, resulting in redshift. Scientists can compare the actual distance to a galaxy with its redshift using a phenomenon called baryon acoustic oscillations, and this can show how fast the universe is expanding — which is directly related to dark energy.
it’s because it is impossible to see distant galaxies in other areas of the sky
In combination, these methods should help cosmologists learn more about dark matter and dark energy than ever before. To gather the data, Euclid will take around 1 million images from 12 billion objects over the course of its mission. That should get us one step closer to being able to both detect and study these elusive phenomena, and to understanding the composition of the universe around us.
“It’s more than a space telescope,” Laureijs said, “it’s really a dark energy detector.”
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Cosmology & The Universe
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By Matt WilliamsFor decades, scientists have theorized that beyond the edge of the Solar System, at a distance of up to 50,000 AU (0.79 ly) from the Sun, there lies a massive cloud of icy planetesimals known as the Oort Cloud. Named in honor of Dutch astronomer Jan Oort, this cloud is believed to be where long-term comets originate from. However, to date, no direct evidence has been provided to confirm the Oort Cloud’s existence. The layout of the solar system, including the Oort Cloud, on a logarithmic scale. - Image Credit: NASA This is due to the fact that the Oort Cloud is very difficult to observe, being rather far from the Sun and dispersed over a very large region of space. However, in a recent study, a team of astrophysicists from the University of Pennsylvania proposed a radical idea. Using maps of the Cosmic Microwave Background (CMB) created by the Planck mission and other telescopes, they believe that Oort Clouds around other stars can be detected.The study – “Probing Oort clouds around Milky Way stars with CMB surveys“, which recently appeared online – was led by Eric J Baxter, a postdoctoral researcher from the Department of Physics and Astronomy at the University of Pennsylvania. He was joined by Pennsylvania professors Cullen H. Blake and Bhuvnesh Jain (Baxter’s primary mentor).To recap, the Oort Cloud is a hypothetical region of space that is thought to extend from between 2,000 and 5,000 AU (0.03 and 0.08 ly) to as far as 50,000 AU (0.79 ly) from the Sun – though some estimates indicate it could reach as far as 100,000 to 200,000 AU (1.58 and 3.16 ly). Like the Kuiper Belt and the Scattered Disc, the Oort Cloud is a reservoir of trans-Neptunian objects, though it is over a thousands times more distant from our Sun as these other two. This cloud is believed to have originated from a population of small, icy bodies within 50 AU of the Sun that were present when the Solar System was still young. Over time, it is theorized that orbital perturbations caused by the giant planets caused those objects that had highly-stable orbits to form the Kuiper Belt along the ecliptic plane, while those that had more eccentric and distant orbits formed the Oort Cloud.According to Baxter and his colleagues, because the existence of the Oort Cloud played an important role in the formation of the Solar System, it is therefore logical to assume that other star systems have their own Oort Clouds – which they refer to as exo-Oort Clouds (EXOCs). As Dr. Baxter explained to Universe Today via email:“One of the proposed mechanisms for the formation of the Oort cloud around our sun is that some of the objects in the protoplanetary disk of our solar system were ejected into very large, elliptical orbits by interactions with the giant planets. The orbits of these objects were then affected by nearby stars and galactic tides, causing them to depart from orbits restricted to the plane of the solar system, and to form the now-spherical Oort cloud. You could imagine that a similar process could occur around another star with giant planets, and we know that there are many stars out there that do have giant planets.” As Baxter and his colleagues indicated in their study, detecting EXOCs is difficult, largely for the same reasons for why there is no direct evidence for the Solar System’s own Oort Cloud. For one, there is not a lot of material in the cloud, with estimates ranging from a few to twenty times the mass of the Earth. Second, these objects are very far away from our Sun, which means they do not reflect much light or have strong thermal emissions.For this reason, Baxter and his team recommended using maps of the sky at the millimeter and submillimeter wavelengths to search for signs of Oort Clouds around other stars. Such maps already exist, thanks to missions like the Planck telescope which have mapped the Cosmic Microwave Background (CMB). As Baxter indicated:“In our paper, we use maps of the sky at 545 GHz and 857 GHz that were generated from observations by the Planck satellite. Planck was pretty much designed *only* to map the CMB; the fact that we can use this telescope to study exo-Oort clouds and potentially processes connected to planet formation is pretty surprising!”This is a rather revolutionary idea, as the detection of EXOCs was not part of the intended purpose of the Planck mission. By mapping the CMB, which is “relic radiation” left over from the Big Bang, astronomers have sought to learn more about how the Universe has evolved since the the early Universe – circa. 378,000 years after the Big Bang. However, their study does build on previous work led by Alan Stern (the principal investigator of the New Horizons mission). All-sky data obtained by the ESA’s Planck mission, showing the different wavelenghts. - Image Credit: ESA In 1991, along with John Stocke (of the University of Colorado, Boulder) and Paul Weissmann (from NASA’s Jet Propulsion Laboratory), Stern conducted a study titled “An IRAS search for extra-solar Oort clouds“. In this study, they suggested using data from the Infrared Astronomical Satellite (IRAS) for the purpose of searching for EXOCs. However, whereas this study focused on certain wavelengths and 17 star systems, Baxter and his team relied on data for tens of thousands of systems and at a wider range of wavelengths.Other current and future telescopes which Baxter and his team believe could be useful in this respect include the South Pole Telescope, located at the Amundsen–Scott South Pole Station in Antarctica; the Atacama Cosmology Telescope and the Simons Observatory in Chile; the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) in Antarctica; the Green Bank Telescope in West Virgina, and others.“Furthermore, the Gaia satellite has recently mapped out very accurately the positions and distances of stars in our galaxy,” Baxter added. “This makes choosing targets for exo-Oort cloud searches relatively straightforward. We used a combination of Gaia and Planck data in our analysis.”To test their theory, Baxter and is team constructed a series of models for the thermal emission of exo-Oort clouds. “These models suggested that detecting exo-Oort clouds around nearby stars (or at least putting limits on their properties) was feasible given existing telescopes and observations,” he said. “In particular, the models suggested that data from the Planck satellite could potentially come close to detecting an exo-Oort cloud like our own around a nearby star.” The relative sizes of the inner Solar System, Kuiper Belt and the Oort Cloud. - Image Credit: NASA, William Crochot In addition, Baxter and his team also detected a hint of a signal around some of the stars that they considered in their study – specifically in the Vega and Formalhaut systems. Using this data, they were able to place constraints on the possible existence of EXOCs at a distance of 10,000 to 100,000 AUs from these stars, which roughly coincides with the distance between our Sun and the Oort Cloud.However, additional surveys will be needed before the existence any of EXOCs can be confirmed. These surveys will likely involve the James Webb Space Telescope, which is scheduled to launch in 2021. In the meantime, this study has some rather significant implications for astronomers, and not just because it involves the use of existing CMB maps for extra-solar studies. As Baxter put it:“Just detecting an exo-Oort cloud would be really interesting, since as I mentioned above, we don’t have any direct evidence for the existence of our own Oort cloud. If you did get a detection of an exo-Oort cloud, it could in principle provide insights into processes connected to planet formation and the evolution of protoplanetary disks. For instance, imagine that we only detected exo-Oort clouds around stars that have giant planets. That would provide pretty convincing evidence that the formation of an Oort cloud is connected to giant planets, as suggested by popular theories of the formation of our own Oort cloud.”As our knowledge of the Universe expands, scientists become increasingly interested in what our Solar System has in common with other star systems. This, in turn, helps us to learn more about the formation and evolution of our own system. It also provides possible hints as to how the Universe changed over time, and maybe even where life could be found someday.Source: Universe Today - Further Reading: arXiv If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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Topline
The long-awaited first images from the James Webb Telescope captivated the American public this week, with a shot of a distant galaxy cluster making for the top posts on Facebook and Twitter, in a break from the divisive political messaging that tends to dominate the platforms. An image released by NASA shows thousands of galaxies in the SMACS 0723 cluster. NASA, ESA, CSA, STScI, Webb ERO Key Facts NASA published the top two U.S.-based Facebook posts this week, led by Monday's release of what the space agency called "the deepest and sharpest infrared image of the distant universe so far," showing thousands of galaxies. That post garnered more than 940,000 interactions, through over 680,000 reactions, around 242,000 shares and about 19,000 comments, according to data compiled by social media tracking firm NewsWhip. NASA followed up Tuesday with a post featuring a series of additional shots, led by an image of "Cosmic Cliffs" showing stars being formed in a gargantuan dust cloud, which attracted more than 750,000 interactions. The galaxy cluster shot also topped Twitter this week, albeit in the form of a joke: @psa10memes shared a side-by-side image juxtaposing the vivid shot of galaxies distant lightyears away with purportedly grainy security camera footage, drawing more than 1.1 million likes and over 126,000 retweets. Key Background
President Joe Biden unveiled the galaxy cluster photo at a White House event Monday, touting the image as a signal to "the American people—especially our children—that there’s nothing beyond our capacity." The image shows the SMACS 0723 cluster as it appeared 4.6 billion years ago, as that is how long it took for the light captured in the picture to reach the Webb Telescope. The initial images are the culmination of around two decades of work to develop the $10 billion telescope, which is a successor to the Hubble Space Telescope, launched in 1990. The Webb Telescope has enough fuel onboard to keep shooting photos for 20 years, according to NASA.
Big Number
13.1 billion years. That's the age of the oldest light captured in the galaxy cluster image, according to NASA, from a galaxy that appears as a tiny red dot. Astronomers believe the universe was less than 1 billion years old at the time the light was emitted. Further Reading
NASA Releases Vivid First Image Of Space From James Webb Telescope (Forbes)
NASA Reveals More Stunning Images Of The Universe From The James Webb Telescope (Forbes)
Ben Shapiro Cheering Florida’s Math Textbook Ban Topped Facebook This Week (Forbes)
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Cosmology & The Universe
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In a new study, an international team of astrophysicists has discovered several mysterious objects hiding in images from the James Webb Space Telescope: six potential galaxies that emerged so early in the universe’s history and are so massive they should not be possible under current cosmological theory.
Each of the candidate galaxies may have existed at the dawn of the universe roughly 500 to 700 million years after the Big Bang, or more than 13 billion years ago. They’re also gigantic, containing almost as many stars as the modern-day Milky Way Galaxy.
“It’s bananas,” said Erica Nelson, co-author of the new research and assistant professor of astrophysics at the University of Colorado Boulder. “You just don’t expect the early universe to be able to organize itself that quickly. These galaxies should not have had time to form.”
Nelson and her colleagues, including first author Ivo Labbé of the Swinburne University of Technology in Australia, published their results Feb. 22 in the journal Nature.
The latest finds aren’t the earliest galaxies observed by James Webb, which launched in December 2021 and is the most powerful telescope ever sent into space. Last year, another team of scientists spotted four galaxies that likely coalesced from gas around 350 million years after the Big Bang. Those objects, however, were downright shrimpy compared to the new galaxies, containing many times less mass from stars.
The researchers still need more data to confirm that these galaxies are as big as they look, and date as far back in time. Their preliminary observations, however, offer a tantalizing taste of how James Webb could rewrite astronomy textbooks.
“Another possibility is that these things are a different kind of weird object, such as faint quasars, which would be just as interesting,” Nelson said.
Fuzzy dots
There’s a lot of excitement going around: Last year, Nelson and her colleagues, who hail from the United States, Australia, Denmark and Spain, formed an ad hoc team to investigate the data James Webb was sending back to Earth.
Their recent findings stem from the telescope’s Cosmic Evolution Early Release Science (CEERS) Survey. These images look deep into a patch of sky close to the Big Dipper—a relatively boring, at least at first glance, region of space that the Hubble Space Telescope first observed in the 1990s.
Nelson was peering at a postage stamp-sized section of one image when she spotted something strange: a few “fuzzy dots” of light that looked way too bright to be real.
“They were so red and so bright,” Nelson said. “We weren’t expecting to see them.”
She explained that in astronomy, red light usually equals old light. The universe, Nelson said, has been expanding since the dawn of time. As it expands, galaxies and other celestial objects move farther apart, and the light they emit stretches out—think of it like the cosmic equivalent of saltwater taffy. The more the light stretches, the redder it looks to human instruments. (Light from objects coming closer to Earth, in contrast, looks bluer).
The team ran calculations and discovered that their old galaxies were also huge, harboring tens to hundreds of billions of sun-sized stars worth of mass, on par with the Milky Way.
These primordial galaxies, however, probably didn’t have much in common with our own.
“The Milky Way forms about one to two new star every year,” Nelson said. “Some of these galaxies would have to be forming hundreds of new stars a year for the entire history of the universe.”
Nelson and her colleagues want to use James Webb to collect a lot more information about these mysterious objects, but they’ve seen enough already to pique their curiosity. For a start, calculations suggest there shouldn’t have been enough normal matter—the kind that makes up planets and human bodies—at that time to form so many stars so quickly.
“If even one of these galaxies is real, it will push against the limits of our understanding of cosmology,” Nelson said.
Seeing back in time
For Nelson, the new findings are a culmination of a journey that began when she was in elementary school. When she was 10, she wrote a report about Hubble, a telescope that launched in 1990 and is still active today. Nelson was hooked.
“It takes time for light to go from a galaxy to us, which means that you're looking back in time when you're looking at these objects,” she said. “I found that concept so mind blowing that I decided at that instant that this was what I wanted to do with my life.”
The fast pace of discovery with James Webb is a lot like those early days of Hubble, Nelson said. At the time, many scientists believed that galaxies didn’t begin forming until billions of years after the Big Bang. But researchers soon discovered that the early universe was much more complex and exciting than they could have imagined.
“Even though we learned our lesson already from Hubble, we still didn’t expect James Webb to see such mature galaxies existing so far back in time,” Nelson said. “I’m so excited.”
Other co-authors on the new study include Pieter van Dokkum of Yale University; Katherine Suess of the University of California, Santa Cruz; Joel Leja, Elijah Matthews and Bingjie Wang of the Pennsylvania State University; Gabriel Brammer and Katherine Whitaker of the University of Coppenhagen; and Mauro Stefanon of the University of Valencia.
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Cosmology & The Universe
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It promised “a front-row seat to the cosmos” — an opportunity to look back through space and time like never before and imagery that would “blow minds”.“Prepare for a new way to see the universe beyond where we’ve been, beyond what we know, beyond time itself,” Nasa boasted as it prepared to share the first set of images and data from the $10 billion James Webb Space Telescope.When it came to the big reveal, the US space agency and its partners outshone even their own assurances, delivering snapshots of the evolution of the universe in dazzling, gulp-inducing, champagne-toasting detail.“It’s like the moon landing for astronomy,” said Günther Hasinger, director of science at the European Space Agency (ESA).Webb is the largest, most
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Cosmology & The Universe
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02:37 - Source: CNN Why is NASA crashing a spacecraft into an asteroid? Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. CNN — On Monday, a NASA spacecraft will deliberately slam into an asteroid called Dimorphos. The Double Asteroid Redirection Test mission, or DART, aims to see if this kind of kinetic impact can help deflect an asteroid posing a threat to Earth. “We are moving an asteroid,” said Tom Statler, NASA program scientist for the DART mission. “We are changing the motion of a natural celestial body in space. Humanity has never done that before.” Here’s what you need to know about this mission. The DART spacecraft is about the size of a school bus. It has been traveling to reach its asteroid target since launching in November 2021. The spacecraft will arrive at the asteroid system on September 26. Impact is expected at 7:14 p.m. ET. The spacecraft is heading for a double-asteroid system, where a tiny “moon” asteroid, named Dimorphos, orbits a larger asteroid, Didymos. Didymos. which means “twin” in Greek, is roughly 2,560 feet (780 meters) in diameter. Meanwhile, Dimorphos measures 525 feet (160 meters) across, and its name means “two forms.” At the time of impact, Didymos and Dimorphos will be relatively close to Earth – within 6.8 million miles (11 million kilometers). Neither Dimorphos nor Didymos is at risk of colliding with Earth – before or after the collision takes place. DART is going down in a blaze of glory. It will set its sights on Dimorphos, accelerate to 13,421 miles per hour (21,600 kilometers per hour) and crash into the moon nearly head-on. The spacecraft is about 100 times smaller than Dimorphos, so it won’t obliterate the asteroid. Instead, DART will try to change the asteroid’s speed and path in space. The mission team has compared this collision to a golf cart crashing into one of the Great Pyramids – enough energy to leave an impact crater. The impact will change Dimorphos’ speed by 1% as it orbits Didymos. It doesn’t sound like much, but doing so will change the moon’s orbital period. The nudge will shift Dimorphos slightly and make it more gravitationally bound to Didymos – so the collision won’t change the binary system’s path around the Earth or increase its chances of becoming a threat to our planet. The spacecraft will share its view of the double-asteroid system through an instrument known as the Didymos Reconnaissance and Asteroid Camera for Optical navigation, or DRACO. This imager, which serves as DART’s eyes, will allow the spacecraft to identify the double-asteroid system and distinguish which space object it’s supposed to strike. This instrument also is a high-resolution camera that aims to capture images of the two asteroids to be streamed back to Earth at a rate of one image per second in what will appear nearly like a video. You can watch the live stream on NASA’s website, beginning at 6 p.m. ET Monday. Didymos and Dimorphos will appear as pinpricks of light about an hour before impact, gradually growing larger and more detailed in the frame. Dimorphos has never been observed before, so scientists can finally take in its shape and the appearance of its surface. We should be able to see Dimorphos in exquisite detail before DART crashes into it. Given the time it takes for images to stream back to Earth, they will be visible for eight seconds before a loss of signal occurs and DART’s mission ends – if it was successful. The spacecraft also has its own photojournalist along for the ride. A briefcase-size satellite from the Italian Space Agency hitched a ride with DART into space. Called the Light Italian CubeSat for Imaging of Asteroids, or LICIACube, it detached from the spacecraft on September 11. The satellite is traveling behind DART to record what happens from a safe perspective. Three minutes after impact, LICIACube will fly by Dimorphos to capture images and video of the impact plume and maybe even spy on the impact crater. The CubeSat will turn to keep its cameras pointed at Dimorphos as it flies by. The images and video, while not immediately available, will be streamed back to Earth in the days and weeks following the collision. The LICIACube won’t be the only observer watching. The James Webb Space Telescope, the Hubble Space Telescope and NASA’s Lucy mission will observe the impact. The Didymos system may brighten as its dust and debris is ejected into space, said Statler, the NASA program scientist. But ground-based telescopes will be key in determining if DART successfully changed the motion of Dimorphos. The Didymos system was discovered in 1996, so astronomers have plenty of observations of the system. After the impact, observatories around the world will watch as Dimorphos crosses in front of and moves behind Didymos. Dimorphos takes 11 hours and 55 minutes to complete an orbit of Didymos. If DART is successful, that time could decrease by 73 seconds, “but we actually think we’re going to change it by about 10 minutes,” said Edward Reynolds, DART project manager at the Johns Hopkins University Applied Physics Laboratory. Statler said he would be surprised if a measurement of the period change came in less than a few days but even more so if it took more than three weeks. “I’m highly confident that we were going to hit on Monday, and it will be a complete success,” said Lindley Johnson, NASA planetary defense officer. But if DART misses its proverbial dart board, the team will be ready to ensure the spacecraft is safe and all its information downloaded to figure out why it didn’t hit Dimorphos. The Applied Physics Laboratory’s Mission Operations Center will intervene if necessary, even though DART will have been operating autonomously for the final four hours of its journey. It takes 38 seconds for a command to travel from Earth to the spacecraft, so the team can react quickly. The DART team has 21 contingency plans it has rehearsed, said Elena Adams, DART mission systems engineer at the Applied Physics Lab. Dimorphos was chosen for this mission because its size is comparable to asteroids that could pose a threat to Earth. An asteroid the size of Dimorphos could cause “regional devastation” if it hit Earth. The asteroid system is “the perfect natural laboratory” for the test, Statler said. The mission will allow scientists to have a better understanding of the size and mass of each asteroid, which is crucial to understanding near-Earth objects. Near-Earth objects are asteroids and comets with an orbit that places them within 30 million miles (48.3 million kilometers) from Earth. Detecting the threat of near-Earth objects that could cause grave harm is a primary focus of NASA and other space organizations around the world. No asteroids are currently on a direct impact course with Earth, but more than 27,000 near-Earth asteroids exist in all shapes and sizes. The valuable data collected by DART will contribute to planetary defense strategies, especially the understanding of what kind of force can shift the orbit of a near-Earth asteroid that could collide with our planet. Movies make combating asteroid approaches seem like a hurried scramble to protect the planet, but “that’s not the way to do planetary defense,” Johnson said. Blowing up an asteroid could be more dangerous because then its pieces could be on a collision course with Earth. But NASA is considering other methods of changing the motion of asteroids. The DART spacecraft is considered to be a kinetic impactor that could change the speed and path of Dimorphos. If DART is successful, it could be one tool for deflecting asteroids. Another option is a gravity tractor, which relies on mutual gravitational attraction between a spacecraft and an asteroid to tug the space rock out of its impacting trajectory into a more benign one, Johnson said. Another technique is ion beam deflection, or shooting an ion engine at an asteroid for long periods of time until the ions change the asteroid’s velocity and orbit. But both of these take time. “Any technique that you can imagine that changes the orbital speed of the asteroid in orbit is a viable technique,” Johnson said. An international forum called the Space Planning Commission has brought 18 national space agencies together to assess what might be best to deflect an asteroid, depending on its size and path. Finding populations of hazardous asteroids and determining their sizes are priorities of NASA and its international partners, Johnson said. The design for a space-based telescope called the Near-Earth Object Surveyor mission is currently in review. The Didymos system won’t be lonely for too long. To survey the aftermath of the impact, the European Space Agency’s Hera mission will launch in 2024. The spacecraft, along with two CubeSats, will arrive at the asteroid system two years later. Hera will study both asteroids, measure physical properties of Dimorphos, and examine the DART impact crater and the moon’s orbit, with the aim of establishing an effective planetary defense strategy.
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Cosmology & The Universe
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This image shows the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on the James Webb Space Telescope, this image reveals previously obscured areas of star birth, according to NASA. (NASA, ESA, CSA, and STScI/NASA, ESA, CSA, and STScI via AP)GREENBELT, Md. — NASA on Tuesday unveiled a new batch of images from its new powerful space telescope, including a foamy blue and orange shot of a dying star.The first image from the $10 billion James Webb Space Telescope was released Monday at the White House — a jumble of distant galaxies that went deeper into the cosmos than humanity has ever seen.The four additional photos released Tuesday included more cosmic beauty shots.With one exception, the latest images showed parts of the universe seen by other telescopes. But Webb’s sheer power, distant location off Earth and use of the infrared light spectrum showed them in new light.“Every image is a new discovery and each will give humanity a view of the humanity that we’ve never seen before,’’ NASA Administrator Bill Nelson said Tuesday, rhapsodizing over images showing “the formation of stars, devouring black holes.”Webb’s use of the infrared light spectrum allows the telescope to see through the cosmic dust and “see light from faraway light from the corners of the universe,” he said.“We’ve really changed the understanding of our universe,” said European Space Agency director general Josef Aschbacher.The European and Canadian space agencies joined NASA in building the powerful telescope.On tap Tuesday:— Southern Ring Nebula, which is sometimes called “eight-burst.” About 2,500 light-years away, it shows an expanding cloud of gas surrounding a dying star. A light-year is 5.8 trillion miles.— Carina Nebula, one of the bright stellar nurseries in the sky, about 7,600 light-years away.— Five galaxies in a cosmic dance, 290 million light-years away. Stephan’s Quintet was first seen 225 years ago in the constellation Pegasus.— A blueish giant planet called WASP-96b. It’s about the size of Saturn and is 1,150 light-years away. A gas planet, it’s not a candidate for life elsewhere but a key target for astronomers.The images were released one-by-one at an event at NASA’s Goddard Space Center that included cheerleaders with pompoms the color of the telescope’s golden mirrors.The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.Webb is considered the successor to the highly successful, but aging Hubble Space Telescope.
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Cosmology & The Universe
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Scientists finally got a glimpse of what the universe looked like more than 13 billion years ago. And what they found could change everything we know about the dawn of the universe.
When the tiny, young, baby galaxies." What they found, however, was something far greater – six massive galaxies dating back about 13.1 billion years that appeared to be just as old as the is now.from the James Webb Space Telescope were released last July, astronomers got their earliest look at cosmic history yet, seeing captured images of what the universe looks like billions of light years away. They expected to maybe see some "
"These objects are way more massive than anyone expected," astronomer Joel Leja said. "...We've discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe."
Ivo Labbé, the lead author of the study, said they started realizing they were onto something barely a week after the telescope images were released.
"Little did I know that among the pictures is a small red dot that will shake up our understanding of how the first galaxies formed after the Big Bang," Labbé said. "...I run the analysis software on the little pinprick and it spits out two numbers: distance 13.1 billion light years, mass 100 billion stars, and I nearly spit out my coffee. We just discovered the impossible. Impossibly early, impossibly massive galaxies."
That red dot was just the beginning. The next day, they found five more apparent galaxies. And the pictures taken by JWST show them as they were when our 13.8 billion-year-old universe was a mere 700 million years old. And if that's the case, they said, that would mean that the galaxies formed "as many stars as our present-day Milky Way. In record time."
They were able to identify the objects thanks to the telescope's infrared-sensing technology that's able to find the light of ancient space bodies.
"What's funny is we have all these things we hope to learn from James Webb and this was nowhere near the top of the list," Leja said. "We've found something we never thought to ask the universe — and it happened way faster than I thought, but here we are."
Leja said that while the objects so far do appear to be galaxies, there is a "real possibility" that some of the entities they found could be supermassive black holes — areas in space where a large amount of matter is packed into an area millions times as and where NASA says gravity is "so strong that nothing, not even light, can escape."
But even if it turns out that some of the six objects they found are black holes, it still shows "an astounding change."
"Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought," Leja said. "...The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science. We've been informally calling these objects 'universe breakers' — and they have been living up to their name so far."
The objects, they said, are so big that scientists may have to alter cosmology models or force a total consensus revision of the belief that galaxies start out as little dust clouds and take a long time to become giant entities.
Now, researchers are trying to pinpoint exactly what these objects are. Leja hopes they can take a spectrum image, which he said will reveal just how big and far away the objects really are.
"We looked into the very early universe for the first time and had no idea what we were going to find," Leja added. "It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question."
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Cosmology & The Universe
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By Dan Hooper - University of ChicagoThe past few decades have ushered in an amazing era in the science of cosmology. A diverse array of high-precision measurements has allowed us to reconstruct our universe’s history in remarkable detail.And when we compare different measurements – of the expansion rate of the universe, the patterns of light released in the formation of the first atoms, the distributions in space of galaxies and galaxy clusters and the abundances of various chemical species – we find that they all tell the same story, and all support the same series of events.This line of research has, frankly, been more successful than I think we had any right to have hoped. We know more about the origin and history of our universe today than almost anyone a few decades ago would have guessed that we would learn in such a short time.But despite these very considerable successes, there remains much more to be learned. And in some ways, the discoveries made in recent decades have raised as many new questions as they have answered.One of the most vexing gets at the heart of what our universe is actually made of. Cosmological observations have determined the average density of matter in our universe to very high precision. But this density turns out to be much greater than can be accounted for with ordinary atoms.After decades of measurements and debate, we are now confident that the overwhelming majority of our universe’s matter – about 84 percent – is not made up of atoms, or of any other known substance. Although we can feel the gravitational pull of this other matter, and clearly tell that it’s there, we simply do not know what it is. This mysterious stuff is invisible, or at least nearly so. For lack of a better name, we call it “dark matter.” But naming something is very different from understanding it. For almost as long as we’ve known that dark matter exists, physicists and astronomers have been devising ways to try to learn what it’s made of. They’ve built ultra-sensitive detectors, deployed in deep underground mines, in an effort to measure the gentle impacts of individual dark matter particles colliding with atoms.They’ve built exotic telescopes – sensitive not to optical light but to less familiar gamma rays, cosmic rays and neutrinos – to search for the high-energy radiation that is thought to be generated through the interactions of dark matter particles.And we have searched for signs of dark matter using incredible machines which accelerate beams of particles – typically protons or electrons – up to the highest speeds possible, and then smash them into one another in an effort to convert their energy into matter. The idea is these collisions could create new and exotic substances, perhaps including the kinds of particles that make up the dark matter of our universe.As recently as a decade ago, most cosmologists – including myself – were reasonably confident that we would soon begin to solve the puzzle of dark matter. After all, there was an ambitious experimental program on the horizon, which we anticipated would enable us to identify the nature of this substance and to begin to measure its properties. This program included the world’s most powerful particle accelerator – the Large Hadron Collider – as well as an array of other new experiments and powerful telescopes. But things did not play out the way that we expected them to. Although these experiments and observations have been carried out as well as or better than we could have hoped, the discoveries did not come.Over the past 15 years, for example, experiments designed to detect individual particles of dark matter have become a million times more sensitive, and yet no signs of these elusive particles have appeared. And although the Large Hadron Collider has by all technical standards performed beautifully, with the exception of the Higgs boson, no new particles or other phenomena have been discovered.The stubborn elusiveness of dark matter has left many scientists both surprised and confused. We had what seemed like very good reasons to expect particles of dark matter to be discovered by now. And yet the hunt continues, and the mystery deepens.In many ways, we have only more open questions now than we did a decade or two ago. And at times, it can seem that the more precisely we measure our universe, the less we understand it. Throughout the second half of the 20th century, theoretical particle physicists were often very successful at predicting the kinds of particles that would be discovered as accelerators became increasingly powerful. It was a truly impressive run.But our prescience seems to have come to an end – the long-predicted particles associated with our favorite and most well-motivated theories have stubbornly refused to appear. Perhaps the discoveries of such particles are right around the corner, and our confidence will soon be restored. But right now, there seems to be little support for such optimism.In response, droves of physicists are going back to their chalkboards, revisiting and revising their assumptions. With bruised egos and a bit more humility, we are desperately attempting to find a new way to make sense of our world.Source: The Conversation If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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A mysterious alignment of stellar "ghosts" from dead stars haunts the heart of the Milky Way, and scientists may finally know why.
These cosmic specters exist in the form of planetary nebulas, clouds of gas that are expelled by dying stars at the end of their lives. These can resemble butterflies or hourglasses with the smoldering remains of the star at their heart. The sun, when it runs out of fuel for nuclear fusion at its core and after it has swelled out as a red giant and swallowed the inner planets in around 5 billion years, will leave similar gaseous remains around a white dwarf star.
Astronomers know a great deal about planetary nebulas, but an arrangement of such clouds in the galactic bulge at the center of our Milky Way galaxy has still been a puzzle since its discovery 10 years ago by Manchester Ph.D. student Bryan Rees. Now, this mystery has been exorcised thanks to a team of astronomers using images previously produced by the Hubble Space Telescope.
"Planetary nebulas offer us a window into the heart of our galaxy and this insight deepens our understanding of the dynamics and evolution of the Milky Way's bulge region," University of Manchester astrophysicist Albert Zijlstra said in a statement.
Studying 136 planetary nebulas in the thickest part of the Milky Way, the galactic bulge, with the Very Large Telescope (VLT), the team discovered that each is unrelated and comes from different stars, which died at different times and spent their lives in different locations.
The researchers also found that the shapes of these planetary nebulas line up in the sky in the same way. Not only this, but they are also aligned almost parallel to the plane of the Milky Way.
These findings were also reflected in the work of Rees, which featured 40 planetary nebulas, which the team re-examined using Hubble images.
But what wasn't known until now was the fact that this alignment is only present in the planetary nebulas that have a close stellar companion. In these cases, the companion stars orbit the stellar remnant at the heart of the planetary nebulas at a distance closer than our solar system's innermost planet Mercury is to the sun.
The alignment is absent in planetary nebulas that lack such a companion star, and this implies that the alignment could be created as a result of the rapid orbital motion of the companion star, which may even end up orbiting inside the remains of the main star. The observed alignment of the planetary nebulas may also reveal that close binary systems form with their orbits inclined in the same plane.
"The formation of stars in the bulge of our galaxy is a complex process that involves various factors such as gravity, turbulence, and magnetic fields. Until now, we have had a lack of evidence for which of these mechanisms could be causing this process to happen and generating this alignment," Zijlstra concluded. "The significance in this research lies in the fact that we now know that the alignment is observed in this very specific subset of planetary nebulas."
The team's research is published in the Astrophysical Journal Letters.
Originally posted on Space.com.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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Home News Science & Astronomy The Hyades star cluster (pink) curls across the sky amid well-known constellations (green). The cluster is at the center of a controversial new study proposing an alternative to Newton's theory of gravity.
(Image credit: ESA/Gaia/DPAC, CC BY-SA 3.0) Astronomers observing star clusters in our galaxy have found evidence that controversially challenges Newton's laws of gravity and could upend our understanding of the universe. The puzzling finding could support a controversial idea that does away entirely with dark matter.The researchers found this evidence by observing open star clusters, or loosely bound groups of up to a few hundred stars sitting within larger galaxies. Open star clusters have trails of stars, known as "tidal tails," in front of and behind them. The researchers' observations indicate that such clusters have many more stars sitting in the overall direction of their travel through space than trailing behind. This throws into question Isaac Newton's law of universal gravitation, which suggests that there should be the same number of stars in both tidal tails."It's extremely significant," astrophysicist Pavel Kroupa of the University of Bonn told Live Science. "There is a huge effect."Related: Cosmic 'tug-of-war' between galaxies created a tidal tail of whipped-away starsKroupa is the lead author of a study published Oct. 26 (opens in new tab) in the Monthly Notices of the Royal Astronomical Society that argues the observations are evidence of modified Newtonian dynamics (MOND) — an alternative theory of gravity to Newton's widely accepted universal law of gravitation.This uneven distribution of stars is noticeable, but not extreme enough for any sort of dark matter — an invisible substance thought to exert a powerful gravitational pull on the universe's visible matter (opens in new tab) — to be involved, Kroupa said."This is basically a game-changer," he said. "This destroys all the work done on galaxies and on cosmology [that] assumes dark matter and Newtonian gravity."Dark matter?Issac Newton's universal law of gravitation, published in 1687, states that every particle in the universe attracts every other with a force proportional to their masses and inversely proportional to the square of their distance. Albert Einstein later incorporated this law into his theory of general relativity, which was published in 1915.But Kroupa said that at the time of both Newton and Einstein, astronomers didn't know that galaxies even existed, and so MOND was developed to bring it up to date with observations.In the star cluster Hyades (top), the number of stars (black) in the front tidal tail is significantly larger than those in the rear. In the computer simulation with MOND (below), a similar picture emerges. (Image credit: University of Bonn)MOND, also known as Milgromian dynamics after astrophysicist Mordehai Milgrom (opens in new tab) who developed it in the early 1980s, argues that regular Newtonian dynamics don't apply on the very large scales of galaxies and galactic clusters — although most astrophysicists think they do.The main consequence of MOND is that dark matter doesn't exist — an idea that most astrophysicists dismiss, Kroupa said. "The majority of scientists completely reject MOND," he said. "Many serious scientists don't think MOND is serious, and so they wouldn't consider looking at it."Stellar clustersIn their study, the authors report observations of five of the closest open stellar clusters to Earth, including the Hyades — a roughly spherical group of hundreds of stars that is only about 150 light-years from our sun.The researchers observed that stars had accumulated in the leading tidal tail in all five of the clusters, while the greatest discrepancy from regular Newtonian dynamics was seen in the Hyades cluster, where there are better measurements, Kroupa said. The observed discrepancies strengthen the case for MOND, but they can't be a result of the invisible action of dark matter.In the case of the Hyades, "we would have to have a clump of dark matter there like 10 million solar masses" to explain the results, he said. "But it's just not in the data."Future studies will use more precise data on the positions of stars from new space telescopes, such as the European Space Agency's Gaia, he said.However, because MOND is not widely accepted by many scientists, the new study's findings are controversial. Sabine Hossenfelder (opens in new tab), an astrophysicist at the Frankfurt Institute Advanced Studies, told Live Science in an email that she was pleased to see researchers working on gravitational simulations of MOND.But "as they admit the paper themselves, they are using an approximate calculation that needs to be confirmed… [and] they haven't quantified how large the disagreement with data is," she said. "So I think it remains to be seen how good this argument actually is." Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.
Tom Metcalfe is a freelance journalist and regular Live Science contributor who is based in London in the United Kingdom. Tom writes mainly about science, space, archaeology, the Earth and the oceans. He has also written for the BBC, NBC News, National Geographic, Scientific American, Air & Space, and many others.
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Cosmology & The Universe
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The concept of a city-sized telescope on the moon has piqued NASA's interest.
The space agency recently awarded(opens in a new tab) researchers a grant to further develop the plan for a sprawling array of antennae on the moon's cryptic far side — using minerals mined from the moon. At this stage of the game, a proposal for a 77-square-mile telescope snaking over the lunar surface is an idea, not nearly a funded endeavor. But such a radio telescope, called the FarView Observatory, would allow astronomers to see what no other instrument today can: A period of time before the stars, called the universe's "Dark Ages."
"I've personally been advocating for a radio telescope on the moon for 40 years now," Jack Burns, a professor in the Department of Astrophysical and Planetary Sciences at CU Boulder who's a member of the FarView project, told Mashable. "It's going to probe a part of the universe we haven't been able to see before."
Radio telescopes have a lot in common with the radio antenna on your car. But they're not tuning into The Rolling Stones and Metallica. Radio telescopes — often built as giant dishes — capture radio waves emanating through the cosmos from exploding stars, forming stars, black holes, and beyond. Radio telescopes have to be big, because radio waves from the deep universe are extremely weak sources of energy. ("These are very faint signals. The amount of energy collected in radio astronomy's history is less than the energy needed to melt a snowflake," Yvette Cendes, an astronomer and postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics(opens in a new tab), told Mashable earlier this year.)
But the radio telescope arrays on Earth, as vast as they are(opens in a new tab), receive too much interference to pick up the faintest signals in the universe. A lofty part of our atmosphere, called the ionosphere, reflects extremely distant and stretched-out radio waves. And then, there's us. "Random radio emissions from our noisy civilization can interfere with radio astronomy as well, drowning out the faintest signals," NASA explains(opens in a new tab).
"It's going to probe a part of the universe we haven't been able to see before."
A telescope on the moon's dark far side, however, is free of this noise. There's little to no lunar atmosphere. And the moon itself blocks pesky radio waves from our boisterous planet.
On the moon's far side, there's a (relatively) clear view into the deepest of the cosmos. All we need is an extremely large telescope.
Building a city-sized telescope
The idea is indeed hugely ambitious. But perhaps not as far-fetched as it sounds.
NASA is funding the further conceptual development of FarView, proposed by the aerospace company Lunar Resources, through its "NASA Innovative Advanced Concepts" program. At this Phase II round, researchers receive up to $600,000 to advance their ideas. Also included in this year's recipients is a planetary defense endeavor that would "pulverize" an incoming asteroid or comet, an "astropharmacy" to make needed drugs (for radiation exposure and other ailments) in deep space, and a fast-moving spacecraft powered by a "radioisotope electric propulsion system," among other concepts.
A major selling point for the sprawling lunar observatory, emphasizes Burns, is that nearly all the metallic materials are available on the moon. Giant, expensive rockets won't need to haul bounties of conducting metal for the antennae.
"We don't have to bring all that material from Earth," Burns said. "We can in fact build an array with 100,000 antennas with only a few flights to the moon."
"In some ways, this is 1950s technology."
Similar to a giant spiderweb laid on the ground, robotic rovers would lay strips of aluminum extracted from the lunar soil on relatively flat expanses of the moon (as shown in the graphic above). These thin metal strips act like the metal rods or wires commonly seen in antennas, which catch radio signals traveling by (just like your car's antenna).
