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  • richardmitnick 3:48 pm on August 14, 2015 Permalink | Reply
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    From NYT: “A Teensy Black Hole, Just 200,000 Miles Wide” 

    New York Times

    The New York Times

    August 14, 2015

    An artist’s illustration of the black hole at the center of dwarf galaxy RGG 118. Credit Chandra X-ray Observatory

    For a monster it’s pretty cute.

    Buried in a smush of stars known as RGG 118 — and noticeable only by a plaintive squeal of X-ray radiation — astronomers have discovered a new black hole. By the standards of normal life it’s not so small, a pit in space-time 200,000 miles across into which the equivalent of 50,000 suns have disappeared. But on a cosmic scale it’s not so big.

    Almost every galaxy, like the Milky Way, has a supermassive black hole millions or billions of times as massive as the sun sitting at it center. The bigger the galaxy, the more massive the black monster at its heart. Nobody knows why.

    The new black hole is the first one found in a dwarf galaxy. RGG 118, as it is elegantly named, is 340 million light-years away and about a hundredth the mass of our own Milky Way, whose central black hole weighs some 4 million suns.

    A team from the University of Michigan and Princeton, led by Vivienne Baldassarre, a Michigan graduate student, found and measured it by using NASA’s Chandra X-Ray Observatory and an optical telescope in Chile* to chart the speeds of stars and gas swirling around in the small galaxy.

    NASA Chandra Telescope

    Observing the behavior of such a teensy, so to speak, black hole, Ms. Baldassare and her colleagues hope, will help them understand where the monstrous black holes found in regular galaxies come from and how they grow so big. Some astronomers speculate that they are seeded from giant clouds of primordial gas, or the collapse of gargantuan stars that inhabited the dawn of time, and then grew by merging with other black holes as galaxies collided during the rough and tumble days of the early universe.

    The RGG 118 black hole is like finding a preteenager on the verge of all this. In the fullness of cosmic time, it could grow into a true monster.

    *optical telescope in Chile went unnamed in the article. Bad taste.

    See the full article here.

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  • richardmitnick 6:59 am on August 4, 2015 Permalink | Reply
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    From NRAO: “Neutron Stars Strike Back at Black Holes in Jet Contest” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    4 August 2015
    Dave Finley, Public Information Officer
    (575) 835-7302

    Artist’s impression of material flowing from a companion star onto a neutron star. The material forms an accretion disk around the neutron star and produces a superfast jet of ejected material. The material closest to the neutron star is so hot that it glows in X-rays, while the jet is most prominent at radio wavelengths. A similar mechanism is at work with black holes. CREDIT: Bill Saxton, NRAO/AUI/NSF.

    Some neutron stars may rival black holes in their ability to accelerate powerful jets of material to nearly the speed of light, astronomers using the Karl G. Jansky Very Large Array (VLA) have discovered.

    “It’s surprising, and it tells us that something we hadn’t previously suspected must be going on in some systems that include a neutron star and a more-normal companion star,” said Adam Deller, of ASTRON, the Netherlands Institute for Radio Astronomy.

    Black holes and neutron stars are respectively the densest and second most dense forms of matter known in the Universe. In binary systems where these extreme objects orbit with a more normal companion star, gas can flow from the companion to the compact object, producing spectacular displays when some of the material is blasted out in powerful jets at close to the speed of light

    Previously, black holes were the undisputed kings of forming powerful jets. Even when only nibbling on a small amount of material, the radio emission that traces the jet outflow from the black hole was relatively bright. In comparison, neutron stars seemed to make relatively puny jets — the radio emission from their jets was only bright enough to see when they were gobbling material from their companion at a very high rate. A neutron star sedately consuming material was therefore predicted to form only very weak jets, which would be too faint to observe.

    Recently, however, combined radio and X-ray observations of the neutron star PSR J1023+0038 completely contradicted this picture. PSR J1023+0038, which was discovered by ASTRON astronomer Anne Archibald in 2009, is the prototypical “transitional millisecond pulsar”– a neutron star which spends years at a time in a non-accreting state, only to “transition” occasionally into active accretion. When observed in 2013 and 2014, it was accreting only a trickle of material, and should have been producing only a feeble jet.

    “Unexpectedly, our radio observations with the Very Large Array showed relatively strong emission, indicating a jet that is nearly as strong as we would expect from a black hole system,” Deller said.


    Two other such “transitional” systems are now known, and both of these now have been shown to exhibit powerful jets that rival those of their black-hole counterparts. What makes these transitional systems special compared to their other neutron star brethren? For that, Deller and colleagues are planning additional observations of known and suspected transitional systems to refine theoretical models of the accretion process.

    Deller led a team of astronomers who reported their findings in the Astrophysical Journal.

    See the full article here.

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    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    ALMA Array




    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

  • richardmitnick 8:07 am on July 23, 2015 Permalink | Reply
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    From RAS: “Treasure hunting in archive data reveals clues about black holes’ diet” 

    Royal Astronomical Society

    Royal Astronomical Society

    23 July 2015

    Media contact
    Dr Hannelore Hämmerle
    Max-Planck-Institut für extraterrestrische Physik
    Tel: +49 (0)89 30000 3980

    Science contact
    Dr Andrea Merloni
    Max-Planck-Institut für extraterrestrische Physik
    Tel: +49 (0)89 30000-3893

    A snapshot image from a computer simulation of a star disrupted by a supermassive black hole. The red-orange plumes show the debris of the star after its passage near the black hole (located close to the bottom left corner of the image). About half of the disrupted star moves in elliptical orbits around the black hole and forms an accretion disc which eventually shines brightly in optical and X-ray wavelengths. Credit: J. Guillochon (Harvard University) and E. Ramirez-Ruiz (University of California).

    Using archival data from the Sloan Digital Sky Survey [SDSS], and the XMM-Newton and Chandra X-ray telescopes, a team of astronomers have discovered a gigantic black hole, which is probably destroying and devouring a massive star in its vicinity.

