Tag Archives: black holes

Japans Troubled X-Ray Satellite Is Dead

The Japanese Space Agency, JAXA, has announced that it is not possible to recover its ASTRO-H X-ray astronomy satellite, Hitomi. The sad news follows several weeks of uncertainty after the satellite was found to be out of control in orbit.

In a statement, JAXA said they would now try to find out what went wrong with the satellite, rather than attempting to restore communications. We will carefully review all phases from design, manufacturing, verification, and operations to identify the causes that may have led to this anomaly including background factors, they said.

Launched on February 17, 2016, Hitomi was set to be a groundbreaking mission that would use four X-ray telescopes and two gamma-ray telescopes to probe black holesand the distant universe. Costing an estimated $286 million, the project was a joint collaboration between JAXA, NASA, and other partners.

But on March 26, things started to go wrong. While being pointed towards the center of a distant galaxy, the spacecraft began to spin wildly out of control. Observations from the ground suggested bits of the satellite may have broken off. Preliminary investigations indicate that the planned rotationcaused its solar panels to snap, with some reports saying human errorcaused the breakage, possibly due to an errant command being sent to the spacecraft.

The team thought the mission might be salvageable, because they were receiving what they thought were signals from Hitomi. But in their statement, JAXA said these were likely from a different source, and the satellite has long been dead.

Takashi Kubota (right), space program director of JAXA, at a press conference in Tokyo yesterday announcing the end of the Hitomi mission. STR/AFP/Getty Images

JAXA expresses the deepest regret for the fact that we had to discontinue the operations of ASTRO-H and extends our most sincere apologies to everyone who has supported ASTRO-H believing in the excellent results ASTRO-H would bring, the agency announced solemnly.

This failed mission goes to show that space travel, no matter how successful we continue to be, is hard. Hitomi joins a host of failed spacecraft that have been launched over the last few decades. Some, like Japans Akatsuki Venus mission or NASAs Kepler spacecraft, have been recovered thanks to a bit of luck and/or ingenuity. Others, like Hitomi or Phobos-Grunt, are lost for good.

It will be 12 years until a similar satellite,ATHENA, is launched in 2028 by the European Space Agency (ESA). For Japan, and scientistsaround the world, it will be a long time to mourn this major loss to astronomy.

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Read more: http://www.iflscience.com/space/japan-s-troubled-x-ray-satellite-dead

Preserving the X-ray Universe for future generations

A collage of the eight images NASA's Chandra X-ray Observatory has released from its archive

October is designated as American Archive Month, to promote an awareness of the importance of historical records. While many think ‘archive’ may only apply to books and letters, there are other important archives. Archives are used for major telescopes and observatories, including NASA’s Chandra X-ray Observatory.

The primary role of the Chandra Data Archive (CDA) is to store and distribute data so the astronomical community, as well as the general public, have access to it. The CDA does this with the aid of powerful search engines. This archive collection will preserve the legacy of the Chandra mission for generations.

In celebration of American Archive Month, the Chandra team chose images from a group of eight objects in the CDA to be released to the public for the first time. These are but a few of the thousands of objects that Chandra’s archive has made permanently available to the public. 

G266.2-1.2

Chandra’s observation of this supernova remnant, located around 2,400 light years away in the constellation Vela, revealed extremely high-energy particles. These particles are produced as the shock wave from the explosion expands into interstellar space. The X-rays from Chandra (purple) have been combined with optical data from the Digitized Sky Survey (red, green, and blue).

3C353

This is a wide and double-lobed jet, generated by a supermassive black hole at the centre of a galaxy about 410 million light years away, in the constellation Ophiuchus. The jet itself is the tiny point in the centre while the giant plumes of radiation can be seen in X-rays from Chandra (purple) and radio data from the Very Large Array (orange).

NGC 3576

This nebula is located around 9,000 light years away from Earth, in the Sagittarius arm of the Milky Way galaxy. The scattered X-ray data detected by Chandra (blue) are probably due to the winds from young, massive stars blowing throughout the nebula. Optical data from ESO are shown in orange and yellow.

NGC 4945

This galaxy is similar in appearance to our own, but contains a much more active supermassive black hole within the white area near the top. NGC 4945 is only about 13 million light years from Earth, in the constellation Centaurus, and is seen edge-on. X-rays from Chandra (blue), have been overlaid on an optical image from the European Space Observatory to reveal the presence of the supermassive black hole at the centre of this galaxy.