"In some ways, this is 1950s technology," Burns marveled.
Yet the radio waves Burns and other astronomers hope to catch on the moon are quite long, at some 20, 30, or more meters. (FM radio waves are some 3 meters long.(opens in a new tab)) The universe is constantly expanding, and the different types of light (visible light, infrared light, X-rays, radio waves, and beyond) is stretched out as space expands. That's a critical reason why an observatory that seeks some of the oldest signals in the cosmos must be so big: The radio waves have been stretched like taffy.
Of course, the greater telescope project will require more than mining aluminum from the moon's soil. A swarm of robotic rovers will need to lay the wiring. Solar panels must be constructed to power the machines. And some level of human oversight will be required, perhaps from astronauts who will inhabit the Lunar Gateway, an outpost that will orbit the moon(opens in a new tab).
A colossal looming question, of course, is cost. NASA is considering other large-scale lunar telescope(opens in a new tab) ideas. But cutting the transportation of metals to the moon is a great boon for such an expansive project. And with the rise and success of commercial rockets, any necessary launch costs are falling. Overall, it's too early to know the bill for such a sprawling telescope. But it will almost certainly be billions.
NASA and Congress, however, have been historically committed to spending billions on scientific endeavors into how the universe formed, and where we and the Milky Way galaxy came from. The James Webb Space Telescope(opens in a new tab) cost taxpayers nearly $11 billion(opens in a new tab) – with much of it built and assembled in the U.S. Other scientific endeavors, like the Mars Perseverance rover, cost some $2.7 billion(opens in a new tab). And the first launches of NASA's new megarocket, the Space Launch System, will cost over $4 billion per launch, as it supports exploration and scientific endeavors on the moon.
A project like FarView might be especially enticing to NASA, noted Burns, because it would advance robotic exploration and industrial creation on another world. The space agency wants to establish a permanent presence on and around the moon. And it wants to go to Mars. For such deeper space endeavors it will need proven building and industrial technology. "NASA is interested in the technology and engineering along with the science," said Burns, speaking of FarView.
A price tag for constructing a sprawling array of metallic rods on the moon won't be cheap. But it could be reasonable, considering the scope of the project. And the returns could be scientifically, and technologically, invaluable.
"It would be the biggest telescope ever built — and we're going to do it using robots," Burns said.
Want more science and tech news delivered straight to your inbox? Sign up for Mashable's Top Stories newsletter today.
How to peer into the universe's Dark Ages
NASA's pioneering Webb space telescope can see some of the earliest galaxies ever formed, around 300 million years after the Big Bang. A giant radio telescope like FarView would peer beyond this early period.
The "Dark Ages" began just some 370,000 years after the universe was born. By this time, the cosmos had cooled and the first atoms, hydrogen, had formed. There were no stars, and wouldn't be for hundreds of millions of years, astronomers say.
Yet the cosmos were flooded with clouds of hydrogen, which emanate energy via radio waves. This is what a telescope on the far side of the moon would view.
Amid the Dark Ages, astronomers could now see — for the first time — how large clumps of gas ultimately formed the first, extremely hot stars. "They were 30 to 300 times more massive than our sun and millions of times brighter," NASA explained. Those stars would lead to the very first galaxies long before ours existed.
The Dark Ages wouldn't be so dark, anymore. But we'll need a giant telescope. In the coming decades, it could be FarView.
"It's the ultimate cosmology telescope," Burns said.
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Cosmology & The Universe
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President Joe Biden on Monday will reveal the first image from NASA’s new space telescope — the deepest view of the cosmos ever captured.The first image from the $10 billion James Webb Space Telescope is going to show the farthest humanity has ever seen in both time and distance, closer to the dawn of the universe and the edge of the cosmos. That image will be followed Tuesday by the release of four more galactic beauty shots from the telescope’s initial outward gazes.NASA said Biden will show a “deep field" image. That shot is likely to be be filled with lots of stars, with massive galaxies in the foreground distorting the light of the objects behind, telescoping them and making faint and extremely distant galaxies visible. Part of the image will be of light from not too long after the Big Bang.The images to be released Tuesday include a view of a giant gaseous planet outside our solar system, two images of a nebula where stars are born and die in spectacular beauty and an update of a classic image of five tightly clustered galaxies that dance around each other.The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.The plan is to use the telescope to peer back so far that scientists will get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.Webb is considered the successor to the highly successful, but aging Hubble Space Telescope. Hubble has stared as far back as 13.4 billion years. It found the light wave signature of an extremely bright galaxy in 2016.Thomas Zurbuchen, NASA’s science mission chief said, with the new telescope, the cosmos is “giving up secrets that had been there for many, many decades, centuries, millennia.”“It’s not an image. It’s a new world view that you’re going to see,” he said during a recent media briefing.Zurbuchen said when he saw the images he got emotional and so did his colleagues: “It’s really hard to not look at the universe in new light and not just have a moment that is deeply personal.”NASA is collaborating on Webb with the European and Canadian space agencies.___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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Cosmology & The Universe
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Scientists using the H.E.S.S. observatory in Namibia have detected the highest energy gamma rays ever from a dead star called a pulsar. The energy of these gamma rays clocked in at 20 tera-electronvolts, or about ten trillion times the energy of visible light. This observation is hard to reconcile with the theory of the production of such pulsed gamma rays, as the international team reports in the journal Nature Astronomy.
Pulsars are the left-over corpses of stars that spectacularly exploded in a supernova. The explosions leave behind a tiny, dead star with a diameter of just some 20 kilometres, rotating extremely fast and endowed with an enormous magnetic field. "These dead stars are almost entirely made up of neutrons and are incredibly dense: a teaspoon of their material has a mass of more than five billion tonnes, or about 900 times the mass of the Great Pyramid of Giza," explains H.E.S.S. scientist Emma de Oña Wilhelmi, a co-author of the publication working at DESY.
Pulsars emit rotating beams of electromagnetic radiation, somewhat like cosmic lighthouses. If their beam sweeps across our solar system, we see flashes of radiation at regular time intervals. These flashes, also called pulses of radiation, can be searched for in different energy bands of the electromagnetic spectrum. Scientists think that the source of this radiation are fast electrons produced and accelerated in the pulsar's magnetosphere, while traveling towards its periphery. The magnetosphere is made up of plasma and electromagnetic fields that surround and co-rotate with the star. "On their outward journey, the electrons acquire energy and release it in the form of the observed radiation beams," says Bronek Rudak from the Nicolaus Copernicus Astronomical Center (CAMK PAN) in Poland, also a co-author.
The Vela pulsar, located in the Southern sky in the constellation Vela (sail of the ship), is the brightest pulsar in the radio band of the electromagnetic spectrum and the brightest persistent source of cosmic gamma rays in the giga-electronvolts (GeV) range. It rotates about eleven times per second. However, above a few GeV, its radiation ends abruptly, presumably because the electrons reach the end of the pulsar's magnetosphere and escape from it.
But this is not the end of the story: using deep observations with H.E.S.S., a new radiation component at even higher energies has now been discovered, with energies of up to tens of tera-electronvolts (TeV). "That is about 200 times more energetic than all radiation ever detected before from this object," says co-author Christo Venter from the North-West University in South Africa. This very high-energy component appears at the same phase intervals as the one observed in the GeV range. However, to attain these energies, the electrons might have to travel even farther than the magnetosphere, yet the rotational emission pattern needs to remain intact.
"This result challenges our previous knowledge of pulsars and requires a rethinking of how these natural accelerators work," says Arache Djannati-Atai from the Astroparticle & Cosmology (APC) laboratory in France, who led the research. "The traditional scheme according to which particles are accelerated along magnetic field lines within or slightly outside the magnetosphere cannot sufficiently explain our observations. Perhaps we are witnessing the acceleration of particles through the so-called magnetic reconnection process beyond the light cylinder, which still somehow preserves the rotational pattern? But even this scenario faces difficulties to explain how such extreme radiation is produced."
Whatever the explanation, next to its other superlatives, the Vela pulsar now officially holds the record as the pulsar with the highest-energy gamma rays discovered to date. "This discovery opens a new observation window for detection of other pulsars in the tens of teraelectronvolt range with current and upcoming more sensitive gamma-ray telescopes, hence paving the way for a better understanding of the extreme acceleration processes in highly magnetised astrophysical objects," says Djannati-Atai.
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Cosmology & The Universe
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Never-before-seen details of an area of space where three galaxies are merging have been revealed in a mesmerising new view of the cosmos.
The fascinating picture is the latest deep field image taken by NASA's new super space telescope, James Webb.
It captures a region known as Pandora's Cluster, where several already massive galaxies are coming together to form a megacluster that is so big its gravity distorts space time around it.
'The ancient myth of Pandora is about human curiosity and discoveries that delineate the past from the future, which I think is a fitting connection to the new realms of the universe Webb is opening up, including this deep-field image of Pandora's Cluster,' said astronomer Rachel Bezanson, of the University of Pittsburgh.
'When the images of Pandora's Cluster first came in from Webb, we were honestly a little star struck.
'There was so much detail in the foreground cluster and so many distant lensed galaxies, I found myself getting lost in the image. Webb exceeded our expectations.'
The new view of Pandora's Cluster stitches four Webb snapshots together into one panoramic image, displaying roughly 50,000 sources of near-infrared light.
It works like a magnifying glass because it uses the combined mass of the galaxy clusters to create a powerful gravitational lens — a natural magnification effect of gravity.
This method has the potential to open up a new frontier in the study of cosmology and galaxy evolution, astronomers say, because it could allow many more distant galaxies in the early universe to be observed.
Natural magnification is one thing, but how distant galaxies appear is also affected by so-called gravitational lensing.
This is a phenomenon caused by an object's influence on the space-time around it, causing far away galaxies to look very different to those in the foreground.
Massive objects like galaxy clusters warp and distort space-time so much that light from these distant objects ends up being deflected or bent, creating weird shapes or bizarre optical illusions.
For example, to the lower right in the new Webb image there are hundreds of distant lensed galaxies which appear like faint arced lines.
Zooming in on the region reveals more and more of them.
'Pandora's Cluster, as imaged by Webb, shows us a stronger, wider, deeper, better lens than we have ever seen before,' said astronomer Ivo Labbe, of the Swinburne University of Technology in Melbourne.
'My first reaction to the image was that it was so beautiful, it looked like a galaxy formation simulation.
'We had to remind ourselves that this was real data, and we are working in a new era of astronomy now.'
The Pandora megacluster, which is the product of violent and simultaneous collisions of galaxies over 350 million years, was first spotted by Hubble in 2011.
It is of huge interest to astronomers because when massive clusters of galaxies crash together in such a way, the resulting mess is a treasure trove of information.
Webb scientists used the telescope's Near-Infrared Camera (NIRCam) to capture the cluster with exposures lasting 4-6 hours, for a total of about 30 hours of observing time.
They now plan to go through the imaging data with a fine tooth comb, before selecting galaxies for follow-up observation with Webb's Near-Infrared Spectrograph (NIRSpec).
This will provide precise distance measurements and detailed information about the lensed galaxies' compositions, which experts hope will prove new insights into the early era of galaxy assembly and evolution.
They plan to reveal this data in the summer.
'This is just the beginning of all the amazing Webb science to come,' said Gabriel Brammer, of the Niels Bohr Institute's Cosmic Dawn Center at the University of Copenhagen.
Webb was launched from Guiana Space Centre on Christmas Day 2021 with the aim of looking back in time to the dawn of the universe.
Astronomers hope the $10 billion (£7.4 billion) observatory will be able to reveal what happened just a couple of hundred million years after the Big Bang.
The observatory is set to spend more than a decade at an area of balanced gravity between the sun and Earth called L2.
While there, it will explore the universe in the infrared spectrum so that it can gaze through clouds of gas and dust where stars are being born.
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Cosmology & The Universe
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Astronomers use dead stars to measure gravitational waves produced by ancient black holes
An international team of astronomers has detected a faint signal of gravitational waves reverberating through the universe. By using dead stars as a giant network of gravitational wave detectors, the collaboration—called NANOGrav—was able to measure a low-frequency hum from a chorus of ripples of spacetime.
Though members of the team behind this new discovery aren't yet certain, they strongly suspect that the background hum of gravitational waves they measured was caused by countless ancient merging events of supermassive black holes.
Using dead stars for cosmology
Gravitational waves are ripples in spacetime caused by massive accelerating objects. Albert Einstein predicted their existence in his general theory of relativity, in which he hypothesized that when a gravitational wave passes through space, it makes the space shrink then expand periodically.
Researchers first detected direct evidence of gravitational waves in 2015, when the Laser Interferometer Gravitational-Wave Observatory, known as LIGO, picked up a signal from a pair of merging black holes that had traveled 1.3 billion light-years to reach Earth.
The NANOGrav collaboration is also trying to detect spacetime ripples, but on an interstellar scale. The team used pulsars, rapidly spinning dead stars that emit a beam of radio emissions. Pulsars are functionally similar to a lighthouse—as they spin, their beams can sweep across the Earth at regular intervals.
The NANOGrav team used pulsars that rotate incredibly fast—up to 1,000 times per second—and these pulses can be timed like the ticking of an extremely accurate cosmic clock. As gravitational waves sweep past a pulsar at the speed of light, the waves will very slightly expand and contract the distance between the pulsar and the Earth, ever so slightly changing the time between the ticks.
Pulsars are such accurate clocks that it is possible to measure their ticking with an accuracy to within 100 nanoseconds. That lets astronomers calculate the distance between a pulsar and Earth to within 100 feet (30 meters). Gravitational waves change the distance between these pulsars and Earth by tens of miles, making pulsars easily sensitive enough to detect this effect.
Finding a hum within cacophony
The first thing the NANOGrav team had to do was control for the noise in its cosmic gravitational wave detector. This included noise in the radio receivers it used and subtle astrophysics that affect the behavior of pulsars. Even accounting for these effects, the team's approach was not sensitive enough to detect gravitational waves from individual supermassive black hole binaries. However, it had enough sensitivity to detect the sum of all the massive black hole mergers that have occurred anywhere in the universe since the Big Bang—as many as a million overlapping signals.
In a musical analogy, it is like standing in a busy downtown and hearing the faint sound of a symphony somewhere in the distance. You can't pick out a single instrument because of the noise of the cars and the people around you, but you can hear the hum of a hundred instruments. The team had to tease out the signature of this gravitational wave "background" from other competing signals.
The team was able to detect this symphony by measuring a network of 67 different pulsars for 15 years. If some disruption in the ticking of one pulsar was due to gravitational waves from the distant universe, all the pulsars the team was watching would be affected in a similar way. On June 28, 2023, the team published four papers describing its project and the evidence it found of the gravitational wave background.
The hum the NANOGrav collaboration found is produced from the merging of black holes that are billions of times more massive than the sun. These black holes spin around one another very slowly and produce gravitational waves with frequencies of one-billionth of a hertz. That means the spacetime ripples have an oscillation every few decades. This slow oscillation of the wave is the reason the team needed to rely on the incredibly accurate timekeeping of pulsars.
These gravitational waves are different from the waves LIGO can detect. LIGO's signals are produced when two black holes 10 to 100 times the mass of the sun merge into one rapidly spinning object, creating gravitational waves that oscillate hundreds of times per second.
If you think of black holes as a tuning fork, the smaller the event, the faster the tuning fork vibrates and the higher the pitch. LIGO detects gravitational waves that "ring" in the audible range. The black hole mergers the NANOGrav team has found "ring" with a frequency billions of times too low to hear.
Giant black holes in the early universe
Astronomers have long been interested in studying how stars and galaxies first emerged in the aftermath of the Big Bang. This new finding from the NANOGrav team is like adding another color—gravitational waves—to the picture of the early universe that is just starting to emerge, in large part thanks to the James Webb Space Telescope.
A major scientific goal of the James Webb Space Telescope is to help researchers study how the first stars and galaxies formed after the Big Bang. To do this, James Webb was designed to detect the faint light from incredibly distant stars and galaxies. The farther away an object is, the longer it takes the light to get to Earth, so James Webb is effectively a time machine that can peer back over 13.5 billion years to see light from the first stars and galaxies in the universe.
It has been very successful in the quest, having found hundreds of galaxies that flooded the universe with light in the first 700 million years after the big bang. The telescope has also detected the oldest black hole in the universe, located at the center of a galaxy that formed just 500 million years after the Big Bang.
These findings are challenging existing theories of the evolution of the universe.
It takes a long time to grow a massive galaxy. Astronomers know that supermassive black holes lie at the center of every galaxy and have mass proportional to their host galaxies. So these ancient galaxies almost certainly have the correspondingly massive black hole in their centers.
The problem is that the objects James Webb has been finding are far bigger than current theory says they should be.
These new results from the NANOGrav team emerged from astronomers' first opportunity to listen to the gravitational waves of the ancient universe. The findings, while tantalizing, aren't quite strong enough to claim a definitive discovery. That will likely change, as the team has expanded its pulsar network to include 115 pulsars and should get results from this next survey around 2025. As James Webb and other research challenges existing theories of how galaxies evolved, the ability to study the era after the Big Bang using gravitational waves could be an invaluable tool.
Provided by The Conversation
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Cosmology & The Universe
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NASA’s $10 billion telescope peers deeper into space than ever, revealing previously undetectable details in the cosmos. The Carina Nebula, as captured by the James Webb Space Telescope. Space Telescope Science Institute / NASA, ESA, CSA, STScIJuly 12, 2022, 9:17 PM UTCThe first images from the James Webb Space Telescope are just a preview of the impressive capabilities of NASA’s $10-billion, next-generation observatory. Billed as the successor to the iconic Hubble Space Telescope, which launched into orbit in 1990, Webb was designed to peer deeper into space than ever before, with powerful instruments that can capture previously undetectable details in the cosmos. Here’s how the Webb telescope stacks up to its famous predecessor.CARINA NEBULAThe Carina Nebula is an active star-forming region located roughly 7,600 light-years away in the constellation Carina. Hubble’s view of the stellar nursery was already stunning, but Webb’s infrared cameras are able to pierce through cosmic dust, revealing previously invisible areas where new stars are being born.SOUTHERN RING NEBULANASA officials likened the Southern Ring Nebula, an expanding shell of gas surrounding a star in its final throes, to the last “performance” of a dying star. The Webb telescope captured features of the Southern Ring Nebula in exquisite new detail, including rings of gas and dust expelled in all directions by the dimmer of two stars at its center.STEPHAN’S QUINTETBoth Hubble and Webb snapped images of a distant group of five galaxies known as Stephan’s Quintet. This band of galaxies is located nearly 300 million light-years away in the constellation Pegasus. Webb’s mosaic reveals some never-before-seen details, including bundles of young stars, active starburst regions and huge shock waves as one of the galaxies smashes through the cluster.SMACS 0723Among the Webb telescope’s first images was a spectacular view of a galaxy cluster known as SMACS 0723. Thousands of bright galaxies can be seen speckled across a small patch of sky, including extremely distant celestial objects from the early days of the universe. By comparing Hubble and Webb’s infrared images of SMACS 0723, it’s possible to see how the Webb telescope will be able to peer deeper into the universe than ever before, bringing some of the faintest objects in the cosmos into sharp, new focus.Denise Chow is a reporter for NBC News Science focused on general science and climate change.Jiachuan Wu is a national interactive journalist for NBC News Digital.
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Cosmology & The Universe
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November 18, 2022• Physics 15, 180Spectra from quasars suggest that intergalactic gas may have been heated by a form of dark matter called dark photons. K. G. Lee/Max Planck Institute for Astronomy and C. Stark/UC Berkeley Cloudy forecast. Light from distant quasars travels through the Universe toward Earth and is imprinted with the absorption signatures from hydrogen gas it encounters along the way. These absorption lines suggest anomalous heating that could be explained by dark matter.Cloudy forecast. Light from distant quasars travels through the Universe toward Earth and is imprinted with the absorption signatures from hydrogen gas it encounters along the way. These absorption lines suggest anomalous heating that could be explai... Show more
Dense gas clouds across the Universe absorb light from distant quasars, producing absorption lines in the quasar spectra. A new study shows that the larger-than-predicted widths of these lines from nearby gas clouds could result from a form of dark matter called dark photons [1]. These particles could heat the clouds, leading to a widening of the absorption lines. Other explanations of the broadening—based on more conventional heating sources—have been proposed, but if the dark-photon mechanism is at work, it might also cause heating in low-density clouds from earlier epochs of the Universe. Researchers are already planning to test this prediction.
When viewing the spectrum of a distant quasar, astronomers often observe absorption lines coming from the intervening clouds of gas. The most prominent absorption line is the Lyman-alpha line of hydrogen. Indeed, some quasar spectra have a “forest” of Lyman-alpha lines, with each coming from a cloud at a different distance from our Galaxy (or different epochs). By examining the widths, depths, and other details of the line shapes, researchers can extract information about the density, the temperature, and other features of the clouds. This information can be compared with the results of cosmological simulations that try to reproduce the clumping of matter into galaxies and other large-scale structures.
Comparisons between forest data and simulations have generally shown good agreement, but a discrepancy appears for relatively nearby gas clouds. Observations show that these so-called low redshift clouds produce broader absorption lines than predicted in simulations. “This may be an indication of a particular candidate of dark matter, which is called a dark photon,” says Andrea Caputo from CERN in Switzerland. “This dark photon can inject some energy and heat up the gas, [which makes] the lines a bit broader, in better agreement with the data.” P. Gaikwad/Kavli Institute for Cosmology, Cambridge Seeing the trees. The light from a distant quasar passes through regions of dense gas (purple) in the intergalactic medium. The gas absorbs light at specific frequencies, leading to a “forest” of absorption lines in the quasar spectra (green).
To explore how this energy injection might work, Caputo and his colleagues ran cosmic simulations with dark photons. The theory of dark photons assumes that the particles can spontaneously turn into normal photons with some small probability, but this conversion can be enhanced when dark photons enter an ionized gas satisfying a resonance condition. The condition amounts to the gas having a certain density, which is determined by the dark photon’s mass. If an intergalactic cloud has this density, then the ordinary photons generated by the resonance conversion will heat the gas.
Caputo stresses that a cloud’s density changes over time, so the resonance condition will be met for only a certain period of time. This time-dependent heating is unique to dark photons, as other proposed types of heat-producing dark matter, such as those that decay or annihilate, are expected to be “switched on” all the time. However, models of continuous heating are constrained by other cosmological observations, such as the cosmic microwave background, which don’t show signs of unexplained heating.
The simulations of Caputo and colleagues suggest that dark photons with an extremely small mass of around 10−14 eV/c2 (roughly 1019 times smaller than the electron mass) would resonantly convert to photons in low-redshift Lyman-alpha clouds. This conversion would inject between 5 and 7 eV of energy per hydrogen atom into the gas, enough to account for the observations.
In addition, the team predicts that dark-photon heating might have occurred at higher redshift, but only in so-called under-dense clouds, which in the past had higher densities—potentially high enough to meet the resonance condition. The team is currently running simulations to see if this predicted heating would agree with observations of high-redshift clouds.
However, exotic dark matter physics models may not be required to explain the Lyman-alpha data, says astrophysicist Blakesley Burkhart from Rutgers University in New Jersey. She says dark photons are an exciting possibility, but researchers have not yet ruled out more conventional heating sources, such as supermassive black hole jets at the centers of galaxies, known as active galactic nuclei.
Sam Witte—a cosmologist from the University of Amsterdam—agrees that the dark photon explanation is more speculative than other scenarios, but he thinks the researchers have made a convincing case with testable predictions. “Should future studies exclude conventional astrophysical explanations, it is compelling to consider the possibility that we might be observing the first nongravitational imprint of dark matter,” he says.–Michael SchirberMichael Schirber is a Corresponding Editor for Physics Magazine based in Lyon, France.ReferencesJ. S. Bolton et al., “Comparison of low-redshift Lyman-𝛼 forest observations to hydrodynamical simulations with dark photon dark matter,” Phys. Rev. Lett. 129, 211102 (2022).Subject AreasRelated Articles More Articles
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Cosmology & The Universe
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By Robert Scherrer - Professor and Chair of Physics and Astronomy, Vanderbilt UniversityThe nature of dark energy is one of the most important unsolved problems in all of science. But what, exactly, is dark energy, and why do we even believe that it exists? Step back a minute and consider a more familiar experience: what happens when you toss a ball straight up into the air? It gradually slows down as gravity tugs on it, finally stopping in mid-air and falling back to the ground. Of course, if you threw the ball hard enough (about 25,000 miles per hour) it would actually escape from the Earth entirely and shoot into space, never to return. But even in that case, gravity would continue to pull feebly on the ball, slowing its speed as it escaped the clutches of the Earth.But now imagine something completely different. Suppose that you tossed a ball into the air, and instead of being attracted back to the ground, the ball was repelled by the Earth and blasted faster and faster into the sky. This would be an astonishing event, but it’s exactly what astronomers have observed happening to the entire universe! Scientists have known for almost a century that the universe is expanding, with all of the galaxies flying apart from each other. And until recently, scientists believed that there were only two possible options for the universe in the future. It could expand forever (like the ball that you tossed upward at 25,000 miles an hour), but with the expansion slowing down as gravity pulled all of the galaxies toward each other. Or gravity might win out in the end and bring the expansion of the universe to a halt, finally collapsing it back down in a “big crunch,” just like your ball plunging back to the ground.So imagine scientists’ surprise when two different teams of astronomers discovered, back in 1998, that neither of these behaviors was correct. These astronomers were measuring how fast the universe was expanding when it was much younger than today. But how could they do this without building a time machine?Luckily, a telescope is a time machine. When you look up at the stars at night, you aren’t seeing what they look like today – you’re seeing light that left the stars a long time ago – often many hundreds of years. By looking at distant supernovae, which are tremendously bright exploding stars, astronomers can look back hundreds of millions of years. They can then measure the expansion rate back then by comparing the distance to these far-off supernovae with the speed at which they are flying away from us. And by comparing how fast the universe was expanding hundreds of millions of years ago to its rate of expansion today, these astronomers discovered that the expansion is actually speeding up instead of slowing down as everyone had expected. Instead of pulling the galaxies in the universe together, gravity seems to be driving them apart. But how can gravity be repulsive, when our everyday experience shows that it’s attractive? Einstein’s theory of gravity in fact predicts that gravity can repel as well as attract, but only under very special circumstances.Repulsive gravity requires a new form of energy, dubbed “dark energy,” with very weird properties. Unlike ordinary matter, dark energy hasnegative pressure, and it’s this negative pressure that makes gravity repulsive. (For ordinary matter, gravity is always attractive). Dark energy appears to be smoothly smeared out through the entire universe, and it interacts with ordinary matter only through the action of gravity, making it nearly impossible to test in the laboratory.The simplest form of dark energy goes by two different names: a cosmological constant or vacuum energy. Vacuum energy has another strange property. Imagine a box that expands as the universe expands. The amount of matter in the box stays the same as the box expands, but the volume of the box goes up, so the density of matter in the box goes down. In fact, the density of everything goes down as the universe expands. Except for vacuum energy - its density stays exactly the same. (Yes, that’s as bizarre as it sounds. It’s like stretching a string of taffy and discovering that it never gets any thinner).
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Cosmology & The Universe
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Credit: NASA/CXC/U.Texas Astrophysicists have performed a powerful new analysis that places the most precise limits yet on the composition and evolution of the universe. With this analysis, dubbed Pantheon+, cosmologists find themselves at a crossroads. Pantheon+ convincingly finds that the cosmos is composed of about two-thirds dark energy and one-third matter—mostly in the form of dark matter—and is expanding at an accelerating pace over the last several billion years. However, Pantheon+ also cements a major disagreement over the pace of that expansion that has yet to be solved.
By putting prevailing modern cosmological theories, known as the Standard Model of Cosmology, on even firmer evidentiary and statistical footing, Pantheon+ further closes the door on alternative frameworks accounting for dark energy and dark matter. Both are bedrocks of the Standard Model of Cosmology but have yet to be directly detected and rank among the model's biggest mysteries. Following through on the results of Pantheon+, researchers can now pursue more precise observational tests and hone explanations for the ostensible cosmos.
"With these Pantheon+ results, we are able to put the most precise constraints on the dynamics and history of the universe to date," says Dillon Brout, an Einstein Fellow at the Center for Astrophysics | Harvard & Smithsonian. "We've combed over the data and can now say with more confidence than ever before how the universe has evolved over the eons and that the current best theories for dark energy and dark matter hold strong."
Brout is the lead author of a series of papers describing the new Pantheon+ analysis, published jointly today in a special issue of The Astrophysical Journal.
Pantheon+ is based on the largest dataset of its kind, comprising more than 1,500 stellar explosions called Type Ia supernovae. These bright blasts occur when white dwarf stars—remnants of stars like our Sun—accumulate too much mass and undergo a runaway thermonuclear reaction. Because Type Ia supernovae outshine entire galaxies, the stellar detonations can be glimpsed at distances exceeding 10 billion light years, or back through about three-quarters of the universe's total age. Given that the supernovae blaze with nearly uniform intrinsic brightnesses, scientists can use the explosions' apparent brightness, which diminishes with distance, along with redshift measurements as markers of time and space. That information, in turn, reveals how fast the universe expands during different epochs, which is then used to test theories of the fundamental components of the universe.
The breakthrough discovery in 1998 of the universe's accelerating growth was thanks to a study of Type Ia supernovae in this manner. Scientists attribute the expansion to an invisible energy, therefore monikered dark energy, inherent to the fabric of the universe itself. Subsequent decades of work have continued to compile ever-larger datasets, revealing supernovae across an even wider range of space and time, and Pantheon+ has now brought them together into the most statistically robust analysis to date.
"In many ways, this latest Pantheon+ analysis is a culmination of more than two decades' worth of diligent efforts by observers and theorists worldwide in deciphering the essence of the cosmos," says Adam Riess, one of the winners of the 2011 Nobel Prize in Physics for the discovery of the accelerating expansion of the universe and the Bloomberg Distinguished Professor at Johns Hopkins University (JHU) and the Space Telescope Science Institute in Baltimore, Maryland. Riess is also an alum of Harvard University, holding a Ph.D. in astrophysics.
Brout's own career in cosmology traces back to his undergraduate years at JHU, where he was taught and advised by Riess. There Brout worked with then-Ph.D.-student and Riess-advisee Dan Scolnic, who is now an assistant professor of physics at Duke University and another co-author on the new series of papers.
Several years ago, Scolnic developed the original Pantheon analysis of approximately 1,000 supernovae.
Now, Brout and Scolnic and their new Pantheon+ team have added some 50 percent more supernovae data points in Pantheon+, coupled with improvements in analysis techniques and addressing potential sources of error, which ultimately has yielded twice the precision of the original Pantheon.
"This leap in both the dataset quality and in our understanding of the physics that underpin it would not have been possible without a stellar team of students and collaborators working diligently to improve every facet of the analysis," says Brout.
Taking the data as a whole, the new analysis holds that 66.2 percent of the universe manifests as dark energy, with the remaining 33.8 percent being a combination of dark matter and matter. To arrive at even more comprehensive understanding of the constituent components of the universe at different epochs, Brout and colleagues combined Pantheon+ with other strongly evidenced, independent and complementary measures of the large-scale structure of the universe and with measurements from the earliest light in the universe, the cosmic microwave background.
Another key Pantheon+ result relates to one of the paramount goals of modern cosmology: nailing down the current expansion rate of the universe, known as the Hubble constant. Pooling the Pantheon+ sample with data from the SH0ES (Supernova H0 for the Equation of State) collaboration, led by Riess, results in the most stringent local measurement of the current expansion rate of the universe.
Pantheon+ and SH0ES together find a Hubble constant of 73.4 kilometers per second per megaparsec with only 1.3% uncertainty. Stated another way, for every megaparsec, or 3.26 million light years, the analysis estimates that in the nearby universe, space itself is expanding at more than 160,000 miles per hour.
However, observations from an entirely different epoch of the universe's history predict a different story. Measurements of the universe's earliest light, the cosmic microwave background, when combined with the current Standard Model of Cosmology, consistently peg the Hubble constant at a rate that is significantly less than observations taken via Type Ia supernovae and other astrophysical markers. This sizable discrepancy between the two methodologies has been termed the Hubble tension.
The new Pantheon+ and SH0ES datasets heighten this Hubble tension. In fact, the tension has now passed the important 5-sigma threshold (about one-in-a-million odds of arising due to random chance) that physicists use to distinguish between possible statistical flukes and something that must accordingly be understood. Reaching this new statistical level highlights the challenge for both theorists and astrophysicists to try and explain the Hubble constant discrepancy.
"We thought it would be possible to find clues to a novel solution to these problems in our dataset, but instead we're finding that our data rules out many of these options and that the profound discrepancies remain as stubborn as ever," says Brout.
The Pantheon+ results could help point to where the solution to the Hubble tension lies. "Many recent theories have begun pointing to exotic new physics in the very early universe, however such unverified theories must withstand the scientific process and the Hubble tension continues to be a major challenge," says Brout.
Overall, Pantheon+ offers scientists a comprehensive lookback through much of cosmic history. The earliest, most distant supernovae in the dataset gleam forth from 10.7 billion light years away, meaning from when the universe was roughly a quarter of its current age. In that earlier era, dark matter and its associated gravity held the universe's expansion rate in check. Such state of affairs changed dramatically over the next several billion years as the influence of dark energy overwhelmed that of dark matter. Dark energy has since flung the contents of the cosmos ever-farther apart and at an ever-increasing rate.
"With this combined Pantheon+ dataset, we get a precise view of the universe from the time when it was dominated by dark matter to when the universe became dominated by dark energy," says Brout. "This dataset is a unique opportunity to see dark energy turn on and drive the evolution of the cosmos on the grandest scales up through present time."
Studying this changeover now with even stronger statistical evidence will hopefully lead to new insights into dark energy's enigmatic nature.
"Pantheon+ is giving us our best chance to date of constraining dark energy, its origins, and its evolution," says Brout. More information: Dillon Brout et al, The Pantheon+ Analysis: Cosmological Constraints, The Astrophysical Journal (2022). DOI: 10.3847/1538-4357/ac8e04 Citation: The most precise accounting yet of dark energy and dark matter (2022, October 19) retrieved 20 October 2022 from https://phys.org/news/2022-10-precise-accounting-dark-energy.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Cosmology & The Universe
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To those of us who aren't astronomers, it's hard to see what the big deal is. An image of points of light, coloured blobs and spirals of galaxies of the kind we're familiar with.
But in fact, this image is something very different indeed.Compared to the previous picture of this region of space captured by the Hubble Space Telescope, the image from the James Webb Space Telescope (JWST) is jam-packed with galaxies. Twitter Due to your consent preferences, you’re not able to view this. Open Privacy Options These are new objects, likely never seen before through any telescope. This new view of the universe is possible because the Webb is huge - with a mirror more than twice the size of the Hubble.
But as well as that, Webb sees infrared light. More on Nasa The deepest view of the universe ever captured: NASA releases first image from new space telescope NASA criticises Russia for using space station to stage propaganda photographs NASA prepares to power-down Voyager spacecraft after more than 44 years The universe has been expanding for 13.8 billion years, meaning the light from the first stars and galaxies has been "stretched" from shorter visible wavelengths to longer infrared ones.This is what allows Webb to see the universe in unprecedented new detail.That detail may be pretty to us, but it's a rich seam of new data for astronomers, astrophysicists and cosmologists.But, this image excites those experts for another reason - it's looking further back in space and time than ever before. Image: First image from James Webb Space Telescope It's not just a picture of any random bit of space. At its centre, you can see the hint of a spherical-like object traced out by curved and distorted galaxies.This is a gravitational lens, a natural, if mind-boggling, feature of the universe predicted by Einstein's theory of general relativity.A huge cluster of galaxies in the centre of the image is so massive that is distorting space, bending the light that travels through it and magnifying the objects behind it. Please use Chrome browser for a more accessible video player Watch timelapse of telescope build Hiding in this image, brought into crude focus by this gravitational lens, are quite probably the oldest galaxies we've ever seen.Their light, when analysed carefully by other instruments on JWST, will give new insights into the earliest time in the universe just a few hundred million years after the Big Bang.It's an image that's a window into a new way of understanding how the universe we live in came to be.And it's just the first of millions that this new telescope will produce over its 20-year lifetime.
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Cosmology & The Universe
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Scientists have determined the possible effects of a neutron star collision happening near Earth, finding that these so-called kilonovas could be real killers that would doom humanity. But don't worry, the collision would have to be really close to wreak havoc on our world. Nonetheless, here's what would probably go down.
"We found that if a neutron star merger were to occur within around 36 light-years of Earth, the resulting radiation could cause an extinction-level event," Haille Perkins, team leader and a scientist at the University of Illinois Urbana-Champaign, told Space.com.
Neutron star clashes that create bursts of light, called kilonovas, are considered the most violent and powerful events in the known universe. This is perhaps unsurprising, given that neutron stars are the collapsed remnants of dead stars and are made of matter so dense a teaspoon of one brought to Earth would weigh about 10 million tons. That's equivalent to 350 Statues of Liberty balanced on a spoon.
Not only do these dead star mergers create blasts of gamma rays and showers of charged particles moving at near-light speeds , known as cosmic rays, but they also generate the only environments we know of turbulent enough to forge elements heavier than lead, like gold and platinum. These elements can't even be created at the incredible ultra-high temperatures and pressures found in the hearts of massive stars.
Further, neutron star mergers set the very fabric of space "ringing" with ripples called gravitational waves, which can be detected here on Earth — even after traveling across billions of light years.
"Neutron stars can exist in binary systems, and when they merge, they produce a rare but spectacular event," Perkins said.
The team's research was based on observations of the neutron star merger behind gravitational wave signal GW 170817, picked up by Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2017, and gamma-ray burst GRB 170817A.
Occurring about 130 million light-years away, this is the only neutron star merger thus far seen in electromagnetic radiation and heard in gravitational waves, making it a natural choice for investigating these powerful events.
A killer-nova?
Neutron star merger gamma rays are arguably the most obviously threatening aspect of these events. That's because this type of radiation carries enough energy to strip electrons from atoms, a process called ionization. And these ionizing blasts of radiation could easily destroy the Earth's ozone layer, resulting in our planet receiving lethal doses of ultraviolet radiation from the sun.
Perkins and her colleagues determined gamma rays coming from neutron star mergers — in twin narrow jets from either side of the merger — would pretty much roast any living thing that falls directly in their path for a distance of about 297 light-years. Fortunately, however, that effect has an extremely narrow range. In other words, it really would take a "direct hit" from a jet to give rise to such dramatic effects. But, there's another issue.
These jets are cocooned with gamma radiation in general, which would also affect the ozone layer of Earth if our planet was in their wider path — within about 13 light-years of them. This "off-axis" gamma-ray cocoon's ozone damage would also take 4 years to recover from. All in all, the gamma-ray cocoon strike would leave the Earth's surface exposed to harmful ultraviolet light for nearly half a decade.
Though gamma-ray effects of neutron star mergers are relatively short-lived, there is also another form of ionizing radiation these emissions give rise to, which is less energetic but longer-lasting.
When the jets of gamma rays hit gas and dust around stars, called the interstellar medium, this creates powerful X-ray emissions called the X-ray afterglow. Such X-ray emission lives longer than gamma-ray emissions and could also ionize the ozone layer, the team says. This, therefore, is arguably more lethal. Earth would need to be quite close to this afterglow before we have to be concerned about our fate, however — within a distance of 16.3 light years to be exact.
And we haven't gotten to the worst part yet.
The most threatening effect of the neutron star smash-up that the team discovered comes from those highly energetic charged particles, or cosmic rays, that spread away from the event's epicenter in the form of an expanding bubble. Were these cosmic rays to strike Earth, they would strip the ozone layer and leave the planet vulnerable to being blasted by ultraviolet rays for a period of thousands of years.