    Sloan Digital Sky Survey Telescope
    SDSS telescope at Apache Point, NM, USA

    ESA XMM Newton

    NASA Chandra Telescope

    With a mass of 100 million times more than our Sun, this is the largest black hole caught in this act so far. The results of this study are published in a paper in the journal Monthly Notices of the Royal Astronomical Society.

    Andrea Merloni and members of his team, from the Max-Planck Institute for Extraterrestrial Physics (MPE) in Garching, near Munich, were exploring the huge archive of the Sloan Digital Sky Survey (SDSS) in preparation for a future X-ray satellite mission. The SDSS has been observing a large fraction of the night sky with its optical telescope. In addition, spectra (where light is dispersed across wavelengths, allowing astronomers to deduce properties like composition and temperature) have been taken of distant galaxies and black holes.

    These plots show two SDSS spectra of the object; the different luminosities as a function of wavelength between the two epochs are clearly visible. In particular, the red dashed vertical lines show the hydrogen Balmer lines which dramatically change their shape: in the red spectrum they are much broader, which provides a “fingerprint” signature of the accretion onto a central black hole. Credit: © SDSS/MPE.

    For a variety of reasons, the spectra of some objects were taken more than once. And when the team was looking at one of the objects with multiple spectra, they were struck by an extraordinary change in one of the objects under study, with the catalogue number SDSS J0159+0033, a galaxy in the constellation of Cetus. The huge distance to the galaxy means that we see it as it was 3.5 billion years ago.

    “Usually distant galaxies do not change significantly over an astronomer’s lifetime, i.e. on a timescale of years or decades,” explains Andrea Merloni, “but this one showed a dramatic variation of its spectrum, as if the central black hole had switched on and off.”

    This happened between 1998 and 2005, but nobody had noticed the odd behaviour of this galaxy until late last year, when two groups of scientists preparing the next (fourth) generation of SDSS surveys independently stumbled across these data.

    Luckily enough, the two flagship X-ray observatories, the ESA-led XMM-Newton and the NASA-led Chandra took snapshots of the same area of the sky close in time to the peak of the flare, and again about ten years later. This gave the astronomers unique information about the high-energy emission that reveals how material is processed in the immediate vicinity of the central black hole.

    Gigantic black holes are at home in the nuclei of large galaxies all around us. Most astronomers believe that they grew to the enormous sizes that we can observe today by feeding mostly on interstellar gas from their surroundings, which is unable to escape the immense gravitational pull. Such a process takes place over a very long time (tens to hundreds of millions of years), and is capable of turning a small black hole created in the explosion of a heavy star into the super-heavyweight monsters that lurk at the centre of galaxies.

    However, galaxies also contain a huge number of stars. Some unlucky ones may happen to pass too close to the central black hole, where they are destroyed and eventually swallowed by the black hole. If this is compact enough, the strong, tidal gravitational forces tear the star apart in a spectacular way. Subsequently bits and pieces swirl into the black hole and thus produce huge flares of radiation that can be as luminous as all of the rest of the stars in the host galaxy for a period of a few months to a year. These rare events are called Tidal Disruption Flares (TDF).

    Merloni and his collaborators quite quickly realised that ‘their’ flare matched almost perfectly all the expectations of this model. Moreover, because of the serendipitous nature of the discovery, they realised that this was an even more peculiar system than those which had been found through active searches until now. With an estimated mass of 100 million solar masses, this is the biggest black hole caught in the act of star-tearing so far.

    However, the sheer size of the system is not the only intriguing aspect of this particular flare; it is also the first one for which scientists can assume with some degree of certainty that the black hole was on a more standard ‘gas diet’ very recently (a few tens of thousands of years). This is an important clue to finding out which sort of food black holes mostly live on.

    Download video here: https://www.youtube.com/watch?feature=player_embedded&v=hggUYcmSjlI
    This computer simulation of the disruption of a star by a black hole shows the formation of an accretion disk of stellar material spiralling into the black hole. This sequence shows an early stage in the formation of the disk. The stellar material is coloured according to its temperature, with red being colder and purple hotter. Credit: J. Guillochon and E. Ramirez Ruiz

    “Louis Pasteur said: ‘Chance favours the prepared mind’ – but in our case, nobody was really prepared,” marvels Merloni. “We could have discovered this unique object already ten years ago, but people did not know where to look. It is quite common in astronomy that progress in our understanding of the cosmos is helped by serendipitous discoveries. And now we have a better idea of how to find more such events, and future instruments will greatly expand our reach.”

    In less than two years’ time a new powerful X-ray telescope eROSITA, which is currently being built at MPE, will be put into orbit on the Russian-German SRG satellite.


    It will scan the entire sky with the right cadence and sensitivity needed to discover hundreds of new tidal disruption flares. Big optical telescopes are also being designed and built with the goal of monitoring the variable sky, and will greatly contribute to solving the mystery of black hole eating habits. Astronomers will have to be prepared to catch these dramatic last acts of a star’s life. But however prepared they’ll be, the sky will be full of new surprises.

    Further information

    The new work appears in A tidal disruption flare in a massive galaxy? Implications for the fuelling mechanisms of nuclear black holes, A. Merloni, T. Dwelly, M. Salvato, A. Georgakakis, J. Greiner, M. Krumpe, K. Nandra, G. Ponti, A. Rau, Monthly Notices of the Royal Astronomical Society, Oxford University Press.
    The other group, who independently discovered the strange light curve of this object, was Stephanie Lamassa (Yale) and her collaborators. They were the fastest to alert the community about this object, but did not explore the stellar disruption interpretation for this event.
    Tidal Disruption Flares are very rare, with perhaps one occurring every few tens of thousands of year in any given galaxy. In addition, because they do not last very long, they are very hard to find. Only about twenty of them have been studied so far, but with the advent of larger telescopes designed to survey large areas of the sky in a short time, more and more dedicated searches are being carried out, and the pace of discovery is rapidly increasing.