IC 1396A

The nebula otherwise known as the Elephant Trunk Nebula is located about 2,800 light years away in the constellation of Cepheus. Radiation and winds from massive young stars seem to be triggering new generations of stars to form. X-rays from Chandra (purple) have been combined with optical (red, green, and blue) and infrared (orange and cyan) to give a more complete picture of this source.

3C 397 (G41.1-0.3)

Also known as G41.1-0.3, this is a Galactic supernova remnant with an unusual shape found around 33,000 light years away in the constellation Aquila. Its box-like shape is possibly produced as the heated remains of the exploded star interacts with the cooler gas enveloping it. The exploded star was detected by Chandra in X-rays (purple) and this composite of the area around 3C 397 also contains infrared emission from Spitzer (yellow) and optical data from the Digitized Sky Survey (red, green, and blue).

SNR B0049-73.6

This supernova is located approximately about 180,000 light years away in the constellation Tucana, within our neighbouring galaxy of the Small Magellanic Cloud. Observations of the dynamics as well as the composition of the debris from the explosion provide evidence that the explosion was produced by the collapse of the central core of a star. In this image, X-rays from Chandra (purple) are combined with infrared data from the 2MASS survey (red, green, and blue).

NGC 6946

Nicknamed the ‘Fireworks Galaxy’, this medium-sized, face-on spiral galaxy is found about 22 million light years away from Earth in the constellation Cygnus. Eight supernovae have been observed to explode in the arms of this galaxy in the last 100 years. Chandra observations (purple) have revealed three of the oldest supernovas ever detected in X-rays. This composite image also includes optical data from the Gemini Observatory in red, yellow, and cyan.

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Read more: http://www.iflscience.com/space/preserving-x-ray-universe-future-generations

Interstellar Gives a Spectacular View of Hard Science

Note: this article has spoilers.

In Interstellar’s near-ish future, our climate has failed catastrophically, crops die in vast blights and America is a barely-habitable dustbowl. Little education beyond farming methods is tolerated and students are taught that the Apollo landings were Cold War propaganda hoaxes.

Against this unpromising background, a former space pilot receives mysterious directions to a secure facility. Therein, he finds the American space agency NASA’s last remnants devoting dwindling resources to sending a spacecraft through a new-found wormhole mouth orbiting Saturn.

Worlds galactic distances away have been discovered via the wormhole, some of them apparently habitable and apt for colonisation. A small expedition traverses the wormhole and visits several planets, some near a giant black hole. Peril, conflict and soul-searching ensue.

Fictional worlds collide

Science and science fiction are uneasy relatives, and classic sci-fi often folds under scientific scrutiny. HG Wells wrote great and prophetic sci-fi, but the great (such as The War of the Worlds) wasn’t prophetic and the prophetic (such as The Argonauts of the Air) wasn’t great. Science fiction usually uses scientifically derived fictional concepts to pit humanity against a hostile universe.

Worthwhile sci-fi can be downright inaccurate. Wells’s rampaging Martian tripods survive in the public imagination while more realistic predictions of mechanised warfare fade. Orwell’s Nineteen Eighty-Four remains the relevant parable about totalitarian mind-control for all that its titular year came and went without copying its namesake. However, so-called Hard Science Fiction takes its science seriously, only adopting as premises real theoretical possibilities recognised by current science.

Hard sci-fi gives writers interesting constraints, but the results can date quickly and narrative needs can tempt even the “hardest” writers to fudge facts. That is the case with Christopher Nolan’s Interstellar. It might appear to be very “hard” – dealing with concepts rooted in actual science, but it only aspires to those ideals. The story plot fudges many scientific aspects.

Of course, there are science-fiction treats on offer: gnarly space-flight vessels spinning to produce centrifugal pseudo-gravity, hibernation in eerie-looking pods, a planet with icy clouds, familial relations strained by time dilation and witty robots that initially annoy but end up more sympathetic than most humans.

Habitable world? Warner Bros.