This would qualify as an extinction-level event, and Earth could be affected even if our planet were around 36 light-years away.
"The specific distance of safety and component that is most dangerous is uncertain as many of the effects depend on properties like viewing angle to the event, the energy of the blast, the mass of material ejected, and more," Perkins continued. "With the combination of parameters we select, it seems that the cosmic rays will be the most threatening."
Again, don't panic just yet!
Before lamenting that the end is nigh, it is worth weighing the apocalyptic picture painted by the impact of neutron star mergers against some other factors surrounding these events.
"Neutron star mergers are extremely rare but quite powerful, and this, combined with the relatively small range of lethality, means an extinction caused by a binary neutron star merger should not be a concern of the people on Earth," Perkins assured.
To get a picture of this rarity, throughout the 100 billion stars in the Milky Way, scientists have thus far only found one potential kilonova progenitor system, CPD-29 2176, which is located about 11,400 light-years from Earth.
"There are several other more common events like solar flares, asteroid impacts, and supernova explosions that have a better chance of being harmful," Perkins continued.
She added that some of these other events have been associated with mass extinction events on Earth already, with the most striking example of this being the impact of a massive asteroid that wiped out the non-avian dinosaurs and three-quarters of life on Earth around 66 million years ago in the Cretaceous-Tertiary extinction event.
Where this research does have important connotations is in the search for life elsewhere in the universe, as it certainly gives us an idea of the systems that aren't likely to enjoy the conditions needed to support life. (Life as we know it, at least.)
"Their conclusion that kilonovas could have a similar lethality to supernovas, but are much less common, coincides with what I believe would be likely to be the case," Niels Bohr Institute Cosmic Dawn Center scientist Darach Watson, who also studies kilonovas and was not involved in this research, told Space.com. "So overall, this is likely to be more of a threat for planets in old galaxies where the star-formation has ended, not so much in the Milky Way."
As for the team behind this research, Perkins explained that the next step is to observe more of these neutron star collision events.
"Currently, we only have one confirmed detection of a kilonova from a binary neutron star merger, so any more observations will constrain the unknowns," she concluded.
The team's research is published on the open-access paper repository arXiv.
Originally posted on Space.com.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI The latest James Webb Space Telescope image released by NASA on September 21 shows Neptune. It is the clearest view of the planet's rings in over 30 years. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/PDRS4all The inner region of the Orion Nebula as seen by the James Webb Space Telescope's NIRCam instrument. The image reveals intricate details about how stars and planetary systems are formed. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI/Webb ERO Production Team NASA released a mosaic image of the Tarantula Nebula on Tuesday, September 6. The image, which spans 340 light-years, shows tens of thousands of young stars that were previously obscured by cosmic dust. Photos: Observing the universe with the James Webb Space Telescope NASA Webb's first direct image of an exoplanet showcases it in different bands of infrared light. The planet, called HIP 65426 b, is a gas giant. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA A new image of the Phantom Galaxy, which is 32 million light-years away from Earth, combines data from the James Webb Space Telescope and the Hubble Space Telescope. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/Jupiter ERS Team NASA released an image of Jupiter on Monday, August 22, that shows the planet's famous Great Red Spot appearing white. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI The James Webb Space Telescope captured the Cartwheel galaxy, which is around 500 million light-years away, in a photo released by NASA on August 2. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI Webb's landscape-like view, called "Cosmic Cliffs," is actually the edge of a nearby, young, star-forming region called NGC 3324 in the Carina Nebula. The telescope's infrared view reveals previously invisible areas of star birth. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI The five galaxies of Stephan's Quintet can be seen here in a new light. The galaxies appear to dance with one another, showcasing how these interactions can drive galactic evolution. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI This side-by-side comparison shows observations of the Southern Ring Nebula in near-infrared light, left, and mid-infrared light, right, from NASA's Webb telescope. The Southern Ring Nebula is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star, as well as a secondary star earlier on in its evolution. Photos: Observing the universe with the James Webb Space Telescope NASA/ESA/CSA/STScI President Joe Biden released one of Webb's first images on July 11, and it's "the deepest and sharpest infrared image of the distant universe to date," according to NASA. The image shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this created Webb's first deep field view of incredibly old and distant, faint galaxies. Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. CNN — New images released Wednesday from NASA’s James Webb Space Telescope are revealing Neptune, and the planet’s hard-to-detect rings, in a fresh light. “It has been three decades since we last saw these faint, dusty rings, and this is the first time we’ve seen them in the infrared,” said Heidi Hammel, a Neptune expert and interdisciplinary scientist on the Webb project, in a news release. In addition to several crisp, narrow rings, the Webb images show Neptune’s fainter dust bands. Some of the rings haven’t been observed since NASA’s Voyager 2 got the first photographic proof of the existence of Neptune’s rings during its flyby in 1989. Dark, cold and whipped by supersonic winds, Neptune is the most distant planet in our solar system. The planet and its neighbor Uranus are known as “ice giants” because their interiors are made up of heavier elements than the gas giants Jupiter and Saturn, which are richer in hydrogen and helium. In the new images, Neptune looks white, as opposed to the typical blue appearance it has in views captured at visible wavelengths of light. This is because gaseous methane, part of the planet’s chemical makeup, doesn’t appear blue to Webb’s Near-Infrared Camera (NIRCam). Also visible in the images are methane-ice clouds – bright streaks and spots that reflect sunlight before it is absorbed by methane gas. It’s also possible to spot a bright, thin line circling the planet’s equator, which could be “a visual signature of global atmospheric circulation that powers Neptune’s winds and storms,” according to the release. Webb also captured seven of Neptune’s 14 known moons, including its largest moon, Triton, which moves around the planet at an unusual backward orbit. Astronomers think Triton was perhaps an object in the Kuiper Belt – a region of icy objects at the edge of the solar system – that fell into Neptune’s gravitational grasp. Scientists plan to use Webb to further study Triton and Neptune in the coming years. Located 30 times farther from the sun than Earth, Neptune moves through its solar orbit in the remote, dark region of the outer solar system. At that distance, the sun is so small and faint that noon on Neptune is similar to a dim twilight on Earth, the news release said. Webb is a more than 10-year mission run by NASA, the European Space Agency and the Canadian Space Agency. Compared with other telescopes, the space observatory’s massive mirror can see fainter galaxies that are farther away and has the potential to enhance scientists’ understanding of the origins of the universe. However, it’s also using its stable and precise image quality to illuminate our own solar system, with images of Mars, Jupiter and now Neptune.
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Cosmology & The Universe
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Planets and other objects in our Solar System. – Image Credit: NASA. Humanity’s understanding of what constitutes a planet has changed over time. Whereas our most notable magi and scholars once believed that the world was a flat disc (or ziggurat, or cube), they gradually learned that it was in fact spherical. And by the modern era, they came to understand that the Earth was merely one of several planets in the known Universe.And yet, our notions of what constitutes a planet are still evolving. To put it simply, our definition of planet has historically been dependent upon our frame of reference. In addition to discovering extra-solar planets that have pushed the boundaries of what we consider to be normal, astronomers have also discovered new bodies in our own backyard that have forced us to come up with new classification schemes.History of the TermTo ancient philosophers and scholars, the Solar Planets represented something entirely different than what they do today. Without the aid of telescopes, the planets looked like particularly bright stars that moved relative to the background stars. The earliest records on the motions of the known planets date back to the 2nd-millennium BCE, where Babylonian astronomers laid the groundwork for western astronomy and astrology. These include the Venus tablet of Ammisaduqa, which catalogued the motions of Venus. Meanwhile, the 7th-century BCE MUL.APIN tablets laid out the motions of the Sun, the Moon, and the then-known planets over the course of the year (Mercury, Venus, Mars, Jupiter and Saturn). The Enuma anu enlil tablets, also dated to the 7th-century BCE, were a collection of all the omens assigned to celestial phenomena and the motions of the planets.By classical antiquity, astronomers adopted a new concept of planets as bodies that orbited the Earth. Whereas some advocated a heliocentric system – such as 3rd-century BCE astronomer Aristarchus of Samos and 1st-century BCE astronomer Seleucus of Seleucia – the geocentric view of the Universe remained the most widely-accepted one. Astronomers also began creating mathematical models to predict their movements during this time.This culminated in the 2nd century CE with Ptolemy’s (Claudius Ptolemaeus) publication of the Almagest, which became the astronomical and astrological canon in Europe and the Middle East for over a thousand years. Within this system, the known planets and bodies (even the Sun) all revolved around the Earth. In the centuries that followed, Indian and Islamic astronomers would added to this system based on their observations of the heavens.By the time of the Scientific Revolution (ca. 15th – 18th centuries), the definition of planet began to change again. Thanks to Nicolaus Copernicus, Galileo Galilei, and Johannes Kepler, who proposed and advanced the heliocentric model of the Solar System, planets became defined as objects that orbited the Sun and not Earth. The invention of the telescope also led to an improved understanding of the planets, and their similarities with Earth.Between the 18th and 20th centuries, countless new objects, moons and planets were discovered. This included Ceres, Vesta, Pallas (and the Main Asteroid Belt), the planets Uranus and Neptune, and the moons of Mars and the gas giants. And then in 1930, Pluto was discovered by Clyde Tombaugh, which was designated as the 9th planet of the Solar System.Throughout this period, no formal definition of planet existed. But an accepted convention existed where a planet was used to described any “large” body that orbited the Sun. This, and the convention of a nine-planet Solar System, would remain in place until the 21st century. By this time, numerous discoveries within the Solar System and beyond would lead to demands that a formal definition be adopted.Working Group on Extrasolar PlanetsWhile astronomers have long held that other star systems would have their own system of planets, the first reported discovery of a planet outside the Solar System (aka. extrasolar planet or exoplanet) did not take place until 1992. At this time, two radio astronomers working out of the Arecibo Observatory (Aleksander Wolszczan and Dale Frail) announced the discovery of two planets orbiting the pulsar PSR 1257+12.The first confirmed discovery took place in 1995, when astronomers from the University of Geneva (Michel Mayor and Didier Queloz) announced the detection of 51 Pegasi. Between the mid-90s and the deployment of the Kepler space telescope in 2009, the majority of extrasolar planets were gas giants that were either comparable in size and mass to Jupiter or significantly larger (i.e. “Super-Jupiters”). Earlier today, NASA announced that Kepler had confirmed the existence of 1,284 new exoplanets, the most announced at any given time. – Image Credit: NASA These new discoveries led the International Astronomical Union (IAU) to create the Working Group of Extrasolar Planets (WGESP) in 1999. The stated purpose of the WGESP was to “act as a focal point for international research on extrasolar planets.” As a result of this ongoing research, and the detection of numerous extra-solar bodies, attempts were made to clarify the nomenclature.As of February 2003, the WGESP indicated that it had modified its position and adopted the following “working definition” of a planet:1) Objects with true masses below the limiting mass for thermonuclear fusion of deuterium (currently calculated to be 13 Jupiter masses for objects of solar metallicity) that orbit stars or stellar remnants are “planets” (no matter how they formed). The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in our Solar System.2) Substellar objects with true masses above the limiting mass for thermonuclear fusion of deuterium are “brown dwarfs”, no matter how they formed nor where they are located.3) Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not “planets”, but are “sub-brown dwarfs” (or whatever name is most appropriate).As of January 22nd, 2017, more than 2000 exoplanet discoveries have been confirmed, with 3,565 exoplanet candidates being detected in 2,675 planetary systems (including 602 multiple planetary systems). The number of confirmed exoplanet discoveries, by year. - Image Credit: NASA 2006 IAU ResolutionDuring the early-to-mid 2000s, numerous discoveries were made in the Kuiper Belt that also stimulated the planet debate. This began with the discovery of Sedna in 2003 by a team of astronomers (Michael Brown, Chad Trujillo and David Rabinowitz) working at the Palomar Observatory in San Diego. Ongoing observations confirmed that it was approx 1000 km in diameter, and large enough to undergo hydrostatic equilibrium.This was followed by the discovery of Eris – an even larger object (over 2000 km in diameter) – in 2005, again by a team consisting of Brown, Trujillo, and Rabinowitz. This was followed by the discovery of Makemake on the same day, and Haumea a few days later. Other discoveries made during this period include Quaoar in 2002, Orcus in 2004, and 2007 OR10 in 2007.The discovery of a several objects beyond Pluto’s orbit that were large enough to be spherical led to efforts on behalf of the IAU to adopt a formal definition of a planet. By October 2005, a group of 19 IAU members narrowed their choices to a shortlist of three characteristics. These included:A planet is any object in orbit around the Sun with a diameter greater than 2000 km. (eleven votes in favour)A planet is any object in orbit around the Sun whose shape is stable due to its own gravity. (eight votes in favour)A planet is any object in orbit around the Sun that is dominant in its immediate neighbourhood. (six votes in favour) After failing to reach a consensus, the committee decided to put these three definitions to a wider vote. This took place in August of 2006 at the 26th IAU General Assembly Meeting in Prague. On August 24th, the issue was put to a final draft vote, which resulted in the adoption of a new classification scheme designed to distinguish between planets and smaller bodies. These included:(1) A “planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.(2) A “dwarf planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and(d) is not a satellite.(3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as “Small Solar-System Bodies”.In accordance with this resolution, the IAU designated Pluto, Eris, and Ceres into the category of “dwarf planet”, while other Trans-Neptunian Objects (TNOs) were left undeclared at the time. This new classification scheme spawned a great deal of controversy and some outcries from the astronomical community, many of whom challenged the criteria as being vague and debatable in their applicability.For instance, many have challenged the idea of a planet clearing its neighborhood, citing the existence of near-Earth Objects (NEOs), Jupiter’s Trojan Asteroids, and other instances where large planets share their orbit with other objects. However, these have been countered by the argument that these large bodies do not share their orbits with smaller objects, but dominate them and carry them along in their orbits.Another sticking point was the issue of hydrostatic equilibrium, which is the point where a planet has sufficient mass that it will collapse under the force of its own gravity and become spherical. The point at which this takes place remains entirely unclear thought, and some astronomers therefore challenge it being included as a criterion.In addition, some astronomers claim that these newly-adopted criteria are only useful insofar as Solar planets are concerned. But as exoplanet research has shown, planets in other star star systems can be significantly different. In particular, the discovery of numerous “Super Jupiters” and “Super Earths” has confounded conventional notions of what is considered normal for a planetary system.In June 2008, the IAU executive committee announced the establishment of a subclass of dwarf planets in the hopes of clarifying the definitions further. Comprising the recently-discovered TNOs, they established the term “plutoids”, which would thenceforth include Pluto, Eris and any other future trans-Neptunian dwarf planets (but excluded Ceres). In time, Haumea, Makemake, and other TNOs were added to the list. Despite these efforts and changes in nomenclature, for many, the issue remains far from resolved. What’s more, the possible existence of Planet 9 in the outer Solar System has added more weight to the discussion. And as our research into exoplanets continues – and uncrewed (and even crewed) mission are made to other star systems – we can expect the debate to enter into a whole new phase!We have written many interesting articles about the planets here at Universe Today. Here’s How Many Planets are there in the Solar System?, What are the Planets of the Solar System, The Planets of our Solar System in Order of Size, Why Pluto is no Longer a Planet, Evidence Continues to Mount for Ninth Planet, and What are Extrasolar Planets?.For more information, take a look at this article from Scientific American, What is a Planet?, and the video archive from the IAU.Astronomy Cast has an episode on Pluto’s planetary identity crisis.Sources:Universe TodayNASA: Solar System Exploration – PlanetsWikipedia – Definition of PlanetIAU – 2006 General Assembly
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Cosmology & The Universe
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Black holes swallow everything—including light—which explains why we can’t see them. But we can observe their immediate surroundings and learn about them. And when they’re on a feeding binge, their surroundings become even more luminous and observable.
This increased luminosity allowed astronomers to find a black hole that was feasting on material only 800 million years after the Universe began.
Even with everything astrophysicists have learned, black holes are still mysterious. We know that the largest ones—supermassive black holes (SMBH)—reside in the centers of galaxies like the Milky Way. But the history of their formation, growth, and evolution is still shrouded in cosmic mystery.
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Astrophysicists can infer the presence of these monsters in the heart of galaxies by the effect their massive gravitational pull has on nearby stars. But a better opportunity to study them is when they’re actively feeding. An actively feeding black hole is called an active galactic nucleus (AGN,) and when an AGN is extremely luminous, it’s called a quasar. As material swirls around their accretion disks, it heats up and emits x-rays.
Scientists have struggled to locate quasars in the early Universe, but it’s an important goal in black hole research. They need to find them in order to trace their development over time. One stumbling block in their efforts is the time period correlating with redshifts greater than z=6, about 12.716 billion years ago, or about one billion years after the Big Bang.
Now a team of researchers from the Max Planck Institute for Extraterrestrial Physics (MPE) has found an extremely x-ray luminous quasar at redshift z=6.56, only about 800 million years after the Big Bang. They presented their findings in a paper published in the journal Astronomy and Astrophysics. Their paper is “X-ray emission from a rapidly accreting narrow-line Seyfert 1 galaxy at z = 6.56.” The lead author is Julien Wolf, a Ph.D. student in high-energy astrophysics at MPE.
The x-rays from this quasar, named J0921+0007, had to travel a long way through space and time to reach us. The instrument it reached was the eROSITA (extended ROentgen Survey with an Imaging Telescope Array) x-ray instrument on the Spektr-RG space observatory. eROSITA found the quasar in its Final Equatorial-Depth Survey (FEDS.) The Chandra Space Telescope also spotted it.
That survey is important because, currently, astrophysicists know of only 50 quasars with redshift z>5.7, when the Universe was less than one billion years old. By finding more, scientists hope to place a lower limit on black hole accretion well into the Epoch of Re-ionization, when the first stars and galaxies formed.
This quasar is especially interesting because its so bright in x-rays. But it’s also a low-mass black hole with only 250 million solar masses. Most high redshift galaxies like this one host black holes with between one to ten billion solar masses. For this one to be detected, it must be accreting matter at a very high rate and it must be growing rapidly. That’s the only explanation for its brightness in x-rays.
“We did not expect to find such a low-mass AGN already in our very first mini-survey with eROSITA”, said lead author Wolf, who searches for the most distant supermassive black holes in eROSITA data as part of his Ph.D. “It is the most distant serendipitous X-ray detection to date and its properties are rather atypical for quasars at such high redshifts: it is intrinsically faint in visible light but very luminous in X-rays.”
This quasar is similar to a type of galaxy called narrow-line Seyfert-1 galaxies. They’re a type of active galaxy in the local Universe. They’re associated with SMBHs with less than 100 million solar masses that are accreting matter at a high rate. They could be younger than their higher-mass SMBH counterparts.
What does it mean to find this quasar this early in the Universe? It sheds light on the earliest stages of black hole formation.
It takes an extraordinarily high concentration of mass to form a black hole. In the modern Universe, those densities are found only in stars. But in the early Universe, before so much expansion, there were other densities. Somehow, they may have collapsed into black holes, and the only reason that entire Universe didn’t collapse into one is that expansion overpowered it.
Understanding the density fluctuations in the early Universe that allowed black holes to form is part of the cutting edge in astrophysics and cosmology. So while this single detection of an actively feeding and rapidly growing black hole in the Epoch of Reionization won’t answer all of our questions, it’s a piece of the puzzle.
How black holes formed in the early Universe is only one question. Another question is how did they grow? One way astrophysicists try to track black hole growth is by tracing their accretion through cosmic time via the X-ray Luminosity Function (XLF.) XLF is associated with accretion and there are varying models explaining the association. Detecting these ancient quasars in x-rays helps place constraints on the XLF and will help astrophysicists clarify these models.
“At z = 6.56, J0921+0007 is the most distant X-ray-selected AGN to date and can therefore be used to impose constraints on the high-z XLF,” the authors point out in their paper.
The Eddington limit also plays a role in this work. The Eddington limit is the maximum luminosity that an object can achieve when outward radiation and inward gravitation are balanced. Astrophysicists think that the Universe’s earliest black holes can exceed this limit because conditions are right for rapid accretion. To find out more about these super-Eddington black holes and the overall black hole accretion density in the early Universe, researchers need to find more of them. “In order to quantify how much of the accretion density is in fact driven by young, super-Eddington black holes, a wider survey area will be required at this depth to obtain a more informative sample. This will be made possible in the cumulative eROSITA All-Sky Survey,” the authors write in their conclusion.
This ancient black hole isn’t the only piece of the puzzle found by eROSITA and its Final Equatorial-Depth Survey. The survey has already found five more of them. The MPE research team will present those findings in a future paper. Based on all of these detections, the scientists expect to find hundreds more of them with the survey.
Super-massive black holes are dominant objects in the Universe. How they formed, how they grew so large, and how they became symbiotic with the growth of huge galaxies are all unanswered questions.
But this work shows researchers are making progress.
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Cosmology & The Universe
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Scientists discover the highest energy gamma-rays ever from a pulsar
Scientists using the H.E.S.S. observatory in Namibia have detected the highest energy gamma rays ever from a dead star called a pulsar. The energy of these gamma rays clocked in at 20 tera-electronvolts, or about 10 trillion times the energy of visible light. This observation is hard to reconcile with the theory of the production of such pulsed gamma rays, as the international team reports in the journal Nature Astronomy.
Pulsars are the left-over corpses of stars that spectacularly exploded in a supernova. The explosions leave behind a tiny, dead star with a diameter of just some 20 kilometers, rotating extremely fast and endowed with an enormous magnetic field.
"These dead stars are almost entirely made up of neutrons and are incredibly dense: a teaspoon of their material has a mass of more than five billion tons, or about 900 times the mass of the Great Pyramid of Giza," explains H.E.S.S. scientist Emma de Oña Wilhelmi, a co-author of the publication working at DESY.
Pulsars emit rotating beams of electromagnetic radiation, somewhat like cosmic lighthouses. If their beam sweeps across our solar system, we see flashes of radiation at regular time intervals. These flashes, also called pulses of radiation, can be searched for in different energy bands of the electromagnetic spectrum.
Scientists think that the source of this radiation are fast electrons produced and accelerated in the pulsar's magnetosphere, while traveling towards its periphery. The magnetosphere is made up of plasma and electromagnetic fields that surround and co-rotate with the star.
"On their outward journey, the electrons acquire energy and release it in the form of the observed radiation beams," says Bronek Rudak from the Nicolaus Copernicus Astronomical Center (CAMK PAN) in Poland, also a co-author.
The Vela pulsar, located in the Southern sky in the constellation Vela (sail of the ship), is the brightest pulsar in the radio band of the electromagnetic spectrum and the brightest persistent source of cosmic gamma rays in the giga-electronvolts (GeV) range. It rotates about eleven times per second. However, above a few GeV, its radiation ends abruptly, presumably because the electrons reach the end of the pulsar's magnetosphere and escape from it.
But this is not the end of the story: using deep observations with H.E.S.S., a new radiation component at even higher energies has now been discovered, with energies of up to tens of tera-electronvolts (TeV).
"That is about 200 times more energetic than all radiation ever detected before from this object," says co-author Christo Venter from the North-West University in South Africa. This very high-energy component appears at the same phase intervals as the one observed in the GeV range. However, to attain these energies, the electrons might have to travel even farther than the magnetosphere, yet the rotational emission pattern needs to remain intact.
"This result challenges our previous knowledge of pulsars and requires a rethinking of how these natural accelerators work," says Arache Djannati-Atai from the Astroparticle & Cosmology (APC) laboratory in France, who led the research.
"The traditional scheme according to which particles are accelerated along magnetic field lines within or slightly outside the magnetosphere cannot sufficiently explain our observations. Perhaps we are witnessing the acceleration of particles through the so-called magnetic reconnection process beyond the light cylinder, which still somehow preserves the rotational pattern? But even this scenario faces difficulties to explain how such extreme radiation is produced."
Whatever the explanation, next to its other superlatives, the Vela pulsar now officially holds the record as the pulsar with the highest-energy gamma rays discovered to date.
"This discovery opens a new observation window for detection of other pulsars in the tens of teraelectronvolt range with current and upcoming more sensitive gamma-ray telescopes, hence paving the way for a better understanding of the extreme acceleration processes in highly magnetized astrophysical objects," says Djannati-Atai.
More information: Discovery of a Radiation Component from the Vela Pulsar Reaching 20 Teraelectronvolts, Nature Astronomy (2023). DOI: 10.1038/s41550-023-02052-3
Journal information: Nature Astronomy
Provided by Deutsches Elektronen-Synchrotron
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Cosmology & The Universe
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The standard story of the birth of the cosmos goes something like this: Nearly 14 billion years ago, a tremendous amount of energy materialized as if from nowhere.In a brief moment of rapid expansion, that burst of energy inflated the cosmos like a balloon. The expansion straightened out any large-scale curvature, leading to a geometry that we now describe as flat. Matter also thoroughly mixed together, so that now the cosmos appears largely (though not perfectly) featureless. Here and there, clumps of particles have created galaxies and stars, but these are just minuscule specks on an otherwise unblemished cosmic canvas.That theory, which textbooks call inflation, matches all observations to date and is preferred by most cosmologists. But it has conceptual implications that some find disturbing. In most regions of space-time, the rapid expansion would never stop. As a consequence, inflation can’t help but produce a multiverse—a technicolor existence with an infinite variety of pocket universes, one of which we call home. To critics, inflation predicts everything, which means it ultimately predicts nothing. “Inflation doesn’t work as it was intended to work,” said Paul Steinhardt, an architect of inflation who has become one of its most prominent critics.In recent years, Steinhardt and others have been developing a different story of how our universe came to be. They have revived the idea of a cyclical universe: one that periodically grows and contracts. They hope to replicate the universe that we see—flat and smooth—without the baggage that comes with a bang.To that end, Steinhardt and his collaborators recently teamed up with researchers who specialize in computational models of gravity. They analyzed how a collapsing universe would change its own structure, and they ultimately discovered that contraction can beat inflation at its own game. No matter how bizarre and twisted the universe looked before it contracted, the collapse would efficiently erase a wide range of primordial wrinkles.“It’s very important, what they claim they’ve done,” said Leonardo Senatore, a cosmologist at Stanford University who has analyzed inflation using a similar approach. There are aspects of the work he hasn’t yet had a chance to investigate, he said, but at first glance “it looks like they’ve done it.”Squeezing the ViewOver the last year and a half, a fresh view of the cyclic, or “ekpyrotic,” universe has emerged from a collaboration between Steinhardt, Anna Ijjas, a cosmologist at the Max Planck Institute for Gravitational Physics in Germany, and others—one that achieves renewal without collapse.When it comes to visualizing expansion and contraction, people often focus on a balloonlike universe whose change in size is described by a “scale factor.” But a second measure—the Hubble radius, which is the greatest distance we can see—gets short shrift. The equations of general relativity let them evolve independently, and, crucially, you can flatten the universe by changing either.Picture an ant on a balloon. Inflation is like blowing up the balloon. It puts the onus of smoothing and flattening primarily on the swelling cosmos. In the cyclic universe, however, the smoothing happens during a period of contraction. During this epoch, the balloon deflates modestly, but the real work is done by a drastically shrinking horizon. It’s as if the ant views everything through an increasingly powerful magnifying glass. The distance it can see shrinks, and thus its world grows more and more featureless.Illustration: Lucy Reading-Ikkanda/Quanta MagazineSteinhardt and company imagine a universe that expands for perhaps a trillion years, driven by the energy of an omnipresent (and hypothetical) field, whose behavior we currently attribute to dark energy. When this energy field eventually grows sparse, the cosmos starts to gently deflate. Over billions of years a contracting scale factor brings everything a bit closer, but not all the way down to a point. The dramatic change comes from the Hubble radius, which rushes in and eventually becomes microscopic. The universe’s contraction recharges the energy field, which heats up the cosmos and vaporizes its atoms. A bounce ensues, and the cycle starts anew.In the bounce model, the microscopic Hubble radius ensures smoothness and flatness. And whereas inflation blows up many initial imperfections into giant plots of multiverse real estate, slow contraction squeezes them essentially out of existence. We are left with a cosmos that has no beginning, no end, no singularity at the big bang, and no multiverse.From Any Cosmos to OursOne challenge for both inflation and bounce cosmologies is to show that their respective energy fields create the right universe no matter how they get started. “Our philosophy is that there should be no philosophy,” Ijjas said. “You know it works when you don’t have to ask under what condition it works.”She and Steinhardt criticize inflation for doing its job only in special cases, such as when its energy field forms without notable features and with little motion. Theorists have explored these situations most thoroughly, in part because they are the only examples tractable with chalkboard mathematics. In recent computer simulations, which Ijjas and Steinhardt describe in a pair of preprints posted online in June, the team stress-tested their slow-contraction model with a range of baby universes too wild for pen-and paper analysis.Adapting code developed by Frans Pretorius, a theoretical physicist at Princeton University who specializes in computational models of general relativity, the collaboration explored twisted and lumpy fields, fields moving in the wrong direction, even fields born with halves racing in opposing directions. In nearly every case, contraction swiftly produced a universe as boring as ours.“You let it go and—bam! In a few cosmic moments of slow contraction it looks as smooth as silk,” Steinhardt said.Katy Clough, a cosmologist at the University of Oxford who also specializes in numerical solutions of general relativity, called the new simulations “very comprehensive.” But she also noted that computational advances have only recently made this kind of analysis possible, so the full range of conditions that inflation can handle remains uncharted.“It’s been semi-covered, but it needs a lot more work,” she said.While interest in Ijjas and Steinhardt’s model varies, most cosmologists agree that inflation remains the paradigm to beat. “[Slow contraction] is not an equal contender at this point,” said Gregory Gabadadze, a cosmologist at New York University.The collaboration will next flesh out the bounce itself—a more complex stage that requires novel interactions to push everything apart again. Ijjas already has one bounce theory that upgrades general relativity with a new interaction between matter and space-time, and she suspects that other mechanisms exist too. She plans to put her model on the computer soon to understand its behavior in detail.The group hopes that after gluing the contraction and expansion stages together, they’ll identify unique features of a bouncing universe that astronomers might spot.The collaboration has not worked out every detail of a cyclic cosmos with no bang and no crunch, much less shown that we live in one. But Steinhardt now feels optimistic that the model will soon offer a viable alternative to the multiverse. “The roadblocks I was most worried about have been surpassed,” he said. “I’m not kept up at night anymore.”Editor’s note: Some of this research was funded in part by the Simons Foundation, which also funds Quanta, an editorially independent magazine. Simons Foundation funding decisions play no role in Quanta's coverage. More details are available here.Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.More Great WIRED StoriesHow to outrun a dinosaur (just in case)Inside Citizen, the app that asks you to report on the crime next doorThe age of mass surveillance will not last foreverA study finds sex differences in the brain. Does it matter?These Black founders succeeded in spite of Silicon Valley🎙️ Listen to Get WIRED, our new podcast about how the future is realized. Catch the latest episodes and subscribe to the 📩 newsletter to keep up with all our shows💻 Upgrade your work game with our Gear team’s favorite laptops, keyboards, typing alternatives, and noise-canceling headphones
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Cosmology & The Universe
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Home News The Hyades star cluster (pink) curls across the sky amid well-known constellations (green). The cluster is at the center of a controversial new study proposing an alternative to Newton's theory of gravity.
(Image credit: ESA/Gaia/DPAC, CC BY-SA 3.0) Astronomers observing star clusters in our galaxy have found evidence that controversially challenges Newton's laws of gravity and could upend our understanding of the universe. The puzzling finding could support a controversial idea that does away entirely with dark matter.The researchers found this evidence by observing open star clusters, or loosely bound groups of up to a few hundred stars sitting within larger galaxies. Open star clusters have trails of stars, known as "tidal tails," in front of and behind them. The researchers' observations indicate that such clusters have many more stars sitting in the overall direction of their travel through space than trailing behind. This throws into question Newton's law of universal gravitation, which suggests that there should be the same number of stars in both tidal tails."It's extremely significant," astrophysicist Pavel Kroupa of the University of Bonn told Live Science. "There is a huge effect."Kroupa is the lead author of a study published Oct. 26 in the Monthly Notices of the Royal Astronomical Society that argues the observations are evidence of modified Newtonian dynamics (MOND) — an alternative theory of gravity to Newton's widely accepted universal law of gravitation.This uneven distribution of stars is noticeable, but not extreme enough for any sort of dark matter — an invisible substance thought to exert a powerful gravitational pull on the universe's visible matter — to be involved, Kroupa said."This is basically a game-changer," he said. "This destroys all the work done on galaxies and on cosmology [that] assumes dark matter and Newtonian gravity."In the star cluster Hyades (top), the number of stars (black) in the front tidal tail is significantly larger than those in the rear. In the computer simulation with MOND (below), a similar picture emerges. (Image credit: University of Bonn)Dark matter?Issac Newton's universal law of gravitation, published in 1687, states that every particle in the universe attracts every other with a force proportional to their masses and inversely proportional to the square of their distance. Albert Einstein later incorporated this law into his theory of general relativity, which was published in 1915.But Kroupa said that at the time of both Newton and Einstein, astronomers didn't know that galaxies even existed, and so MOND was developed to bring it up to date with observations.MOND, also known as Milgromian dynamics after astrophysicist Mordehai Milgrom who developed it in the early 1980s, argues that regular Newtonian dynamics don't apply on the very large scales of galaxies and galactic clusters — although most astrophysicists think they do.The main consequence of MOND is that dark matter doesn't exist — an idea that most astrophysicists dismiss, Kroupa said. "The majority of scientists completely reject Mond," he said. "Many serious scientists don't think Mond is serious, and so they wouldn't consider looking at it."Stellar clustersIn their study, the authors report observations of five of the closest open stellar clusters to Earth, including the Hyades — a roughly spherical group of hundreds of stars that is only about 150 light-years from our sun.The researchers observed that stars had accumulated in the leading tidal tail in all five of the clusters, while the greatest discrepancy from regular Newtonian dynamics was seen in the Hyades cluster, where there are better measurements, Kroupa said. The observed discrepancies strengthen the case for MOND, but they can't be a result of the invisible action of dark matter.In the case of the Hyades, "we would have to have a clump of dark matter there like 10 million solar masses" to explain the results, he said. "But it's just not in the data."Future studies will use more precise data on the positions of stars from new space telescopes, such as the European Space Agency's Gaia, he said.However, because MOND is not widely accepted by many scientists, the new study's findings are controversial. Sabine Hossenfelder, an astrophysicist at the Frankfurt Institute Advanced Studies, told Live Science in an email that she was pleased to see researchers working on gravitational simulations of MOND.But "as they admit the paper themselves, they are using an approximate calculation that needs to be confirmed… [and] they haven't quantified how large the disagreement with data is," she said. "So I think it remains to be seen how good this argument actually is." Tom Metcalfe is a freelance journalist and regular Live Science contributor who is based in London in the United Kingdom. Tom writes mainly about science, space, archaeology, the Earth and the oceans. He has also written for the BBC, NBC News, National Geographic, Scientific American, Air & Space, and many others.
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Cosmology & The Universe
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When we imagine a world embraced by cosmic haloes, we typically envision Saturn. Honestly, one might argue Saturn based its entire personality on those dazzling rings, and rightfully so. They're solid. Visible. Luxurious even. But if you didn't already know, it is my honor to tell you Neptune has rings too. They're just much daintier and therefore superhard to see without superpowered telescopes. The planet itself, in fact, lies 30 times farther from the sun than Earth does and appears to standard stargazing instruments as nothing more than a weak speck of light. Despite our inability to admire Neptune's fragile hoops from here, scientists caught a wonderful glimpse of them girding the azure realm in 1989 thanks to NASA's traveling probe Voyager -- and on Wednesday, the agency's equally exceptional James Webb Space Telescope presented us with round two. "It has been three decades since we last saw these faint, dusty rings, and this is the first time we've seen them in the infrared," Heidi Hammel, Neptune system expert and interdisciplinary scientist for the JWST, said in a statement. "Webb's extremely stable and precise image quality permits these very faint rings to be detected so close to Neptune." And as if that weren't enough, this new image exhibits Neptune, surely emanating a soft lavender glow under the JWST's Near-Infrared lens, against a backdrop of galaxies deftly picked up by the same piece of next-gen space tech. It's unambiguous proof that the JWST is far too sensitive to capture what we might consider "blank space." This machine is powerful enough to serendipitously open a box of treasure every single time it gazes into the void. Without further ado, Neptune:In this image by Webb's Near-Infrared Camera (NIRCam), a smattering of hundreds of background galaxies, varying in size and shape, appear alongside the Neptune system. It was officially captured on July 12, 2022. ESA Of every image taken by the JWST so far, this one is simply my favorite. Its depth of field gives me existential butterflies because it's disquieting to see a full-on planet, rings included, solely floating in front of deceptively small galaxies that are, in reality, hundreds of thousands of light-years across. These galaxies sit at gigantic distances from our solar system's cosmic neighborhood (home to our very own Neptune), yet carry wads more cosmic neighborhoods.For comparison, here's what Voyager captured of Neptune's rings in 1989. NASA, JPL Breaking down the JWST's lens on NeptuneThe brilliant luminescence we see in the JWST's portrait of Neptune exists only because it's filtered by the telescope's infrared powers. We're looking at a depiction of invisible, infrared wavelengths emanated by the gaseous world. We aren't looking at the sort of visible wavelengths we're used to -- ones that show us color, like the kind the Hubble Space Telescope works with, for instance. Neptune still has its signature blue tint stemming from elements on the planet, such as methane gas, but the JWST can't show them to us. That's not what it was built to do.The Hubble Space Telescope shows Neptune in its blue glory while tracking two dark storms on the planet. The larger one is toward the center top and the smaller one is to the right. NASA, ESA, STScI, M.H. Wong (University of California, Berkeley), and L.A. Sromovsky and P.M. Fry (University of Wisconsin-Madison) "In fact, the methane gas is so strongly absorbing that the planet is quite dark at Webb wavelengths," the European Space Agency said in a press release, "Except where high-altitude clouds are present. Such methane-ice clouds are prominent as bright streaks and spots, which reflect sunlight before it is absorbed by methane gas."You can further see a thin line of brightness circling the planet's equator, which the team says may indicate global atmospheric circulation attached to Neptune's winds and storms. "The atmosphere descends and warms at the equator, and thus glows at infrared wavelengths more than the surrounding, cooler gasses," NASA said. At the northern pole, the agency says, there's also an "intriguing brightness," and at the southern pole, further proof of a vortex present on the orb's surface.Last but definitely not least, of Neptune's 14 known moons, the JWST caught seven: Galatea, Naiad, Thalassa, Despina, Proteus, Larissa and Triton. Exhibiting the JWST's signature six-spiked glare, Triton is seen in its weird backward orbit, offering hope to astronomers that the JWST can help decode the bizarre situation.The JWST captured seven of Neptune's moons. NASA, ESA, CSA and STScI "Dominating this Webb portrait of Neptune is a very bright point of light sporting the signature diffraction spikes seen in many of Webb's images," ESA said. "It's not a star, but Neptune's most unusual moon, Triton."It's the context of the image that really gets me, though. If we zoom out from Triton and those delicately dusted Neptune rings and those polar vortex mysteries, it becomes evident we can see these cosmic details only by sheer coincidence of existing in this iota of the universe.
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Cosmology & The Universe
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A supermassive black hole discovered at the heart of an ancient galaxy is five times larger than expected for the number of stars it contains, astronomers say.
Researchers spotted the immense black hole in a galaxy known as GS-9209 that lies 25bn light-years from Earth, making it one of the most distant to have been observed and recorded.
The team at Edinburgh University used the James Webb space telescope (JWST) to observe the galaxy and reveal fresh details about its composition and history.
Dr Adam Carnall, who led the effort, said the telescope – the most powerful ever built – showed how galaxies were growing “larger and earlier” than astronomers expected in the first billion years of the universe.