    See the full article here.

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    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

  • richardmitnick 1:19 pm on July 20, 2015 Permalink | Reply
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    From NOVA: “Black Holes Could Turn You Into a Hologram, and You Wouldn’t Even Notice” 



    01 Jul 2015
    Tim De Chant

    Black holes may not have event horizons, but fuzzy surfaces.

    Few things are as mysterious as black holes. Except, of course, what would happen to you if you fell into one.

    Physicists have been debating what might happen to anyone unfortunate enough to slip toward the singularity, and so far, they’ve come up with approximately 2.5 ways you might die, from being stretched like spaghetti to burnt to a crisp.

    The fiery hypothesis is a product of Stephen Hawking’s firewall theory, which also says that black holes eventually evaporate, destroying everything inside. But this violates a fundamental principle of physics—that information cannot be destroyed—so other physicists, including Samir Mathur, have been searching for ways to address that error.

    Here’s Marika Taylor, writing for The Conversation:

    The general relativity description of black holes suggests that once you go past the event horizon, the surface of a black hole, you can go deeper and deeper. As you do, space and time become warped until they reach a point called the “singularity” at which point the laws of physics cease to exist. (Although in reality, you would die pretty early on on this journey as you are pulled apart by intense tidal forces).

    In Mathur’s universe, however, there is nothing beyond the fuzzy event horizon.

    Mathur’s take on black holes suggests that they aren’t surrounded by a point-of-no-return event horizon or a firewall that would incinerate you, but a fuzzball with small variations that maintain a record of the information that fell into it. What does touch the fuzzball is converted into a hologram. It’s not a perfect copy, but a doppelgänger of sorts.

    Perhaps more bizarrely, you even wouldn’t be aware that of the transformation. Say you were to be sucked toward a black hole. At the point where you’d normally hit the event horizon, Mathur says, you’d instead touch the fuzzy surface. But instead of noticing anything, the fuzzy surface would appear like any other part of space immediately around you. Everything would seem the same as it was, except that you’d be a hologram.

    See the full article here.

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    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

  • richardmitnick 3:12 pm on July 10, 2015 Permalink | Reply
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    Keck’s Take on the Black Hole in CID-947″ 

    Keck Observatory

    Keck Observatory

    The subject was previously covered in an earlier post, “From Chandra: ‘A Precocious Black Hole'”. But the writers at Keck spent a lot of time on this, and their views are always excellent, so it is worth seeing their work.

    Keck Observatory

    “Gigantic, Early Black Hole Could Upend Evolutionary Theory”

    July 9, 2015

    Benny Trakhtenbrot
    ETH Zürich
    Institute for Astronomy, Switzerland
    +41 (0)44-632-4213

    Steve Jefferson
    W. M. Keck Observatory

    In this illustration a black hole emits part of the accreted matter in the form of energetic radiation (blue), without slowing down star formation within the host galaxy (purple regions). Credit: M. Helfenbein, Yale University / OPAC

    An international team of astrophysicists led by Benny Trakhtenbrot, a researcher at ETH Zurich’s Institute for Astronomy, discovered a gigantic black hole in an otherwise normal galaxy, using W. M. Keck Observatory’s 10-meter, Keck I telescope in Hawaii. The team, conducting a fairly routine hunt for ancient, massive black holes, was surprised to find one with a mass of more than 7 billion times our Sun making it among the most massive black holes ever discovered. And because the galaxy it was discovered in was fairly typical in size, the study calls into question previous assumptions on the development of galaxies. Their findings are being published today in the journal Science.

    The data, collected with Keck Observatory’s newest instrument called MOSFIRE, revealed a giant black hole in a galaxy called CID-947 that was 11 billion light years away.

    Keck MOSFIRE

    The incredible sensitivity of MOSFIRE coupled to the world’s largest optical/infrared telescope meant the scientists were able to observe and characterize this black hole as it was when the Universe was less than two billion years old, just 14 percent of its current age (almost 14 billion years have passed since the Big Bang).

    Even more surprising than the black hole’s record mass, was the relatively ordinary mass of the galaxy that contained it.

    Most galaxies host black holes with with masses less than one percent of the galaxy. In CID-947, the black hole mass is 10 percent that of its host galaxy. Because of this remarkable disparity, the team deduced this black hole grew so quickly the host galaxy was not able to keep pace, calling into question previous thinking on the co-evolution of galaxies and their central black holes.

    “The measurements of CID-947 correspond to the mass of a typical galaxy,” Trakhtenbrot said. “We therefore have a gigantic black hole within a normal size galaxy. The result was so surprising, two of the astronomers had to verify the galaxy mass independently. Both came to the same conclusion.”

    “Black holes are objects that possess such a strong gravitational force that nothing – not even light – can escape,” said Professor Meg Urry of Yale University, co-author of the study. ” Einstein’s theory of relativity describes how they bend space-time itself. The existence of black holes can be proven because matter is greatly accelerated by the gravitational force and thus emits particularly high-energy radiation.”

    Until now, observations have indicated that the greater the number of stars present in the host galaxy, the bigger the black hole. “This is true for the local Universe, which merely reflects the situation in the Universe’s recent past,” Urry said.

    Furthermore, previous studies suggest the radiation emitted during the growth of the black hole controlled, or even stopped, the creation of stars as the released energy heated up the gas. This cumulative evidence led scientists to assume the growth of black holes and the formation of stars go hand-in-hand.

    The latest results, however, suggest that these processes work differently, at least in the early Universe.

    The distant young black hole observed by Trakhtenbrot, Urry and their colleagues had roughly 10 times less mass than its galaxy. In today’s local Universe, black holes typically reach a mass of 0.2 to 0.5 percent of their host galaxy’s mass. “That means this black hole grew much more efficiently than its galaxy – contradicting the models that predicted a hand-in-hand development,” he said.