And it shows this with stunning imagery. There are beautiful depictions of gravitational-lensing by wormhole, distorted starscapes during wormhole transit and faux Earth interiors on a giant, revolving space-habitat. Wormhole mouths and black holes are depicted as genuinely three-dimensional holes, while the high-energy colliding matter in the accretion disc around a black hole’s equator is vividly portrayed. So impressively does Interstellar render these phenomena that if we ever see such things close-up, reality may suffer by comparison.

Nolan tries to get the science right most of the time. Just as one harrumphs: “genetic diversity?” when there is a mention of seeding other worlds, Anne Hathaway’s character neatly addresses the problem. Relativity does allow gravitation and motion to produce time dilation, which means that time plays out at different speeds for different people. Wormholes could theoretically connect otherwise distant space-time points. And, yes, “Hawking Radiation” means black holes aren’t strictly “black”.

Plot twists, scientific compromises

But where it might annoy Hard sci-fi fans is that some essentials get fluffed. Visits to a planet’s surface could produce temporal discrepancies – an hour-long jaunt on the surface might seem to take years from the point of view of an observer in orbit – but only if the surface gravity is thousands of times stronger than that of Earth. Wormholes traversable by crewed spacecraft require unfeasible quantities of gravitationally repulsive “exotic matter”, which theoretically has negative energy density and breaks just about every energy condition we know.

Sneaking past a black hole’s event horizon, scanning the hole’s singularity and retrieving gravity-mastering data is impossible. As for falling into a black hole and seeing tidal forces disintegrate your vessel without making you into spaghetti, then entering a region prepared by your future self only to re-emerge into normal space-time via wormhole… well, criticism seems superfluous.

And, yet, this is a film worth watching. Interstellar offers much besides visuals to commend. It takes climate change seriously, is realistically cynical about political and educational preparedness for the future, doesn’t soften ethical dilemmas in saving humanity and suggests climate solutions will owe everything to scientific imagination and initiative.

Alasdair Richmond does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

The Conversation

Read more: http://www.iflscience.com/space/interstellar-gives-spectacular-view-hard-science

Gravitational Waves Found: How We Proved The Power Of The Dark Side

One hundred years ago Albert Einstein in his general theory of relativity predicted the existence of a dark side to the cosmos. He thought there were invisible gravitational waves, ripples in space-time produced by some of the most violent events in the cosmos exploding stars, colliding black holes, perhaps even the Big Bang itself. For decades, astronomers have gathered strong corroborative evidence of the existence of these waves, but they have never been detected directly until now. They were the last part of the general theory still to be verified.

Astronomers have used light to study the universe with optical telescopes for hundreds of years. We have expanded that view hugely since the middle of the 20th century, by building detectors and instruments sensitive to all the forms of what physicists mean by light: the electromagnetic spectrum, from gamma rays to radio. Yet the discovery of gravitational waves represents our first steps into studying the universe through the gravitational-wave spectrum, which exists independently from light, probing directly the effects of gravity as it spreads across the cosmos. It is the first page in a whole new chapter for astronomy, and science.

How we made the discovery

The discovery dates back to last September, when two giant measuring devices in different parts of the US called LIGO (Laser Interferometer Gravitational-Wave Observatory) caught a passing gravitational wave from the collision of two massive black holes in a faraway galaxy. LIGO is what we call an interferometer, consisting of two 4km arms set at right angles to each other, protected by concrete tubes, and a laser beam which is shone and reflected back and forth by mirrors at each end.

When a gravitational wave passes by, the stretching and squashing of space causes these arms alternately to lengthen and shrink, one getting longer while the other gets shorter and then vice versa. As the arms change lengths, the laser beams take a different time to travel through them. This means that the two beams are no longer in step and what we call an interference pattern is produced hence the name interferometer.

The changes in the length of the arms are actually tiny roughly one million millionth the width of a human hair. This is because the signal from a gravitational wave from far out in the cosmos is mind-bogglingly small by the time it reaches us. As if detecting this were not difficult enough, all manner of local disturbances on Earth make it worse, from the ground shaking to power-grid fluctuations; and instrumental noises that could mimic or indeed completely swamp a real signal from the cosmos.

To achieve the astounding sensitivity required, almost every aspect of the LIGO detectors’ design has been upgraded over the past few years. We at the University of Glasgow led a consortium of UK institutions that played a key role developing, constructing and installing the sensitive mirror suspensions at the heart of the LIGO detectors that were crucial to this first detection. The technology was based on our work on the earlier UK/German GEO600 detector. This turned LIGO into Advanced LIGO, arguably the most sensitive scientific instrument ever, to give us our first direct glimpse of the dark universe.