“This work gives us our first really detailed look at the properties of these early galaxies, charting in detail the history of GS-9209, which managed to form as many stars as our own Milky Way in just 800m years after the big bang,” he said.
Carnall said the “very massive black hole” at the centre of GS-9209 was a “big surprise” that lent weight to the theory that such enormous black holes are responsible for shutting down star formation in early galaxies.
“The evidence we see for the supermassive black hole was really unexpected,” said Carnall. “This is the kind of detail we’d never have been able to see without JWST.”
The GS-9209 galaxy was discovered in 2004 by Karina Caputi, a former PhD student at Edinburgh who is now a professor of observational cosmology at the University of Groningen in the Netherlands.
While GS-9209 has roughly as many stars as our home galaxy, with a combined mass equal to 40bn suns, it is only one-tenth the size of the Milky Way. It is the earliest known example of a galaxy that has stopped forming stars, the researchers said.
Supermassive black holes can shut down star formation because their growth releases huge quantities of high-energy radiation, which can heat up and drive gas out of galaxies. Galaxies need vast clouds of gas and dust to collapse under their own gravity, thereby creating new stars.
“The fact [that the black hole] is so massive means it must have been very active in the past, with lots of gas falling in, which would have shone extremely brightly as a quasar,” Carnall said. “All that energy spewing out from the black hole in the centre of the galaxy would have seriously disrupted the whole galaxy, stopping gas from collapsing to form new stars.”
More details are published in Nature.
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Cosmology & The Universe
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It's just a "speck of the universe."The first image from NASA's James Webb Space Telescope offered humanity a stunning new view of the universe on Monday — a first-of-its-kind infrared image so distant in the cosmos that it shows stars and galaxies as they appeared 13 billion years ago.President Joe Biden revealed the new image Monday at the White House alongside Vice President Kamala Harris and NASA officials. Dubbed "Webb's First Deep Field," it is the first full-color image from the $10 billion observatory that launched into space last year, and the highest-resolution infrared view of the universe yet captured.Against the blackness of space, Webb's First Deep Field shows a kaleidoscope of galaxies — some appearing as luminous points while others look "bent" and streaky, warped by gravity on their long journey to Earth.It's a photo that offers humanity a fresh perspective on the mind-bending scale of the universe.“If you held a grain of sand on the tip of your finger at arm’s length, that is the part of the universe that you’re seeing,” said NASA Administrator Bill Nelson. “Just one little speck of the universe.”The image, reminiscent of the Hubble Deep Fields that first stunned scientists with photos of ancient and seemingly infinite galaxies, shows the galaxy cluster SMACS 0723 as it appeared 4.6 billion years ago, according to NASA. The mass of the galaxy cluster is magnifying and distorting far more distant objects behind it — a phenomenon known as gravitational lensing. The University of California Santa Cruz made the image available in a zoomable format, allowing people to hone in on individual galaxies for a closer look.The Webb telescope's infrared eyes have pulled these normally faint and distant objects into sharp focus, providing a view of some never-before-seen galaxies and star clusters, NASA officials said. The oldest light from some of these objects date back roughly 13 billion years ago, in the early days of the universe.What were once blips to Hubble are now galaxies to Webb."These images are going to remind the world that America can do big things, and to remind the American people, especially our children, that there's nothing beyond our capacity," Biden said shortly before the image was revealed.In a news briefing last month to preview the image, Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate, said it will likely represent a turning point in humanity's understanding of the cosmos."It's not an image. It's a new worldview," Zurbuchen said at the time.The image offers a glimpse of the universe as it was 13 billion years ago. Telescopes essentially function as time machines because it takes time for light to travel through space. As such, light that reaches the Webb telescope from the most distant galaxies in the universe does not show present conditions but rather provide insights into how the universe was billions of years ago.Scientists have said that the James Webb Space Telescope could unlock mysteries from as far back as 100 million years after the Big Bang.The Webb observatory's infrared “eyes” allow it to see distant stars and galaxies beyond the range of human sight and other telescopes, such as the Hubble Space Telescope, that see primarily visible light.Infrared instruments are better suited for trying to detect the universe’s earliest stars and galaxies because the longer wavelengths of infrared light can pierce through dust and gas that might otherwise obscure some celestial objects. Since the universe is also expanding, light from the earliest stars and galaxies is stretched, shifting into longer infrared wavelengths undetectable by Hubble or the human eye.In a separate event on Tuesday, NASA will release more images from the Webb telescope, including the observatory's first spectrum of an exoplanet, showing light emitted at different wavelengths from a planet in another star system. These types of observations could help scientists search for signs of life beyond Earth.The James Webb Space Telescope is a collaboration among NASA, the European Space Agency and the Canadian Space Agency. The tennis court-sized observatory is designed to study the early days after the Big Bang and help astronomers piece together how the modern universe came to be.Denise Chow is a reporter for NBC News Science focused on general science and climate change.
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Cosmology & The Universe
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Less than a century ago, we — humans — believed the universe ended at the very edge of the Milky Way. At the point where the last starlight of our home galaxy winked out, an endless nothing began. Until Edwin Hubble. The famed astronomer diligently scoured the sky for blinking stars from Mount Wilson Observatory in California. His work with the Hooker telescope practically doubled the size of the universe in 1923, when he and others helped reveal that Andromeda was not a tightly packed bundle of stars within the Milky Way, but its very own galaxy, 2.5 million light-years away. Hubble knew how powerful technological advances were: Bigger, better telescopes would help expand our horizons ever further.Eighty years later, Hubble's namesake space telescope would alter our view of the cosmic horizon once again with the release of the Hubble Ultra Deep Field image, a photograph of the universe that extends so far back in space and time that it revealed galaxies birthed just 600 million years after the Big Bang. Today, our horizon expands once more. One hundred years of progress – in telescopy, astronomy, astrophysics, engineering, rocket science, mathematics, hell, even streaming online video – has led to NASA unveiling the first image obtained by the James Webb Space Telescope. After a protracted wait which led to a heated discussion of NASA TV's "hold music" online, it was President Joe Biden who had the honor of releasing Webb's first look across the universe, an image dubbed "Webb's First Deep Field" on Monday. The press conference last for 10 minutes, but it delivered a historic first image from across the cosmos. "If you held a grain of sand on the tip of your finger at arm's length, that is the part of the universe that you're seeing — just one little speck," said NASA Administrator Bill Nelson during the press conference.The full image is available below. You can click to enlarge it.The highest resolution image of the infrared universe yet. NASA, ESA, CSA, and STScI The Deep Field examines a corner of space known as SMACS 0723, which has been eyed by space telescopes such as Hubble. It contains a mammoth cluster of galaxies which function as a lens, magnifying the light of galaxies from much further into the cosmos. One of the most notable aspects of this Webb image — and the images to come — is the six-pointed light you can see in the image, a function of how James Webb's mirrors are shaped. There's also a seemingly circular smudging of light. This is the "lensing" effect. The gravity of huge foreground clusters altering the way light from deep, deep space reaches the telescope. Because of Webb's powerful optics, we're seeing some of these galaxies for the first time ever.The image itself is not exactly "hot off the telescope." This isn't what Webb sees. Webb's imaging capabilities capture infrared light from cosmic objects in black and white, similar to Hubble, and image processing software is used to reveal all the subtleties of space. Those who helped create the images then perform a feat of technical and artistic wizardry: They map the infrared wavelengths to colors to highlight the most significant features in an image.While the Deep Field delights, it's merely the entrée. Tomorrow, NASA will provide a buffet of Webb images to feast on in a breakthrough look across deep space. The release will highlight dazzling nebulas, illuminate alien worlds and pull back the curtain on a group of colliding galaxies. If this first image is anything to go by, you'll want to gorge yourself on those too. We've got you covered: Here's when and where to catch the drop.
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Cosmology & The Universe
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Galaxies are not scattered randomly across the universe. They gather together not only into clusters, but into vast interconnected filamentary structures with gigantic barren voids in between. This "cosmic web" started out tenuous and became more distinct over time as gravity drew matter together.
Astronomers using NASA's James Webb Space Telescope have discovered a thread-like arrangement of 10 galaxies that existed just 830 million years after the big bang. The 3 million light-year-long structure is anchored by a luminous quasar -- a galaxy with an active, supermassive black hole at its core. The team believes the filament will eventually evolve into a massive cluster of galaxies, much like the well-known Coma Cluster in the nearby universe.
"I was surprised by how long and how narrow this filament is," said team member Xiaohui Fan of the University of Arizona in Tucson. "I expected to find something, but I didn't expect such a long, distinctly thin structure."
"This is one of the earliest filamentary structures that people have ever found associated with a distant quasar," added Feige Wang of the University of Arizona in Tucson, the principal investigator of this program.
This discovery is from the ASPIRE project (A SPectroscopic survey of biased halos In the Reionization Era), whose main goal is to study the cosmic environments of the earliest black holes. In total, the program will observe 25 quasars that existed within the first billion years after the big bang, a time known as the Epoch of Reionization.
"The last two decades of cosmology research have given us a robust understanding of how the cosmic web forms and evolves. ASPIRE aims to understand how to incorporate the emergence of the earliest massive black holes into our current story of the formation of cosmic structure," explained team member Joseph Hennawi of the University of California, Santa Barbara.
Growing Monsters
Another part of the study investigates the properties of eight quasars in the young universe. The team confirmed that their central black holes, which existed less than a billion years after the big bang, range in mass from 600 million to 2 billion times the mass of our Sun. Astronomers continue seeking evidence to explain how these black holes could grow so large so fast.
"To form these supermassive black holes in such a short time, two criteria must be satisfied. First, you need to start growing from a massive 'seed' black hole. Second, even if this seed starts with a mass equivalent to a thousand Suns, it still needs to accrete a million times more matter at the maximum possible rate for its entire lifetime," explained Wang.
"These unprecedented observations are providing important clues about how black holes are assembled. We have learned that these black holes are situated in massive young galaxies that provide the reservoir of fuel for their growth," said Jinyi Yang of the University of Arizona, who is leading the study of black holes with ASPIRE.
Webb also provided the best evidence yet of how early supermassive black holes potentially regulate the formation of stars in their galaxies. While supermassive black holes accrete matter, they also can power tremendous outflows of material. These winds can extend far beyond the black hole itself, on a galactic scale, and can have a significant impact on the formation of stars.
"Strong winds from black holes can suppress the formation of stars in the host galaxy. Such winds have been observed in the nearby universe but have never been directly observed in the Epoch of Reionization," said Yang. "The scale of the wind is related to the structure of the quasar. In the Webb observations, we are seeing that such winds existed in the early universe."
These results were published in two papers in The Astrophysical Journal Letters on June 29.
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Cosmology & The Universe
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Stephen Hawking and I created his final theory of the cosmos—here's what it reveals about the origins of time and life
The late physicist Stephen Hawking first asked me to work with him to develop "a new quantum theory of the Big Bang" in 1998. What started out as a doctoral project evolved over some 20 years into an intense collaboration that ended only with his passing on March 14 2018.
The enigma at the center of our research throughout this period was how the Big Bang could have created conditions so perfectly hospitable to life. Our answer is being published in a new book, "On the Origin of Time: Stephen Hawking's Final Theory."
Questions about the ultimate origin of the cosmos, or universe, take physics out of its comfort zone. Yet this was exactly where Hawking liked to venture. The prospect—or hope—to crack the riddle of cosmic design drove much of Hawking's research in cosmology. "To boldly go where Star Trek fears to tread" was his motto—and also his screen saver.
Our shared scientific quest meant that we inevitably grew close. Being around him, one could not fail to be influenced by his determination and optimism that we could tackle mystifying questions. He made me feel as if we were writing our own creation story, which, in a sense, we did.
In the old days, it was thought that the apparent design of the cosmos meant there had to be a designer—a God. Today, scientists instead point to the laws of physics. These laws have a number of striking life-engendering properties. Take the amount of matter and energy in the universe, the delicate ratios of the forces, or the number of spatial dimensions.
Physicists have discovered that if you tweak these properties ever so slightly, it renders the universe lifeless. It almost feels as if the universe is a fix—even a big one.
But where do the laws of physics come from? From Albert Einstein to Hawking in his earlier work, most 20th-century physicists regarded the mathematical relationships that underlie the physical laws as eternal truths. In this view, the apparent design of the cosmos is a matter of mathematical necessity. The universe is the way it is because nature had no choice.
Around the turn of the 21st century, a different explanation emerged. Perhaps we live in a multiverse, an enormous space that spawns a patchwork of universes, each with its own kind of Big Bang and physics. It would make sense, statistically, for a few of these universes to be life-friendly.
However, soon such multiverse musings got caught in a spiral of paradoxes and no verifiable predictions.
Turning cosmology inside out
Can we do better? Yes, Hawking and I found out, but only by relinquishing the idea, inherent in multiverse cosmology, that our physical theories can take a God's-eye view, as if standing outside the entire cosmos.
It is an obvious and seemingly tautological point: cosmological theory must account for the fact that we exist within the universe. "We are not angels who view the universe from the outside," Hawking told me. "Our theories are never decoupled from us."
We set out to rethink cosmology from an observer's perspective. This required adopting the strange rules of quantum mechanics, which governs the microworld of particles and atoms.
According to quantum mechanics, particles can be in several possible locations at the same time—a property called superposition. It is only when a particle is observed that it (randomly) picks a definite position. Quantum mechanics also involves random jumps and fluctuations, such as particles popping out of empty space and disappearing again.
In a quantum universe, therefore, a tangible past and future emerge out of a haze of possibilities by means of a continual process of observing. Such quantum observations don't need to be carried out by humans. The environment or even a single particle can "observe".
Countless such quantum acts of observation constantly transform what might be into what does happen, thereby drawing the universe more firmly into existence. And once something has been observed, all other possibilities become irrelevant.
We discovered that when looking back at the earliest stages of the universe through a quantum lens, there's a deeper level of evolution in which even the laws of physics change and evolve, in sync with the universe that is taking shape. What's more, this meta-evolution has a Darwinian flavor.
Variation enters because random quantum jumps cause frequent excursions from what's most probable. Selection enters because some of these excursions can be amplified and frozen, thanks to quantum observation. The interplay between these two competing forces—variation and selection—in the primeval universe produced a branching tree of physical laws.
The upshot is a profound revision of the fundamentals of cosmology. Cosmologists usually start by assuming laws and initial conditions that existed at the moment of the Big Bang, then consider how today's universe evolved from them. But we suggest that these laws are themselves the result of evolution.
Dimensions, forces, and particle species transmute and diversify in the furnace of the hot Big Bang—somewhat analogous to how biological species emerge billions of years later—and acquire their effective form over time.
Moreover, the randomness involved means that the outcome of this evolution—the specific set of physical laws that makes our universe what it is—can only be understood in retrospect.
In some sense, the early universe was a superposition of an enormous number of possible worlds. But we are looking at the universe today at a time when humans, galaxies and planets exist. That means we see the history that led to our evolution.
We observe parameters with "lucky values". But we are wrong to assume they were somehow designed or always like that.
The trouble with time
The crux of our hypothesis is that, reasoning backward in time, evolution towards more simplicity and less structure continues all the way. Ultimately, even time and, with it, the physical laws fade away.
This view is especially borne out of the holographic form of our theory. The "holographic principle" in physics predicts that just as a hologram appears to have three dimensions when it is in fact encoded in only two dimensions, the evolution of the entire universe is similarly encoded on an abstract, timeless surface.
Hawking and I view time and causality as "emergent qualities", having no prior existence but arising from the interactions between countless quantum particles. It's a bit like how temperature emerges from many atoms moving collectively, even though no single atom has temperature.
One ventures back in time by zooming out and taking a fuzzier look at the hologram. Eventually, however, one loses all information encoded in the hologram. This would be the origin of time—the Big Bang.
For almost a century, we have studied the origin of the universe against the stable background of immutable laws of nature. But our theory reads the universe's history from within and as one that includes, in its earliest stages, the genealogy of the physical laws. It isn't the laws as such but their capacity to transmute that has the final word.
Future cosmological observations may find evidence of this. For instance, precision observations of gravitational waves—ripples in the fabric of spacetime—may reveal signatures of some of the early branches of the universe. If spotted, Hawking's cosmological finale may well prove to be his greatest scientific legacy.
Provided by The Conversation
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Cosmology & The Universe
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Stephen Hawking's last collaborator on physicist's final theory
When Thomas Hertog was first summoned to Stephen Hawking's office in the late 1990s, there was an instant connection between the young Belgian researcher and the legendary British theoretical physicist.
"Something clicked between us," Hertog said.
That connection would continue even as Hawking's debilitating disease ALS robbed him of his last ways to communicate, allowing the pair to complete a new theory that aims to turn how science looks at the universe on its head.
The theory, which would be Hawking's last before his death in 2018, has been laid out in full for the first time in Hertog's book "On the Origin of Time", published in the UK last month.
In an interview with AFP, the cosmologist spoke about their 20-year collaboration, how they communicated via facial expression, and why Hawking ultimately decided his landmark book "A Brief of History of Time" was written from the wrong perspective.
The 'designed' universe
During their first meeting at Cambridge University in 1998, Hawking wasted no time in bringing up the problem bothering him.
"The universe we observe appears designed," Hawking told Hertog, communicating via a clicker connected to a speech machine.
Hertog explained that "the laws of physics—the rules on which the universe runs—turn out to be just perfect for the universe to be habitable, for life to be possible."
This remarkable string of good luck stretches from the delicate balance that makes it possible for atoms to form molecules necessary for chemistry to the expansion of the universe itself, which allows for vast cosmic structures such as galaxies.
One "trendy" answer to this problem has been the multiverse, an idea that has recently become popular in the movie industry, Hertog said.
This theory explains away the seemingly designed nature of the universe by making it just one of countless others—most of which are "crap, lifeless, sterile", the 47-year-old added.
But Hawking realized the "great mire of paradoxes the multiverse was leading us into", arguing there must be a better explanation, Hertog said.
Outsider's perspective
A few years into their collaboration, "it began to sink in" that they were missing something fundamental, Hertog said.
The multiverse and even "A Brief History of Time" were "attempts to describe the creation and evolution of our universe from what Stephen would call a 'God's eye perspective'," Hertog said.
But because "we are within the universe" and not outside looking in, our theories cannot be decoupled from our perspective, he added.
"That was why (Hawking) said that 'A Brief History of Time' is written from the wrong perspective."
For the next 15 years, the pair used the oddities of quantum theory to develop a new theory of physics and cosmology from an "observer's perspective".
But by 2008, Hawking had lost the ability to use his clicker, becoming increasingly isolated from the world.
"I thought it was over," Hertog said.
Then the pair developed a "somewhat magical" level of non-verbal communication that allowed them to continue working, he said.
Positioned in front of Hawking, Hertog would ask questions and look into the physicist's eyes.
"He had a very wide range of facial expressions, ranging from extreme disagreement to extreme excitement," he said.
"It's impossible to disentangle" which parts of the final theory came from himself or Hawking, Hertog said, adding that many of the ideas had been developed between the pair over the years.
'One grand evolutionary process'
Their theory is focused on what happened in the first moments after the Big Bang.
Rather than an explosion that followed a pre-existing set of rules, they propose that the laws of physics evolved along with the universe.
This means that if you turn back the clock far enough, "the laws of physics themselves begin to simplify and disappear", Hertog said.
"Ultimately, even the dimension of time evaporates."
Under this theory, the laws of physics and time itself evolved in a way that resembles biological evolution—the title of Hertog's book is a reference to Darwin's "On the Origin of Species".
"What we're essentially saying is that (biology and physics) are two levels of one grand evolutionary process," Hertog said.
He acknowledged that it is difficult to prove this theory because the first years of the universe remain "hidden in the mist of the Big Bang".
One way to lift this veil could be by studying gravitational waves, ripples in the fabric of space time, while another could be via quantum holograms constructed on quantum computers, he said.
© 2023 AFP
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Cosmology & The Universe
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Home News Science & Astronomy An artist's depiction of the James Webb Space Telescope at work.
(Image credit: ESA/ATG medialab) It's been almost a year since the most ambitious — and costly — space telescope ever built was launched toward the L2 Lagrange point on the far side of the Earth from the sun. Following a nerve-shredding deployment that saw its mirrors and sunshield successfully unfold while navigating 344 potential points of failure, the $10 billion James Webb Space Telescope (Webb or JWST) has been churning out fantastic astronomical data since the summer.Even less than six months into observations, this data is transformative, and scientists have already used it to make several important and record-breaking discoveries. JWST was heralded as a revolutionary telescope before it launched; now that it is in business, we look at some of the many ways that it is already succeeding in transforming astronomy.Seeing farther into the past than ever before Inset are close-ups of two high redshift galaxies seen by JWST. One is at a redshift of 10.5, the other at 12.5. Most of the foreground galaxies are part of the Abell 2744 cluster. (Image credit: NASA/ESA/CSA/T. Treu (UCLA))To see the precious rare photons from the most distant galaxies in the universe, the bigger the telescope, the better — and space telescopes don't come bigger than JWST, with its 21-foot (6.5 meters) primary mirror. But that's only half the job done, because the more distant an object is, the more its light is redshifted. The farther a galaxy is from us, the faster it is receding from us because of the expansion of the universe, so the more its light becomes stretched, shifting the light toward redder wavelengths. The most distant galaxies, which are also the earliest galaxies we can see, emit light that is shifted all the way into near-infrared wavelengths by the time it reaches Earth. It's this redshift that prompted scientists to design JWST to specialize in near- and mid-infrared light. The combination of the large mirror and infrared vision has enabled JWST to see more distant, earlier galaxies than astronomers ever have before, promising to transform our understanding how these galaxies form.Prior to JWST's launch, the most distant known galaxy was one called GN-z11. It has a redshift of 11.1, which corresponds to seeing the galaxy as it was 13.4 billion years ago, just 400 million years after the Big Bang. That was the absolute limit of what telescopes before JWST could detect.But very soon after the first data from JWST was released, that record was smashed. Astronomers took advantage of foreground galaxy clusters like Abell 2744 that act as gravitational lenses: Objects of great mass, such as galaxy clusters, warp space with their gravity, creating a magnifying lens-like effect that amplifies light from more distant objects. Astronomers began finding faint, red smudges in the background of these lenses — and these smudges have turned out to be the most distant galaxies ever seen. First was a galaxy at a redshift of 12.5, called GLASS-z12 (GLASS is the name of a specific survey program, the "Grism Lens-Amplified Survey from Space"). We see this galaxy as it existed 13.45 billion years ago, or 350 million years after the Big Bang, astronomers calculated. Galaxies with even greater redshifts soon followed. One, nicknamed Maisie's Galaxy, is seen as it existed just 280 million years after the Big Bang, at a redshift of 14.3, while another, at redshift 16.7, is seen just 250 million years after the Big Bang. There have even been claims for a galaxy at an astounding redshift of 20, which if confirmed would have existed just 200 million years after the Big Bang.JWST is also working to confirm these finds as well, using a second instrument to split light by wavelength. Astronomers have already confirmed a galaxy with a redshift of 13.2, which we see as it was when the universe was just 325 million years old.Discovering what lit up the universe An artist's depiction of the universe's path from the Big Bang, at the right, to the present, at the left; in between, the very first stars and black holes created enough light to end the cosmic dark ages. (Image credit: NASA/STScI)Following the Big Bang, but before stars and galaxies had formed, the universe was dark and shrouded in a fog of neutral hydrogen gas. Ultimately light, particularly ultraviolet radiation, ionized that fog. But where did that light initially come from to end the cosmic dark ages? Astronomers believe that light came either from young galaxies filled with stars, or from active supermassive black holes, which are surrounded by accretion disks of brilliantly hot gas and shoot powerful jets into space. The question of which came first — galaxies or their black holes — is one of the biggest conundrums in cosmology, a kind of chicken or egg question.Already, JWST has found that the early galaxies it is detecting are brighter and more structured than expected, with distinct disks around bulbous cores already filled with stars. This characteristic suggests that fully-formed galaxies were on the scene quickly — but whether they already contained supermassive black holes remains to be seen. Fortunately, JWST is designed to answer this question, and when it does it will provide a huge piece of the jigsaw that is the puzzle of the early universe.Measuring exoplanet atmospheres An artist's impression of the gas giant exoplanet WASP-39b; JWST has characterized its atmosphere. (Image credit: NASA/ESA/CSA/J. Olmsted (STScI))Astronomers have now found more than 5,000 exoplanets and counting, but despite this remarkable haul, we still know next to nothing about many of them. JWST isn't designed to discover new exoplanets, but it does aim to paint much more detailed pictures of known worlds by conducting something called transit spectroscopy. When a planet passes in front of its star, some of the star's light filters through the planet's atmosphere, and molecules in the atmosphere can absorb some of that starlight, creating dark lines in the star's spectrum, a barcode-like breakdown of light by wavelength. Knowing what's in a planet's atmosphere, or even whether it has an atmosphere at all, can teach astronomers about how a planet might have formed and evolved, what its conditions are like and what chemical processes are taking place in that atmosphere.The atmospheric composition of exoplanet WASP-39b. (Image credit: NASA/ESA/CSA/J. Olmsted (STScI))Early results have been hugely encouraging. In August, astronomers announced that JWST had made the first confirmed detection of carbon dioxide gas in the atmosphere of an exoplanet, in this case WASP-39b, which is 700 light years-away. Later, in November, astronomers released a more complete spectrum showing the absorption lines of elements and molecules in WASP-39b's atmosphere, including not only carbon dioxide but also carbon monoxide, potassium, sodium, sulfur dioxide and water vapor. The findings were described as the most detailed analysis of an exoplanet's atmosphere yet. The spectrum showed that there was a lot more oxygen in the planet's atmosphere than carbon, as well as an abundance of sulfur. Scientists think that sulfur must have come from numerous collisions that WASP-39b experienced with smaller planetesimals when it was forming, giving us clues to the planet's evolution that could also hint at how the gas giants in our own solar system, Jupiter and Saturn, formed. In addition, the existence of sulfur dioxide is the first example of a product of photochemistry on a planet beyond the solar system, since the compound forms when a star's ultraviolet light reacts with molecules in a planetary atmosphere.Searching for hints of life and habitability An artist's depiction of the seven planets in the TRAPPIST-1 system. (Image credit: NASA/JPL-Caltech)Studies of planets such as WASP-39b are one thing, but one of the holy grails of exoplanet science is to find another planet that is habitable, like Earth, and JWST is well positioned to characterize alien worlds.The aforementioned observations of WASP-39b bode well for forthcoming studies of the planets of the TRAPPIST-1 system of seven rocky planets orbiting a red dwarf star located 40.7 light-years away from Earth. Four of these worlds lie in the star's putative habitable zone, where temperatures would permit liquid water to persist on the surface; given the right conditions they could potentially be habitable to varying degrees. Initial observations with JWST are focusing on TRAPPIST-1c, which is the easiest to observe. Models predict that it will have an atmosphere similar to Venus, with lots of carbon dioxide. While TRAPPIST-1c is likely too hot to be habitable, determining whether it has an atmosphere and, if so, whether that atmosphere possesses carbon dioxide will be a big step toward characterizing Earth-size worlds. It will also be a big task, requiring 100 hours of observing time with JWST, which is tackling about 10,000 hours of observations during its first year of science.From TRAPPIST-1c, things could become more ambitious, with JWST targeting the other worlds in the TRAPPIST-1 system that are more likely to be habitable, as well as similar worlds around other nearby stars. Astronomers will be on the lookout for biosignatures, such as the presence of both methane and oxygen in an atmosphere. The discovery of photochemical reactions in WASP-39b's atmosphere is also an important step, since photochemical reactions drive the formation of the carbon-based molecular building blocks of life.Cosmic chemistry and the evolution of galaxies Galaxy mergers, such as that of IC 1623 pictured here, can drive star formation, which in turn increases the chemical abundance of a galaxy. (Image credit: ESA–Webb/NASA/CSA/L. Armus & A. Evans)Some stars live for billions upon billions of years, but others exist for just a short time before either exploding in a supernova or expanding to become a red giant that then puffs off its outer layers into deep space. In both situations, the stars disperse large amounts of cosmic dust formed from elements heavier than hydrogen and helium across space.It turns out that there is a relationship between a galaxy's mass, its star-formation rate and its chemical abundances. Deviations from this relationship at high redshift might indicate that galaxies evolved differently in the early universe. Prior to JWST, astronomers could only reliably measure the abundances of various elements in galaxies up to a redshift of 3.3; in other words, galaxies that existed about 11.5 billion years ago. But how abundant these heavy elements were in galaxies earlier than this is a bit of a mystery, and fertile ground for JWST to really revolutionize our understanding.Early results from JWST have shown that the relationship between star formation and mass does hold for galaxies at redshifts as high as 8, but that their abundance of heavier elements is three times lower than expected. This discrepancy suggests that stars and galaxies formed more quickly than we realized, before enough generations of stars had the chance to die out and disperse their elements into the cosmos.JWST sets its sights on the solar system Brilliant Jupiter, its faint rings and several of its small moons imaged by JWST. (Image credit: NASA/ESA/Jupiter ERC Team/Ricardo Hueso (UPV/EHU) and Judy Schmidt)Although JWST was designed to probe deep space, it can also be used to observe our nearest neighbors, and the results have been pleasantly surprising.Astronomers were not sure what to expect when JWST pointed at Jupiter because of how fast it moves and how bright the planet is compared to the faint distant galaxies JWST usually observes. Scientists worried that Jupiter might overload JWST's sensitive detectors or wipe out fainter features with its glare, but the results were better than could be imagined. JWST's images showed Jupiter's faint rings and some of its small moons, as well as the planet's atmospheric bands and auroras. By observing in near- and mid-infrared light, with the high resolution that JWST's giant mirror provides, astronomers are able to peer deeper into Jupiter's atmosphere to see what's going on beneath the cloud tops and learn how deeply the clouds extend.On the left is a simulated map of Mars, and on the right is JWST's image of thermal emission from the surface of the planet. (Image credit: NASA/ESA/CSA/STScI/Mars JWST–GTO team)JWST has also imaged faraway Neptune, Saturn's moon Titan and Mars. While JWST's portrait of the Red Planet may not be aesthetically pleasing, it shows temperature variations on Mars' surface and absorption by carbon dioxide in its atmosphere. In the future, JWST will observe Mars to track more tenuous gases, such as mysterious seasonal plumes of methane that could originate in either geological or biological activity. Star formation JWST's mid-infrared image of the Pillars of Creation. (Image credit: NASA/ESA/CSA/STScI/J. DePasquale (STScI)/A. Pagan (STScI))One of the Hubble Space Telescope's most iconic images was that of the Pillars of Creation — columns of molecular gas many light-years long found in the Eagle Nebula. Those columns are cosmic nurseries where stars are born. JWST has revisited the Pillars of Creation, and the resulting images in near- and mid-infrared light are just as special as the original.But the new views are also more than just pretty pictures. JWST's infrared vision is able to penetrate through the dust in the Pillars to gain a better view of the star formation going on inside, showing knots of molecular gas on the verge of collapsing into nascent stars. When those stars are just a few hundred thousand years old, they begin to shoot out jets that erode the edges of the Pillars. Elsewhere, JWST has provided one of the most detailed looks at such a protostar, known as L1527, and how it is interacting with the molecular gas that is accreting onto it, prompting outbursts that are clearing out two cavities in the butterfly-shaped nebula.Before JWST, optical observations of young stars were limited because dust blocks their light. Radio and submillimeter observations can detect some of what is going on, and previous infrared telescopes could see broad strokes but nothing detailed. JWST now offers the resolution necessary to reveal the secrets of star formation in far greater detail than ever before.Changing how space telescopes are built JWST's 6.5-meter segmented mirror is an innovation that will be used on many large space telescope in the future. (Image credit: NASA/Chris Gunn)JWST took a lot of trouble and money to eventually get into orbit. Years overdue and billions of dollars over-budget, its revolutionary design has nevertheless blazed a new trail for space telescopes. In particular, its massive, golden primary mirror, formed by unfolding 18 hexagonal segments, was brand-new engineering to permit a telescope of such great size to be launched into space. In the future, the effort of designing and building JWST will pay off not only in the revolutionary scientific discoveries that it will make, but also in how it will inspire the design of the next generation of large space telescopes.The U.S. National Academies' decadal report on the astrophysics priorities over the next 10 years recommends as the top-priority project the development of a large optical and ultraviolet telescope to replace Hubble sometime in the 2040s. This telescope would have at minimum a mirror diameter of 26 feet (8 m), a feat that can be achieved only by the segmented design pioneered by JWST. The size of a rocket no longer constrains the size of your telescope; if it doesn't fit inside the rocket faring then the telescope can be folded up, just like JWST was. Whatever discoveries these future space telescopes make, we will have JWST to thank. Follow Keith Cooper on Twitter @21stCenturySETI. Follow us on Twitter @Spacedotcom and on Facebook. Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.
Keith Cooper is a freelance science journalist and editor in the United Kingdom, and has a degree in physics and astrophysics from the University of Manchester. He's the author of "The Contact Paradox: Challenging Our Assumptions in the Search for Extraterrestrial Intelligence" (Bloomsbury Sigma, 2020) and has written articles on astronomy, space, physics and astrobiology for a multitude of magazines and websites.
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Cosmology & The Universe
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Webb telescope discovers oldest galaxies ever observed
The James Webb Space Telescope has discovered the four most distant galaxies ever observed, one of which formed just 320 million years after the Big Bang when the universe was still in its infancy, new research said on Tuesday.
The Webb telescope has unleashed a torrent of scientific discovery since becoming operational last year, peering farther than ever before into the universe's distant reaches—which also means it is looking back in time.
By the time light from the most distant galaxies reaches Earth, it has been stretched by the expansion of the universe and shifted to the infrared region of the light spectrum.
The Webb telescope's NIRCam instrument has an unprecedented ability to detect this infrared light, allowing it to quickly spot a range of never-before-seen galaxies—some of which could reshape astronomers' understanding of the early universe.
In two studies published in the Nature Astronomy journal, astronomers revealed they have "unambiguously detected" the four most distant galaxies ever observed.
The galaxies date from 300 to 500 million years after the Big Bang more than 13 billion years ago, when the universe was just two percent of its current age.
That means the galaxies are from what is called "the epoch of reionisation," a period when the first stars are believed to have emerged. The epoch came directly after the cosmic dark ages brought about by the Big Bang.
'Surprising'
Stephane Charlot, a researcher at the Astrophysics Institute of Paris and co-author of the two new studies, told AFP that the farthest galaxy—called JADES-GS-z13-0—formed 320 million years after the Big Bang.
That is the greatest distance ever observed by astronomers, he said.
The Webb telescope also confirmed the existence of JADES-GS-z10-0, which dates from 450 million years after the Big Bang and had previously been spotted by the Hubble Space Telescope.
All four galaxies are "very low in mass," weighing roughly a hundred million solar masses, Charlot said. The Milky Way, in comparison, weighs 1.5 trillion solar masses by some estimations.
But the galaxies are "very active in star formation in proportion to their mass," Charlot said.
Those stars were forming "at around the same rate as the Milky Way," a speed that was "surprising so early in the Universe," he added.
The galaxies were also "very poor in metals," he added.
This is consistent with the standard model of cosmology, science's best understanding of how the universe works, which says that the closer to the Big Bang, the less time there is for such metals to form.
Technical tour de force'
However in February, the discovery of six massive galaxies from 500-700 million years after the Big Bang led some astronomers to question the standard model.
Those galaxies, also observed by the Webb telescope, were bigger than thought possible so soon after the birth of the universe—if confirmed, the standard model could need updating.
Pieter van Dokkum, an astronomer at Yale University not involved in the latest research, hailed the confirmation of the four newly-discovered distant galaxies as a "technical tour de force".
"The frontier is moving almost every month," van Dokkum commented in Nature, adding that there was now "only 300 million years of unexplored history of the universe between these galaxies and the Big Bang".
The Webb telescope has observed possible galaxies even closer to the Big Bang, but they have yet to be confirmed, he said.
More information: B. E. Robertson et al, Identification and properties of intense star-forming galaxies at redshifts z > 10, Nature Astronomy (2023). DOI: 10.1038/s41550-023-01921-1
Emma Curtis-Lake et al, Spectroscopic confirmation of four metal-poor galaxies at z = 10.3–13.2, Nature Astronomy (2023). DOI: 10.1038/s41550-023-01918-w
Pieter van Dokkum, An exciting era of exploration, Nature Astronomy (2023). DOI: 10.1038/s41550-023-01946-6
Journal information: Nature Astronomy
© 2023 AFP
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Cosmology & The Universe
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Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
Astronomers have detected a mysterious blast of radio waves that have taken 8 billion years to reach Earth. The fast radio burst is one of the most distant and energetic ever observed.
Fast radio bursts, or FRBs, are intense, millisecond-long bursts of radio waves with unknown origins. The first FRB was discovered in 2007, and since then, hundreds of these quick, cosmic flashes have been detected coming from distant points across the universe.
The burst, named FRB 20220610A, lasted less than a millisecond, but in that fraction of a moment, it released the equivalent of our sun’s energetic emissions over the course of 30 years, according to a study published Thursday in the journal Science.
Many FRBs release super bright radio waves lasting only a few milliseconds at most before disappearing, which makes fast radio bursts difficult to observe.
Radio telescopes have helped astronomers trace these quick cosmic flashes, including the ASKAP array of radio telescopes, located on Wajarri Yamaji Country in Western Australia. Astronomers used ASKAP to detect the FRB in June 2022 and determine where it originated.
“Using ASKAP’s array of (radio) dishes, we were able to determine precisely where the burst came from,” said study coauthor Dr. Stuart Ryder, astronomer at Macquarie University in Australia, in a statement. “Then we used (the European Southern Observatory’s Very Large Telescope) in Chile to search for the source galaxy, finding it to be older and (farther) away than any other FRB source found to date and likely within a small group of merging galaxies.”
The research team traced the burst to what appears to be a group of two or three galaxies that are in the process of merging, interacting and forming new stars. This finding aligns with current theories that suggest fast radio bursts may come from magnetars, or highly energetic objects that result from the explosions of stars.
Scientists believe that fast radio bursts may be a unique method that can be used to “weigh” the universe by measuring the matter between galaxies that remains unaccounted for.
“If we count up the amount of normal matter in the Universe — the atoms that we are all made of — we find that more than half of what should be there today is missing,” said study coauthor Ryan Shannon, a professor at Swinburne University of Technology in Australia, in a statement. “We think that the missing matter is hiding in the space between galaxies, but it may just be so hot and diffuse that it’s impossible to see using normal techniques.”
So far, the results of current methods used to estimate the universe’s mass don’t agree with one another, which suggests the entire scope of the universe isn’t included.
“Fast radio bursts sense this ionised material,” Shannon said. “Even in space that is nearly perfectly empty they can ‘see’ all the electrons, and that allows us to measure how much stuff is between the galaxies.”
This method of using fast radio bursts to detect missing matter was demonstrated by the late Australian astronomer Jean-Pierre Macquart in 2020.
“J-P showed that the (farther) away a fast radio burst is, the more diffuse gas it reveals between the galaxies. This is now known as the Macquart relation,” Ryder said. “Some recent fast radio bursts appeared to break this relationship.
Our measurements confirm the Macquart relation holds out to beyond half the known Universe.”
Nearly 50 fast radio bursts have been traced to date back to their origin points, and about half of them have been found using ASKAP.
“While we still don’t know what causes these massive bursts of energy, the paper confirms that fast radio bursts are common events in the cosmos and that we will be able to use them to detect matter between galaxies, and better understand the structure of the Universe,” Shannon said.
Astronomers said they hope that future radio telescopes, currently under construction in South Africa and Australia, will enable the detection of thousands more fast radio bursts at greater distances.
“The fact that FRBs are so common is also amazing,” Shannon said. “It shows how promising the field can be, because you’re not just going to do this for 30 bursts, you can do this for 30,000 bursts, make a new map of the structure of the universe, and use it to answer big questions about cosmology.”