    The researchers also concluded stars were still forming even though the black hole had reached the end of its growth. Contrary to previous assumptions, the energy and gas flow propelled by the black hole did not stop the creation of stars.

    “From the available Chandra data for the source, we also concluded that the black hole has a very low accretion rate, and is therefore reached the end of its growth. On the other had, other data suggests that stars were still forming throughout the host galaxy,” Trakhtenbrot said.

    NASA Chandra Telescope

    The galaxy could continue to grow in the future, but the relationship between the mass of the black hole and that of the stars would remain unusually large. The researchers believe CID-947 could be a precursor of the most extreme, massive systems that we observe in today’s local Universe, such as the galaxy NGC 1277 in the constellation of Perseus, some 220 million light years away from our Milky Way.

    MOSFIRE (Multi-Object Spectrograph for Infrared Exploration) is a highly-efficient instrument that can take images or up to 46 simultaneous spectra. Using a sensitive state-of-the-art detector and electronics system, MOSFIRE obtains observations fainter than any other near infrared spectrograph. MOSFIRE is an excellent tool for studying complex star or galaxy fields, including distant galaxies in the early Universe, as well as star clusters in our own Galaxy. MOSFIRE was made possible by funding provided by the National Science Foundation and astronomy benefactors Gordon and Betty Moore.

    See the full article here.

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    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
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  • richardmitnick 3:08 pm on July 9, 2015 Permalink | Reply
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    From Chandra: “A Precocious Black Hole” 

    NASA Chandra

    July 9, 2015

    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.

    Credit: Illustration: M. Helfenbein, Yale University / OPAC

    Researchers have discovered a black hole that grew much more quickly than its host galaxy. The discovery calls into question previous assumptions on the development of galaxies.

    The black hole was originally discovered using NASA’s Hubble Space Telescope, and was then detected in the Sloan Digital Sky Survey and by ESA’s XMM-Newton and NASA’s Chandra X-ray Observatory.

    Benny Trakhtenbrot, from ETH Zurich’s Institute for Astronomy, and an international team of astrophysicists, performed a follow-up observation of this black hole using the 10 meter Keck telescope in Hawaii and were surprised by the results. The data, collected with a new instrument, revealed a giant black hole in an otherwise normal, distant galaxy, called CID-947. Because its light had to travel a very long distance, the scientists were observing it at a period when the universe was less than two billion years old, just 14 percent of its current age (almost 14 billion years have passed since the Big Bang).

    An analysis of the data collected in Hawaii revealed that the black hole in CID-947, with nearly 7 billion solar masses, is among the most massive black holes discovered up to now. What surprised researchers in particular was not the black hole’s record mass, but rather the galaxy’s mass. “The measurements correspond to the mass of a typical galaxy,” says Trakhtenbrot, a postdoctoral fellow working within the Extragalactic Astrophysics research group of Professor Marcella Carollo. “We therefore have a gigantic black hole within a normal size galaxy.” The result was so surprising that two of the astronomers, including Hyewon Suh from the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, MA, had to verify the galaxy mass independently. Both came to the same conclusion. The team reports its findings in the current issue of the scientific journal Science.

    Was anything different in the early Universe?

    Most galaxies, including our Milky Way, have a black hole at their center that holds millions to billions of solar masses. “Black holes are objects that possess such a strong gravitational force that nothing – not even light – can escape. Einstein’s theory of relativity describes how they bend space-time itself,” explains ETH professor Kevin Schawinski, co-author of the new study. The existence of black holes can be proven because matter is greatly accelerated by the gravitational force and thus emits particularly high-energy radiation.

    Until now, observations have indicated that the greater the number of stars present in the host galaxy, the bigger the black hole. “This is true for the local universe, which merely reflects the situation in the Universe’s recent past,” says Trakhtenbrot. This link, along with other evidence, led the scientists to assume that the growth of black holes and the formation of stars go hand-in-hand. This is quite reasonable, if a common reservoir of cold gas was responsible for the formation of the stars and the ‘feeding’ of the black hole at the galaxy’s center, says Trakhtenbrot. Furthermore, previous studies suggested that the radiation emitted during the growth of the black hole controlled, or even stopped the creation of stars, as the released energy heated up the gas. The latest results, however, suggest that these processes work differently, at least in the early universe.

    Star formation continues

    The distant young black hole observed by Trakhtenbrot and his colleagues weighs about 10% of its host galaxy’s mass. In today’s local universe, black holes typically reach a mass of 0.2% to 0.5% of their host galaxy’s mass. “That means this black hole grew much more efficiently than its galaxy – contradicting the models that predicted a hand-in-hand development,” explains the ETH researcher. From the available Chandra data for this source, the researchers also concluded that the black hole had reached the end of its growth. However, other data suggests stars were still forming throughout the host galaxy. Contrary to previous assumptions, the energy and gas flow, propelled by the black hole, did not stop the creation of stars.

    The galaxy could continue to grow in the future, but the relationship between the mass of the black hole and that of the stars would remain unusually large. The researchers believe that CID-947 could thus be a precursor of the most extreme, massive systems that we observe in today’s local universe, such as the galaxy NGC 1277 in the constellation of Perseus, some 220 million light years away from our Milky Way. They hope to gain further insight into the links between the black hole and the host galaxy, through observations with the Alma radio telescope in Chile.

    The black hole was selected from a 2011 paper published by Francesca Civano, from Yale University in New Haven, CT and CfA, as part of the Chandra Cosmic Evolution Survey. The full list of authors of the Science paper are Benny Trakhtenbrot ; Megan Urry from Yale University in New Haven, CT; Francesca Civano; David Rosario from the Max Planck Institute for Astrophysics in Garching, Germany; Martin Elvis from CfA; Kevin Schawinski; Hyewon Suh; Angela Bongiorno from the National Institute for Astrophysics in Rome, Italy and Brooke D. Simmons from Oxford University in the UK.

    NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the agency’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.
    An interactive image, a podcast, and a video about the findings are available at:


    For more Chandra images, multimedia and related materials, visit:


    See the full article here.