A long time ago

What a glimpse it was. The two black holes that collided were respectively about 29 times and 36 times the mass of our sun (shown in the computer visualisation below). It is incidentally the first direct evidence that black holes exist, can exist in a pair, and can collide and merge. Comparing our data with Einsteins predictions allowed us to test whether general relativity correctly describes such a collision they passed with flying colours.

The black-hole collision

The merger occurred more than one billion light years from Earth, converting three times the mass of the sun into gravitational wave energy. In a fraction of a second, the power radiated through these waves was more than ten times greater than the combined luminosity of every star and galaxy in the observable universe. This was a truly cataclysmic event a long time ago in a galaxy far, far away. In Star Wars Darth Vader tells us not to underestimate the power of the dark side. This amazing discovery shows how right he was.

Of course our discovery isnt just about checking if Einstein was right. Detecting gravitational waves will help us to probe the most extreme corners of the cosmos the event horizon of a black hole, the innermost heart of a supernova, the internal structure of a neutron star: regions that are completely inaccessible to electromagnetic telescopes.

Could we ever harness gravitational waves for practical applications here on Earth? Could new insights about the dark universe help us, perhaps in the far future, not just to measure gravitational fields but to manipulate them, as imagined in the space colonies and wormholes of Christopher Nolans Interstellar? That is much harder to predict, but the lesson of history is that new phenomena we discover and explore frequently lead to disruptive technologies that come to underpin our everyday lives. It might take a few centuries, but I am confident the same will be true with gravitational waves.

Martin Hendry, Professor of Gravitational Astrophysics and Cosmology, University of Glasgow

Cover Image Credit: Two black holes collide. University of Glasgow

Read more: http://www.iflscience.com/gravitational-waves-found-how-we-proved-power-dark-side

European Gravitational Wave Observatory Gets Thumbs Up From Report

A major European report looking at a $1 billionproposal to build a space-based gravitational wave observatory has concluded that the idea is more than just feasible;its development should be accelerated to make the most of this exciting new area of astronomy as soon as possible.

The announcement of the first-ever detection of gravitational waves earlier this year deservedly made headlines around the world. The detection by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United Statesconfirmed the existence of gravitational waves,tiny ripples in space-time caused by huge events such as merging black holes.

Onthe back of this discovery, a report from a group called the Gravitational Observatory Advisory Team (GOAT), an expert panel commissioned by the European Space Agency (ESA), has recommended that ESA pusheahead with its own plans to launch a more sensitive gravitational wave observatory in 2034 as soon as possible.

In a single step, gravitational wave astronomy has been placed on a secure observational footing, opening the panorama to the next robust steps in a space-based gravitational wave observatory, the report stated, commenting on the LIGO discovery.

ESAs preferred proposal for such an observatory, known as the Evolved Laser Interferometer Space Antenna(eLISA), is to fly three spacecraft in a huge triangle formation in space, each separated by a distance of 1 million kilometers (620,000 miles). Lasers would then be fired between the spacecraft, and by detecting tiny fluctuations in the lasers, gravitational waves could be observed. This is known as laser interferometry, the same technique (albeit on a smaller scale) that was used by LIGO.

The technology for eLISA, which will likely involve a contribution from NASA, is already being tested on the LISA Pathfinder mission, which was launched in December 2015. But the discovery of the first gravitational waves by LIGO has made the mission all the more promising, boosting the opinion in the science community that such an observatory can successfully observe gravitational waves, allowing us to detect phenomenanot possible with other forms of astronomy.

In fact, speaking to BBC News, GOAT chairman Dr. Michael Perryman said they were proposing that the project should be accelerated by five years. After submitting our report, ESA came back to us and asked what we thought might be technically possible, putting aside the money,” he said. “We are in the process of finalizing a note on that, which will suggest the third quarter of 2029. So, 13 years from now.

Merging black holes and binary stars are thought to produce gravitational waves.R. Hurt/Caltech-JPL

The report by GOAT looked at a number of other technologies that could be used on a gravitational wave observatory, including an untested idea to use atom interferometry, essentially detecting fluctuations in an arrangement of atoms fired between two points rather than photons in a laser. But the conclusion was that laser interferometry, as proposed for eLISA, was the most attractive option, being not only proven but also possible with current technologies.