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Cosmology & The Universe
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Pinpoint simulations provide perspective on universe structure
The universe is peppered with galaxies, which, on large scales, exhibit a filamentary pattern, referred to as the cosmic web. This heterogeneous distribution of cosmic material is in some ways like blueberries in a muffin where material clusters in certain areas but may be lacking in others.
Based on a series of simulations, researchers have begun to probe the heterogeneous structure of the universe by treating the distribution of galaxies as a collection of points—like the individual particles of matter that make up a material—rather than as a continuous distribution. This technique has enabled the application of mathematics developed for materials science to quantify the relative disorder of the universe, enabling a better understanding of its fundamental structure.
"What we found was that the distribution of galaxies in the universe is quite different from the physical properties of conventional materials, having its own unique signature," explained Oliver Philcox, a co-author of the study.
This work, now published in Physical Review X, was conducted by Salvatore Torquato, frequent Member and Visitor at the Institute for Advanced Study and Lewis Bernard Professor of Natural Sciences based in Princeton University's departments of chemistry and physics; and Oliver Philcox a visiting Ph.D. student at the Institute from September 2020 to August 2022, now a Junior Fellow in the Simons Society of Fellows, hosted at Columbia University.
The pair analyzed public simulation data generated by Princeton University and the Flatiron Institute. Each of the 1,000 simulations consists of a billion dark matter "particles," whose clusters, formed by gravitational evolution, serve as a proxy for galaxies.
One of the main results of the paper concerns the correlations of pairs of galaxies that are topologically connected to one another by means of the pair-connectedness function. Based on this—and the array of other descriptors that arise in the theory of heterogeneous media—the research team showed that on the largest scales (on the order of several hundred megaparsecs), the universe approaches hyperuniformity, while on smaller scales (up to 10 megaparsecs) it becomes almost antihyperuniform and strongly inhomogeneous.
"The perceived shift between order and disorder depends largely on scale," stated Torquato. "The pointillist technique of Georges Seurat in the painting A Sunday on La Grande Jatte produces a similar visual effect; the work appears disordered when viewed up-close and highly ordered from afar. In terms of the universe, the degree of order and disorder is more subtle, as with a Rorschach inkblot test that can be interpreted in an infinite number of ways."
Statistical tools, specifically nearest-neighbor distributions, clustering diagnostics, Poisson distributions, percolation thresholds, and the pair-connectedness function, allowed the researchers to develop a consistent and objective framework for measuring order. Therefore, their findings, while made in a cosmological context, translate to a number of other dynamical, physical systems.
This interdisciplinary work, combining the techniques of cosmology and condensed matter physics, has future implications for both fields. Beyond the distribution of galaxies, many other features of the universe can be explored with these tools, including cosmic voids and the ionized hydrogen bubbles that formed during the reionization phase of the universe.
Conversely, the novel phenomena discovered about the universe may also provide insight into various material systems on Earth. The team recognizes that more work will be needed before these techniques can be applied to real data, but this work provides a strong proof-of-concept with significant potential.
More information: Oliver H. E. Philcox et al, Disordered Heterogeneous Universe: Galaxy Distribution and Clustering across Length Scales, Physical Review X (2023). DOI: 10.1103/PhysRevX.13.011038
Journal information: Physical Review X
Provided by Institute for Advanced Study
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Cosmology & The Universe
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For the first time, astronomers have linked mysterious pulses of energy called fast radio bursts (FRBs) with the ripples in space-time emitted by collapsed, colliding stars. The findings, published March 27 in the journal Nature Astronomy (opens in new tab), propose a new explanation for FRBs, which have vexed scientists for more than a decade.
FRBs are massive blasts of radio energy that can outshine every star in an entire galaxy combined, while lasting just fractions of a second. Though FRBs were discovered in 2007, their origins remain shrouded in mystery. That's partially because, while some FRBs repeat periodically, many appear and disappear in mere milliseconds.
Magnetars — the ultradense, collapsed cores of exploded stars (known as neutron stars) with powerful magnetic fields — are the leading candidates for the emission of FRBs. But recent observations suggest there may be multiple possible sources, which may include neutron star collisions.
In April 2019, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected ripples in space-time known as gravitational waves from a neutron star merger designated GW190425. Hours later, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) spotted a bright, nonrepeating FRB from the same region of space.
"We discovered a burst of radio waves, lasting one-thousandth of a second, was generated two and a half hours after the merger of two neutron stars, which are the extremely dense remnants of exploded massive stars," study co-author Clancy James (opens in new tab), a radio astronomer at Curtin University in Australia, told Live Science via email. "Our theory is that this burst of radio waves occurred because the merger created a 'supermassive' neutron star which, when its spin slowed down, collapsed into a black hole."
While neutron star mergers have been suggested as possible causes of FRBs in the past, the new observations provide the first evidence that the theory may be correct. The team used three primary pieces of information to make this connection.
"Firstly the timing of the events,” James said; the FRB arrived just 2.5 hours after the gravitational wave signal. Secondly, the location of the FRB was consistent with that of the gravitational wave.
"And thirdly the distance," James added. "It was especially the distance that helped."
While most FRBs arrive from billions of light-years away, gravitational wave detectors such as LIGO are sensitive to distances of only around 500 million light-years. This FRB was unusually close, and its estimated distance was spot-on with that estimated from GW190425.
"What surprised us was just how much all the pieces fell into place!" James said. "This was a beautiful clean pulse — exactly what you might expect from a cataclysmic event."
According to James, these results indicate that there are at least two different families of FRBs: one-off FRBs from cataclysmic events such as neutron star mergers, and repeating FRBs produced by magnetars or another unknown source.
This discovery may also affect scientists' understanding of neutron stars, as it suggests that the largest possible mass of these stellar remnants could be greater than currently expected.
"This is because the resulting object from the two merging neutron stars didn't collapse immediately into a black hole, but could temporarily resist gravity," James said. "In turn, this tells us something about the fundamental nature of matter at extreme densities and pressures, which we can't study here on Earth. It may even be evidence of a new kind of star — a quark star."
The team hopes to strengthen the relationship between FRBs and neutron star mergers as the world's gravitational wave observatories begin new observations this spring.
"The next operating run of the gravitational wave observatories, O4, begins in May and CHIME and other radio telescopes like the Murchison Widefield Array that I work with are waiting to see if there's an FRB from any neutron star mergers that are seen," James said. "We're also commissioning a new instrument to detect more FRBs and pinpoint them to their galaxies. Hopefully, that'll start working shortly!
Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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We’ve now seen farther, deeper and more clearly into space than ever before. A stellar birthplace, a nebula surrounding a dying star, a group of closely interacting galaxies, the first spectrum of an exoplanet’s light. These are some of the first images from the James Webb Space Telescope, released in a NASA news briefing on July 12. This quartet of cosmic scenes follows on the heels of the very first image released from the telescope, a vista of thousands of distant galaxies, presented in a White House briefing on July 11. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox “First of all, it’s really gorgeous. And it’s teeming with galaxies,” said JWST Operations Scientist Jane Rigby of NASA’s Goddard Space Flight Center in Greenbelt, Md., at the July 12 briefing. “That’s been true of every image we’ve taken with Webb. We can’t take [an image of] blank sky. Everywhere we look, there’s galaxies everywhere.” Going deep The galaxies captured in the first released image lie behind a cluster of galaxies about 4.6 billion light-years away. The mass from those closer galaxies distorts spacetime in such a way that objects behind the cluster are magnified, giving astronomers a way to peer more than 13 billion years into the early universe. Even with that celestial assist, other existing telescopes could never see so far. But the James Webb Space Telescope, also known as JWST, is incredibly large — at 6.5 meters across, its mirror is nearly three times wider than that of the Hubble Space Telescope. It also sees in the infrared wavelengths of light where distant galaxies appear. Those features give it an edge over previous observatories. “There’s a sharpness and a clarity we’ve never had,” Rigby said. “You can really zoom in and play around.” Specks of light from ancient galaxies whose light traveled 13 billion years to reach us sparkle in this first image released from the James Webb Space Telescope. The composite of images is the deepest view of the universe ever captured — a record astronomers don’t expect to last long.NASA, ESA, CSA, STScI Although that first image represents the deepest view of the cosmos to date, “this is not a record that will stand for very long,” astronomer Klaus Pontoppidan of the Space Telescope Science Institute in Baltimore said in a June 29 news briefing. “Scientists will very quickly beat that record and go even deeper.” But JWST wasn’t built only to peer deeper and farther back in time than ever before. The cache of first images and data showcases space scenes both near and far, glimpses of single stars and entire galaxies, and even a peek into the chemical composition of a far-off planet’s atmosphere. “These are pictures just taken over a period of five days. Every five days, we’re getting more data,” said European Space Agency science advisor Mark McCaughrean. (JWST is an international collaboration among NASA, ESA and the Canadian Space Agency.) “It’s a culmination of decades of work, but it’s just the beginning of decades. What we’ve seen today with these images is essentially that we’re ready now.” Cosmic cliffs This image shows the “Cosmic Cliffs,” part of the enormous Carina nebula, a region about 7,600 light-years from Earth where many massive stars are being born. Some of the most famous Hubble Space Telescope images feature this nebula in visible light, but JWST shows it in “infrared fireworks,” Pontoppidan says. JWST’s infrared detectors can see through dust, so the nebula appears especially spangled with stars. Newborn stars sculpt the gas and dust around them in this JWST image of the Cosmic Cliffs in the Carina nebula, a star-forming region in the Milky Way galaxy.NASA, ESA, CSA, STScI “We’re seeing brand new stars that were previously completely hidden from our view,” said NASA astrophysicist Amber Straughn. But molecules in the dust itself are glowing too. Energetic winds from baby stars in the top of the image are pushing and sculpting the wall of gas and dust that runs across the middle. “We see examples of bubbles and cavities and jets that are being blown out from newborn stars,” Straughn said. And gas and dust are the raw material for new stars — and new planets. “It reminds me that our sun and our planets, and ultimately us, were formed out of this same stuff that we see here,” Straughn said. “We humans really are connected to the universe. We’re made out of the same stuff.” Foamy nebula The Southern Ring nebula is an expanding cloud of gas that surrounds a dying star about 2,000 light-years from Earth. In previous Hubble images, the nebula looks like an oblong swimming pool with a fuzzy orange deck and a bright diamond, a white dwarf star, in the middle. JWST expands the view far beyond that, showing more tendrils and structures in the gas than previous telescopes could see. “You see this bubbly, almost foamy appearance,” said JWST astronomer Karl Gordon. In the left hand image, which captures near-infrared light from JWST’s NIRCam instrument, the foaminess traces molecular hydrogen that formed as dust expanded away from the center. The center appears blue due to hot ionized gas heated by the leftover core of the star. Rays of light escape the nebula like the sun peeking through patchy clouds. In the right hand image, taken by the MIRI mid-infrared camera, the outer rings look blue and trace hydrocarbons forming on the surface of dust grains. The MIRI image also reveals a second star in the nebula’s core. “We knew this was a binary star, but we didn’t see much of the actual star that produced this nebula,” Gordon said. “Now in MIRI this star glows red.” JWST captured an image of the Southern Ring nebula in near-infrared (left) and mid-infrared (right) light, highlighting wispy structures at the nebula’s edge and revealing a second star in the middle.NASA, ESA, CSA, STScI A galactic quintet Stephan’s Quintet is a group of galaxies about 290 million light-years away that was discovered in 1877. Four of the galaxies are engaged in an intimate gravitational dance, with one member of the group passing through the core of the cluster. (The fifth galaxy is actually much closer to Earth and just appears in a similar spot on the sky.) JWST’s images show off more structure within the galaxies than previous observations did, revealing where stars are being born. “This is a very important image and area to study,” because it shows the sort of interactions that drive the evolution of galaxies, said JWST scientist Giovanna Giardino of the European Space Agency. This composite image of Stephan’s Quintet shows five galaxies in mid- and near-infrared light. Four of the galaxies are bound by each others’ gravity in an endless looping dance. The fifth, the large galaxy to the left, is in the foreground, much closer to Earth than the other four. NASA, ESA, CSA, STScI In an image from the MIRI instrument alone, the galaxies look like wispy skeletons reaching towards each other. Two galaxies are clearly close to merging. And in the top galaxy, evidence of a supermassive black hole comes to light. Material swirling around the black hole is heated to extremely high temperatures and glows in infrared light as it falls into the black hole. An exoplanet’s sky This “image” is clearly different from the others, but it’s no less scientifically exciting. It shows the spectrum of light from the star WASP 96 as it passes through the atmosphere of its gas giant planet, WASP 96b. “You get a bunch of what looks like bumps and wiggles to some people but it’s actually full of information content,” said NASA exoplanet scientist Knicole Colón. “You’re actually seeing bumps and wiggles that indicate the presence of water vapor in the atmosphere of this exoplanet.” The planet is about half the mass of Jupiter and orbits its star every 3.4 days. Previously astronomers thought it had no clouds in its sky, but the new data from JWST show signs of clouds and haze. “There is evidence of clouds and hazes because the water features are not quite as large as we predicted,” Colón said. Probing a planet JWST took a spectrum of light from the star WASP 96 filtering through the atmosphere of its giant planet WASP 96b. The bumps and wiggles show how much light at various wavelengths gets absorbed by the atmosphere, revealing signs of water vapor, haze and unexpected clouds. Spectrum of exoplanet WASP 96b’s atmosphere NASA, ESA, CSA, STScINASA, ESA, CSA, STScI A long time coming These first images and data have been a very long time coming. The telescope that would become JWST was first dreamed up in the 1980s, and the planning and construction suffered years of budget issues and delays (SN: 10/6/21). The telescope finally launched on December 25. It then had to unfold and assemble itself in space, travel to a gravitationally stable spot about 1.5 million kilometers from Earth, align its insectlike primary mirror made of 18 hexagonal segments and calibrate its science instruments (SN: 1/24/22). There were hundreds of possible points of failure in that process, but the telescope unfurled successfully and got to work. “We are so thrilled that it works because there’s so much at risk,” says JWST senior project scientist John Mather. “The world has trusted us to put our billions into this and make it go, and it works. So it’s an immense relief.” The James Webb Space Telescope (illustrated) spent months unfolding and calibrating its instruments after it launched on December 25. Adriana Manrique Gutierrez/CIL/GSFC/NASA In the months following, the telescope team released teasers of imagery from calibration, which already showed hundreds of distant, never-before-seen galaxies. But the images now being released are the first full-color pictures made from the data scientists will use to start unraveling mysteries of the universe. “It sees things that I never dreamed were out there,” Mather says. For the telescope team, the relief in finally seeing the first images was palpable. “It was like, ‘Oh my god, we made it!’” says image processor Alyssa Pagan, also of Space Telescope Science Institute. “It seems impossible. It’s like the impossible happened.” In light of the expected anticipation surrounding the first batch of images, the imaging team was sworn to secrecy. “I couldn’t even share it with my wife,” says Pontoppidan, leader of the team that produced the first color science images. “You’re looking at the deepest image of the universe yet, and you’re the only one who’s seen that,” he says, of the first picture released July 11. “It’s profoundly lonely.” Soon, though, the team of scientists, image processors and science writers was seeing something new every day for weeks as the telescope downloaded the first images. “It’s a crazy experience,” Pontoppidan says. “Once in a lifetime.” For Pagan, the timing is perfect. “It’s a very unifying thing,” she says. “The world is so polarized right now. I think it could use something that’s a little bit more universal and connecting. It’s a good perspective, to be reminded that we’re part of something so much greater and beautiful.” JWST is just getting started as it now begins its first round of full science operations. “There’s lots more science to be done,” Mather says. “The mysteries of the universe will not come to an end anytime soon.” Asa Stahl contributed to this story.
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Cosmology & The Universe
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Astronomers have spotted the wreckage left by a massive collision between two huge icy planets around a distant, sunlike star.
Using a NASA spacecraft that monitors the sky for asteroids, the scientists also detected the bright afterglow generated by the planetary smash-up and the resulting dust cloud that crossed the face of the system's parent star, dimming it significantly.
A curious astronomer tipped the team off about the collision after spotting that the star — designated ASASSN-21qj and located around 3,600 light-years from Earth — had a strange light output that doubled in intensity in infrared light before fading in visible light three years later.
"An astronomer on social media pointed out that the star brightened up in the infrared over a thousand days before the optical fading. I knew then this was an unusual event," Matthew Kenworthy, study co-lead and a researcher at Leiden University, said in a statement. "To be honest, this observation was a complete surprise to me."
The researchers continued to study ASASSN-21qj for two years, watching how its brightness changed over time. They published their findings on Oct. 11 in the journal Nature.
The team found that the collision of two ice giants likely caused the system to double in brightness at infrared wavelengths three years before ASASSN-21qj started to fade in visible light.
Simulating a cool collision
The researchers conducted a simulation of how such a collision would proceed, modeling the initial impact and then the dispersal of particles flung out by the clash. This revealed that the ASASSN-21qj planets likely collated into a single body after the collision.
The simulation enabled the team to determine how the debris cloud would have expanded outwards from the collision site, taking three years to travel far enough to cover ASASSN-21qj as seen from Earth, causing it to dim in visible light.
"Our calculations and computer models indicate the temperature and size of the glowing material, as well as the amount of time the glow has lasted, is consistent with the collision of two ice giant exoplanets," co-lead author Simon Lock, a researcher at the University of Bristol, explained.
Determining the temperature of this planetary wreckage also helped the team to deduce what the infrared glow created by this violent event would look like. An emission matching this profile had been detected by NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft, which hunts for asteroids and comets within our solar system.
The scientists aren't finished observing ASASSN-21qj and its planetary wreckage just yet. They will watch the system over the coming years, and they expect that the debris cloud will spread out along the orbit of the destroyed planets. The researchers may attempt to catch light scattering off this dust cloud using ground-based observatories and space-based telescopes like the James Webb Space Telescope.
"It will be fascinating to observe further developments. Ultimately, the mass of material around the remnants may condense to form a retinue of moons that will orbit around this new planet," study co-author Zoë Leinhardt, an associate professor of Astrophysics at the University of Bristol, said.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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This image provided by NASA on Monday, July 11, 2022, shows galaxy cluster SMACS 0723, captured by the James Webb Space Telescope. The telescope is designed to peer back so far that scientists can get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.(Uncredited / ASSOCIATED PRESS)Our view of the universe just expanded: The first image from NASA’s new space telescope unveiled Monday is brimming with galaxies and offers the deepest look of the cosmos ever captured.The first image from the $10 billion James Webb Space Telescope is the farthest humanity has ever seen in both time and distance, closer to the dawn of time and the edge of the universe. That image will be followed Tuesday by the release of four more galactic beauty shots from the telescope’s initial outward gazes.The “deep field” image released at a White House event is filled with lots of stars, with massive galaxies in the foreground and faint and extremely distant galaxies peeking through here and there. Part of the image is light from not too long after the Big Bang, which was 13.8 billion years ago.“We’re going to give humanity a new view of the cosmos,” NASA Administrator Bill Nelson told reporters last month in a briefing. “And it’s a view that we’ve never seen before.”This image provided by NASA on Monday, July 11, 2022, shows galaxy cluster SMACS 0723, captured by the James Webb Space Telescope. The telescope is designed to peer back so far that scientists can get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus. (NASA/ESA/CSA via AP)(Uncredited / ASSOCIATED PRESS)The images on tap for Tuesday include a view of a giant gaseous planet outside our solar system, two images of a nebula where stars are born and die in spectacular beauty and an update of a classic image of five tightly clustered galaxies that dance around each other.The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.Webb is considered the successor to the highly successful, but aging Hubble Space Telescope. Hubble has stared as far back as 13.4 billion years. It found the light wave signature of an extremely bright galaxy in 2016. Astronomers measure how far back they look in light-years with one light-year being 5.8 trillion miles (9.3 trillion kilometers).“Webb can see backwards in time to just after the Big Bang by looking for galaxies that are so far away that the light has taken many billions of years to get from those galaxies to our telescopes,” said Jonathan Gardner, Webb’s deputy project scientist said during the media briefing.How far back did that first image look? Over the next few days, astronomers will do intricate calculations to figure out just how old those galaxies are, project scientist Klaus Pontoppidan said last month.The deepest view of the cosmos “is not a record that will stand for very long,” Pontoppidan said, since scientists are expected to use the telescope to go even deeper.Thomas Zurbuchen, NASA’s science mission chief said when he saw the images he got emotional and so did his colleagues: “It’s really hard to not look at the universe in new light and not just have a moment that is deeply personal.”At 21 feet (6.4 meters), Webb’s gold-plated, flower-shaped mirror is the biggest and most sensitive ever sent into space. It’s comprised of 18 segments, one of which was smacked by a bigger than anticipated micrometeoroid in May. Four previous micrometeoroid strikes to the mirror were smaller. Despite the impacts, the telescope has continued to exceed mission requirements, with barely any data loss, according to NASA.NASA is collaborating on Webb with the European and Canadian space agencies.“I’m now really excited as this dramatic progress augurs well for reaching the ultimate prize for many astronomers like myself: pinpointing “Cosmic Dawn” — the moment when the universe was first bathed in starlight,” Richard Ellis, professor of astrophysics at University College London, said via email.Get the breaking newsGet email alerts on breaking news stories as soon as they happen.By signing up you agree to our privacy policyMost Popular on DallasNews.com123456
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Cosmology & The Universe
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The bright galaxies found by the James Webb Space Telescope (JWST) in the very early universe could be the product of bursts of massive star formation — and it's likely that this fact renders the galaxies more luminous than expected for the era in which they exist. This is the conclusion drawn by researchers who used computer simulations to model how these galaxies formed and began producing stars.
When the JWST began science operations in the summer of 2022, its deep observations of the universe quickly began turning up high-redshift galaxies. These are galaxies that seemed to have existed earlier in the universe than astronomers had ever seen before. In fact, the galaxies, which were seen as they were when the universe was less than 400 million years old, appeared more luminous than what the standard model of cosmology predicts for the era. This led to claims that the standard model —which depicts galaxies starting off small and then growing hierarchically through mergers driven by filaments and haloes of dark matter in the cosmic web — must be wrong.
"The discovery of these galaxies was a big surprise because they were substantially brighter than anticipated," Claude-André Faucher-Giguère of Northwestern University said in a statement. "Typically, a galaxy is bright because it's big, but since these galaxies formed at cosmic dawn, not enough time has passed since the Big Bang. How could these massive galaxies assemble so quickly?"
Faucher-Giguère is a member of a team led by Guochao Sun of Caltech, who together are performing simulations of how the first galaxies formed. They found that rather than being big, the galaxies observed by the JWST are luminous because they are seen during a time when they underwent a frenzy of star formation. The simulations succeed in not only modeling the luminosity of the galaxies, but also their abundance, both of which exactly match what the JWST observes.
"A system doesn’t need to be that massive," said Sun. "If star formation happens in bursts, it will emit flashes of light. That is why we see several very bright galaxies."
Starbursts like these are not unusual. Astronomers even witness them happening in galaxies today, sometimes when there has been a collision with another galaxy. This sort of merger can result in molecular gas being stirred up to the point that gravity takes hold and forces the gas to fragment and collapse, forming a bunch of stars all at once. In the early universe, where the environment was still pretty tumultuous, the first galaxies may not have accreted all their star-forming material at an even rate.
"Bursty star formation is especially common in low-mass galaxies," said Faucher-Giguère. "What we think happens is that a burst of stars form, then a few million years later those stars explode as supernovae. The gas gets kicked out [of the galaxy] and then falls back in to form new stars, driving the cycle of star formation."
In the early universe, galaxies were much smaller than they are today, and grew partly by accreting intergalactic clouds of gas, but also by merging with other galaxies. The larger they became, the more gravity they had, reaching a point where they could hang on to more of their star-forming material. This steadied the rate of star formation, and today galaxies such as our Milky Way form stars at a more sedate pace.
Most importantly, the results from the new simulations fit with the hierarchical growth model of galaxies as depicted in the standard model of cosmology.
"Our simulations show that galaxies have no problem forming this brightness by cosmic dawn,"said Faucher-Giguère.
The findings were published on Oct. 3 in The Astrophysical Journal Letters.
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Cosmology & The Universe
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WASHINGTON -- A stellar nursery where stars are born, interactions between galaxies and a unique view of an exoplanet are just some of the new cosmic images that will be shared Tuesday.After decades of waiting, it's finally time for the world to see the first images taken by the most powerful space telescope ever -- the James Webb Space Telescope.Development of the world's premier space observatory began in 2004, and after years of delays, the telescope and its massive gold mirror finally launched on December 25.The images are worth the wait -- and they will forever change the way we see the universe.President Joe Biden released one of Webb's first images on Monday, and it is "the deepest and sharpest infrared image of the distant universe to date," according to NASA. The rest of the high-resolution color images will make their debut on Tuesday.There are several events taking place during Tuesday's image release, and all of them will stream live on NASA's website.MORE: NASA's new space telescope in home stretch of tests, delivering stunning image of neighboring galaxyOpening remarks by NASA leadership and the Webb team are scheduled to begin Tuesday at 9:45 a.m. ET, followed by an image release broadcast that kicks off at 10:30 a.m. ET. Images will be revealed one by one, and a news conference at 12:30 p.m. ET will offer details about them.The space observatory can investigate the mysteries of the universe by observing them through infrared light, which is invisible to the human eye.Webb will peer into the very atmospheres of exoplanets, some of which are potentially habitable, and it could uncover clues in the ongoing search for life outside of Earth.The telescope will also look at every phase of cosmic history, including the first glows after the big bang that created our universe and the formation of the galaxies, stars and planets that fill it today.Now, Webb is ready to help us understand the origins of the universe and begin to answer key questions about our existence, such as where we came from and if we're alone in the cosmos.The first imagesThe first image, released on Monday, shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this created Webb's first deep field view that includes incredibly old and faint galaxies.Some of these distant galaxies and star clusters have never been seen before. The galaxy cluster is shown as it appeared 4.6 billion years ago.The image, taken by Webb's Near-Infrared Camera, is composed of images taken at different wavelengths of light over a collective 12.5 hours. Deep field observations are lengthy observations of regions of the sky that can reveal faint objects.SEE ALSO: NASA says something strange is happening with our universeWebb's other primary targets for the first image release include the Carina Nebula, WASP-96b, the Southern Ring Nebula and Stephan's Quintet.Located 7,600 light-years away, the Carina Nebula is a stellar nursery, where stars are born. It is one of the largest and brightest nebulae in the sky and home to many stars much more massive than our sun.Webb's study of the giant gas planet WASP-96b will be the first full-color spectrum of an exoplanet. The spectrum will include different wavelengths of light that could reveal new information about the planet, such as whether it has an atmosphere. Discovered in 2014, WASP-96b is located 1,150 light-years from Earth. It has half the mass of Jupiter and completes an orbit around its star every 3.4 days.The Southern Ring Nebula, also called the "Eight-Burst," is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star.The space telescope's view of Stephan's Quintet will reveal the way galaxies interact with one another. This compact galaxy group, first discovered in 1787, is located 290 million light-years away in the constellation Pegasus. Four of the five galaxies in the group "are locked in a cosmic dance of repeated close encounters," according to a NASA statement.The targets were selected by an international committee, including members from NASA, the European Space Agency, the Canadian Space Agency and the Space Telescope Science Institute in Baltimore.The mission, originally expected to last for 10 years, has enough excess fuel capability to operate for 20 years, according to NASA Deputy Administrator Pam Melroy.These will be just the first of many images to come from Webb over the next two decades, which promises to fundamentally alter the way we understand the cosmos.The-CNN-Wire ™ & © 2022 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.
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Cosmology & The Universe
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GREENBELT, Md. — NASA on Tuesday unveiled a new batch of images from its new powerful space telescope, including a foamy blue and orange shot of a dying star.The first image from the $10 billion James Webb Space Telescope was released Monday at the White House — a jumble of distant galaxies that went deeper into the cosmos than humanity has ever seen.The four additional photos released Tuesday included more cosmic beauty shots.This image released by NASA on Tuesday, July 12, 2022, shows the edge of a star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on the James Webb Space Telescope, this image reveals previously obscured areas of star birth, according to NASA. (Uncredited / ASSOCIATED PRESS)With one exception, the latest images showed parts of the universe seen by other telescopes. But Webb’s sheer power, distant location off Earth and use of the infrared light spectrum showed them in new light.“Every image is a new discovery and each will give humanity a view of the humanity that we’ve never seen before,’’ NASA Administrator Bill Nelson said Tuesday, rhapsodizing over images showing “the formation of stars, devouring black holes.”Webb’s use of the infrared light spectrum allows the telescope to see through the cosmic dust and “see light from faraway light from the corners of the universe,” he said.“We’ve really changed the understanding of our universe,” said European Space Agency director general Josef Aschbacher.The European and Canadian space agencies joined NASA in building the powerful telescope.Related:First image of universe from James Webb Telescope shared by NASA, White HouseOn tap Tuesday:— The Southern Ring Nebula, which is sometimes called “eight-burst.’ About 2,500 light-years away, it shows an expanding cloud of gas surrounding a dying star. A light-year is 5.8 trillion miles.— Carina Nebula, one of the bright stellar nurseries in the sky, about 7,600 light-years away.— Five galaxies in a cosmic dance, 290 million light-years away. Stephan’s Quintet was first seen 225 years ago in the constellation Pegasus.This image provided by NASA on Tuesday, July 12, 2022, shows Stephan's Quintet, a visual grouping of five galaxies captured by the Webb Telescope. This mosaic was constructed from almost 1,000 separate image files, according to NASA. (NASA / ASSOCIATED PRESS)— A blueish giant planet called WASP-96b. It’s about the size of Saturn and is 1,150 light-years away. A gas planet, it’s not a candidate for life elsewhere but a key target for astronomers.This combo of images released by NASA on Tuesday, July 12, 2022, shows a side-by-side comparison of the Southern Ring Nebula in near-infrared light, at left, and mid-infrared light, at right, from the Webb Telescope.(Uncredited / ASSOCIATED PRESS)The images were released one-by-one at an event at NASA’s Goddard Space Center that included cheerleaders with pompoms the color of the telescope’s golden mirrors.The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.Webb is considered the successor to the highly successful, but aging Hubble Space Telescope.FILE - In this April 13, 2017 photo provided by NASA, technicians lift the mirror of the James Webb Space Telescope using a crane at the Goddard Space Flight Center in Greenbelt, Md. The telescope is designed to peer back so far that scientists will get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects.(Laura Betz / ASSOCIATED PRESS)
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Cosmology & The Universe
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Euclid mission releases its first images
The Euclid mission, which will investigate the mysteries of dark matter and dark energy, released its first five science images Tuesday, Nov. 7. The observatory, led by ESA (European Space Agency) with NASA contributions, is scheduled to begin regular science operations in early 2024.
The new images include views of a large cluster of thousands of distant galaxies, close-ups of two nearby galaxies, a gravitationally bound group of stars called a globular cluster, and a nebula (a cloud of gas and dust in space where stars form)—all depicted in vibrant colors.
"The Euclid observatory will uncover a treasure trove of scientific discoveries that will be used across the world, including by U.S. scientists, for years to come," said Nicola Fox, associate administrator, Science Mission Directorate, at NASA Headquarters in Washington.
"Together, NASA and ESA are paving the way for a new era of cosmology for NASA's forthcoming Nancy Grace Roman Space Telescope, which will build upon what Euclid learns and will additionally survey objects on the outskirts of our solar system, discover thousands of new planets, explore nearby galaxies, and more."
Euclid launched on July 1 from Cape Canaveral, Florida, then traveled nearly 1 million miles to its vantage point. Following a period of commissioning (testing of the instruments and other components), the space telescope is performing as expected.
NASA's Jet Propulsion Laboratory in Southern California delivered critical hardware for one of the Euclid spacecraft's instruments. In addition, NASA has established a U.S.-based Euclid science data center, and NASA science teams will join other Euclid scientists in studying dark energy, galaxy evolution, and dark matter.
The agency's Nancy Grace Roman mission will also study dark energy—in ways that are complementary to Euclid. Mission planners will use Euclid's findings to inform Roman's dark energy work.
Surveying the dark universe
During its planned six-year mission, Euclid will produce the most extensive 3D map of the universe yet, covering nearly one-third of the sky and containing billions of galaxies up to 10 billion light-years away from Earth.
To do this, Euclid needs a wide field of view, which enabled these new images covering a relatively large area. In this way, Euclid differs from targeted observatories like NASA's James Webb Space Telescope that focus on a smaller area of the sky at any one time but typically offer higher-resolution images. Wide-field observatories like Euclid can observe large sections of the sky much faster than targeted telescopes. In addition, Euclid has high resolution compared to previous survey missions, which means it will be able to see more galaxies in each image than previous telescopes.
For example, Euclid's wide view was able to capture the entirety of the Perseus galaxy cluster, and many galaxies beyond it, in just one image. Located 240 million light-years from Earth, Perseus is among the most massive structures known in the universe. Euclid's full survey will ultimately cover an area 30,000 times larger than this image.
The telescope's survey approach is necessary to study dark energy, the mysterious driver behind our universe's accelerating expansion. While gravity should pull everything in the universe together, everything is instead moving apart faster and faster. "Dark energy" is the term scientists use for this unexplained expansion.
To study the phenomenon, scientists will map the presence of another cosmic mystery, dark matter. This invisible substance can be observed only by its gravitational effect on "regular" matter and objects around it, like stars, galaxies, and planets.
Dark matter is five times more common in the cosmos than regular matter, so if dark energy's expansive influence on the universe has changed over time, the change should be recorded in how dark matter is distributed on large scales across the universe, and Euclid's 3D map should capture it.
"Euclid's first images mark the beginning of a new era of studying dark matter and dark energy," said Mike Seiffert, Euclid project scientist at JPL. "This is the first space telescope dedicated to dark universe studies, and the sheer scale of the data we're going to get out of this will be unlike anything we've had before. These are big mysteries, so it's exciting for the international cosmology community to see this day finally arrive."
NASA's Roman mission will study a smaller section of sky than Euclid, but it will provide higher-resolution images of hundreds of millions of galaxies and peer deeper into the universe's past, providing complementary information. Scheduled to launch by May 2027.
The data from the new Euclid images is now available to the scientific community, and scientific papers analyzing that data are expected to follow. As the mission progresses, Euclid's bank of data will grow. New batches will be released once per year and will be available to the global scientific community via the Astronomy Science Archives hosted at ESA's European Space Astronomy Centre in Spain.
Provided by NASA
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Cosmology & The Universe
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Supermassive black holes could be the engines driving the expansion of the universe, according to research that proposes a solution to "one of the biggest problems in cosmology."
By comparing supermassive black holes across nine billion years of cosmic history, astronomers have discovered a clue that the ravenous behemoths lurking at the hearts of most galaxies may be the source of dark energy — the mysterious force that makes up 68% of the known universe and causes its accelerating expansion. The researchers published their findings Feb 2. and Feb 15. in two papers in The Astrophysical Journal and The Astrophysical Journal Letters.
"If the theory holds, then this is going to revolutionize the whole of cosmology, because at last we've got a solution for the origin of dark energy that's been perplexing cosmologists and theoretical physicists for more than 20 years," co-author Chris Pearson (opens in new tab), an astrophysicist at the Rutherford Appleton Laboratory (RAL) in the U.K. said in a statement (opens in new tab).
Dark energy revealed
Over the last century, astronomers discovered that the universe was expanding at an ever faster pace. This was surprising given that, acting on its own, gravity should be expected to slowly crumple the cosmos together in an event known as the Big Crunch. To explain the discrepancy, scientists proposed something powerful enough to counteract gravity — pushing everything in the cosmos further apart. They named that something dark energy.
But for dark energy to reverse the universe’s collapse, it would have to be present in such enormous quantities that it makes up the vast majority of the universe. Yet, until now, it has been nowhere to be seen.
Now, the new studies have seemingly found a clue as to how the hidden phenomenon works. Both teams compared the masses of black holes at the center of two sets of galaxies. One group was young and remote, with light that arrived to us from nine billion years in the past, while a nearer and older group sits only some millions of light-years away. The astronomers found that the giant black holes had grown to be seven to 20 times larger than they once were — a monstrous growth that couldn't be explained simply by black holes devouring stars or colliding and combining with each other.
Instead, the researchers propose that black holes are growing in lockstep with the universe. They overcome the star-crushing, light-capturing forces at their cores with something called vacuum energy that enables them to expand outwards, and they somehow drag the fabric of the cosmos out with them.
"This is a really surprising result. We started off looking at how black holes grow over time, and may have found the answer to one of the biggest problems in cosmology," co-author Dave Clements (opens in new tab), an astrophysicist at Imperial College London, said in the statement.
If expansionary dark energy does lurk inside the cores of black holes, it will solve two long-standing puzzles faced by Einstein’s general theory of relativity, which describes how gravity affects the universe at large scales. Firstly, it would explain how the universe doesn’t collapse due to the large and ubiquitous force of gravitational attraction and, secondly, it would do away with the need for singularities (infinitesimal points where the laws of physics break down) to explain the workings of black holes' dark hearts.
"We're really saying two things at once: that there's evidence the typical black hole solutions don't work for you on a long, long timescale, and we have the first proposed astrophysical source for dark energy," first-author Duncan Farrah (opens in new tab), an astronomer at the University of Hawaii, said in the statement. "What that means, though, is not that other people haven't proposed sources for dark energy, but this is the first observational paper where we're not adding anything new to the universe as a source for dark energy: black holes in Einstein's theory of gravity are the dark energy.''
To confirm this conclusion, astrophysicists will need to ensure that nothing else is contributing to the black holes' mysterious growth by making even more detailed observations of their masses throughout time, while also closely tracking the increase to these masses with the expansion of the universe.
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Cosmology & The Universe
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The image, known as “Webb’s First Deep Field,” will be the deepest and highest-resolution infrared view of the universe ever captured. Biden is scheduled to release it on Monday.July 10, 2022, 10:00 PM UTCPresident Joe Biden will unveil the much-anticipated first full-color image from NASA's James Webb Space Telescope on Monday, agency officials confirmed.The image, known as "Webb's First Deep Field," will be the deepest and highest-resolution infrared view of the universe ever captured, showing myriad galaxies as they appeared up to 13 billion years in the past, according to NASA. The agency and its partners, the European Space Agency and the Canadian Space Agency, are set to release a separate batch of full-color images from the Webb telescope on Tuesday, but Biden, Vice President Kamala Harris and the public will get a sneak peek a day early.NASA will brief the president and the vice president on Monday, agency officials said, and the first image will be revealed at an event at 5 p.m. ET at the White House.The $10 billion James Webb Space Telescope is humanity’s largest and most powerful space telescope, and experts have said it could revolutionize our understanding of the cosmos.After the White House event, NASA will unveil more images in an event streamed live Tuesday at 10:30 a.m. ET. NASA officials said that batch will include the Webb telescope’s first spectrum of an exoplanet, showing light emitted at different wavelengths from a planet in another star system. The images could offer new insights into the atmospheres and chemical makeups of other exoplanets in the cosmos.Some images included in the Tuesday release will show how galaxies interact and grow, and others will depict the life cycle of stars, from the emergence of new ones to violent stellar deaths.The Webb telescope launched into space on Dec. 25. The tennis-court-size observatory is able to peer deeper into the cosmos and in greater detail than any telescope that has come before it.Denise Chow is a reporter for NBC News Science focused on general science and climate change.