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    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

  • richardmitnick 11:41 am on June 10, 2015 Permalink | Reply
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    From NYT: “An Earthling’s Guide to Black Holes” 

    New York Times

    The New York Times

    JUNE 8, 2015

    Welcome, earthlings, to the place of no return — a region in space where the gravitational pull is so strong, not even light can escape it. This is a black hole.

    It’s ok to feel lost here. Even [Albert] Einstein — whose Theory of General Relativity made it possible to conceive of such a place — thought the concept was too bizarre to exist. But Einstein was wrong, and here you are.

    You shouldn’t be here. You will surely get pulled in. But fear not dear Earthling, this is just your mind thinking. It has taken your brain millions of years to get here. So let’s get started.

    Bright flares are visible near the event horizon of a super-massive black hole at the center of the Milky Way. Credit NASA/CXC, via MIT, via F.K.Baganoff

    The black hole is a hungry beast.

    It swallows up everything too close, too slow or too small to fight its gravitational force — even light. With every planet, gas, star or bit of mass consumed, the black hole grows.

    At the edge of a black hole, its event horizon, is the point of no return. Stay far away from the event horizon, because that’s where the hole pulls in light. And nothing is faster than light. At the event horizon, everything enters the black hole.

    The brightest white spot in the middle is the very center of the Milky Way galaxy, which also marks the site of a supermassive black hole. Credit NASA/JPL-Caltech

    Pretty much everything we understand about how the universe works, depends on the black hole.

    Someone is wrong, or we have to admit that earthlings still aren’t equipped to understand the universe. The firewall paradox calls to question the most definitive theories of science. Albert Einstein, Joseph Polchinski or Stephen Hawking, or none, everything we know about the universe could change if we could know for certain what happens to information inside a black hole.

    An interpretation of a black hole, created for an educational video game. Credit Denver Museum of Nature and Science

    If you fell into a black hole, it’s not clear how you would die.

    Will gravity rip you apart and crush you into the black hole’s core? Or will a firewall of energy sizzle you into oblivion? Could some essence of you ever emerge from a black hole? First posited by a group of theorists including Donald Marolf, Ahmed Almheiri, James Sully and Joseph Polchinski in March 2012, the question of how you would die inside a black hole is probably the biggest debate in physics right now. It’s called the firewall paradox.

    Based on the mathematics in Einstein’s 1915 General Theory of Relativity, you would fall through the event horizon unscathed before gravity’s force pulled you into a noodle and ultimately crammed you into singularity, the black hole’s infinitely dense core.

    But Dr. Polchinski and his team pitted Einstein against quantum theory, which posited that the event horizon would become a blazing firewall of energy that would torch your body to smithereens.

    Keep both theories, the physicist Stephen Hawking said in January 2014. Black holes aren’t what we thought they were. There is no event horizon, and there is no singularity. They’re just different.

    According to Dr. Hawking, at the edge of a black hole, the fourth dimension known as space-time fluctuates like weather, making the crisp edge we assume impossible. Instead, Dr. Hawking’s “apparent horizon” would be like a purgatory for light rays attempting to escape a black hole, slowly dissolving and moving inward, but never being pulled into singularity. The event horizon, he says, remains the same, or even shrinks as a black hole slowly leaks energy. Suspended in the apparent zone, you would scramble and leak out into the cosmos as “Hawking radiation.”

    Galaxy NGC 1275. Credit NASA

    Black holes can sing.

    In 2003, an international team led by the X-ray astronomer Andrew Fabian discovered the longest, oldest, lowest note in the universe — a black hole’s song — using NASA’s Chandra X-ray Observatory.

    NASA Chandra Telescope

    Although it is too low and deep for humans to hear, the B flat note, 57 octaves below middle C, appeared as sound waves that moved out from explosive events at the edge of a supermassive black hole in the galaxy NGC 1275.

    NGC 1275 per NASA/ESA Hubble

    The notes stayed in the galaxy and never reached us, but we couldn’t have heard them anyway. The lowest note the human ear can detect has an oscillation period of one-twentieth of a second. This B flat’s period was 10 million years.

    The “songs” of black holes may be behind a declining birth rate of stars in the universe. In clusters of galaxies such as Perseus, the home of NGC 1275, the energy these notes carry is thought to keep the gases too hot to condense and form stars.

    A big galaxy gobbles a tiny one. Credit Swinburne University of Technology/Reuters

    Meet the management: Black holes may control the size of a galaxy.

    Playing music that keeps the intergalactic clusters too hot for stars might not be the only way black holes help maintain galaxies.

    Astronomers think that the energy that forms when galactic masses swirl and heat up around a black hole shoots out in X-ray beams that fuel quasars, supermassive black holes that are actively chomping down gas at the centers of distant galaxies.

    The Milky Way as visible from the desert southwest of Cairo. Credit Amr Abdallah Dalsh/Reuters

    Astronomers have evidence for black holes in nearly every galaxy in the universe.

    Although no black hole is close enough to Earth to pull the planet into its depths, there are so many black holes in the universe that counting them is impossible. Nearly every galaxy — our own Milky Way as well as the 100 billion or so other galaxies visible from Earth — shows signs of a black hole.

    Of the billions of stars in the Milky Way, about one in every thousand new stars is massive enough to become a black hole. Our sun isn’t. But a star 25 times heavier is. Stellar-mass black holes result from the death of these stars, and can exist anywhere in the galaxy.

    Supermassive black holes — a million to a billion times more massive than our sun — exist only in the center of a galaxy. At the center of the Milky Way, 26,000 light-years from Earth, scientists are hoping to make an image of Sagittarius A*, which is believed to be our own supermassive black hole, with the mass of four million suns. How supermassive black holes form is still a mystery.

    Sagittarius A* from NASA’s Chandra X-Ray Observatory

    Black holes are stellar tombstones.