The Committee has identified no fundamental technical issues which might question or invalidate the measurement of gravitational waves from a laser interferometry based space mission, the report concluded. Based on an evaluation of the alternative measurement approaches, laser interferometry remains the preferred option.

It added: The technical and scientific knowledge base now residing in Europe argues for the early implementation of a gravitational wave observatory under European leadership.

The next step is for a detailed proposal for the mission to be put forward, before ESA can consider giving the go-ahead for development of the mission to begin. Given the findings of this report, and the clamor for more gravitational wave-based astronomy, that looks to be a near certainty.

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Read more: http://www.iflscience.com/space/european-gravitational-wave-observatory-gets-thumbs-report

Physicist Claims to Have Proven Mathematically That Black Holes Do Not Exist

There has been a great deal of study and debate surrounding the mysteries of black holes. The University of North Carolina’s Laura Mersini-Houghton believes that the reason there is so much uncertainty is because black holes don’t exist. Her paper has been submitted to ArXiv, but has not been subjected to peer review. Earlier this year, she published a paper with approximate solutions in the journal Physics Letters B

Astrophysicists have been studying black holes for decades. It is widely believed that when a star 20 times more massive than our Sun or larger dies and collapses, it can condense into an incredibly small area known as the singularity that is extremely dense. It is surrounded by an event horizon, which is a region where the gravitational pull is so strong, not even light can escape. It is essentially the “point of no return.”

Stephen Hawking first theorized in 1974 that due to quantum effects at the event horizon, it releases radiation now known as Hawking radiation. Over time, shedding this radiation can pull mass away, in a process known as evaporation. However, Mersini-Houghton states that so much radiation is shed from the star when it collapses, it is simply not possible for it to form a black hole.

Mersini-Houghton claims that she has clearly and effectively reconciled Einstein’s Theory of Relativity with quantum mechanics. Though the two have never necessarily been at odds on a large scale, physicists have previously been unable to merge the two cohesively. In terms of relativity, the formation of the black hole can be predicted. However, in quantum mechanics, the uncertainty principle doesn’t really permit one to know exactly where something is located. It’s possible to get pretty close, but not exactly. This is just one of many ways in which quantum theory and Einstein’s classical field theory fail to align when it comes to black holes. 

“Physicists have been trying to merge these two theories – Einstein’s theory of gravity and quantum mechanics – for decades, but this scenario brings these two theories together, into harmony,” Mersini-Houghton stated in a press release. “And that’s a big deal.”

However, not everyone is on board with Mersini-Houghton’s conclusions. William Unruh, a theoretical physicist from the University of British Columbia, pointed out some fatal flaws in the paper’s argument. 

“The [paper] is nonsense,” Unruh said in an email to IFLS. “Attempts like this to show that black holes never form have a very long history, and this is only the latest. They all misunderstand Hawking radiation, and assume that matter behaves in ways that are completely implausible.”

According to Unruh, black holes don’t emit enough Hawking radiation to shrink the mass of the black hole down to where Mersini-Houghton claims in a timely manner. Instead, “it would take 10^53 (1 followed by 53 zeros) times the age of the universe to evaporate,” he explains.

“The standard behaviour by such people [who don’t understand Hawking radiation] is to project that outgoing energy back closer and closer to the horizon of the black hole, where its energy density gets larger and larger,” he continued. “Unfortunately explicit calculations of the energy density near the horizon show it is really, really small instead of being large– Those calculations were already done in the 1970s. To call bad speculation “has been proven mathematically” is, shall we say, and overstatement.”

Read more: http://www.iflscience.com/physics/physicist-claims-have-proven-mathematically-black-holes-do-not-exist

Astronomers discover a black hole orbiting a ‘spinning’ star for the first time

Binary systems are quite common, but astronomers have just discovered one system that was previously only hypothesized: a black hole orbiting a spinning star, known as a Be star. The research was led by Jorge Casares of Astrofísica de Canarias and was published in Nature.

