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Post by auntym on Jan 15, 2011 21:12:41 GMT -6
www.stumbleupon.com/su/1mn2fe/www.dailygalaxy.com/my_weblog/2011/01/supermassive-black-holes-observed-devouring-whole-galaxies-weekend-most-popular.htmlSupermassive Black Holes Observed Devouring Entire Galaxies January 15, 2011 Black holes -Stephen Hawking's enigmatic "bad boys of the Universe"- have been discovered to have the ability to strip massive galaxies of the cool gases required to form new stars, leaving ageing red giants to fade out of existence with no stars to replace them. The study, led by Asa Bluck of the University of Nottingham's School of Physics and Astronomy and a Fellow of the Royal Society, used images of unprecedented depth and resolution from the Hubble Space Telescope and the Chandra X-Ray Observatory to detect black holes in distant galaxies. Researchers looked for galaxies emitting high levels of radiation and x-rays — a classic signature of black holes devouring gas and dust through accretion, or attracting matter gravitationally., used images of unprecedented depth and resolution from the Hubble Space Telescope and the Chandra X-Ray Observatory to detect black holes in distant galaxies. Researchers looked for galaxies emitting high levels of radiation and x-rays — a classic signature of black holes devouring gas and dust through accretion, or attracting matter gravitationally. Funded by the Science and Technology Facilities Council and NASA, the research led to some startling results: in supermassive black holes this radiation can reach huge proportions, emitting X-ray radiation in far greater quantities then is emitted by the rest of the objects in the galaxy combined — meaning that the black hole ‘shines’ far brighter than the entire galaxy it lies at the heart of. In fact, the amount of energy released is sufficient to strip the galaxy of gas at least 25 times over. Results have also shown that the vast majority of the X-ray radiation present in the universe is produced in these accretion discs surrounding supermassive black holes, with a small proportion produced by all other objects, including galaxies and neutron stars. The accretions discs surrounding supermassive black holes produce so much energy that they heat up the cold gases lying at the heart of massive galaxies. The accretion disc shines across all wavelengths — from radio waves to gamma waves. This speeds up the random motions of the gas, making it rise in temperature and pushing it away from the galactic center, where it becomes less dense. Gas needs to be cold and dense to collapse under gravity to form new stars, this resulting hot, low-density material must cool down before gravity will take effect — a process which would take longer than the age of the universe to achieve. Old stars are therefore left to die out with no new stars replacing them, leaving the galaxy to grow dark and die. And by pushing gas away from the galactic centre, the accretion disc starves the supermassive black hole of new material to devour, leading to its eventual demise. “It’s thought that black holes form inside their host galaxies and grow in proportion to them, forming an accretion disc which will eventually destroy the host. In this sense they can be described as viral in nature,” said Asa Bluck. “Massive galaxies are in the minority in our visible universe — about one in a thousand galaxies is thought to be massive, but it may be much less. And at least a third of these have supermassive black holes at their centre. That’s why it’s so interesting that this type of black hole produces most of the X-ray light in the universe. They are the minority but they dominate energy output.” Jason McManus via University of Nottingham
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Post by Deleted on Jun 17, 2011 19:09:07 GMT -6
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Post by skywalker on Jun 18, 2011 4:33:53 GMT -6
According to the article this thing has been blasting us with gamma radiation for several months now, and there is no telling how long it will continue. I wonder if this increased radiation will have any effect on the Earth? I wonder how long it will continue. I would imagine that if a star is being destroyed it's not something that would just go "Blip!" and be gone. It's probably going to take a while.
It is kind of cool to be experiencing something that only happens once every hundred million years though...assuming that that estimate is correct.
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Post by skywalker on Jun 18, 2011 4:40:56 GMT -6
Is this the illustration that you were trying to post? It does look kind of cool. I bet it looks even better in real life. Illustration by Mark A. Garlick, University of Warwick.
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Post by Deleted on Jun 18, 2011 13:19:03 GMT -6
Kewl!
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Post by lois on Jun 18, 2011 13:41:09 GMT -6
Jo..... all I can say is WOW!
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Post by paulette on Jun 18, 2011 14:31:40 GMT -6
Mutation time on the old earth ranch.