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Cosmology & The Universe
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NASA, along with the European and Canadian space agencies, will be releasing the first science images from the brand new James Webb Space Telescope on Tuesday, and now we know what celestial bodies we'll be seeing in those historic pictures. JWST is the long-awaited successor to the Hubble Space Telescope that finally launched on Christmas Day after years of delays. On Friday, NASA revealed the list of cosmic objects that JWST will target for its first batch of full-color images offering unprecedented and detailed views of deep space. If the telescope's stunning first test image is any indication, it's going to be as good as any Instagram feed out there. The targets include the Carina Nebula and Southern Ring Nebula, which are bright areas of gas and other material. The Carina Nebula (pictured above) is a so-called stellar nursery where stars are forming, and it's filled with massive stars that help make it one of the largest and brightest nebulas in the sky. The Southern Ring Nebula is a planetary nebula -- in this case, a wide cloud of gas half a light-year in diameter surrounding a dying star -- and relatively close on a cosmic scale, at just 2,000 light-years away. The southern ring nebula is also known as the "Eight-Burst" Nebula because of it appears to be a figure-8 when seen through some telescopes. NASA/The Hubble Heritage Team (STScI/AURA/NASA) Two other targets we'll see in fantastic high resolution next week are the galaxy group Stephan's Quintet, a particularly photogenic grouping of galaxies that seem to be dancing around each other for eternity, and SMACS 0723, which is a massive galaxy cluster that can act as a so-called gravitational lens to help scientists see deeper into space and observe fainter galaxies. This quintet of galaxies is made up of four galaxies that are actually near each other and a fifth that appears nearby but is really in the foreground and much closer to Earth. NASA, ESA, and the Hubble SM4 ERO Team JWST also is taking a look at the planet WASP-96b, a gas giant world about half the mass of Jupiter and located 1,150 light-years from Earth. The powerful new instruments on the space telescope should be able to provide new insights into the composition of the planet's atmosphere and a fun teaser of what we'll soon discover about other exoplanets, including those that are more Earth-like. The images that the space agencies will unveil on July 12 are just the beginning. Scientists have applied to use the telescope through a competitive process, and the first year of observations have already been scheduled. It's quite likely that JWST will change our perspective on some aspects of the universe in the months and years to come.
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Cosmology & The Universe
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Persistent radio signals from a galaxy billions of light-years away were detected by astronomers at the Massachusetts Institute of Technology and universities throughout both the United States and Canada. The waves occur in a regular pattern, similar to that of a heartbeat. The signal is categorized as a fast radio burst, or FRB, which is a large occurrence of radio waves, the origin of which is unknown. These typically only last a few milliseconds, according to MIT News. KRISTI NOEM TO ADDRESS HUNDREDS OF YOUNG CONSERVATIVES IN DC AMID 2024 SPECULATION The recently detected signal lasted nearly three seconds, making it a peculiar discovery, as it is 1,000 times longer than the average FRB. When astronomers analyzed the waves within the three seconds, they found that there was an evident pattern in which the waves repeated every 0.2 seconds. The captured signal has been named "FRB 20191221A" by researchers. It is both the clearest and longest FRB ever discovered. According to Daniele Michilli, a postdoctoral scholar at MIT’s Kavli Institute for Astrophysics and Space Research, “there are not many things in the universe that emit strictly periodic signals.” CLICK HERE TO READ MORE FROM THE WASHINGTON EXAMINER “Examples that we know of in our own galaxy are radio pulsars and magnetars," Michilli continued, "which rotate and produce a beamed emission similar to a lighthouse. And we think this new signal could be a magnetar or pulsar on steroids.”
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Cosmology & The Universe
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WASHINGTON -- The first glimpse of how the James Webb Space Telescope will change the way people see the universe has arrived.President Joe Biden released one of Webb's first images Monday at the White House during a preview event with NASA Administrator Bill Nelson.The image shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this created Webb's first deep field view of thousands of galaxies, including incredibly old and distant, faint ones."This slice of the vast universe covers a patch of sky approximately the size of a grain of sand held at arm's length by someone on the ground," according to a NASA release."It is the deepest image of our universe that has ever been taken," according to Nelson.The rest of the high-resolution color images will make their debut as planned on Tuesday, July 12.MORE: NASA's new space telescope in home stretch of tests, delivering stunning image of neighboring galaxyThe space observatory, which launched in December, will be able to peer inside the atmospheres of exoplanets and observe some of the first galaxies created after the universe began by viewing them through infrared light, which is invisible to the human eye.The first image release will highlight Webb's science capabilities as well as the ability of its massive golden mirror and science instruments to produce spectacular images.There are several events taking place during Tuesday's image release, and all of them will stream live on NASA's website.Opening remarks by NASA leadership and the Webb team will begin Tuesday at 9:45 a.m. ET, followed by an image release broadcast that kicks off at 10:30 a.m. ET. Images will be revealed one by one, and a news conference at 12:30 p.m. ET will offer details about them.The first imagesNASA shared Webb's first cosmic targets on Friday, providing a teaser for what else Tuesday's image release will include: the Carina Nebula, WASP-96b, the Southern Ring Nebula and Stephan's Quintet.Located 7,600 light-years away, the Carina Nebula is a stellar nursery, where stars are born. It is one of the largest and brightest nebulae in the sky and home to many stars much more massive than our sun.Webb's study of the giant gas planet WASP-96b will be the first full-color spectrum of an exoplanet. The spectrum will include different wavelengths of light that could reveal new information about the planet, such as whether it has an atmosphere. Discovered in 2014, WASP-96b is located 1,150 light-years from Earth. It has half the mass of Jupiter and completes an orbit around its star every 3.4 days.SEE ALSO: NASA says something strange is happening with our universeThe Southern Ring Nebula, also called the "Eight-Burst," is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star.The space telescope's view of Stephan's Quintet will reveal the way galaxies interact with one another. This compact galaxy group, first discovered in 1787, is located 290 million light-years away in the constellation Pegasus. Four of the five galaxies in the group "are locked in a cosmic dance of repeated close encounters," according to a NASA statement.The targets were selected by an international committee, including members from NASA, the European Space Agency, the Canadian Space Agency and the Space Telescope Science Institute in Baltimore.Looking aheadThese will be the first of many images to come from Webb, the most powerful telescope ever launched into space. The mission, originally expected to last for 10 years, has enough excess fuel capability to operate for 20 years, according to NASA Deputy Administrator Pam Melroy."Webb can see backwards in time just after the big bang by looking for galaxies that are so far away, the light has taken many billions of years to get from those galaxies to ourselves," said Jonathan Gardner, Webb deputy senior project scientist at NASA, during a recent news conference. "Webb is bigger than Hubble so that it can see fainter galaxies that are further away."The initial goal for the telescope was to see the first stars and galaxies of the universe, essentially watching "the universe turn the lights on for the first time," said Eric Smith, Webb program scientist and NASA Astrophysics Division chief scientist.Smith has worked on Webb since the project began in the mid-1990s."The James Webb Space Telescope will give us a fresh and powerful set of eyes to examine our universe," Smith wrote in an update on NASA's website. "The world is about to be new again."The-CNN-Wire & 2022 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.RELATED: NASA's new James Webb Space Telescope to make out-of-this-world discoveries
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Cosmology & The Universe
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Ordinarily, science journalists do not report on the work of their close relatives. But on the occasion of certain special anniversaries, an exception may be allowed. In this case, the occasion is the 50th anniversary of the Drake equation, the formula for predicting how many detectable civilizations exist in the Milky Way galaxy. That equation was first written on a blackboard on November 1, 1961, at a conference organized by Frank Drake, who is today chairman emeritus at the SETI Institute, the organization whose mission is the search for extraterrestrial intelligence. He is the father of Science News astronomy writer Nadia Drake, who recently interviewed him about the origin of his equation and its relevance to the search for intelligent life in faraway stellar systems today. Why did you write the Drake equation? I was motivated by a desire to understand what governs how many civilizations there are to detect in our galaxy, and to see if I could quantify that number. It became the agenda for a meeting. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox (Interview continues below the box.) Drake Equation
In 1961, astronomer Frank Drake devised on equation for calculating the number of detectable, intelligent civilizations in the Milky Way galaxy. Known as the Drake equation, it defines the ingredients needed to cook up an intelligent civilization and combines estimates of the availability of those ingredients to produce the number of detectable civilizations. Here are Drake’s assessments of the terms of his equation today. R: 10 per year. Fp: It’s been traditional to put 0.5 there, but that should probably be raised to 0.8. Ne: That one depends on whether you accept Europas as abodes of detectable life. Using our own system, it’s 3 — Venus, Earth, maybe Mars. Venus would be habitable if it didn’t have so much CO2. Fl: I think that’s 1. Some people don’t think that. We’ve found so many chemical pathways to the production of biologically relevant molecules — no bottlenecks, no showstoppers, no freak events required. There are so many ways to make life that I think life appears everywhere. This is supported by the evidence that life appeared on Earth at the earliest time it could have. Fi: I think that’s 1. I think you always get an intelligent creature — in fact, I think you will get many of them, with enough time. They may not coexist. Some people think this is problematic because of a misunderstanding of evolution. The fossil record evidence is that the size of brain has increased. Eventually one species becomes intelligent, and inevitably, it will look around and discover it’s the only one! It shouldn’t be surprised. Given more time, lots more could, and will, become intelligent. Fc: 1. If you have a toolmaking capability, that’s inevitable. It’s happened at least five times on Earth, from starting from organized agriculture with tools, to weapons, to all the things we have, like motorcycles and airplanes. Fc is 1. L: 10,000. Well, somewhere between 1 and a billion. What was the meeting? Well, Project Ozma [the first SETI search] happened in the spring of 1960. And it got a lot of press attention, much more than it deserved, and this caused the National Academy of Sciences to say, “Well, gee. This is a surprise, maybe we should have some kind of study to see how real this is, and what the chances are of actually succeeding.” So they asked me to convene a meeting of experts in the field to discuss the subject and arrive at what it’s going to take to succeed. And that was in 1961. I organized the meeting in the summer of 1961, almost a year after the original experiment. It ended up being a three-day meeting held at Green Bank [West Virginia], just after Halloween. I was the whole organizing committee — the local organizing committee, the scientific organizing committee, the entertainment organizer. Around Halloween, I realized we couldn’t all just get together in a room and start talking. So I thought, “Well, we should have a subject for each session. We ought to talk about key aspects of this whole life in the universe thing, what we knew about it, and what needed to be done.” I’d been thinking about it for months, and all that thinking was based on the history of the solar system and life on Earth. It had to do with planetary formation, how many planetary systems there are, how often life arrives, how inevitable is the evolution of intelligence, how often do you develop a detectable technology, and how long that technology lasts. I knew all these things were crucial to the end result, which was the total number of detectable civilizations. So I decided to make each one of them the topic for a session. And I realized then that if you multiplied these factors together, you got the thing you were after, which is the number of detectable civilizations. Then? Then I just wrote that thing down and started the meeting on November 1 by putting the equation on the blackboard. There is now a plaque on the wall saying, “This is where the equation was first written.” I didn’t jump up and down yell “Eureka!” or wave my arms or anything. It was just something that had been in my mind for months. It wasn’t “a-ha,” it was just — to me — obvious. Who was at the meeting? I invited everybody in the world who I knew was interested in this subject, and that amounted to 12 people. Among them were Carl Sagan, Otto Struve — the great astrophysicist of the 20th century, who was then the director of Green Bank — John Lilly, who’d dealt with the intelligence of dolphins and was making the case that intelligence was a very widespread phenomenon. And Melvin Calvin, who was very big on the fundamentals of biology, and the origins of life and all that. He’s the one who identified the chemical processes that take place during photosynthesis [Calvin’s Nobel Prize was announced during the meeting]. And then there were some other people from the electronics industry, and people who worked on the theories of the origin and abundance of planetary systems. Barney Oliver was one of them. What was their reaction to the equation? They thought it was a wonderful way of describing, with one equation, the history of intelligent life in our solar system. They thought it was a succinct, clear way to tell what was important and what we needed to quantify. As a thinking tool, it’s very good. What was the reaction of the broader astronomical community? Were they critical, accepting? They accepted it, didn’t consider it some great breakthrough or something. They noted that it was an interesting observation, if you will. An observation? An observation of the way to quantify the history of life, and intelligent life, on a place like the Earth. And the equation slowly took hold because people started realizing it was really helpful in organizing their thinking. The main product or benefit that’s come from it is that it organizes people’s thinking, gets them to thinking about what’s important. The nature of the equation is that everything is equally important — it’s all there in the first power. Nothing is squared, there are no logarithms, no trigonometry. It’s all very simple. It shows that everything is equally important. Now it appears in most of the astronomy textbooks. There’s one book out about history’s most important equations, and there are about three equations in it, and it’s one of them. That boggles my mind. It’s right there next to E=mc2. A couple of weeks ago, I was wearing my Drake equation T-shirt, and people would stop and say, “Oh, I know what that is!” Does it surprise you that it’s so popular, even outside of astronomy? It used to surprise me, but it doesn’t surprise me now. People do use it often in teaching and in science magazines. It’s a great teaching tool, and it’s been repeated over and over in articles about ET life. A lot of people know about it. Sometimes people use it to make jokes, or use the form of the equation to find something else. There’s one on the Web where the person does a calculation of the probability of finding a desirable date in Chicago. And the “Flake Equation” calculates the number of people who claim they’ve been abducted by UFOs. Its comes out to about the right answer…. Is there anything you would change or modify, if you were writing the equation today? I wouldn’t change it. I wouldn’t change the factors, but I would discuss each one, and what you mean by them. Because what you mean depends on what answer you’re after — whether it’s the number of civilizations, or the number of detectable ones, or something else. What are some of the criticisms you’ve heard, and what is your response? Mostly the criticisms are actually suggesting the adding or modifying of factors in the equation. My usual response is, “what you’re saying is correct but what you’re wanting to add is something that’s in the existing factors.” For example, when it comes to the fraction of creatures that have developed intelligence, you may have to exclude creatures like dolphins, which are intelligent, but could never develop a technology. Same thing with developing a detectable technology. You can’t think every intelligent creature could do that. On a water planet, for example, it seems unlikely that creatures could build giant telescopes and radio transmitters. Nobody ever says the whole thing is wrong or needs replacing. It has survived for 50 years without really needing any additions or changes. But you do have to be very precise in just what the factors mean. For example, the equation can be used in several ways. L could be the lifetime a civilization exists, in general. Then the answer is just the number of civilizations, not detectable civilizations. It’s the lifetime, period, and has nothing to do with whether they ever have detectable technology or not. The number of detectable civilizations is going to be much less than the total number of intelligent civilizations. Another problem is the number of detectable planets – does a thing like Europa count? It’s an ocean world, there’s no land mass, there’s no way to process ores, there’s no fire. Does that count or not? If you’re just trying to get the number of habitable planets, then you include the Europas. But if you’re trying to arrive at the number of technology-using planets, then you might exclude the Europas. You have to be precise about what you’re talking about. Do you really just mean habitable, or do you mean the potential for having detectable technologies? And of course, Europa is actually a moon. That’s right. When we talk about the number of habitable planets, what we really mean is the number of habitable bodies. There may be systems where there are more habitable moons than planets. So if we’re talking about n-sub-e, and that actually includes habitable moons, that would change the estimate. That’s right. Originally the term did not include moons. It was strictly planets. But now, n-sub-e should probably include any body that can support technology. It should include the moons if they could possibly contribute. And we should always keep in mind that life is extremely opportunistic and adaptable. How does something like NASA’s Kepler planet-searching mission change what we know about these factors? The Kepler search has already shown that planetary systems exist in huge numbers. It’s showing that the majority of sunlike stars have planetary systems. It is also showing that in these systems, there are more low-mass planets than large-mass planets. Unfortunately, the range of observed masses doesn’t extend to Earth-mass yet, but the distribution says there are many, many Earth-mass planets, and of course that makes n-sub-e larger than we used to imagine. In the beginning, we thought only half the stars have planetary systems because half the stars are double stars. But now we know that double stars have planets, too. But if you include moons around planets that are bigger than Earth – and there are many planets that are more massive than Earth – then that would also affect n-sub-e, if you’re considering all bodies instead of just planets. That’s right. And just because a planet is bigger than Earth doesn’t mean it isn’t good for life. Bigger planets might be richer in life than Earth-mass planets. We always seem to think that the solar system is optimum, and that it’s the very best place for life, and that can’t be absolutely correct. We can’t be absolutely optimum — that’s so improbable. It used to be thought that beyond the orbit of Mars, you could have no life. That’s a big misconception. What we’ve learned is that the surface temperature isn’t just dependent on how far a planet is from the star, but how much insulation is being provided by the atmosphere, or an ocean. Venus is incredibly hot, with a deep atmosphere. There’s a liquid ocean on Europa because of insulation from a layer of ice. The giant planets — people don’t realize their atmospheres are so deep that temperatures deep down are the same as on Earth. And, every plausible gas in planetary atmospheres creates a greenhouse effect. It is an interesting fact that there’s no such thing as a negative greenhouse. You can be very far from your star, and still be warm enough for life. You can be subterranean because the temperature goes up as you go down. The habitable zone may go all the way to infinity. There are lots of ways to make a planet warm enough for life. For life as we know it. Well, yeah. Every time we’re talking about life, we’re talking about carbon-based life with DNA and all that… What were some of the more difficult terms to quantify, when you wrote the equation? At that time, we were really very much in the dark. There were many things we did not know — which we still do not know today. And since everything in the equation has equal weight, I knew the answer was going to be only as good as the thing we knew the least about. What were some of these things you did not know? Well, one is the number of habitable planets in a planetary system [F-sub-l]. There were simple models that people put too much faith in, which predicted that the number of habitable planets was either very small, or zero. Of course, zero couldn’t be the right answer because we knew of at least one. Another one was the fraction of biota that would evolve an intelligence [F-sub-i]. There are still a lot of misconceptions in this subject to this day. But the thing that was most troublesome was the longevity of civilizations in a detectable state [L] — which to this day is a very vexed subject. A great difficulty here is that the answer depends a great deal on what is possible to detect. Can you elaborate? If you could detect the signals from people’s cell phones, then you could detect every civilization in existence, practically. If you could only detect very powerful transmissions like those from Arecibo, then the number is very small. The answer to that one is very dependent on your assumption of the capabilities of your detection systems. Is that a question that you think we will ever be able to answer? I think we will. All of these things will be answered as soon as we detect a few other civilizations. It will just open the floodgates, and these things that now have error bars of a factor of a million will become very well known. But until we detect other civilizations, we’re just speculating about what they’re using that makes them detectable. It’s almost in the realm of science fiction. What kinds of technology do you think they’re using? In my optimism, with no basis for it, I am predicting that the use of stars as gravitational lenses will be very widespread because it is such a powerful technique for studying the universe. I think that every civilization that has the technical capability will do it, big-time. This greatly affects not only the detection capability but the power of the signals you can send to other civilizations. It works both ways. You can use the lens for detection, but also to amplify outgoing messages. If the use of stars as gravitational lenses is extremely widespread, then the number of detectable civilizations is huge. A little ways back, you said, “I knew the answer to the equation was going to be only as good as the thing we knew the least about.” Is “L,” the length of time a civilization is detectable, the thing we know the least about? L is definitely the thing we know the least about. The only source of information we have about L is our own history. We have to use ourselves as a model, and assume that we’re “typical,” although we may not be. But we have only been easily detectable since the second world war, when very powerful radio transmitters were invented. So we have been easily detectable for 70 years. The equation collapses to N [the number of detectable civilizations in the galaxy] equals L. So if we have a minimum value of L being 70 years, based on us, does that accurately reflect what N is, at this point? If 70 is actually the rule, there will only be 70 detectable civilizations in the Milky Way at the present time. At the present time. Yeah. That’s good news and bad news. It’s good news that there’s more than one. But it’s bad news because it means the number of stars you have to search is just enormous. It is way more than a million. That’s based on our only being able to detect very powerful radio transmitters, which is our situation right now. Do you have your own favorite number for L? Yep. And? First, it is a curious and intriguing fact that the difficulty of detecting other intelligent life depends as much, or maybe more, on how widespread altruism is in intelligent civilizations, as it does on the qualities of search technology. L is the average length of time a civilization is detectable, and this means L is the average length of time a civilization is using some detectable technology. Now if it’s only using the technology for its own purposes, L could be pretty short. That’s what we do at the present time. We’ve gone 70 years and now we see that our visibility is actually going to start decreasing pretty soon. We’ve invented superior ways of delivering television to people’s homes — we do that by cable, which doesn’t release any indication of our existence to space, or the direct-to-home transmission of TV from satellites. None of that scenario requires any special freaky situation with respect to our civilization or our planet. It’s a scenario that you could expect to play out very similarly anywhere, which says that the lifetime of detectable radio transmission might be on the order of hundreds of years. There are people who argue that it’ll be longer than that because we need to use radar to detect dangerous asteroids and such, so they would say thousands of years. There are also those who think that civilizations — the creatures of other civilizations have much of the same thinking and philosophies as humans do. This gets interesting! One of the key parts of being human is that we are altruistic. The big question is whether intelligent beings in the universe are, on the whole, also altruistic like we are. Because if they are, then they’re likely to do something of an altruistic nature, understanding that there are other civilizations that would like to know about them. They will intentionally transmit very powerful signals for the benefit of other civilizations for a very long time. But that’s an act of altruism because it won’t benefit you. You just think it’s the right thing to do. If there’s altruism, and even only occasionally, it changes everything. You get into the math — the value of L is the average L for civilizations, the arithmetical average. So if 100 percent are only visible for 70 years, then L is 70 years. But if 1 percent has an L of, say, a billion years because they’re altruistic and continually send detectable signals, then the value of L is 0.99 times 70 plus 0.01 times a billion. Which is 10 million. All it takes is 1 percent to be altruistic and transmit a detectable signal essentially indefinitely. That’s a very interesting result, because it’s strictly correct. It’s not crazy. And so, assuming only one in 100 civilizations does this thing, it’s not far-fetched. What this says is that L could be much larger than our intuition would suggest. And therefore, the value of N is much larger. So do you think N could actually be something like 10 million? It could. But when people really press me on this…the assumption that 1 percent transmit for a billion years totally dominates the result, which is intuitively offensive. The answer depends on this one outlier data point, which has no observational statistical basis. An escape from this is to take the geometric mean instead of the arithmetic mean, in which case the outliers don’t so greatly dominate. You come up with an answer of 10,000 years. That’s the number I usually throw out as being plausible. That makes the whole enterprise more promising because there’s 10,000 places we could detect. But at the same time, it means the fraction of stars with transmitting civilizations is 10,000 over maybe 100 billion. So it ends up being one in 10 million. That’s the challenge to anybody designing a search. If they’re going to be realistic about it, they need to design a search for 10 million stars. That’s the bottom line. What do future SETI searches need to be like? Big science, small science…citizen science? It has to be a big science approach, with very high sensitivity. You have very little chance with backyard dishes or amateur telescopes because you need a lot of sensitivity to detect even very powerful transmitters like Arecibo. The way I describe that is, you can build a very beautiful small airplane, but it’ll never get you to the moon. The future of SETI is to build an antenna that will look in all directions at all times. Actually, you need two of them, at opposite sides of the Earth so you can watch everything all the time, because every once in a while, somebody sees a signal which looks like the real thing. They’ll see it for a minute or so, and then it goes away. They’ll go back and look at the star and see nothing. There’s a famous signal, called the “Wow!” signal, detected by a big SETI project at the Ohio State University in 1977. They were using the big antenna that then existed in Ohio. This antenna used the rotation of the Earth to look at various places in the sky. If there was a signal coming from the star, the signal would appear and get strong and decrease because of the response pattern of the antenna. They saw a very strong signal that produced exactly the pattern it would if it was coming from a source that was fixed in the sky. That’s called the “Wow!” signal, because when the person saw it — in those days there weren’t computers, they were recording all this on graph paper — he wrote “Wow!” alongside it. We know of ways that these things can be a product of fortuitous events in our radio equipment, but they’re improbable, but not ridiculously improbable. These signals that look real suggest that real signals might not be on all the time. Other civilizations might be using a strategy where they are sending intentional signals, but can’t send intentional signals to all the stars all the time. You make a very powerful beam, and turn it from one star to the next, over and over and over. Every star may only see it once a year or so. This makes the search much more difficult because not only do you have to look at 10 million stars, you have to look at them over and over, or watch the whole sky continuously. We know how to do that, we can build an antenna that would do that. But it’s very expensive. You create a multitude of beams, they cover the whole visible sky, and the amount of computing that’s required — I happen to know — is of the order of 1020 flops. In the year 2000, when this was proposed, it would take a computer facility the size of a football field to make this thing work. It’s getting better all the time, but it’s still beyond our reach and available finances. Have there been others like the “Wow!” signal? Yeah, another 35, at least. The whole sky was searched by Harvard, in the same way as was done at Ohio State. They saw more than 35 candidate signals. This was done by Paul Horowitz, who’s still very active at Harvard. The Harvard project saw about 35 “Wow!” signals. The well-known SETI@home program saw more than 100. Both Horowitz and the people at Berkeley have gone to places like Arecibo and actually searched for signals at the appropriate locations and frequencies and none of the signals has ever been seen a second time. So here are all these detections that do all the right things, but there are no confirmations. And there hasn’t been observing time to just sit and watch one of these places for a year. But that’s what we need to do. So do you think it’s possible that we’ve already seen evidence for another civilization but we can’t confirm it? Well, some of those candidate signals could be real, but I think they’re all artifacts. This opinion is based on our experience at the SETI Institute where we have actually identified many, many, candidate signals as artifacts, with no residue of unexplained detections. What else they could be? You said they’re hard to produce by accident. About the only other thing it could be is an airplane that just by accident gets radiation into your beam. Radio telescopes have a main beam which is capturing the bulk of what they’re seeing. The telescope captures radiation from a small area, called the beam. But all of them have some additional sensitivity in all directions. If there’s a very powerful signal within the view of the telescope, you could see it and it will create a signal in the system that looks just like a real one, but is phony. Most people say that after all this searching — hundreds, millions of channels, hours and hours and hours — it’s not surprising that occasionally the improbable happens. At the present time the view is that we have to, as serious scientists, assume that all of these candidate detections are artifacts of our equipment. When do you think we might have an answer for the equation? That’s a very standard question. The answer is, when we’ve got enough money. It’s all money-driven. We have the technology, we know how to build radio and optical telescopes of any size that have just about as much sensitivity as is permitted by the laws of physics. But the search has to be so comprehensive in where we look and what wavelengths we look at, and how long we look. It’s got to be a search which can cover many, many, many possibilities. Our search capability is totally limited by available funds. We depend still on donations from private individuals. It’s not a lack of technical know-how, it’s a lack of resources to construct and carry out the technology we know how to build. If we could build an ideal telescope, how long do you think it would take before we found a signal? Depends on what L is. If we take the 10,000-year value, which can’t be all that far wrong, we’re talking 30 to 100 years. With a big, big comprehensive telescope system. What do you think the impact on the world would be, if we found another civilization? Enormous. OK. Well, the first key fact is that almost any civilization we can detect will be much older than we are. They will know much more than we do, have much more experience in dealing with all the things we have to deal with, like environmental destruction. We will be students, we will be the new kids on the block and it will be possible to learn a great deal from them. That’s the main thing. The second thing is that we may not be able to learn much right away. We will just detect evidence of a civilization — a signal, clearly of intelligent origin, but with not enough sensitivity to extract any information from it. This will require a big crash project to build big telescopes. No signal ever dies. The signal always exists — if you build a big enough telescope, you can capture it. We’ll have to build big telescopes so that we can detect signals with enough collecting area, or sensitivity, that we can learn things and capture information from the civilization. In the best of all universes, they would be sending us their encyclopedia once a year or in some reasonable time interval, and telling us all about their history, what works, what doesn’t work, what’s good, what’s bad…. We’re not sending our encyclopedia. No, but we’re sending a tremendous amount of information about ourselves through our television. Capturing television is really the best avenue for gaining formation about a civilization. You don’t have to ask a question and wait 2,000 years for an answer. In the future, how do you hope people will look back on the Drake equation, or be using it? They should think about it and what it says, what its limitations are, particularly the fact that L could be much larger than your intuition suggests. Which makes you optimistic. Almost all the things that would seem peculiar lead to more detectable civilizations. And you should use it as a way of guiding yourself and planning searches. How do you optimize them? We do that now in SETI. When we’re building a radio receiver, do we use more channels, or narrower bandwidths? We trade things off, make calculations about how this allows you to explore the search space more efficiently. The equation will continue to be very useful in planning the search for extraterrestrial intelligent life.
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Cosmology & The Universe
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How did the universe start? Did we begin with a big bang, or was there a bounce? Might the cosmos evolve in a cycle of expansion and collapse, over and over for all eternity? Now, in two papers, researchers have poked holes in different models of a so-called bouncing universe, suggesting the universe we see around us is probably a one-and-done proposition.
Bouncing universe proponents argue that our cosmos didn’t emerge on its own out of nothing. Instead, advocates claim, a prior universe shrunk in on itself and then regrew into the one we live in. This may have happened once or, according to some theories, an infinite number of times.
So which scenario is correct? The most widely accepted explanation for the history of the universe has it beginning with a big bang, followed by a period of rapid expansion known as cosmic inflation. According to that model, the glow left over from when the universe was hot and young, called the cosmic microwave background (CMB), should look pretty much the same no matter which direction you face. But data from the Planck space observatory, which mapped the CMB from 2009 to 2013, showed unexpected variations in the microwave radiation. They could be meaningless statistical fluctuations in the temperature of the universe, or they might be signs of something interesting going on.
One possibility is that the CMB anomalies imply that the universe didn’t emerge out of nothing. Instead it came about after a prior universe collapsed and bounced back to create the space and time we live in today.
Bouncing universe models can explain these CMB patterns as well as account for lingering quibbles about the standard description of the universe’s origin and evolution. In particular, the big bang model of the universe begins with a singularity—a point that appeared out of nothing and contained the precursors of everything in the universe in a region so small that it had essentially no size at all. The idea is that the universe grew from the singularity and, after inflation, settled into the more gradually expanding universe we see today. But singularities are problematic because physics, and math itself, doesn’t make sense when everything is packed into a point that’s infinitely small. Many physicists prefer to avoid singularities.
One bouncing model that averts singularities and makes the CMB anomalies a little less anomalous is known as loop quantum cosmology (LQC). It relies on a bridge between classical physics and quantum mechanics known as loop quantum gravity, which posits that the force of gravity peters out at very small distances rather than increasing to infinity. “Cosmological models inspired by loop quantum gravity can solve some problems,” says University of Geneva cosmologist Ruth Durrer, “especially the singularity problem.” Durrer co-authored one of the two new studies on bouncing universes. In it, she and her colleagues looked for astronomical signs of such models.
In an LQC model, a precursor to our universe might have contracted under the force of gravity until it became extremely compact. Eventually quantum mechanics would have taken over. Instead of collapsing to a singularity, the universe would have started to expand again and may even have gone through an inflationary phase, as many cosmologists believe ours did.
If that happened, says physicist Ivan Agullo of Louisiana State University, it should have left a mark on the universe. Agullo, who was not affiliated with either of the recent analyses, has proposed that the mark would turn up in a feature in the CMB data known as the “bispectrum,” a measure of how different portions of the universe would have interacted in a bouncing scenario. The bispectrum would not be apparent in an image of the CMB, but it would show up in analyses of the frequencies in the ancient CMB microwaves.
“If observed,” Agullo says, the bispectrum “would serve as a smoking gun for the existence of a bounce instead of a bang.” Agullo’s group previously calculated the bispectrum as it would have appeared shortly after a cosmic bounce. Durrer and her colleagues took the calculation further, but when they compared it with the present-day Planck CMB data, there was no significant sign of a bispectrum imprint.
Although lots of other bouncing cosmos models may still be viable, the failure to find a significant bispectrum means that models that rely on LQC to deal with the anomalies in the CMB can be ruled out. It’s a sad result for Agullo, who had high hopes of finding concrete evidence of a bouncing universe. But Paola Delgado, a cosmology Ph.D. candidate at Jagiellonian University in Poland, who worked on the new analysis that was co-authored by Durrer, says there’s one potential upside. “I heard for a long time that [attempts to merge quantum physics and cosmology] cannot be tested,” Delgado says. “I think it was really nice to see that for some classes of models, you still have some contact with observations.”
Ruling out signs of an LQC-driven cosmic bounce in Planck data means the CMB anomalies remain unexplained. But an even larger cosmic issue lingers: Did the universe have a beginning at all? As far as advocates of the big bang are concerned, it did. But that leaves us with the inscrutable singularity that started everything off.
Alternatively, according to theories of so-called cyclic cosmologies, the universe is immortal and is going through endless bounces. Although a bouncing universe may experience one or more cycles, a truly cyclic universe has no beginning and no end. It consists of a series of bounces that go back for an infinite number of cycles and will continue for an infinite number more. And because such a universe doesn’t have a beginning, there’s no big bang and no singularity.
The study that Durrer and Delgado co-authored doesn’t rule out immortal cyclic cosmologies. Plenty of theories describe such a bouncing universe in ways that would be difficult or impossible to distinguish from the “big bang plus inflation” model by looking at Planck CMB data.
But a critical flaw lurks in the idea of an eternally cycling universe, according to physicist William Kinney of the University at Buffalo, who co-authored the second recent analysis. That flaw is entropy, which builds up as a universe bounces. Often thought of as the amount of disorder in a system, entropy is related to the system’s amount of useful energy: the higher the entropy, the less energy available. If the universe increases in entropy and disorder with each bounce, the amount of usable energy available decreases each time. In that case, the cosmos would have had larger amounts of useful energy in earlier epochs. If you extrapolate back far enough, that implies a big bang–like beginning with an infinitely small amount of entropy, even for a universe that subsequently goes through cyclic bounces. (If you’re wondering how this scenario doesn’t violate the law of conservation of energy, we’re talking about available energy. Although the total amount of energy in the cosmos remains static, the amount that can do useful work decreases with increasing entropy.)
New cyclic models get around the problem, Kinney says, by requiring that the universe expands by a lot with each cycle. The expansion allows the universe to smooth out, dissipating the entropy before collapsing again. Although this explanation solves the entropy problem, Kinney and his University at Buffalo co-author Nina Stein calculated in their recent paper that the solution itself ensures that the universe is not immortal. “I feel like we’ve demonstrated something fundamental about the universe,” Kinney says, “which is that it probably had a beginning.” That implies a big bang occurred at some point, even if that event happened many bouncing universes ago, which in turn suggests that it took a singularity to get everything going in the first place.
Kinney’s paper is the latest in the debate over cyclic universes, but proponents of a universe without beginning or end have yet to respond in the scientific literature. Two leading proponents of a cyclic universe, astrophysicists Paul Steinhardt of Princeton University and Anna Ijjas of New York University, declined to comment for this article. If the history of the debate is any indication, though, we may soon hear of a work-around to counter Kinney’s analysis.
Cosmologist Nelson Pinto-Neto of the Brazilian Center for Physics Research, who has studied bouncing and other cyclic models, agrees that the Planck data likely rule out a bounce under loop quantum cosmology, but he’s more sanguine on the question of a cyclic universe. “Existence is a fact. We are all here and now. Nonexistence is an abstraction of the human mind,” Nelson says. “This is the reason I think that a [cyclic universe], which has always existed, is simpler than one that has been created. However, as a scientist, I must be open to both possibilities.”
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Cosmology & The Universe
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To date the only life we know about is here on Earth. Since the beginning of civilization, people have wondered whether there is life elsewhere in the universe. In 1984 American astronomer Jill Tarter and Thomas Pierson launched a project called Search for Extra-Terrestrial Intelligence (SETI), dedicated to that interstellar hunt.The nonprofit institute was designed to pick up radio signals from space. Radio signals can travel long distances because they are less scattered or absorbed compared to other sorts of radiation, making them more likely to be detected by the 42 radio telescopes that make up the one-of-a-kind Allen Telescope Array in the Cascade Mountains of California. But for 30 years, no verified alien signal has been received.Probing ExoplanetsNow, the James Webb Space Telescope (JWST) has been successfully deployed to aid the search. With its gigantic mirror and ultra-sensitive detectors, the world’s most powerful telescope (floating roughly 1 million miles away from Earth) will examine many distant unexplored planets orbiting distant stars. Twenty years ago, no other planets were known apart from those in our solar system. But since then, more than 4,000 other planets, called the exoplanets, have been discovered orbiting other stars. NASA estimates that the true number of exoplanets could be trillions.The first signs of life beyond our solar system might come from extraterrestrial plant life. The Galileo spacecraft, on its way to Jupiter, pointed its instruments back to Earth and picked up the distinct indication of the presence of plants. It detected the vegetation red edge (VRE) biosignature, a mixture of red and infrared light that is reflected by plants. The JWST will measure the VRE of distant Earth-like planets in the habitable zone around stars; and if there is a planet covered in jungle, for example, it should have a large VRE signal that should be easy to detect.There could be important signs of life in the composition of the atmospheres of the exoplanets. When an exoplanet passes across the face of its star, sunlight passes through its atmosphere and could be picked up by the JWST. Spectroscopy would then be used to discover which wavelengths are missing from the light. Atoms and molecules in the atmosphere absorb certain wavelengths and therefore leave a unique fingerprint for the JWST to detect. In that way, the composition of the atmosphere can be determined and the presence of life possibly inferred. If Earth-sized planets were found to have an atmosphere similar to our home planet (that is, containing mainly oxygen, nitrogen and carbon dioxide), that planet could likely support life forms.Technological life could perhaps be identified by looking for the presence of chemicals that don’t occur naturally. If aliens looked at the atmosphere of Earth from a distance, they would probably see chlorofluorocarbons (CFCs), which were manufactured for use in refrigeration and cleaning materials. Jacob Haqq-Misra at the Blue Marble Space Institute in Seattle has suggested that if the JWST detected CFCs in exoplanet atmospheres, then that would be a tell-tale indication that a civilization is there.Recognizing LifeOf course living things on exoplanets might resemble nothing like life on Earth. Sometimes even life on Earth can seem alien, such as “extremophile” organisms. This is a class of organism, mostly microbes, that live in extremely harsh environments where life is impossible for other living creatures. Some live at very high temperatures, up to 250 Fahrenheit. Others survive extreme cold, as low as -4 Fahrenheit. Some live in strong acids with pH below 3, and there are other places on Earth where we would not expect to find life at all.However, it might be sensible initially to start looking at Earth-like planets where life is more likely — rather than those planets that have a temperature of 250 Fahrenheit, for instance, or are bathed in acid. Prime candidates might have a temperature where liquid water could form on the surface, and they’re orbiting around a stable star.Our sun is classified as a G-type yellow star. But these stars tend to be short-lived and less common in space as we know it. More likely subject of study could be planets in orbit around the more numerous red dwarf stars, which are slightly cooler and less luminous than our sun. These stars have much longer lifetimes, so there is more time for life to start up and evolution has more time to develop complicated life forms.First TargetThe first project for JWST is to look at an exoplanet system called TRAPPIST-1, which is 40 light years away from us. This consists of seven rocky Earth-sized planets in orbit around a cool red dwarf star. Three of the rocky planets are in the so-called habitable zone, which means they could have liquid water on their surfaces. The TRAPPIST-1 star is only 1/10 the mass of our sun and is much cooler, but the planets orbit close to the star so they receive light levels similar to here on Earth.Whether there is life anywhere else in the universe is one of the most important questions in science. The universe might be teeming with life, or maybe we are totally alone, marooned on a lonely world in the vastness of space. The definitive answer, either way, will likely require a profound psychological and philosophical adjustments for humankind.