Black holes were first theorized in the late 18th century and were initially termed “dark stars.” Dark stars were believed to have gravity fields so strong, light was not able to escape. There are believed to be three types of black holes: miniature, supermassive, and stellar. While miniature black holes remain theoretical, supermassive black holes are likely found at the center of all galaxies with a mass millions (potentially billions) times higher than our sun. Stellar black holes are formed by the collapse of an extremely massive star and have a mass 3-100 times our sun. The first definitive proof that stellar black holes exist was provided by Casares in 1992.

There are over 80 known Be stars in our galaxy alone. They are in binary pairs, typically with a high-density neutron star. Their name denotes their spectral wavelength in the B-class, while the lowercase e is added to indicate that it has distinct emissions, whose energy transitions do not act in a way that would be expected according to the main tenets of quantum mechanics. Because Be stars spin incredibly fast, they eject a great deal of material and can form a disk around the central star. 

Casares’ team made the discovery while using the Liverpool and Marcator telescopes on the Canary Islands in Spain. They have been studying the star MWC 656 since 2010. It is located 8,500 light years away in the constellation Lacerta. The team knew it was in a binary pair with another object, but the identity of the object was not immediately clear. It was believed to have a mass up to 6.9 times the sun, making it much too massive to be a neutron star. There was also a lack of radiation that was being picked up by the telescopes, which indicated to the team that it had to be a stellar black hole. 

The black hole is likely consuming the matter kicked out by the Be star, which was determined to be spinning at over 1 million kilometers per hour (621,000 mph). The team also found that it is the black hole that is orbiting the Be star, as the star is more massive at approximately 10 solar masses.

Because there are a seemingly endless amount of stars in the sky, astronomical events that have never before been seen are never believed to be the only occurrence; it is just a matter of locating another one. Future research will seek to find other binary systems like this and will attempt to determine how they were formed.

Read more: http://www.iflscience.com/space/astronomers-discover-black-hole-orbiting-%E2%80%98spinning%E2%80%99-star-first-time

Astronomers Find Quasars Are “Aligned” Across Billions Of Light-Years

Quasars separated by billions of light-years are lined up in a mysterious way. Astronomers looking at nearly 100 quasars have discovered that the central black holes of these ultra-bright, faraway galaxies have rotational axes that are aligned with each other. These alignments are the largest known in the universe. 

Quasars are some of the brightest things known, and at the center of these super luminous nuclei of galaxies are very active supermassive black holes. The black hole is surrounded by a spinning disc of extremely hot material, which gets spewed out in long jets all along the quasar’s axis of rotation.

Using the European Southern Observatory’s Very Large Telescope in Chile, a team led by Damien Hutsemékers from the University of Liège in Belgium studied 93 quasars known to form huge groupings. We’re seeing them now at a time when the universe was only about a third of its current age. “The first odd thing we noticed was that some of the quasars’ rotation axes were aligned with each other—despite the fact that these quasars are separated by billions of light-years,” Hutsemékers says in a news release

So the team wanted to find out if the rotation axes were linked at that time—and not just to each other, but also to the structure of the universe on large scales. When looking at the distribution of galaxies on scales of billions of light-years, astronomers have found that galaxies aren’t evenly distributed: They form a web of filaments and clump around huge galaxy-scarce voids. This arrangement of material is known as the large-scale structure.

The team could not see the rotation axes or the jets of the quasars directly. Instead they measured the polarization of the light from each quasar and found a significantly polarized signal for 19 of them. The direction of this polarization helps to deduce the angle of the disc and the direction of the spin axis of the quasar.

These new findings indicate that the rotation axes of quasars tend to be parallel to the large-scale structures that they inhabit. That means that if the quasars are in a long filament, then the spins of their central black holes will point along the filament. (See the image above.) According their estimates, there’s only a one percent probability that these alignments are simply the result of chance.

“A correlation between the orientation of quasars and the structure they belong to is an important prediction of numerical models of evolution of our universe,” says study co-author Dominique Sluse of the Argelander-Institut für Astronomie in Bonn, Germany. “The alignments in the new data, on scales even bigger than current predictions from simulations, may be a hint that there is a missing ingredient in our current models of the cosmos.” 

The findings were published in the journal Astronomy & Astrophysics this week. Here’s a detailed simulation of the large-scale structure centered on a massive galaxy cluster. The distribution of dark matter is shown in blue, the gas distribution in orange. The region shown is about 300 million light-years across.