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Post by auntym on Aug 31, 2012 10:48:12 GMT -6
www.huffingtonpost.com/2012/08/30/black-holes-millions-nasa-wise-space-telescope_n_1843590.html Black Holes: Millions Revealed By NASA's WISE Space Telescope[/color] Posted: 08/30/2012 By: Clara Moskowitz Published: 08/29/2012 on SPACE.com A jackpot of previously unknown black holes across the universe has been discovered by the infrared eyes of a prolific NASA sky-mapping telescope. The cosmic find comes from data collected by NASA's Wide-field Infrared Survey (WISE) telescope, which scanned the entire sky in infrared light from December 2009 to February 2011. The full catalog of observations by WISE during its mission was publicly released in March, and astronomers are still poring through this celestrial trove for discoveries. "WISE has found a bonanza of black holes in the universe," astronomer Daniel Stern of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said during a news briefing today (Aug. 29). WISE turned up about three times as many black holes as have been found by comparable surveys in visible light, offering up a total of 2.5 million new sources across the sky. These black holes aren't the average tiny, dense objects created by the collapse of dead stars, but rather humongous "supermassive" black holes that have been caught feasting on matter falling into them. Such active black holes are known as quasars, and are some of the brightest objects in the universe, because of light released by the infalling matter. [Photos: Millions of Black Holes Seen by WISE Telescope] "We expected that there should be this large population of hidden quasars in the universe, but WISE can now identify them across the sky," Stern said. "We think these quasars are really important for shaping how galaxies look today." This zoomed-in view of a portion of the all-sky survey from WISE shows a collection of quasar candidates. Cosmic Hot DOGsIn addition to this haul of gorging black holes, WISE has turned up a smaller population of rarer objects researchers are dubbing "hot DOGs," for hot, dust-obscured galaxies. These galaxies are thought to be extremely bright, but appear very faint to us because their light is shrouded by dust. "It is actually the most obscured objects in the WISE sky that are among the brightest objects in the universe," said Peter Eisenhardt, a WISE project scientist at JPL. "They're definitely a different type of beast than we’ve seen before." The hot DOGs observed by WISE number about 1,000, and are mostly spotted from very far away, meaning they existed in the early days of the universe, because their light has taken billions of years to travel to Earth. Scientists suspect these weird objects may represent a missing link in galaxy evolution, capturing a brief phase in the life of a galaxy that is transitioning from being a spiral disk galaxy like our milky way to what's called an elliptical galaxy. CONTINUE READING: www.huffingtonpost.com/2012/08/30/black-holes-millions-nasa-wise-space-telescope_n_1843590.html
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Post by Deleted on Jun 20, 2013 10:03:53 GMT -6
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Post by skywalker on Jun 20, 2013 20:00:26 GMT -6
I'm not sure what the stuff spewing out of the center is. It said it is hot radiation but from what? If black holes are so powerful that they can suck light into them why does this radioactive stuff get blasted out?
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Post by Deleted on Jun 20, 2013 22:05:41 GMT -6
I thought that 'stuff' was dust? No?
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Post by skywalker on Jun 20, 2013 22:30:47 GMT -6
Whatever it was it was very hot as it came out but cooled off as it drifted away. I thought that everything was sucked into the hole, not spit out of it. I can see why it is changing the way they think about black holes. This goes totally against what they have been saying.
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Post by auntym on May 20, 2014 12:35:44 GMT -6
www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html?cmpid=514648_20140519_24229614Black Holes: Facts, Theory & Definitionby Nola Taylor Redd, SPACE.com Contributor February 08, 2013 Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough. Albert Einstein first predicted black holes in 1916 with his general theory of relativity. The term "black hole" was coined in 1967 by American astronomer John Wheeler, and the first one was discovered in 1971. There are three types: stellar black holes, supermassive black holes and intermediate black holes.
Stellar black holes — small but deadlyWhen a star burns through the last of its fuel, it may find itself collapsing. For smaller stars, up to about three times the sun's mass, the new core will be a neutron star or a white dwarf. But when a larger star collapses, it continues to fall in on itself to create a stellar black hole. Black holes formed by the collapse of individual stars are (relatively) small, but incredibly dense. Such an object packs three times or more the mass of the sun into a city-size range. This leads to a crazy amount of gravitational force pulling on objects around it. Black holes consume the dust and gas from the galaxy around them, growing in size.