    It wasn’t a nuclear bomb, and it wasn’t terrestrial. On July 2, 1967, a network of satellites recorded an explosion of gamma rays coming from outer space. In retrospect, this was one of the first indications that black holes are real. Today, scientists believe that the gamma ray burst is the final breath of a dying star and the birth of a stellar-mass black hole.

    The dramatic transformation starts when a massive star runs out of fuel to power itself. As the star begins to collapse, it explodes. The star’s outer layers spew out into space, but the inside implodes, becoming denser and denser, until there is too much matter in too little space. The core succumbs to its own gravitational pull and collapses into itself, in extreme cases forming a black hole.

    Theoretically, if you shrunk any mass down into a certain amount of space, it could become a black hole. Our earth would be one if you tried to cram the earth into a pea.

    NASA’s Hubble Space Telescope captured a high energy blast, likely a black hole eating, at the center of a galaxy. Credit NASA

    ‘A black hole has no hair.’

    On March 28, 2011, astronomers detected a long gamma ray burst coming from the center of a galaxy four billion light-years away. This was the first time humans observed what might have been a dormant black hole eating a star.

    No matter what a black hole eats — a star, a donkey, an iPhone, your grammar teacher — it’s all the same. As the physicist John Archibald Wheeler put it, “A black hole has no hair,” meaning that a black hole remembers only the mass, spin and charge of its dinner.

    The more a black hole eats, the more it grows. In 2011, scientists discovered one of the biggest black holes ever, more than 300 million light-years away. It weighs enough to have gobbled up 21 billion suns. Scientists want to know if the biggest black holes are the result of two holes merging or one hole eating a lot. But scientists don’t know how they grew so large.

    The Event Horizon Telescope is attempting to get the first ever portrait of the hungry monster at the center of our galaxy. Credit James D. Lowenthal/Smith College Astronomy Department

    To find the darkness, follow the light.

    Because light can’t escape a black hole, seeing what’s inside it is impossible. Getting a picture of a black hole’s edge is difficult, and getting a clear picture is an event.

    Actually, it has never been done. Scientists suspect black holes when their tools detect high-energy radio waves, such as those that may result from a collapsing star, gamma ray burst, supernova or the energy an object might release before reaching the black hole’s event horizon. Generally, if there is a lot of energy with a massive core at the center of a galaxy, the core is probably a black hole.

    The Event Horizon Telescope, the one Sheperd Doeleman and his colleagues used to try to photograph Sagittarius A* and M87, another black hole, featured a cast of more than 100 scientists on three continents and one very important crystal used to calibrate atomic clocks. The scientists staked out seven telescopes atop six mountains, synchronized time, pointed their discs at the sky and waited. For the first time ever, scientists may have seen a rough image of a black hole’s event horizon.

    An artist’s conception of stars moving in the central regions of a giant elliptical galaxy that harbors a black hole. Credit Lynette Cook/Gemini Observatory, via Nature, via Associated Press

    A black hole is not forever.

    As Hawking radiation leaks out into the universe, quantum effects suggest that a black hole will evaporate — eventually. It would take many times the age of the universe for a black hole to fully evaporate.

    Dr. Hawking, like Einstein, at first did not believe his own theory. But the numbers were right. Physicists now view his result as the backbone for whatever future theory will bring together gravity and quantum theory.

    This magnet is part of The Large Hadron Collider, the world’s largest and most powerful particle accelerator. [at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. ] Credit Fabrice Coffrini/Agence France-Presse — Getty Images

    A giant magnet in Europe will not destroy the planet.

    Before the European Organization for Nuclear Research fired up the Large Hadron Collider in 2008, critics worried that smashing together protons in a 17-mile ring underground would create a black hole that would swallow the earth.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Worriers echoed apocalyptic cries about Brookhaven National Laboratory’s Relativistic Heavy Ion Collider that the center’s scientists had squelched nearly 10 years earlier.

    BNL RHIC Campus
    RHIC at BNL

    According to their calculations, ultrahigh-energy cosmic rays already penetrated the earth’s atmosphere and predicted about 100 tiny black holes on earth every year. If tiny black holes were a problem, Earth would have already collapsed into infinity:

    Still, in June 2008, a safety review proclaimed the L.H.C. was indeed safe. Experiments commenced, the Higgs boson was found, and the earth survived after all.

    In the search for the smallest particles in the universe, the consequential mini black holes that scientists might create in contained underground tubes would let them observe general relativity and quantum mechanics in action and may open the door to solving the firewall paradox.

    See the full article here.

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  • richardmitnick 10:05 am on April 21, 2015 Permalink | Reply
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    From Nature: “3D simulations of colliding black holes hailed as most realistic yet” 

    Nature Mag

    20 April 2015
    Ron Cowen

    In-spiral and merger of binary black holes
    Simulations: S. Shapiro, R. Gold, V. Paschalidis, M. Ruiz, Z. Etienne & H. Pfeiffer. Movie: S. Shapiro, S. Connelly, A. Khan and L. Kong.

    When astronomers try to simulate colliding giant black holes, they usually rely on simplified approximations to model the swirling disks of matter that surround and fuel these gravitational monsters. Researchers now report that, for the first time, they have simulated the collision of two supermassive black holes using a full-blown treatment of [Albert] Einstein’s general theory of relativity, allowing a 3D portrayal of these disks of magnetized matter.

    The simulations more accurately describe the radiation that might be detected from such mergers. This includes electromagnetic radiation blasted into space and ripples in space-time known as gravitational waves. Stuart Shapiro of the University of Illinois at Urbana-Champaign presented movies of the simulations at a meeting of the American Physical Society in Baltimore, Maryland, on 13 April. His team had described elements of the study last November, in Physical Review D.

    Gravitational waves generated by black hole merger Simulations: S. Shapiro, R. Gold, V. Paschalidis, M. Ruiz, Z. Etienne & H. Pfeiffer. Movie: S. Shapiro, S. Connelly, A. Khan and L. Kong.