Images: ESO/M. Kornmesser (top), Illustris Collaboration (middle)

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Read more: http://www.iflscience.com/space/quasars-across-billions-light-years-align-each-other

Novel Method of Detecting the Earliest Black Holes

New evidence suggests that the Universe began to form stars later than previously believed. This discovery may have given astronomers a clever new method of finding some of the earliest black holes. The research comes from Rennan Barkana from Tel Aviv University’s School of Physics and Astronomy and was published in Nature.

It was previously believed that gas in the Universe first heated and formed stars about 200 million years after the Big Bang. Now, new research suggests that it could have actually been closer to 400 million years. Because the heavier elements were formed in the core of stars, the earliest stars were made almost solely of hydrogen. As the first stars died, they emitted the hydrogen out into the Universe which can be detected through radio waves. 

The expansion of the Universe has stretched and distorted the light from the earliest stars – but astronomers have ways of correcting for this and actually viewing stars as they existed over 13 billion years ago. With the stars forming slightly later than was previously thought, the light does not need to travel quite as far and scientists might have an easier time of viewing these extraordinary relics. Under the previous time constraints, it was assumed that the first stars are too distant to image. The “cosmic heating” that created the first stars could also be used to identify the first black holes.

It is believed that the first black holes were formed by some of the first stellar binary systems. When one star dies into a supernova, it likely stripped mass from its companion star, forming and feeding the black hole. As the other star gets sucked in by the gravity, high-energy radiation is spewed out. As it travels across the Universe, the radiation might have re-energized some of the hydrogen gas that had already cooled. 

Understanding this re-heating process has allowed the researchers to not only alter the timeline of the early Universe, but also gave them an avenue to exploit the process to detect those earliest black holes. As the x-ray radiation from the destroyed companion star re-heated gas, radio waves were generated. By knowing what to look for, and more specifically when to look, astronomers might just be able to image the first stellar bodies and black holes.

Read more: http://www.iflscience.com/space/novel-method-detecting-earliest-black-holes

Could Supermassive Black Holes At The Center Of Galaxies Be Wormholes?

A duo of theoretical physicists from Fudan University, Shanghai, has proposed a very intriguing hypothesis; supermassive black holes at the center of normal galaxies, including our own Milky Way, may not actually be black holes at all. Instead, they could be wormholes. The paper detailing their theory has been published as a preprint edition and will be soon available in General Relativity and Quantum Cosmology.

Wormholes, although not yet proven to exist, are theorized to be channels, or shortcuts, between either different parts of the universe or even two different universes in a Multiverse model. Wormholes are composed of two mouths, which could be black holes, interconnected by a throat. The possibility of their existence was even suggested by Einstein and his theory of general relativity mathematically predicts their existence.

Sagittarius A* (SgrA*) was first observed back in 1974 as an object at the center of the Milky Way that was found to be emitting radio waves. Further investigation of SgrA* revealed telltale signs that the object was a black hole, for example the behavior of nearby stars, and astronomers have been convinced of this classification ever since.

Although we cannot observe a black hole directly since light is unable to get out, they can be detected by other means. For example, observations of SgrA* reveal plasma orbiting near the event horizon. If SgrA* is a wormhole we would also expect to see orbiting plasma blobs, however, they should differ in appearance since wormholes are predicted to be smaller than supermassive black holes.

Furthermore, wormholes could help to explain the conundrum that even young galaxies are equipped with objects that are believed to be supermassive black holes. These black holes should take a considerable length of time to achieve such size; therefore, theoretically they should not and cannot exist in new galaxies, according to the authors of this paper. Wormholes on the other hand could theoretically appear relatively quickly.

The researchers believe that their theory could be put to the test in a few years when the VLTI instrument GRAVITY is added to the European Southern Observatory in Chile. One of the main objectives of GRAVITY is to discern whether the Galactic Center harbors a black hole of four million solar masses. However, it should also be able to reveal whether the wormhole prediction is correct because the orbiting plasma will look dramatically different dependent on whether the object is a wormhole or a black hole since wormholes would have much smaller photon capture spheres.

For now, we will have to wait patiently until that data is obtained. However, if these predictions are correct, they would certainly represent a major and extremely exciting discovery. 

Read more: http://www.iflscience.com/space/could-supermassive-black-holes-center-galaxies-be-wormholes