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Cosmology & The Universe
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Astronomers have revealed the first photograph of an exoplanet taken by NASA’s James Webb Space Telescope (JWST). The image shows the bright blob of a world seven times heavier than Jupiter that orbits a star nearly 400 light-years away. The groundbreaking result is the latest in a slew of early exoplanet findings from the telescope, and a test of technologies that will enable direct imaging of Earth-like planets by future space telescopes.“It’s exhilarating,” said Aarynn Carter, an astronomer at UC Santa Cruz and part of the team that processed the image. “The result is, honestly, excellent.”The JWST, a telescope decades in the making that launched in December 2021 and now floats a million miles from Earth, became fully operational this summer. It has observed distant galaxies at the dawn of the universe and taken exquisite views of Jupiter, among other early results. Astronomers say the telescope is performing 10 times better than expected at observing exoplanets.The new image, described in an accompanying paper posted online August 31, comes from a team led by the astrophysicist Sasha Hinkley at the University of Exeter in the United Kingdom. The researchers pointed the JWST at the fast-spinning star HIP 65426, where a planet was known to exist; the Spectro-Polarimetric High-Contrast Exoplanet Research instrument (SPHERE) on the Very Large Telescope in Chile first photographed the planet in 2017. Hinkley’s team sought to test and characterize JWST’s ability to see the planet, called HIP 65426 b.Astronomers have directly imaged about two dozen exoplanets, but the JWST will greatly expand the capability by wielding its 6.5-meter-wide hexagonal mirror, outclassing any ground-based observatory. “It is a moment of promise,” said Bruce Macintosh, an astrophysicist and the incoming director of the University of California Observatories.Hot Young GiantTo photograph HIP 65426 b, the JWST blocked the light of its host star using a small mask known as a coronagraph. This revealed the orbiting planet, which is thousands of times fainter, like “a firefly around a searchlight,” said Hinkley.HIP 65426 b orbits about 100 times farther from its star than Earth does the sun, taking 630 years to complete an orbit. This distance means it’s easier to see the planet against the glare of the star; that, coupled with the planet’s extreme heat and thus brightness—it has a scorching temperature of about 900 degrees Celsius, a fever left over from its formation just 14 million years ago—makes it a prime target for direct imaging. “It has a temperature similar to a candle flame,” said Beth Biller, an astronomer at the University of Edinburgh who co-led the team.The James Webb Space Telescope is like nothing ever launched into space. It could explore the universe’s very first stars, uncover evidence of extraterrestrial life — or literally hit a snag and become worthless. Video: Emily Buder/Quanta Magazine
The JWST’s size and sensitivity enabled it to collect more light from this planet than any previous observatory has obtained. (Its photo looks grainier than SPHERE’s only because the JWST observes longer, infrared wavelengths.) This allowed Hinkley, Biller and their team to refine the estimate of the planet’s mass, which they peg at about seven Jupiter masses, less than SPHERE’s estimate of about 10. Their results also help nail down the planet’s radius, which is 1.4 times that of Jupiter. Simple models of planetary evolution can’t easily explain this world’s combination of properties; Carter noted that the precise new data will allow scientists to test models against each other and “tighten our understanding.”HIP 65426 b’s surface features aren’t visible in the image, but Biller said it would “probably look banded” like Jupiter, with belts caused by variations in temperature and composition, and might have spots in its atmosphere caused by storms or vortices.The giant planet is inhospitable to life as we know it, but it represents a class of large planets that scientists are eager to learn more about. Jupiter probably played a key role in sculpting our solar system, perhaps enabling life on Earth to take hold. “It’d be nice to know if that works in other solar systems,” said Macintosh.The Webb telescope’s Near Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) each captured views of the planet HIP 65426 b at multiple infrared wavelengths, providing details that astronomers could use to infer the planet’s properties. The white stars mark the location of the host star HIP 65426, which has been subtracted using coronagraphs and image processing, while the bar shapes in the two NIRCam images are artifacts of the optics, not objects in the scene.Illlustration: NASA/ESA/CSA, A Carter (UCSC), the ERS 1386 team, and A. Pagan (STScI)Because the JWST is so much more stable than expected, scientists say it should be able to photograph smaller exoplanets than anticipated—perhaps as small as a third of Jupiter’s mass. “We could image things like Neptune and Uranus that we’ve never directly imaged before,” said Emily Rickman, an astronomer at the Space Telescope Science Institute in Maryland, which operates the JWST.Now that the JWST’s coronagraph has passed its road test, Hinkley thinks astronomers will be lining up to use it to take otherworldly photos. He expects to see “definitely dozens” by the end of the telescope’s lifetime. “I hope it’s more like hundreds.”Peeking in Distant SkiesIn addition to the exoplanet photo, Hinkley’s team will announce in the coming days that they have discovered an array of molecules in the atmosphere of a suspected brown dwarf—sometimes known as a “failed star”—orbiting a companion star. Almost 20 times heavier than Jupiter, the object has a mass just below the threshold where fusion could begin in its core.Using an instrument on the JWST that picks apart the light’s frequencies, a process called spectroscopy, the scientists found water, methane, carbon dioxide and sodium, all revealed at an unprecedented level of detail. They also detected smokelike clouds of silica in the candidate brown dwarf’s atmosphere, something hinted at before in such objects but never established. “In my mind this is the greatest spectrum ever obtained of a substellar companion,” said Hinkley. “We’ve never seen anything like it.”Illustration: Samuel Velasco/Quanta MagazineThe discovery follows hot on an announcement from two weeks ago, when a different team of astronomers reported that they have used the JWST to detect carbon dioxide in a giant exoplanet called WASP-39 b located 650 light-years from Earth—the first time the gas has ever been seen in an exoplanet. They also spotted a mystery molecule in the atmosphere. That same team is also studying two more giant worlds, with results expected in the coming months that will help piece together an almost complete picture of the atmospheric composition of gas giants like these. “That’s the power of James Webb,” said Jacob Bean, an astronomer at the University of Chicago and the team’s co-leader.The observations will also build up a “chemical inventory” that will show what the JWST might detect in the skies of smaller rocky worlds more similar to Earth, said team leader Natalie Batalha, an astrophysicist at Santa Cruz. She said the team plans to “push JWST to its limits” in upcoming gas giant observations, which will tell them what they "can do on terrestrial planets.”Other teams are conducting the first JWST observations of TRAPPIST-1, a relatively nearby red dwarf star orbited by seven Earth-sized rocky worlds. Several of these planets are in the star’s habitable zone, where conditions favoring liquid water and even life may be possible. While the JWST cannot directly image the planets, spectroscopy will help identify the gases in their atmospheres—possibly even hints of gases that could signify biological activity. “What we really want is Earths,” said Macintosh.Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.
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Cosmology & The Universe
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James Webb Space Telescope uncovers new details in Pandora's Cluster
Astronomers have revealed the latest deep-field image from the NASA/ESA/CSA James Webb Space Telescope, featuring never-before-seen details in a region of space known as Pandora's Cluster (Abell 2744). Webb's view displays three clusters of galaxies—already massive—coming together to form a megacluster.
The combined mass of the galaxy clusters creates a powerful gravitational lens, a natural magnification effect of gravity, allowing much more distant galaxies in the early universe to be observed by using the cluster like a magnifying glass.
Only Pandora's central core has previously been studied in detail by the NASA/ESA Hubble Space Telescope. By combining Webb's powerful infrared instruments with a broad mosaic view of the region's multiple areas of lensing, astronomers aimed to achieve a balance of breadth and depth that will open up a new frontier in the study of cosmology and galaxy evolution.
Astronomers studied the region as part of the Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization (UNCOVER) program. The new view of Pandora's Cluster stitches four Webb snapshots together into one panoramic image, displaying roughly 50 000 sources of near-infrared light.
In addition to magnification, gravitational lensing distorts the appearance of distant galaxies, so they look very different from those in the foreground. The galaxy cluster "lens" is so massive that it warps the fabric of space itself, enough for light from distant galaxies that passes through that warped space to also take on a warped appearance.
In the lensing core to the lower right in the Webb image, which has never been imaged by Hubble, Webb revealed hundreds of distant lensed galaxies that appear like faint arced lines in the image.
The UNCOVER team used Webb's Near-Infrared Camera (NIRCam) to capture the cluster with exposures lasting 4–6 hours, for a total of about 30 hours of observing time. The next step is to meticulously go through the imaging data and select galaxies for follow-up observation with the Near-Infrared Spectrograph (NIRSpec), which will provide precise distance measurements, along with other detailed information about the lensed galaxies' compositions, providing new insights into the early era of galaxy assembly and evolution.
The UNCOVER team expects to make these NIRSpec observations in the summer of 2023.
In the meantime, all of the NIRCam photometric data have been publicly released so that other astronomers can become familiar with them and plan their own scientific studies with Webb's rich datasets.
The imaging mosaics and catalogue of sources on Pandora's Cluster (Abell 2744) provided by the UNCOVER team combine publicly available Hubble data with Webb photometry from three early observation programs: JWST-GO-2561, JWST-DD-ERS-1324, and JWST-DD-2756.
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Cosmology & The Universe
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The James Webb Space Telescope (JWST) launched on Christmas Day 2021, is already transforming our understanding of planets in our Solar System and far beyond. A versatile satellite observatory, JWST has a clear-eyed view from its orbital position, 1.5m km away from Earth in space. This gives it a major advantage over ground-based telescopes which must peer out to space through Earth’s hazy atmosphere.JWST collects five times as much light as the Hubble Space Telescope (HST), allowing it to detect faint signals from distant worlds using its spectroscopic capabilities.‘Before the James Webb Space Telescope, only a very small number of molecules could be observed, such as water, carbon monoxide and sodium,’ said Jérémy Leconte, astrophysicist at the University of Bordeaux in France. Previous missions and observations from Earth have discovered thousands of exoplanets (those outside our Solar System) and astronomers are already taking advantage of JWST’s unique capabilities to study the building blocks of life in the Universe. Alien skiesEarlier this year, the James Webb telescope allowed astrophysicists to observe an exoplanet around a Sun-like star, 700 light-years away. Starlight passing through the atmosphere of the hot Jupiter-like planet WASP-39b gives astronomers a view into the chemistry of alien skies.From Earth, telescopes struggle to observe carbon dioxide on exoplanets, as they must look through the CO2 in the planets’ atmosphere. The JWST observatory allows a greater range of molecules, including carbon dioxide, to be detected in the skies of WASP-39b. The presence of carbon dioxide in the atmosphere may indicate organic life exists on the planet.‘This is really a game-changer,’ said Leconte. ‘We really need to look at planets around stars that are close to us. This is our best chance to characterise their atmospheres.’ “We really need to look at planets around stars that are close to us. This is our best chance to characterise their atmospheres.
In particular, he is interested in seven rocky planets that orbit the dwarf TRAPPIST-1 star, 40 light-years away, and especially their atmospheres. The planets exist in the habitable zone, meaning it has the right temperatures for water to remain liquid.Usually, when scientists make predictions about an exoplanet’s atmosphere, they assume it is homogeneous – the same conditions exist all over it. This is unlikely to be true.Leconte has developed a 3-D simulator (as part of the Horizon-funded WHIPLASH project) to run tests on simulated planets with known characteristics, such as the presence of liquid water. Using simulated planets to run these tests is like having the answers at the back of a math’s book: tests can be run and the answers the models provide can be compared with the known characteristics. Many thousands more exoplanets will likely be discovered in the coming years – including those found using the new space telescope. Scientists want to know if their models can offer accurate insights. Some of the answers to questions about far-away exoplanets might lie close to home in the Solar System, in the four largest planets – Jupiter, Saturn, Uranus and Neptune.The Juno orbiter mission has provided spectacular views of Jupiter, while the Cassini spacecraft revealed details about the planet Saturn. Previously, the Voyager 2 spacecraft flying by Neptune and Uranus took images of their atmospheres.‘We have captured glorious images from these planets, with all these whirling storm systems and candy-coloured stripes, which are large-scale weather circulation patterns,’ said planetary scientist Leigh Fletcher at the University of Leicester, ‘But it is just a snapshot of their atmospheres and climates at a particular moment in time.’ Four giants To understand climate and weather patterns, Fletcher leads a project called GIANTCLIMES that pieced together scattered pieces of the puzzle of their ever-changing atmospheres. They used past observations from telescopes on Earth to understand natural cycles on the four giant planets over many decades. This work has prepared the ground for the highly anticipated new maps of these worlds from the JWST.“We’ve got a collection of diverse planetary atmospheres in our Solar System which form a template for what we might expect to see around other stars.
Uranus and Neptune are the most distant planets in the Solar System and these so-called "ice giants" still retain an air of mystery. They are composed mostly of hydrogen, helium and other gases like methane. ‘There’s so much potential for brand new discoveries (with these two planets),’ said Fletcher. ‘We don’t have a good handle on the workings of the atmospheres of these ice giants compared to the better-studied gas giants (Jupiter & Saturn).’Methane snowMeanwhile, Saturn is known to have massive storm systems, and Neptune may have methane snowstorms. The key variable in weather patterns is always temperature, with frigid cold temperatures on distant Neptune and Uranus.There has been progress already with the publication of the first ever maps of atmospheric temperatures high in the stratosphere of Uranus. This revealed surprising seasonal circulation systems and bright spots over the poles. It also predicts that giant planets, often titled on their axis, have extremely long seasons. ‘We do see seasons modulating atmospheric temperatures and clouds and precipitations as we do on planet Earth,’ said Fletcher, ‘but we also see regular natural cycles in the atmosphere that are not seasonal. We’re just starting to understand the weather on giant planets.’“Two fields are moving fast in astrophysics. They are exoplanets and cosmology, which really comes down to the question of God and life.
Also, Neptune’s atmosphere showed substantial storm and weather activity, but the team were surprised with the finding that the planet seems to have cooled during the summer, rather than warmed.GIANTCLIMES is a supporting act for the arrival of the JWST. The new telescope has already observed Jupiter, and in the near future it will turn towards Uranus and Saturn, and then Neptune early in 2023, allowing for comparisons between planets.‘How the climates work on the four worlds is really the nub of what we are trying to understand,’ said Fletcher. It is expected to offer more insight into the natural cycles of climate variability as detected on Jupiter, Saturn, Uranus and Neptune. Their extremes could even tell us more about Earth’s own climate and weather patterns.Alien life Studies of the four giants are also relevant to exoplanet research. ‘We’ve got a collection of diverse planetary atmospheres in our Solar System which form a template for what we might expect to see around other stars,’ enthused Fletcher. ‘Maybe these exoplanetary targets also exhibit similar natural cycles, and the end goal is to try to have weather prediction or climate prediction for all of the planets, not just those in our Solar System,’ concluded Fletcher.JWST will allow scientists better views into the skies of planets in the far reaches of the Solar System, but also worlds light years away, some of which could be surrounded by protective atmospheres and terrestrial conditions conducive to alien life. ‘Two fields are moving fast in astrophysics. They are exoplanets and cosmology, which really comes down to the question of God and life, so where does the Universe come from and where do we come from,’ said Leconte.Research in this article was funded via the EU’s European Research Council (ERC). If you liked this article, please consider sharing it on social media.
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Cosmology & The Universe
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Between 1984 and 1992 the cosmologist Nick Kaiser, who has died of heart failure aged 68, created many of the ideas now used by astronomers to map the large-scale distribution of dark matter in the universe. His analysis of the clustering of galaxies and the distortion of galaxy shapes by gravitational light deflection are at the heart of the leading modern cosmological experiments, particularly the recently launched Euclid satellite.
Kaiser’s research concentrated on the large-scale structure of the universe. Galaxies such as our own, the Milky Way, are congregated in a vast pattern of density fluctuations – superclusters that extend for at least 100m light years. All this structure probably represents the relic of primordial fluctuations that collapsed under their own gravity, generating galaxies and the stars and planets within them. We see these patterns in the clustering of the galaxy distribution, but much evidence tells us that the galaxies are embedded in invisible underlying dark matter, which dominates the gravity – dragging gas with it, which in turn forms into the stars of the visible galaxies.
Kaiser’s first important contribution to this field came in 1984, when he solved the puzzle of biased clustering. In the early 80s there was great confusion because different classes of galaxy clumped differently, each apparently indicating different levels of cosmic inhomogeneity, indicating different degrees of clumping of the overall mass distribution. Kaiser explained this by appealing to classic statistical tools created for the analysis of noise in telephone systems. He argued that peaks in a random noise field will always have a stronger degree of correlation than the field as a whole, with the highest peaks – clumps of dark matter in this case – tending to be found close to each other. In this way, we now understand how the clustering of different galaxies can be related to a single underlying set of clumps in the dark matter.
Once the idea of the biased relation between light and mass was understood, there remained a strong desire to study the underlying distribution of dark matter directly. In 1987 Kaiser developed a novel way to achieve this, by exploiting the so-called “redshift-space distortions”. These arise in a 3D galaxy survey because the cosmological redshift from the expansion of the universe is changed by Doppler shifts due to the “peculiar velocities” that arise as clumps of matter fall together. The apparent redshift, which is what is used to infer the distance to a given galaxy, is then altered – stretching the map of superclusters along the line of sight. Kaiser showed that this distortion could be used to measure the peculiar velocities and hence determine the total density of the universe.
An alternative means of detecting dark matter directly comes from gravitational lensing: the distortion of background galaxies as their light passes massive foreground galaxies. In 1992, Kaiser published an analysis of “weak lensing”, considering the statistics of small image distortions and how they can reveal the effect of dark matter.
Gravitational lensing can be seen at work in images from the Hubble telescope of the rich galaxy cluster A370. The bright foreground galaxies deflect light from more distant galaxies, distorting their shapes into striking elongated arcs. In more typical directions, this distortion is much smaller: only stretching images by around 1%. But Kaiser showed how such distortions could be averaged over many galaxies to detect and map the dark matter causing the lensing.
This work was far ahead of its time, and is now an entire field of cosmology in its own right. Many ground-based surveys and most recently the Euclid satellite observatory have been devoted to lensing and redshift-space distortions; more than a billion dollars have been invested in order to turn Kaiser’s 1987 and 1992 visions into a working reality.
Kaiser also innovated in the technical arena. Between 2000 and 2008 he led the development of PanSTARRS, a survey telescope in Hawaii with an unprecedentedly wide field of view. Although designed for cosmology, it has also made important contributions to the study of the solar system, and is now used as part of an early warning system for “killer asteroids” that are at risk of making a catastrophic impact on the Earth.
Born and brought up in Sheffield, Nick was the son of Pamela (need Pound) and Tom Kaiser, a physics professor at Sheffield University. After gaining a BSc (1978) at Leeds University, Nick went on to a PhD (1982) at the Institute of Astronomy, Cambridge, under the supervision of Martin Rees.
Following postdoctoral research in California and the UK, Kaiser’s career took him to professorships at the Canadian Institute for Theoretical Astrophysics, Toronto (1988); the University of Hawaii (1998); and the École Normale Supérieure, Paris (2017). He was made a Fellow of the Royal Society (2008); was awarded the gold medal of the Royal Astronomical Society (2017), like his father; and received the Gruber prize in cosmology (2019).
A keen athlete, he became an ultra-runner, participating in innumerable marathons, triathlons and extreme competitions such as Iron Man. Characteristically he made a mathematical analysis of the most effective strategy for energy expenditure in his races.
His marriage to Penelope Corbett ended in divorce. He is survived by his partner, Maureen Miller, and by two sons from his marriage, Alex and Louis.
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Cosmology & The Universe
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To put it simply, the universe's most massive known star is less massive than scientists once believed. But even docked a few levels, this staggering ball of gas is still the universe's most massive known star. That's how utterly huge it is.Lovingly named R136a1, the luminous giant lives 160,000 light-years from Earth in the center of a stunning, stringy star factory known as the Tarantula Nebula. Last week, astronomers announced that celestial observations collected with the Gemini South Telescope in Chile produced the sharpest image ever taken of it -- thus unveiling its true heft. For years, data suggested this star held a mass somewhere between 250 to 350 times the sun's. But according to the team's study slated to appear in The Astrophysical Journal, the new view indicates it's more like 170 to 230 times the mass of our host star.Nevertheless, R136a1 is a gleaming monster. "Even with this lower estimate, R136a1 still qualifies as the most massive known star," the research team said in a press release. For context, the Earth has a mass of around (don't think about this number, just feel it) 6,000,000,000,000,000,000,000,000 kilograms. Jupiter's mass is 318 times even that. This all accounts for just two worlds in our cosmic neighborhood. And yet the sun comprises 99.8% of the mass of the entire solar system. If that hurt your brain, another way to think about the size discrepancy is something like a million Earths could fit inside the sun. So, yeah. R136a1 is between 170 and 230 times more massive than the sun. Do with this information what you will.An artist's illustration of R136a1, the largest known star in the universe, which resides inside the Tarantula Nebula in the Large Magellanic Cloud. Maybe one day we'll get a clear-enough image of this stellar body to rival even this portrait. NOIRLab/NSF/AURA/J. da Silva/Spaceengine For the purpose of scientific advancement, "this suggests that the upper limit on stellar masses may also be smaller than previously thought," Venu M. Kalari, an astronomer at the National Science Foundation's NOIRLab and lead author of the paper, said in the release. Plus, Kalari's results might implicate our understanding of certain elements in the universe, particularly those created from the explosive deaths of stars with over 150 solar masses -- the ones that went with the biggest of bangs.OK, but why didn't we know this before?Basically, the universe's most spectacular, scorching and humongous stars are also typically its most fleeting, faraway and mysterious ones.First of all, really massive stellar bodies tend to exist inside densely populated star clusters that are concealed by residual stardust, like R136a1 resides within the Tarantula Nebula. That makes it pretty difficult for terrestrial equipment to discern precise qualities of a colossal star of interest -- other stars kind of interfere with observations.This image shows how the sharpness and clarity of the Zorro imager on the 8.1-meter Gemini South telescope in Chile (left) compares to to an earlier image of R136a1 taken with the NASA/ESA Hubble Space Telescope (right). International Gemini Observatory/NOIRLab/NSF/AURA Acknowledgment: Image processing: T.A. Rector (University of Alaska Anchorage/NSF's NOIRLab), M. Zamani (NSF's NOIRLab) & D. de Martin (NSF's NOIRLab); NASA/ESA Hubble Space Telescope "Giant stars also live fast and die young," according to the NOIRLab, an organization that operates the Gemini South Telescope, "burning through their fuel reserves in only a few million years. In comparison, our sun is less than halfway through its 10 billion year lifespan." Aka, there's a bit of a time limit for the already-daunting task of identifying super massive stars within a dust-shrouded star cluster.Here's where the Gemini South Telescope comes in. To image R136a1 with unprecedented clarity, this machine used a special instrument called Zorro to get around some (giant) stargazing hurdles. Zorro used a technique known as speckle imaging, which helped the telescope overcome the blurring effect caused by Earth's atmosphere. Atmospheric blurring poses such a big barrier for telescope observations that, in fact, this was the reason NASA launched the Hubble Space Telescope in 1990. At the time, the goal was to get a lens above our planet's atmosphere for beautiful, clear cosmic pictures. Still on the ground, however, Zorro circumvented the atmospheric blur issue in a different way. It essentially took thousands of short-exposure R136a1 images, which were then digitally processed by the study team."Given the right conditions, an 8.1-meter telescope pushed to its limits can rival not only the Hubble Space Telescope when it comes to angular resolution, but also the James Webb Space Telescope," Ricardo Salinas, co-author of the paper and instrument scientist for Zorro, said in the release. "This observation pushes the boundary of what is considered possible using speckle imaging."The eventual image conglomerate was sharp enough to allow the team to separate R136a1's brightness from luminescence shed by stellar companions in its vicinity, which led to a lower estimate of its brightness, and therefore mass. "Astronomers are able to estimate a star's mass by comparing its observed brightness and temperature with theoretical predictions," according to the NOIRLab."We began this work as an exploratory observation to see how well Zorro could observe this type of object," Kalari said. "While we urge caution when interpreting our results, our observations indicate that the most massive stars may not be as massive as once thought."
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Cosmology & The Universe
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"Satellites were mind-boggling"Since the 1970s, when the plane of satellites was first identified, astronomers have made numerous unsuccessful attempts to locate comparable structures in accurate supercomputer models that chart the development of the Universe from the Big Bang to the present. On the other hand, in this most recent study, astronomers took advantage of new data from the GAIA space observatory operated by the European Space Agency. A six-dimensional map of the Milky Way is being created by GAIA, which also provides exact locations and velocity measurements for around a billion stars in our galaxy. With these data, researchers could predict the satellite galaxies' future and previous orbits and observe how the plane formed and disintegrated in a matter of a few hundred million years or a mere blink of an eye in cosmic time."The strange alignment of the Milky Way's satellite galaxies in the sky had perplexed astronomers for decades, so much so that it was deemed to pose a profound challenge to cosmological orthodoxy," said study co-author Professor Carlos Frenk, Ogden Professor of Fundamental Physics in the Institute for Computational Cosmology, at Durham University.
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Cosmology & The Universe
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Superstar astrophysicist and sagacious citizen of the universe Neil deGrasse Tyson really needs no formal introduction when it comes to all matters of a cosmic nature.
The esteemed scientist, lecturer, author, podcaster, NASA consultant, online educator and TV personality enjoys a popularity usually ascribed to heavy metal rock idols, and his role as an elder statesman of astronomy provides laypersons a broad understanding of everything from black holes to time travel.
Now the host of the Emmy Award-winning "Cosmos" has teamed up with longtime StarTalk colleague Lindsey Nyx Walker to provide fresh perspectives on the latest astronomical discoveries in their new 320-page book released September 12 from National Geographic titled "To Infinity and Beyond: A Journey of Cosmic Discovery."
To Infinity and Beyond: A Journey of Cosmic Discovery: $27.00 at Amazon
Neil deGrasse Tyson and StarTalk senior producer Lindsey Nyx Walker draw from on mythology, history, and literature — alongside Tyson's trademark wit and charm — to bring the farthest realms of space within reach of any reader.
Here's the book's official synopsis:
"No one can make the mysteries of the universe more comprehensible and fun than Neil deGrasse Tyson. Drawing on mythology, history, and literature — alongside his trademark wit and charm — Tyson and StarTalk senior producer Lindsey Nyx Walker bring planetary science down to Earth and principles of astrophysics within reach. In this entertaining book, illustrated with vivid photographs and art, readers travel through space and time, starting with the Big Bang and voyaging to the far reaches of the universe and beyond. Along the way, science greets pop culture as Tyson explains the triumphs — and bloopers — in Hollywood's blockbusters: All part of an entertaining ride through the cosmos.
"The book begins as we leave Earth, encountering new truths about our planet's atmosphere, the nature of sunlight, and the many missions that have demystified our galactic neighbors. But the farther out we travel, the weirder things get. What's a void and what's a vacuum? How can light be a wave and a particle at the same time? When we finally arrive in the blackness of outer space, Tyson takes on the spookiest phenomena of the cosmos: parallel worlds, black holes, time travel, and more."
We recently connected with Tyson regarding this informative and highly entertaining guide covering a multiverse of mindblowing material, and how its topical contents should keep backyard astronomers and space junkies fixated for an eternity.
Space.com: What makes this book different from similar volumes about space science, cosmology and astronomy?
Neil de Grasse Tyson: Yes, there's updated content from any book that was published even just a few years ago, any book that's attempting to bring people into the know about the status of our understanding of the universe. It's the third StarTalk book in a series of collaborations with National Geographic Books. "To Infinity and Beyond" continues to capture the StarTalk DNA, which is science blended with humor and pop culture. It's that threading that we've found has the greatest reach. For people who don’t need the humor, I've got other stuff for them. There are people who just want to have fun and think a little bit, I've got stuff for them too.
This is the perfect combination that we've landed upon to tell the story of the human quest to ascend Earth's surface. Going back to Icarus and the consequences of what it was to build wax wings. People thought back then that the higher you go, the closer to the sun you get. It gets hotter and melts the wings and he falls to his death. Not knowing that the sun heats the Earth's surface, it does not directly heat the air.
As you ascend it gets colder and colder. So we have to ask what would our response be when hearing the story of Icarus. Is it, 'Okay we're not trying that ever again.' Or is it advice on how to build a better flying device? How do you respond to failure?
Space.com: How did you organize sections of "To Infinity and Beyond" to provide a logical stairway to the heavens for readers to absorb and ponder?
Tyson: There are four sections that go from Earth into the air, then Earth into the planets, then among the stars, galaxies and then the universe and all of the methods and tools of science and technology that get us there. It's not just the greatest hits.
That's too easy and everybody's written that. It's where did we fail as well, and how did people recover and what kind of delay did it put if people were scared. So it's a candid look at the history of human attempts to go from Earth into the universe and back. Throughout, we draw upon examples in pop culture, typically first-run films or songs or things that you otherwise care about because it's in pop culture, but then you learn there's a lesson or insight in there. And that's part of the threading of what makes StarTalk a unique product on this landscape of science education.
Space.com: Some of the more extreme material exists towards the back of the book so readers can warm up before plunging deep into the astrophysical abyss. Which elements of that final cerebral section did you enjoy presenting?
Tyson: In the "Beyond" part, we talk about traveling through space and serious restrictions that exist on time machines. Next time you see a movie about time travel think about this: You step into the time machine and let's say you go back a week to fix something. You go back a week and then pop out of the machine and if they did it right you'd be in the vacuum of empty space. Earth is not here a week ago. So any time machine has to also be a space-time machine. All the platforms on which you're conducting your time travel are in motion. The sun, and everything in orbit around it, is moving around the center of the galaxy. Earth is rotating. If you go back an hour in your time machine, then you're in an entire time zone away. These are little things to consider and we talk about the consequences if you don't do it right.
In the film "Back to the Future," they pretty much did it right. When Marty goes back in time, he goes back exactly 30 years, from 1985 to 1955. So if you go back in year increments, Earth is going to be in the same place in its orbit. In the wee hours of the morning he ends up at the farm where the strip mall was built. They get a thumbs up for thinking that through.
Space.com: In compiling this far-reaching book, were there any fringe subjects touched upon that reignited discoveries you hadn't thought about for a while?
Tyson: This is the great value of a co-author. Lindsey Walker has been with StarTalk for seven or eight years as producer. She cut her teeth as a journalist writing about astrobiology for NASA's astrobiology magazine, so her mind is there and she's a great writer. More importantly, she was able to think about the biological dimension of what we would add to this. Human physiology in the past and in the future. What can we survive? Her input was to make sure that that part of these conversations were explored. What would be the physiology of an alien be if we come upon one?
Any movies to reference that could highlight that? It adds an important side of this talk about space as this book unfolded as a project. Also it was her initiative to have as much attention that we gave to space-time diagrams. It was a little risky because plotting something doesn't always make things easier for people.
We also talk about a space elevator. If you're a fan of science fiction sometimes it's a big part of the story and the idea that in a geostationary orbit you can just hoist yourself up a cable. So we talk about the feasibility of that and why you might want to do that. It hasn't been realized yet, but that's to infinity and beyond. If we're going to do it, is that any different than Icarus? These are our efforts to send us into space and have space become our next and final frontier.
"To Infinity and Beyond: A Journey of Cosmic Discovery" was released on Sept. 12, 2023.
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Cosmology & The Universe
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Hello, HIP 65426 b! That jumble of letters and numbers belongs to an exoplanet (a planet outside our solar system) that has the honor of being the subject of the James Webb Space Telescope's first direct image of a distant world."This is a transformative moment, not only for Webb but also for astronomy generally," said astronomer Sasha Hinkley of the University of Exeter. Hinkley led an international team of researchers who worked on the landmark exoplanet observation. Before we lose our minds over this, a couple of caveats. Exoplanets have been directly imaged before by other telescopes, and the research highlighted in NASA's Thursday announcement hasn't yet been through the peer-review process, where other scientists scrutinize the information. OK, now you can shout, "Cool!"This graphic shows star HIP 65426 at the top with the inset images showing exoplanet HIP 65426 b in different bands of infrared light, as seen by the James Webb Space Telescope. NASA/ESA/CSA, A Carter (UCSC), the ERS 1386 team, and A. Pagan (STScI) JWST sees in infrared, which gives it the ability to peer far and deep into the universe and spot elusive objects that other telescopes wouldn't be able to capture. The image release highlights how HIP 65426 b looks in four different bands of infrared light. "Obtaining this image felt like digging for space treasure," said postdoctoral researcher Aarynn Carter of the University of California, Santa Cruz. Carter led the image analysis. Webb is able to mask starlight in order to block out a star's glare and capture images like this of elusive exoplanets. It helps that HIP 65426 b orbits its host star at a distance 100 times farther than the Earth from the sun, making it a little easier to mask the light. You'll notice a tiny white star in each of the four planet images. That marks the location of the host star, which has been hidden from view. Hubble and James Webb Space Telescope Images Compared: See the Difference See all photos The planet was already known to exist, thanks to the work of a telescope in Chile that discovered it in 2017. "Webb's view, at longer infrared wavelengths, reveals new details that ground-based telescopes would not be able to detect because of the intrinsic infrared glow of Earth's atmosphere," said NASA.The exoplanet is a youngster, just 15 million to 20 million years old. Here on Earth, we're living on a 4.5-billion-year-old planet. HIP 65426 b is a gas giant, measuring in at six to 12 times the mass of Jupiter. The researchers should be able to dial in its mass more accurately as they work through the data. The team is in process on a research paper that'll head through the peer-review process of a journal before publication. The early results, however, are already worth celebrating.Webb, which launched in late 2021 and went through a lengthy deployment process, has already provided a diverse bouquet of images and observations, ranging from glorious nebulas to spotting carbon dioxide in an exoplanet's atmosphere. The views of HIP 65426 b might look like glowing blobs, but they're just the beginning, a harbinger of the knockout science to come.
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Cosmology & The Universe
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Seen through a giant's eyes, our Universe's galaxies cling like foam to the surface of an eternal ocean, drawing into clumps and strings around inky voids.
This sparkling web has taken eons to come together, congealing gradually under gravity's guidance out of what was, billions of years ago, an evenly-spread fog of white-hot particles fresh out of the Big Bang's oven.
Slow as this growth seems to us mere mortals, University of Michigan physicists Nhat-Minh Nguyen, Dragan Huterer, and Yuewei Wen want to slow it down even further, fixing one of science's most vexing problems in the process.
Their suggested tweak to the model that currently best describes our Universe could resolve a significant conflict in observations of space's expanding waistline.
Complain as you might that you can't get something for nothing these days, there's more empty space up there today than there was yesterday. Something is causing nothingness to grow, squeezing its way into the gaps between galaxies to gently push the large scale structure of the Universe apart at an ever increasing rate.
Since we don't know what is behind this mysterious shoving, we refer to it as dark energy.
"If gravity acts like an amplifier enhancing matter perturbations to grow into large-scale structure, then dark energy acts like an attenuator damping these perturbations and slowing the growth of structure," says Nguyen, the lead author of an investigation into the large-scale structure's growth.
"By examining how cosmic structure has been clustering and growing, we can try to understand the nature of gravity and dark energy."
The precise rate of expansion, known as the Hubble constant (H0), isn't at all clear. Measure the way certain kinds of exploding stars retreat into the distance, you might get an acceleration of 74 kilometers per second per megparsec. Using the 'light echo' of stretched radiation still bouncing about after the Big Bang – the cosmic microwave background (CMB) – H0 is closer to around 67 kilometers per second.
That might not seem like much of a difference, but the discrepancy has persisted through enough investigations that it can no longer be dismissed as some trivial error.
Nguyen, Huterer, and Wen took a fresh look at the flat ΛCDM concordance cosmology model as a potential source of mistaken assumptions. If cosmology was a game of chess, this would be the board and pieces as laid out on general relativity's tiles, moved by dark energy's push, and aligned by dark matter's gravitational influences.
Rewinding the chess pieces we see today, we can effectively see how the game began, from a momentary blink of rapid inflation to a time where the first stars collapse, to the formation of galaxies and their eventual emergence into gargantuan, interconnected threads.
If for some reason this process deviated from what's predicted by the concordance model, impeding the growth of the Universe's large-scale structure, the tension between the different measures of the Universe's accelerating expansion would vanish.
The researchers used a combination of measurements involving ripples in the cosmic web, gravitational lensing events, and details in the cosmic microwave background to come to a statistically convincing conclusion that the cosmic web is growing slower than the flat ΛCDM concordance cosmology model predicts.
"The difference in these growth rates that we have potentially discovered becomes more prominent as we approach the present day," says Nguyen.
"These different probes individually and collectively indicate a growth suppression. Either we are missing some systematic errors in each of these probes, or we are missing some new, late-time physics in our standard model."
While there are no obvious contenders for what might put the brakes on the growth of the cosmic web, future measurements of the Universe's large scale structure might at least hint at whether there's a need to explore the idea further.
The Universe has taken 13.7 billion years to look this good. We can stand to wait a few more years to work out the secrets to such fine looking cosmological wrinkles.
Sources:
Published 11 September 2023 in Physical Review Letters: Evidence for Suppression of Structure Growth in the Concordance Cosmological Model
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Cosmology & The Universe
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The James Webb Space Telescope is still snapping its first pictures of Solar System planets, and the latest batch could be particularly useful. NASA and the ESA have shared early images of Mars, taken on September 5th, that promise new insights into the planet's atmosphere. Data from the near-infrared camera (NIRCam) is already offering a few surprises. For starters, the giant Hellas Basin is oddly darker than nearby areas at the hottest time of the day, NASA's Giuliano Liuzzi and Space.com noted — higher air pressure at the basin's lower altitude has suppressed thermal emissions.
The JWST imagery also gave space agencies an opportunity to share Mars' near-infrared atmospheric composition using the telescope's onboard spectrograph array. The spectroscopic 'map' (pictured at middle) shows the planet absorbing carbon dioxide at several different wavelengths, and also shows the presences of carbon monoxide and water. A future research paper will provide more detail about the Martian air's chemistry.
NASA, ESA, CSA, STScI, Mars JWST/GTO team
It was particularly tricky to record the images. Mars is one of the brightest objects the James Webb telescope can see — a problem for an observatory designed to study the most distant objects in the universe. Researchers countered this by capturing very short exposures and using special techniques to analyze the findings.
This is only the initial wave of pictures and data. It will take more observations to reveal more about Mars. However, the spectral info already hints at more information about the planet's materials. Liuzzi also thinks JWST studies could settle disputes over the presence of methane on Mars, potentially signalling that the Red Planet harbored life in its distant past.All products recommended by Engadget are selected by our editorial team, independent of our parent company. Some of our stories include affiliate links. If you buy something through one of these links, we may earn an affiliate commission. All prices are correct at the time of publishing.
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Cosmology & The Universe
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Astronomers have discovered the most ancient "heartbeat" radio signal, and they want to use it to find the missing half of the universe's matter.
The mysterious signal — a fast radio burst called FRB 20220610A — was found 8 billion years into the universe's past, its light rhythmically pulsing from the heart of three merging galaxies.
As the fast radio burst (FRB) is 1.5 times more ancient and distant than the previous record holder, its light could be used to find an approximate weight to the universe — and perhaps to figure out where half of its matter went, astronomers say. The researchers published their findings Oct. 19 in the journal Nature.
"If we count up the amount of normal matter in the Universe — the atoms that we are all made of — we find that more than half of what should be there today is missing," study co-lead author Ryan Shannon, a professor of astrophysics at Swinburne University in Australia, said in a statement. "We think that the missing matter is hiding in the space between galaxies, but it may just be so hot and diffuse that it's impossible to see using normal techniques."
Currently, there are two ways to approximate the matter contained within our universe. The first uses gravitational lensing to see how much matter warps the path of light from distant galaxies through space; and the second looks at the universe's first light from the cosmic microwave background — remnant radiation from the Big Bang that can reveal where matter clumped together at the dawn of the universe and how it evolved over time.
The problem, however, is that these methods disagree, creating a discrepancy called the Sigma-8 tension that threatens to tear standard theories of cosmology apart. Where the missing matter could be isn't certain, but astronomers have a hunch it is floating in intergalactic space in vast, diffuse clouds of gas and dust. But to measure these clouds, astronomers need powerful sources of light.