    “As a technical achievement, there’s no doubt that this is a giant step forward,” says astronomer Cole Miller of the University of Maryland in College Park, who was not part of the study.

    Collision course

    For the simulations, Shapiro’s team developed a mathematical model to couple Einstein’s equations (which describe the gravitational field around a black hole) with equations that govern the motion of matter moving close to the speed of light in a magnetic field.

    The simulations may take on added significance, says Shapiro, because recent observations hint that a black hole weighing as much as ten billion Suns might be set to collide with a similarly massive partner in a mere seven years.

    Analysing data from a large telescope in Hawaii called Pan-STARRS (Panoramic Survey Telescope & Rapid Response System), Tingting Liu of the University of Maryland and her colleagues spotted what seem to be periodic variations in the radiation emitted by a quasar — a brilliant beacon of light that outshines the entire galaxy in which it resides — from which light has taken 10.4 billion years to reach Earth. The team reported its findings on 14 April in The Astrophysical Journal Letters.

    Pann-STARSR1 Telescope
    Pann-STARRS2 Interior

    Quasars are thought to be fuelled by supermassive black holes at the centres of galaxies. Liu and her colleagues interpret the apparently periodic fluctuations in the quasar light, along with information gleaned from the spectrum of that light, as a sign that the quasar’s black hole is closely orbiting another supermassive black hole in a neighbouring galaxy. If confirmed, the putative merger would be a prime candidate to examine for signs of emitted gravitational waves, says Liu.

    Signal search

    “This merger would be amazing, if we saw it,” says Miller. But strong evidence for an imminent collision is lacking, he adds. Random, low-frequency fluctuations in the quasar’s light could partially mimic a periodic signal, he notes. And even if fluctuations in the quasar’s light are truly periodic, they could be due to the properties of a single black hole and its disk, rather than to the presence of an orbiting partner, Shapiro says.

    Still, he adds, it would be worth trying to spot gravitational waves from the putative merger. One way to do this would involve pulsars: compact, rapidly spinning stars that beam radio waves across the sky like lighthouse beacons. If a radio receiver on Earth could detect a correlated change to signals from an array of pulsars, that might indicate that the passage of a gravitational wave had disturbed the array. Radio receivers are not currently sensitive enough to detect a signal from Liu’s system, but future improvements could bring a detection within reach, says Shapiro.

    Earlier this year, astronomers reported in Nature that they had found a repeating light signal that is best explained by a pair of supermassive black holes poised to spiral into each other. Sadly, the collision is predicted to occur a million years from now.

    See the full article here.

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

  • richardmitnick 1:52 pm on April 7, 2015 Permalink | Reply
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    From SUNY Buffalo: “Black holes don’t erase information, scientists say” 

    SUNY Buffalo

    SUNY Buffalo

    April 2, 2015
    Charlotte Hsu

    An artist’s impression shows the surroundings of a supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus. A new University at Buffalo study finds that information is not lost once it has entered a black hole. Credit: ESO/M. Kornmesser

    The “information loss paradox” in black holes — a problem that has plagued physics for nearly 40 years — may not exist

    Shred a document, and you can piece it back together. Burn a book, and you could theoretically do the same. But send information into a black hole, and it’s lost forever.

    That’s what some physicists have argued for years: That black holes are the ultimate vaults, entities that suck in information and then evaporate without leaving behind any clues as to what they once contained.

    But new research shows that this perspective may not be correct.

    “According to our work, information isn’t lost once it enters a black hole,” says Dejan Stojkovic, PhD, associate professor of physics at the University at Buffalo. “It doesn’t just disappear.”

    Stojkovic’s new study, Radiation from a Collapsing Object is Manifestly Unitary, appeared on March 17 in Physical Review Letters, with UB PhD student Anshul Saini as co-author.

    The paper outlines how interactions between particles emitted by a black hole can reveal information about what lies within, such as characteristics of the object that formed the black hole to begin with, and characteristics of the matter and energy drawn inside.

    This is an important discovery, Stojkovic says, because even physicists who believed information was not lost in black holes have struggled to show, mathematically, how this happens. His new paper presents explicit calculations demonstrating how information is preserved, he says.

    The research marks a significant step toward solving the “information loss paradox,” a problem that has plagued physics for almost 40 years, since Stephen Hawking first proposed that black holes could radiate energy and evaporate over time. This posed a huge problem for the field of physics because it meant that information inside a black hole could be permanently lost when the black hole disappeared — a violation of quantum mechanics, which states that information must be conserved.

    Information hidden in particle interactions

    In the 1970s, Hawking proposed that black holes were capable of radiating particles, and that the energy lost through this process would cause the black holes to shrink and eventually disappear. Hawking further concluded that the particles emitted by a black hole would provide no clues about what lay inside, meaning that any information held within a black hole would be completely lost once the entity evaporated.

    Though Hawking later said he was wrong and that information could escape from black holes, the subject of whether and how it’s possible to recover information from a black hole has remained a topic of debate.

    Stojkovic and Saini’s new paper helps to clarify the story.

    Instead of looking only at the particles a black hole emits, the study also takes into account the subtle interactions between the particles. By doing so, the research finds that it is possible for an observer standing outside of a black hole to recover information about what lies within.

    Interactions between particles can range from gravitational attraction to the exchange of mediators like photons between particles. Such “correlations” have long been known to exist, but many scientists discounted them as unimportant in the past.

    “These correlations were often ignored in related calculations since they were thought to be small and not capable of making a significant difference,” Stojkovic says. “Our explicit calculations show that though the correlations start off very small, they grow in time and become large enough to change the outcome.”

    The study was partially funded by the National Science Foundation.

    See the full article here.

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  • richardmitnick 8:57 am on March 26, 2015 Permalink | Reply
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    From Space.com: “The Strangest Black Holes in the Universe” 2013 But Interesting 

    space-dot-com logo


    July 08, 2013
    Charles Q. Choi

    Black holes are gigantic cosmic monsters, exotic objects whose gravity is so strong that not even light can escape their clutches.

    The Biggest Black Holes
    Credit: Pete Marenfeld

    Nearly all galaxies are thought to harbor at their cores supermassive black holes millions to billions of times the mass of our sun. Scientists recently discovered the largest black holes known in two nearby galaxies.

    One of these galaxies, known as NGC 3842 — the brightest galaxy in the Leo cluster nearly 320 million light years away — has a central black hole containing 9.7 billion solar masses. The other, NGC 4889, the brightest galaxy in the Coma cluster more than 335 million light years away, has a black hole of comparable or larger mass.

    NGC 4889
    Credit: Sloan Digital Sky Survey, Spitzer Space Telescope
    Sloan Digital Sky Survey Telescope
    SDSS telescope

    NASA Spitzer Telescope

    The Smallest Black Hole
    Credit: NASA/Goddard Space Flight Center/CI Lab

    The gravitational range, or “event horizon,” of these black holes is about five times the distance from the sun to Pluto. For comparison, these blaVck holes are 2,500 times as massive as the black hole at the center of the Milky Way galaxy, whose event horizon is one-fifth the orbit of Mercury.

    The smallest black hole discovered to date may be less than three times the mass of our sun. This would put this little monster, officially called IGR J17091-3624, near the theoretical minimum limit needed for a black hole to be stable. As tiny as this black hole may be, it looks fierce, capable of 20 million mph winds (32 million kph) — the fastest yet observed from a stellar-mass black hole by nearly 10 times.

    Cannibalistic Black Holes
    Credit: X-ray: NASA/CXC/SAO/G.Fabbiano et al; Optical: NASA/STScI

    NASA Chandra schematic

    NASA Hubble Telescope
    NASA/ESA Hubble [not in notes but in credit]

    Black holes devour anything unlucky enough to drift too close, including other black holes. Scientists recently detected the monstrous black hole at the heart of one galaxy getting consumed by a still larger black hole in another.

    The discovery is the first of its kind. Astronomers had witnessed the final stages of the merging of galaxies of equal mass — so-called major mergers — but minor mergers between galaxies and smaller companions had long eluded researchers.

    Using NASA’s Chandra X-ray Observatory, investigators detected two black holes at the center of a galaxy dubbed NGC3393, with one black hole about 30 million times the mass of the sun and the other at least 1 million times the mass of the sun, separated from each other by only about 490 light-years.

    Bullet-shooting Black Hole
    Credit: Greg Sivakoff/University of Alberta

    Black holes are known for sucking in matter, but researchers find they can shoot it out as well. Observations of a black hole called H1743-322, which harbors five to 10 times the mass of the sun and is located about 28,000 light-years from Earth, revealed it apparently pulled matter off a companion star, then spat some of it back out as gigantic “bullets” of gas moving at nearly a quarter the speed of light.

    The Oldest Known Black Hole
    Credit: ESO/M. Kornmesser

    The oldest black hole found yet, officially known as ULAS J1120+0641, was born about 770 million years after the Big Bang that created our universe. (Scientists think the Big Bang occurred about 13.7 billion years ago.)

    The ancient age of this black hole actually poses some problems for astronomers. This brilliant enigma appears to be 2 billion times the mass of the sun. How black holes became so massive so soon after the Big Bang is difficult to explain.

    The Brightest Black Hole
    Credit: HST

    Although the gravitational pulls of black holes are so strong that even light cannot escape, they also make up the heart of quasars, the most luminous, most powerful and most energetic objects in the universe.

    As supermassive black holes at the centers of galaxies suck in surrounding gas and dust, they can spew out huge amounts of energy. The brightest quasar we see in the visible range is 3C 273, which lies about 3 billion light-years away.

    Rogue Black Holes
    Credit: David A. Aguilar (CfA)

    When galaxies collide, black holes can get kicked away from the site of the crash to roam freely through space. The first known such rogue black hole, SDSSJ0927+2943, may be approximately 600 million times the mass of the sun and hurtle through space at a whopping 5.9 million mph (9.5 million kph). Hundreds of rogue black holes might wander the Milky Way.

    Middleweight Black Holes
    Credit: NASA

    Scientists have long thought that black holes come in three sizes — essentially small, medium and large. Relatively small black holes holding the mass of a few suns are common, while supermassive black holes millions to billions of solar masses are thought to lurk at the heart of nearly every galaxy. One more massive than four million suns, for example, is thought to hide in the center of the Milky Way.

    However, middle-weight black holes had eluded astronomers for years. Scientists recently discovered an intermediate-mass black hole, called HLX-1 (Hyper-Luminous X-ray source 1), approximately 290 million light-years from Earth, which appears to be about 20,000 solar masses in size.

    Medium-size black holes are thought to be the building blocks of supermassive black holes, so understanding more about them can shed light on how these monsters and the galaxies that surround them evolved.

    Fastest-spinning Black Hole
    Credit: NASA / NASA / CXC / M.Weiss

    Black holes can whirl the fabric of space around themselves at extraordinary speeds. One black hole called GRS 1915+105, in the constellation Aquila (The Eagle) about 35,000 light-years from Earth, is spinning more than 950 times per second.

    An item placed on the edge of the black hole’s event horizon — the edge past which nothing can escape — would spin around it at a speed of more than 333 million mph (536 million kph), or about half the speed of light.

    Tabletop Black Holes
    Credit: Chris Kuklewicz

    Black holes are thankfully quite far away from Earth, but this distance makes it difficult to gather clues that could help solve the many mysteries that surround them. However, researchers are now recreating the enigmatic properties of black holes on tabletops.

    For instance, black holes possess gravitational pulls so powerful that nothing, including light, can escape after falling past a border known as the event horizon. Scientists have created an artificial event horizon in the lab using fiber optics. They have also recreated the so-called Hawking radiation thought to escape from black holes.

    See the full article here.

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