Fast radio bursts are perfect for the job — discharging more energy in a few milliseconds than the sun does in a year. Astronomers have long puzzled over the source of these sudden, bright flashes. But because FRBs erupt predominantly from galaxies millions — or even billions — of light-years away, and flare quickly, scientists have struggled to pin them down.
One known source of FRBs is a radio pulsar or a magnetar, a highly magnetized, rapidly-rotating husk of a dead star. Equipped with unusually strong magnetic fields that are trillions of times more powerful than Earth's, the dead stars spin in space, sweeping out beams of intense radio waves from their poles like giant lighthouses.
As FRB pulses move through space, the matter they move through separates out the light pulse’s different frequencies, producing a lag between the arrival of the high and low frequencies in the signal. From the length of this delay, astronomers can figure out how much matter the burst has moved through.
Until now, astronomers had only detected bursts from a bit more than 5 billion years into the universe's past, too recent to make this calculation. But the new fast radio burst, traced back 8 billion years into the universe's 13 billion year age, gives fresh hope.
"While we still don't know what causes these massive bursts of energy, the paper confirms that fast radio bursts are common events in the cosmos and that we will be able to use them to detect matter between galaxies, and better understand the structure of the Universe," Shannon said.
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Ben Turner is a U.K. based staff writer at Live Science. He covers physics and astronomy, among other topics like tech and climate change. He graduated from University College London with a degree in particle physics before training as a journalist. When he's not writing, Ben enjoys reading literature, playing the guitar and embarrassing himself with chess.
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Cosmology & The Universe
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Researchers have found a new way to measure dark energy — the mysterious force that is causing the expansion of the entire universe to accelerate — using data from our own cosmic backyard.
Ever since its discovery in the late 1990s, dark energy has become the premier problem in cosmology. In short, we have no idea what dark energy is. But whatever it is, it's directly responsible for the accelerated expansion of the universe, and cosmologists have devised a wide variety of tools to try to learn more about it.
For example, astronomers can study the brightness of distant supernova explosions to measure how quickly they are moving away from us. They can look back into the early days of the cosmos and determine the fundamental ingredients playing major roles back then. They can even map out the evolution of the largest structures in the universe, teasing out the effects of dark energy on that evolution.
The main challenge with all those techniques is that they require both deep and broad measurements, probing vast volumes of the universe. That makes sense; we don't feel the effects of dark energy in the solar system or even in the Milky Way galaxy, because overall, dark energy is a very weak effect and is easily swamped by the strong forces operating inside galaxies.
But now, a pair of researchers has found a way to use surprisingly small scales to measure dark energy, as they discuss in a paper submitted to The Astrophysical Journal Letters and available as a preprint on arXiv.
The technique is based on the fact that dark energy affects the relationships between every pair of galaxies. Galaxies naturally want to attract each other, pulling each other close with their strong gravity. But counteracting that natural impulse to clump together is dark energy itself, which acts like an antigravitational force that drives galaxies away from each other.
If galaxies are already close enough, then with enough time, they will overwhelm dark energy and crash together. But if they're too far apart, then their mutual gravitational attraction will never be enough to counteract dark energy, and they will be forever ripped apart.
The nearest galaxy to the Milky Way is the Andromeda galaxy, which sits about 2.5 million light-years away. The two galaxies are on a collision course and will eventually begin merging in about 5 billion years. But this collision won't be directly head-on. The two galaxies slowly orbit each other as they draw closer to each other, taking about 20 billion years to complete a full circuit — which means we won't even complete a single full orbit before the collision and merger begin.
The mutual gravitational attraction is far too strong for dark energy to stop that, but the researchers discovered that the presence of dark energy in the cosmos affects the orbit of the two galaxies around each other and the eventual impact time. So we can use measurements of the precise position and motion of Andromeda to get a handle on dark energy, without having to go out into the wider universe.
The technique is still in its infancy, however. To use Andromeda to measure dark energy, we must have excellent measurements of the mass of both the Milky Way and Andromeda. The more uncertain we are in those measurements, the less precise we can be about the impact of dark energy on our mutual orbit.
So, although the astronomers weren't able to deliver more precise measurements of dark energy, they hope that future refinements of the technique, plus applications to more pairs of colliding galaxies, will help us solve this perplexing dark energy mystery.
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Cosmology & The Universe
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The James Webb Space Telescope (JWST) has discovered that nearly all of the universe's earliest galaxies were filled with dazzling gas clouds that blazed brighter than the emerging stars within them — and it could help solve a mystery that threatens to break cosmology.
Forming as early as 500 million years after the Big Bang, some early galaxies have been seen glowing so brightly that they shouldn't exist: Brightnesses of their magnitude should come only from massive galaxies with as many stars as the Milky Way, yet the galaxies took shape in a fraction of the time our galaxy took to form.
The discovery threatened to upend physicists' understanding of galaxy formation and even the standard model of cosmology, which states that a few million years after the Big Bang (13.8 billion years ago) energy condensed into matter from which the first stars slowly coalesced. Yet when the JWST came online, it saw far too many stars.
Now, astronomers have found a possible answer: a large group of 12 billion-year-old galaxies almost 90% of which were wreathed in bright gas that — after being ignited by light from the surrounding stars — triggered intense bursts of star formation as the gas cooled. The new research has been accepted for publication in The Astrophysical Journal.
"Our paper proves that interactions with the neighboring galaxies are responsible for the unusual brightness of early galaxies," lead author Anshu Gupta, an astrophysicist at Curtin University in Australia, told Live Science in an email. "The explosion of star formation triggered by the interactions could also explain the more massive nature of early galaxies."
Astronomers discovered the bright gas clouds in data collected as part of JWST's Advanced Deep Extragalactic Survey, which used three of the telescope's instruments to collect infrared images of galaxies before analyzing their spectra.
By peering at the frequencies of light the galaxies emitted, the researchers discovered spikes of "extreme emission features" — a clear sign that the gas was capturing light from nearby stars before reemitting it.
"Gas cannot emit light on its own," Gupta said. "But the young, massive stars emit just the right type of radiation to excite the gas — and the early galaxies have lots of young stars."
After comparing this emission spectrum with those found in newer galaxies populating today's universe, the researchers found that around 1% had similar features. The researchers said that by studying these later galaxies, which are easier to measure, they will gain important insight into the earlier galaxies and the beginnings of the universe's chemistry.
"The chemical elements that make up everything tangible on Earth and the universe, except hydrogen and helium, originated in the cores of distant stars," Gupta said. "So, it is critical to understand the conditions surrounding galaxies and stars in the early universe for us to better understand our own world today."
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Ben Turner is a U.K. based staff writer at Live Science. He covers physics and astronomy, among other topics like tech and climate change. He graduated from University College London with a degree in particle physics before training as a journalist. When he's not writing, Ben enjoys reading literature, playing the guitar and embarrassing himself with chess.
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Cosmology & The Universe
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Now, a group of astronomers including at the Universities of Helsinki and Durham, have shown that the Milky Way plane of satellites is, like the constellations of yore, nothing more than a chance alignment – and like the constellations, it is bound to dissolve.
“The plane of satellites was truly mind boggling,” says the study’s lead author, Till Sawala. “It is perhaps unsurprising that a puzzle which has endured for almost fifty years required a combination of methods to solve it - and an international team to come together.”
This breakthrough was made possible, in part, by new data from the European Space Agency's GAIA space observatory. GAIA is charting a six-dimensional map of the Milky Way, providing precise positions and motion measurements for about one billion stars in our Galaxy (about 1 percent of the total) and its companion systems. This allowed them to project the orbits of the satellites into the past and future, and see the plane form and dissolve in a few hundred million years – a mere blink of an eye in cosmic time.
To close the loop, astronomers also searched new, tailor-made cosmological simulations for evidence of planes of satellites. They realised that previous studies based on simulations had been misled by failing to take into account the distances of satellites from the centre of the Galaxy, which made the virtual satellite systems appear much rounder than the real one.
Taking this into account, they found several virtual Milky Ways which boast a plane very similar to what is observed. This removes one of the main objections to the validity of the standard model of cosmology, and means that the concept of dark matter remains the cornerstone of our understanding of the Universe.
“The standard Lambda cold dark matter model is currently the best model we have for our universe and solving the plane of satellites problem resolves another challenge to the model”, says co-author, professor Peter H. Johansson.
"We have been able to remove one of the main outstanding challenges to the cold dark matter theory: it continues to provide a remarkably faithful description of the evolution of our Universe", comments Durham University’s Carlos Frenk.
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Cosmology & The Universe
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By Matt WilliamsFor thousands of years, human being have been contemplating the Universe and seeking to determine its true extent. And whereas ancient philosophers believed that the world consisted of a disk, a ziggurat or a cube surrounded by celestial oceans or some kind of ether, the development of modern astronomy opened their eyes to new frontiers. By the 20th century, scientists began to understand just how vast (and maybe even unending) the Universe really is. And in the course of looking farther out into space, and deeper back in time, cosmologists have discovered some truly amazing things. For example, during the 1960s, astronomers became aware of microwave background radiation that was detectable in all directions. Known as the Cosmic Microwave Background (CMB), the existence of this radiation has helped to inform our understanding of how the Universe began.Description:The CMB is essentially electromagnetic radiation that is left over from the earliest cosmological epoch which permeates the entire Universe. It is believed to have formed about 380,000 years after the Big Bang and contains subtle indications of how the first stars and galaxies formed. While this radiation is invisible using optical telescopes, radio telescopes are able to detect the faint signal (or glow) that is strongest in the microwave region of the radio spectrum. The CMB is visible at a distance of 13.8 billion light years in all directions from Earth, leading scientists to determine that this is the true age of the Universe. However, it is not an indication of the true extent of the Universe. Given that space has been in a state of expansion ever since the early Universe (and is expanding faster than the speed of light), the CMB is merely the farthest back in time we are capable of seeing.Relationship to the Big Bang:The CMB is central to the Big Bang Theory and modern cosmological models (such as the Lambda-CDM model). As the theory goes, when the Universe was born 13.8 billion years ago, all matter was condensed onto a single point of infinite density and extreme heat. Due to the extreme heat and density of matter, the state of the Universe was highly unstable. Suddenly, this point began expanding, and the Universe as we know it began.At this time, space was filled with a uniform glow of white-hot plasma particles – which consisted of protons, neutrons, electrons and photons (light). Between 380,000 and 150 million years after the Big Bang, the photons were constantly interacting with free electrons and could not travel long distances. Hence why this epoch is colloquially referred to as the “Dark Ages”. As the Universe continued to expand, it cooled to the point where electrons were able to combine with protons to form hydrogen atoms (aka. the Recombination Period). In the absence of free electrons, the photons were able to move unhindered through the Universe and it began to appear as it does today (i.e. transparent and permeated by light). Over the intervening billions of years, the Universe continued to expand and cooled greatly.Due to the expansion of space, the wavelengths of the photons grew (became ‘redshifted’) to roughly 1 millimetre and their effective temperature decreased to just above absolute zero – 2.7 Kelvin (-270 °C; -454 °F). These photons fill the Universe today and appear as a background glow that can be detected in the far-infrared and radio wavelengths. History of Study:The existence of the CMB was first theorized by Ukrainian-American physicist George Gamow, along with his students, Ralph Alpher and Robert Herman, in 1948. This theory was based on their studies of the consequences of nucleosynthesis of light elements (hydrogen, helium and lithium) during the very early Universe. Essentially, they realized that in order to synthesize the nuclei of these elements, the early Universe needed to be extremely hot. The Big Bang timeline of the Universe. Cosmic neutrinos affect the CMB at the time it was emitted, and physics takes care of the rest of their evolution until today. - Image credit: NASA / JPL-Caltech / A. Kashlinsky (GSFC). They further theorized that the leftover radiation from this extremely hot period would permeate the Universe and would be detectable. Due to the expansion of the Universe, they estimated that this background radiation would have a low temperature of 5 K (-268 °C; -450 °F) – just five degrees above absolute zero – which corresponds to microwave wavelengths. It wasn’t until 1964 that the first evidence for the CMB was detected.This was the result of American astronomers Arno Penzias and Robert Wilson using the Dicke radiometer, which they had intended to use for radio astronomy and satellite communication experiments. However, when conducting their first measurement, they noticed an excess of 4.2K antenna temperature that they could not account for and could only be explained by the presence of background radiation. For their discovery, Penzias and Wilson were awarded the Nobel Prize in Physics in 1978.Initially, the detection of the CMB was a source of contention between proponents of different cosmological theories. Whereas proponents of the Big Bang Theory claimed that this was the “relic radiation” left over from the Big Bang, proponents of the Steady State Theory argued that it was the result of scattered starlight from distant galaxies. However, by the 1970s, a scientific consensus had emerged that favored the Big Bang interpretation. All-sky data obtained by the ESA’s Planck mission, showing the different wavelenghts. - Image Credit: ESA During the 1980s, ground-based instruments placed increasingly stringent limits on the temperature differences of the CMB. These included the Soviet RELIKT-1 mission aboard the Prognoz 9 satellite (which was launched in July of 1983) and the NASA Cosmic Background Explorer (COBE) mission (who’s findings were published in 1992). For their work, the COBE team received the Nobel Prize in physics in 2006.COBE also detected the CMB’s first acoustic peak, acoustical oscillations in the plasma which corresponds to large-scale density variations in the early universe created by gravitational instabilities. Many experiments followed over the next decade, which consisted of ground and balloon-based experiments whose purpose was to provide more accurate measurements of the first acoustic peak.The second acoustic peak was tentatively detected by several experiments, but was not definitively detected until the Wilkinson Microwave Anisotropy Probe (WMAP) was deployed in 2001. Between 2001 and 2010, when the mission was concluded, WMAP also detected a third peak. Since 2010, multiple missions have been monitoring the CMB to provide improved measurements of the polarization and small scale variations in density. These include ground-based telescopes like QUEST at DASI (QUaD) and the South Pole Telescope at the Amudsen-Scott South Pole Station, and the Atacama Cosmology Telescope and Q/U Imaging ExperimenT (QUIET) telescope in Chile. Meanwhile, the European Space Agency’s Planck spacecraft continues to measure the CMB from space.Future of the CMB:According to various cosmological theories, the Universe may at some point cease expanding and begin reversing, culminating in a collapse followed by another Big Bang – aka. the Big Crunch theory. In another scenario, known as the Big Rip, the expansion of the Universe will eventually lead to all matter and spacetime itself being torn apart.If neither of these scenarios are correct, and the Universe continued to expand at an accelerating rate, the CMB will continue redshifting to the point where it is no longer detectable. At this point, it will be overtaken by the first starlight created in the Universe, and then by background radiation fields produced by processes that are assumed will take place in the future of the Universe. If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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By Brooke Simmons - Lecturer in Astrophysics, Lancaster UniversityGravity is a force between two masses, so gravity exists wherever there is mass. To discover when gravity started to exist, we need to understand what mass is, and when it started to exist. Let’s dive right in: “mass” is what we use to measure how much “matter” there is. Scientists use the term “matter” to describe stuff like stars, planets, oceans, rocks, molecules, atoms, particles like electrons and protons that make up atoms, and even the particles that make up electrons and protons.Very nearly everything you encounter in everyday life counts as “matter”: a book, a glass of water, a bird – anything you might also call “stuff”.There are some exceptions: for example, neither light nor sound is matter, nor are feelings. Light can even travel through completely empty space, where there’s no matter at all.If a feather and a football are both made of matter, you might wonder why they’re so different. Well, a football has much more matter than a feather, so we’d say its “mass” is higher.On the other hand, a kilogram of feathers and a kilogram of iron have the same mass because they weigh the same – even though the feathers take up a lot more space.If you could count every particle in your body, then you could add up all of their masses and you would have a measure of your own mass.Mass, weight and gravityOf course, that isn’t how we actually measure masses in real life. Here on Earth, we measure mass via weight. Mass and weight are not quite the same thing, but they are related.If you took a scale to the moon and weighed yourself on it, the number it showed would be smaller than when you weighed yourself on the Earth – even though your mass is still the same, your weight would change. This is because the scale you use is actually not measuring your mass directly, but rather the gravitational force your mass is feeling from the Earth, or the moon. How strong gravity is depends on the mass of both objects, as well as the distance between them. Because the Earth has a lot more mass than the moon, the force of gravity you experience on Earth is stronger. That’s why you weigh more on Earth than on the moon.A cosmic creationSo, when did mass first appear? Based on our best understanding of the physics of the universe, the first mass was created in the form of tiny particles (a LOT of them) right after the beginning of the universe itself, about 13.7 billion years ago.The creation of matter happened so fast after the creation of the universe that you could fit more than a million of those instants in the time it takes to blink an eye. And from that moment, gravity was at work, pulling matter together, gathering atoms and molecules into dense clouds that eventually formed stars and galaxies and planets.Of course, there are many forces in nature, and gravity is only one of them. The other forces work on matter too, so there has always been a cosmic dance between the different forces in the universe, which makes it look how it does.Gravity might be the force that we’re all most familiar with because we all have felt it since the moment we were born, but actually compared to many of the other forces it’s not especially strong.But since gravity is found anywhere there is mass, it’s basically everywhere, at all times.The same gravity that keeps you on the ground here on Earth also holds the Earth together, holds the Earth in orbit around the sun, and holds the sun in orbit around the rest of the galaxy.Gravity has existed for as long as the universe has, and it will keep existing, for as long as we do, and beyond.Source: The ConversationMore interesting articles on the subject of gravity:Gravity influences how we make decisions – new researchThe possible reality of artificial gravityWhat happens to the brain in zero gravity? If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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Stephen Hawking, a black hole whisperer who divined the secrets of the universe’s most inscrutable objects, left a legacy of cosmological puzzles sparked by his work, and inspired a generation of scientists who grew up reading his books.
Upon Hawking’s death on March 14 at age 76, his most famous discovery — that black holes aren’t entirely black, but emit faint radiation — was still fueling debate.
Hawking “really, really cared about the truth, and trying to find it,” says physicist Andrew Strominger of Harvard University, who collaborated with the famed scientist. Hawking “was deeply committed, his whole life, to this quest of understanding more about the physical universe around us.”
After earning his Ph.D. in 1965 at the University of Cambridge, Hawking continued studying cosmology there for the rest of his life. Due to a degenerative illness, amyotrophic lateral sclerosis, or ALS, Hawking gradually lost control of his body, requiring a wheelchair and eventually a voice synthesizer to speak. Yet his desire to uncover nature’s secrets remained boundless.
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In one of the most significant realizations of his career, Hawking reported in 1974 that black holes emit a faint glow of particles. This effect arises from quantum mechanics, which states that a sea of transient particles and antiparticles pervades all of space. These “virtual” particles usually annihilate in an instant, but if one of those particles is lost inside a black hole’s boundary, or event horizon, its partner can escape, producing what’s now known as Hawking radiation (SN: 5/31/14, p. 16).
As a result, black holes can gradually evaporate and disappear. This led to a still unresolved paradox: Throw an encyclopedia into a black hole and the information will eventually be lost. But according to quantum mechanics, information can never be destroyed.
Many solutions have been proposed for this problem, but none has stuck. In 2016, Hawking and colleagues proposed a path toward a solution: Black holes might have “soft hair,” low-energy particles that would retain information about what fell inside (SN: 2/06/16, p. 16). Hawking’s collaborators, including Strominger, are still working on the research. Standing at the interface between two seemingly incompatible theories — quantum mechanics, which describes the very small, and the general theory of relativity, which describes gravity — the quandary and its resolution may eventually help reveal a unified theory of quantum gravity.
Hawking made many other contributions, including studies of spacetime curvature during the Big Bang and the possibility that mini black holes might have formed in the universe’s infancy. Despite their groundbreaking nature, Hawking’s ideas remained largely theoretical, says Harvard theoretical astrophysicist Avi Loeb. Hawking radiation, for example, has never been directly detected. “That’s, unfortunately, why he didn’t get the Nobel Prize,” Loeb says.
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Yet Hawking achieved a level of fame uncommon among scientists. He excelled at making abstruse science digestible to the public. With his books, most notably the best-selling A Brief History of Time, first published in 1988, Hawking inspired countless future scientists and science lovers (including the author of this article). Theoretical cosmologist Katie Mack of North Carolina State University in Raleigh first opened the book when she was about 10 years old. “I found it so fascinating at the time,” she says. “I found out that Stephen Hawking was called a cosmologist and so I said I wanted to be a cosmologist.” Hawking similarly motivated dozens of her colleagues, Mack says.
Hawking remained active in research even in the last months of his life. A paper on which he is a coauthor, which was updated in the weeks before his death, considered the physics of multiverses, the possibility that a slew of other universes exist in addition to our own.
A funeral was held for Hawking on March 31. Later this year, his ashes will be interred in Westminster Abbey in London, where they will rest alongside the remains of other famous British scientists, including Isaac Newton and Charles Darwin.
Editor’s note: A shorter version of this piece appeared on sciencenews.org on March 14, 2018.
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Cosmology & The Universe
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A micrometeoroid that hit the James Webb Space Telescope in May caused a "significant uncorrectable change" to one of its panels used to observe deep space. So far, Webb has faced at least six deformations on its main mirror panels that have been traced to micrometeoroid strikes, but five of those degradations were negligible or correctable by adjusting the processing formulas, per NASA. The strike in May, however, does not appear to be correctable and slightly reduces the breadth of accurate data the telescope can collect. FIRST FULL-COLOR IMAGE FROM JAMES WEBB SPACE TELESCOPE REVEALED "The effect was small at the full telescope level because only a small portion of the telescope area was affected. After two subsequent realignment steps, the telescope was aligned to a minimum of 59 nm rms, which is about 5-10 nm rms above the previous best wavefront error rms values," NASA said in a recent report. NASA noted that the strike in May "exceeded prelaunch expectations of damage for a single micrometeoroid" but stressed that the telescope's performance broadly has surpassed its expectations as well. To mitigate the toll of the damage on the telescope's performance after the strike in May, engineers realigned the telescope's segments to adjust for the damage done. While the strike in May had a minor impact on the full functionality of the $10 billion telescope as a whole, NASA expressed concerns about the toll future micrometeoroid impacts could have on the telescope. "It is not yet clear whether the May 2022 hit to segment C3 was a rare event," the report said. "The project team is conducting additional investigations into the micrometeoroid population, how impacts affect beryllium mirrors, and the efficacy and efficiency tradeoffs of potential mitigations." Micrometeoroids are fragments of asteroids that can be smaller than a grain of sand, but they travel at high speeds, according to NASA. "The mirrors and sunshield are expected to slowly degrade from micrometeoroid impacts," the report added. "The Project is actively working this issue to ensure a long, productive science mission with JWST." CLICK HERE TO READ MORE FROM THE WASHINGTON EXAMINER Last week, President Joe Biden unveiled the powerful telescope's first image of deep space, the sharpest infrared image of the universe produced. The infrared technology enables the telescope to peer through cosmic dust and obtain a better glimpse of some of the earliest stars and galaxies in the universe. The James Webb telescope was launched into space last December, and scientists are hoping it will last over 20 years in space.
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Cosmology & The Universe
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Scientists are using atomic clocks to investigate some of the universe's greatest mysteries, including the nature of dark matter, in a laboratory. In the process, they say they're bringing cosmology and astrophysics "down to Earth."
The project, which is a collaboration between the University of Sussex and the National Physical Laboratory (NPL) in the U.K., uses the ticks of these incredibly precise clocks to hunt for hitherto unknown ultra-light particles.
These particles could be connected to dark matter, the mysterious substance that makes up an estimated 85% of all matter in the universe but remains effectively invisible to us because it does not interact with light or, more precisely, electromagnetic radiation. Scientists believe most galaxies are enveloped by a cloud of dark matter, but its presence can only be inferred by the effect it has on gravity.
"Our universe, as we know it, is governed by laws of physics, so gravity is governed by general relativity and particle physics by the Standard Model of particle physics," Xavier Calmet, project leader and a professor of physics at the University of Sussex, told Space.com. "We call deviations from these laws 'breakdown in physics' — basically, that is a synonym for new physics beyond our current understanding of the universe."
This new physics could be used to explain the nature of dark matter, something that doesn't fit within the Standard Model.
"One of the biggest mysteries is the nature of dark matter. We know that it is out there, we see its impact in our universe, but we don't have a valid explanation within the Standard Model of particle physics," Calmet continued. "There must be new physics, but we do not know how to describe these new particles and how they couple to regular matter."
How can "new physics" be spotted with atomic clocks?
According to established laws of physics, clocks should tick at a constant rate, but physics beyond the Standard Model's scope would result in tiny charges in atomic energy levels. This should affect the rate at which clocks tick, but the variation would be so small it could only be spotted with an incredibly precise clock — and that's where atomic clocks come in.
"Atomic clocks bring cosmology and astrophysics down to Earth, enabling searches for ultra-light particles that could explain dark matter in a laboratory," Calmet said.
Atomic clocks measure time using atoms with two potential energy states. When atoms absorb energy, they go to a higher energy state. Then, they eventually release this energy and drop back down to their lower ground state.
In atomic clocks, groups of atoms are prepared by placing them in a higher energy state using microwave energy, and the characteristic and consistent rates at which they vibrate between states — their resonance frequencies — are used to precisely measure time.
So, for example, all atoms of cesium resonate at the same frequency, meaning the standard measure of a second can be defined as 9,192,631,770 cycles of cesium. Because this cycling per second occurs with far less variation than, say, the swinging of a pendulum, this makes atomic clocks incredibly precise.
"It has been recently realized that dark matter could be made of ultra-light particles that interact extremely weakly with regular matter," Calmet explained. "If that is the case, dark matter would essentially behave as a classical wave that interacts with electrons and protons. This dark matter wave would give some small kicks to these particles."
Calmet added that these ultra-light dark matter particle kicks to the building blocks of the atom would lead to a time variation in fundamental constants of the universe, such as the fine-structure constant or "alpha" — a measure of how strong particles couple via the electromagnetic force — and the mass of the proton.
"Because atomic clocks are amazingly precise devices, they would be able to detect these kicks and thus discover ultra-light dark matter," he continued. "By comparing two clocks, one sensitive to changes in alpha and the other one less sensitive to changes in alpha, we can obtain a limit on the time variation of this fundamental constant and thus set constraints on ultra-light particles."
Calmet thinks the technique could potentially also be used to investigate another problematic aspect of the universe for physicists: Dark energy, the unknown force that is driving the accelerating expansion of space.
While Calmet acknowledges that dark energy is more likely explained by the cosmological constant, a form of energy that acts almost in opposition to gravity to stretch the fabric of space and push apart galaxies, there is a small chance it could be connected to an ultra-light particle. In this vein, future clocks could also be sensitive to that particle and its associated wave.
"While the clocks have not discovered new physics at this stage, we were able to develop a new theoretical framework to probe generic new physics with clocks and were able to derive the first model-independent limits on physics beyond the standard model within this approach," Calmet concluded. "We are creating a new field at the interface of atomic, molecular, and optical physics and traditional particle physics.
"These are exciting results!"
These results are set to be published in a future edition of the New Journal of Physics.
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Cosmology & The Universe
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When astronomers discovered that the universe is expanding at an accelerating rate, they theorized that some force must be pushing things farther apart and overcoming gravity, which should be slowing things down. That force was suggested to be dark energy, but no one has ever figured out from where it comes.
But a team of 17 international researchers led by the University of Hawaii has discovered the first evidence for the origin point of dark energy: Black holes.
Black holes acquire mass in two ways: accretion of gas and mergers with other black holes. But in studying nine billion years of black hole evolution in dormant giant elliptical galaxies, the researchers discovered that the older black holes are much larger than they should be based on those two methods of growth. That means there must be another way these black holes are acquiring mass. Researchers suggest the answer is dark energy in the form of vacuum energy, "a kind of energy included in spacetime itself ... [that] pushes the universe further apart, accelerating the expansion," according to a statement (opens in new tab).
"If the theory holds, then this is going to revolutionize the whole of cosmology, because at last we've got a solution for the origin of dark energy that's been perplexing cosmologists and theoretical physicists for more than 20 years," Dr. Chris Pearson of STFC RAL Space, a co-author of a study on the discovery, said in a statement.
The idea that black holes are a source of dark energy isn't new. In fact, it's part of Einstein's theory of general relativity. But this is the first time astronomers have obtained observational evidence to support the theory.
"We're really saying two things at once: That there's evidence the typical black hole solutions don't work for you on a long, long timescale, and we have the first proposed astrophysical source for dark energy," said study author Duncan Farrah, University of Hawaii astronomer, in the statement.
A paper on the team's research was published in The Astrophysical Journal Letters (opens in new tab) on Wednesday (Feb 15).
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Cosmology & The Universe
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PASADENA, Calif. — A lucky celestial alignment has given astronomers a rare look at a galaxy in the early universe that is seeding its surroundings with the elements needed to forge subsequent generations of stars and galaxies. Seen as it was just 700 million years after the Big Bang, the distant galaxy has gas flowing over its edges. It is the earliest-known run-of-the-mill galaxy, one that could have grown into something like the Milky Way, to show such complex behavior, astronomer Hollis Akins said June 14 during a news conference at the American Astronomical Society meeting. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox “These results also tell us that this outflow activity seems to be able to shape galaxy evolution, even in this very early part of the universe,” said Akins, an incoming graduate student at the University of Texas at Austin. He and colleagues also submitted their findings June 14 to arXiv.org. The galaxy, called A1689-zD1, shows up in light magnified by Abell 1689, a large galaxy cluster that can bend and intensify, or gravitationally lens, light from the universe’s earliest galaxies (SN: 2/13/08; SN: 10/6/15). Compared with other observed galaxies in the early universe, A1689-zD1 doesn’t make a lot of stars — only about 30 suns each year — meaning the galaxy isn’t very bright to our telescopes. But the intervening cluster magnified A1689-zD1’s light by nearly 10 times. Akins and colleagues studied the lensed light with the Atacama Large Millimeter/submillimeter Array, or ALMA, a large network of radio telescopes in Chile. The team mapped the intensities of a specific spectral line of oxygen, a tracer for hot ionized gas, and a spectral line of carbon, a tracer for cold neutral gas. Hot gas shows up where the bright stars are, but the cold gas extends four times as far, which the team did not expect. “There has to be some mechanism [to get] carbon out into the circumgalactic medium,” the space outside of the galaxy, Akins says. Only a few scenarios could explain that outflowing gas. Perhaps small galaxies are merging with A1689-zD1 and flinging gas farther out where it cools, Akins said. Or maybe the heat from star formation is pushing the gas out. The latter would be a surprise considering the relatively low rate of star formation in this galaxy. While astronomers have seen outflowing gas in other early-universe galaxies, those galaxies are bustling with activity, including converting thousands of solar masses of gas into stars per year. Galaxy A169-zD1 (pictured, in radio waves) exists in the universe’s first 700 million years.ALMA/ESO, NAOJ and NRAO; H. Akins/Grinnell College; B. Saxton/NRAO/AUI/NSF The researchers again used the ALMA data to measure the motions of both the cold neutral and hot ionized gas. The hot gas showed a larger overall movement than the cold gas, which implies it’s being pushed from A1689-zD1’s center to its outer regions, Akins said at the news conference. Despite the galaxy’s relatively low rate of star formation, Akins and his colleagues still think the 30-solar-masses of stars a year heat the gas enough to push it out from the center of the galaxy. The observations suggest a more orderly bulk flow of gas, which implies outflows, however the researchers are analyzing the movement of the gas in more detail and cannot yet rule out alternate scenarios. They think when the hot gas flows out, it expands and eventually cools, Akins said, which is why they see the colder gas flowing over the galaxy’s edge. That heavy-element-rich gas enriches the circumgalactic medium and will eventually be incorporated into later generations of stars (SN: 6/17/15). Due to gravity’s pull, cool gas, often with fewer heavy elements, around the galaxy also falls toward its center so A1689-zD1 can continue making stars. These observations of A1689-zD1 show this flow of gas happens not only in the superbright, extreme galaxies, but even in normal ones in the early universe. “Knowing how this cycle is working helps us to understand how these galaxies are forming stars, and how they grow,” says Caltech astrophysicist Andreas Faisst, who was not involved in the study. Astronomers aren’t done learning about A1689-zD1, either. “It’s a great target for follow-up observations,” Faisst says. Several of Akins’s colleagues plan to do just that with the James Webb Space Telescope (SN: 10/6/21).
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Cosmology & The Universe
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A new map of the cosmos shows the distribution of mysterious dark matter in sharp detail.
The map, which covers a quarter of the sky over Earth and extends deep into the cosmos, was created using a "cosmic fossil" known as the cosmic microwave background (CMB), radiation left over from just after the Big Bang.
The new map, created by the Atacama Cosmology Telescope (ACT) collaboration, has helped confirm a theory of gravity pioneered by Albert Einstein over a century ago.
Einstein's 1915 theory of general relativity posits that objects with mass "warp" the fabric of space-time, giving rise to gravity and leading to specific predictions about how the large-scale structure of the universe formed and evolved to the state we observe today, 13.8 billion years after the Big Bang. These predictions comprise what is known as the "standard model of cosmology."
"We have used the CMB, the oldest light in the universe, emitted soon after the Big Bang, to measure how dark matter — the invisible stuff that makes up the majority of the matter in the universe — is distributed on large scales," ACT team member Adam Hincks, an astrophysicist at the University of Toronto, said in a statement (opens in new tab).
"The distribution agrees very well with theoretical predictions," Hincks said. "It's a really satisfying result scientifically because it shows we have a robust understanding of how our universe grows and evolves."
Using the effects of gravity to 'see' the invisible
To create the map, the scientists used data collected by the ACT, which viewed the heavens from Cerro Toco in the Chilean Atacama Desert for 15 years before it was decommissioned in 2022. The ACT observations allowed the team to study the effect that gravitational lensing, also predicted by general relativity, has on the CMB.
Gravitational lensing arises from the fact that, when gravity warps space-time, it distorts the path of light traveling toward us. The nature of this warping can tell astronomers a lot about the distribution of the mass causing the spatial distortion.
The CMB is effectively the "first light" in the universe, as it comes from an era called the epoch of recombination and an event called "the last scattering." When the universe was an infant, it was filled with a sea of electrons, gluons and quarks. Electrons endlessly scattered photons, particles of light, which meant that light couldn't travel through the cosmos. As a result, the universe was opaque, like a brick.
As the universe cooled, particles could start to stick together. Quarks and gluons formed protons and neutrons, and these bonded with electrons to create the first atoms, around 380,000 years after the Big Bang. With fewer free electrons around, photons could travel unimpeded, and the universe became transparent, like a window.
The CMB is this first freely traveling light. Thanks to the continuing expansion of the universe, this ancient radiation fills the cosmos almost uniformly, with the occasional tiny variation.
The ACT scientists looked at the effect the gravity of the large structure of the universe has on the CMB as the result of gravitational lensing, providing them with a great way of mapping ordinary matter and, especially, dark matter, which makes up about 85% of the material universe but remains mysterious.
Dark matter doesn't interact with light like the "normal" stuff that comprises stars, planets and us, meaning that astronomers can't see it in any wavelength of electromagnetic radiation. But dark matter does have mass and thus it does interact gravitationally. That means that its presence can be inferred as a result of its gravitational interactions with matter and radiation.
Crucially, it also means that dark matter has a gravitational lensing effect, especially when it is in large concentrations like the halos that are theorized to surround most, if not all, galaxies. This lensing effect can be seen in the distortion of the CMB.
This distortion allowed the team to create a highly detailed cosmic map of the distribution of both ordinary matter and dark matter, revealing that the stuff takes the shape predicted by general relativity and the standard model of cosmology that emerged from it.
Related: What is dark matter?
Dark matter is just lumpy enough
The matter distribution map could also help settle a problem in cosmology that emerges from measurements of light from distant stars, which suggest that dark matter isn't as "lumpy" as it should be, according to the standard model of cosmology.
The ACT map suggests that the vast clumps of dark matter observed are just the right size to fit in with the standard model of cosmology. The ACT team said that means that the new findings fit the overall picture scientists have about the evolution of the cosmos.
At the same time, the more accurate measurements that comprise the ACT map should allow researchers to scrutinize that picture on an entirely new and deeper level. This could help finally nail down where discrepancies in different dark matter mapping techniques are coming from, team members said.
"In cosmology, as in all of science, having independent measurements that test the same theoretical model is really important," Hincks said. "The fact that we can successfully explain how our cosmos works with this level of precision is amazing."
The collaboration's research is discussed in three papers soon to be published in the Astrophysical Journal, which are currently available on the Atacama Cosmology Telescope website (opens in new tab).
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Cosmology & The Universe
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Review “This luminous guide to the cosmos encapsulates myriad discoveries. Astrophysicist Jo Dunkley swoops from Earth to the observable limits, then explores stellar life cycles, dark matter, cosmic evolution, and the soup-to-nuts history of the Universe. No less a thrill are her accounts of tenth-century Persian astronomer Abd al-Rahman al-Sufi, twentieth- and twenty-first-century researchers Subrahmanyan Chandrasekhar, Jocelyn Bell Burnell and Vera Rubin, and many more.”―Nature“Dunkley takes her readers on a grand tour of space and time, from our nearest planetary neighbors to the edge of the observable Universe…If you feel like refreshing your background knowledge, or are looking for a present for your curious niece or nephew, this little gem certainly won’t disappoint.”―Govert Schilling, BBC Sky at Night“Combining observational cosmology with a solid theoretical framework, Dunkley’s Our Universe takes us on a cosmic tour…This is a book any future observational or theoretical astrophysicist would love to have.”―Ethan Siegel, Forbes“Provides a high-level overview of our understanding of the universe that is a good introduction for those unfamiliar with astrophysics.”―Jeff Foust, Space Review“What with all the commonly appearing stories about space making their way into both the old and new news media these days, an understanding of just what we presently know about what’s ‘out there,’ how we presently think it formed, how it all works together, and where it’s all going is not only fascinating, it also helps to keep things in perspective.”―Johannes E. Riutta, Well-Read Naturalist“A fascinating, accessible introduction to the universe, covering topics ranging from the Big Bang and the ‘cosmic dawn’ of the first stars to the ongoing search for exoplanets and for dark matter and energy…Dunkley gives readers a commanding view onto the universe and the wonders to be found in it.”―Publishers Weekly“Jo Dunkley is an internationally acclaimed cosmologist. She is also a fine expositor, and this book splendidly conveys what we’ve learnt about the universe, and the exhilarating progress we can expect in coming decades.”―Martin Rees, Astronomer Royal of Great Britain“Jo Dunkley takes us on a fantastic journey through our universe―elegantly weaving together history and the latest scientific discoveries. On her way, she subtly restores all the forgotten women scientists to their rightful places in what has been a male-dominated story until now.”―Andrea Wulf, author of The Invention of Nature“A grand overview of modern cosmology from one of the leaders in the field. Dunkley guides us through astronomical history, at every stage explaining the twists and turns and surprises, right up to the most recent discoveries. Readers will have a real appreciation of the most exciting developments in astrophysics of the last millennium, the last century, and the last year.”―Michael Strauss, Princeton University“Jo Dunkley is an amiable guide to the universe, but there's no dawdling in this fast-paced tour. This slender volume whisks you from our own blue marble out to the edge of the universe and the beginning of time. Dunkley is especially good at explaining how the whispers from the Big Bang itself tell us about dark matter and dark energy and hint at its explosive origin in cosmic inflation.”―Robert P. Kirshner, Harvard University“This book is simply superb―beautifully written and very clear. It incorporates all the major recent results, and indicates what might come from telescopes now being built.”―Jocelyn Bell Burnell, University of Oxford About the Author Jo Dunkley is Professor of Physics and Astrophysical Sciences at Princeton University. She has won awards from the Royal Astronomical Society, the Institute of Physics, and the Royal Society for her work on the origins and evolution of the universe.
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Cosmology & The Universe
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