Supermassive black holes — the birth of giantsSmall black holes populate the universe, but their cousins, supermassive black holes, dominate. Supermassive black holes are millions or even billions of times as massive as the sun, but have a radius similar to that of Earth's closest star. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way. Scientists aren't certain how such large black holes spawn. Once they've formed, they can easily gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to enormous sizes. Illustration of a young black hole, such as the two distant dust-free quasars spotted recently by the Spitzer Space Telescope. More photos of black holes of the universe Credit: NASA/JPL-Caltech Supermassive may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together. Intermediate black holes – stuck in the middleScientists once thought black holes came in only small and large sizes, but recent research has revealed the possibility for the existence of midsize, or intermediate, black holes. Such bodies could form when stars in a cluster collide in a chain reaction. Several of these forming in the same region could eventually fall together in the center of a galaxy and create a supermassive black hole. WATCH VIDEO & CONTINUE READING: www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html?cmpid=514648_20140519_24229614
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Post by auntym on Jun 17, 2014 13:48:51 GMT -6
TRAVEL INSIDE A BLACK HOLEVia Dave Reneke Imagine a trip into a black hole. This tantalizing thought has excited much creative speculation. Science fiction writers have a field day with things like this and so do sci-fi moviemakers. There are two ways to consider the issue. One is to “watch” someone or something — say a small robot spacecraft — fall into the black hole. The odd thing is it never seems to get there. The closer it approaches the hole’s event horizon, the slower it seems to travel. But for the crew inside, there would be no warning of its impending doom….
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Post by auntym on Aug 11, 2014 11:31:36 GMT -6
www.dailygalaxy.com/my_weblog/2014/08/the-black-hole-at-the-beginning-of-time-we-may-have-emerged-from-a-black-hole-in-a-higher-dimensiona.html#moreAugust 10, 2014 The Black Hole at the Beginning of Time --"We may have Emerged from a Black Hole in a Higher-Dimensional Universe"The Daily Galaxy via Colin Hunter/Perimeter Institute What we perceive as the big bang, physicists at the Perimeter Institure argue, could be the three-dimensional “mirage” of a collapsing star in a universe profoundly different than our own. Conventional understanding holds that the big bang began with a singularity – an unfathomably hot and dense phenomenon of spacetime where the standard laws of physics break down. Singularities are bizarre, and our understanding of them is limited. Our universe may have emerged from a black hole in a higher-dimensional universe, proposed a trio of Perimeter Institute researchers in the cover story of the latest Scientific American. “Cosmology’s greatest challenge is understanding the big bang itself,” write Perimeter Institute faculty member, Niayesh Afshordi. The big bang poses a big question: if it was indeed the cataclysm that blasted our universe into existence 13.7 billion years ago, what sparked it? Three Perimeter Institute researchers have a new idea about what might have come before the big bang. It’s a bit perplexing, but it is grounded in sound mathematics, testable, and enticing enough to earn the cover story in Scientific American, called “The Black Hole at the Beginning of Time.” “For all physicists know, dragons could have come flying out of the singularity,” Afshordi says in an interview with Nature. The problem, as the authors see it, is that the big bang hypothesis has our relatively comprehensible, uniform, and predictable universe arising from the physics-destroying insanity of a singularity. It seems unlikely. So perhaps something else happened. Perhaps our universe was never singular in the first place. Their suggestion: our known universe could be the three-dimensional “wrapping” around a four-dimensional black hole’s event horizon. In this scenario, our universe burst into being when a star in a four-dimensional universe collapsed into a black hole. In our three-dimensional universe, black holes have two-dimensional event horizons – that is, they are surrounded by a two-dimensional boundary that marks the “point of no return.” In the case of a four-dimensional universe, a black hole would have a three-dimensional event horizon. In their proposed scenario, our universe was never inside the singularity; rather, it came into being outside an event horizon, protected from the singularity. It originated as – and remains – just one feature in the imploded wreck of a four-dimensional star. CONTINUE READING: www.dailygalaxy.com/my_weblog/2014/08/the-black-hole-at-the-beginning-of-time-we-may-have-emerged-from-a-black-hole-in-a-higher-dimensiona.html#more
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Post by swamprat on Nov 27, 2014 13:24:22 GMT -6
Supermassive Black Holes Even Heavier Than Thoughtby Mike Wall, Space.com Senior Writer November 26, 2014
The enormous black holes that lurk at the hearts of all galaxies are significantly bigger than astronomers had imagined, a new study suggests.
Researchers have used a new method to measure the distance to the active spiral galaxy NGC 4151 — whose core is dubbed the "Eye of Sauron" because of its resemblance to the structure in the "Lord of the Rings" films — with unprecedented precision. This calculation enabled them to determine the mass of NGC 4151's central black hole more accurately — and the results were surprising.
"Our calculations show that the supermassive black holes are 40 percent heavier than previously thought," study co-author Darach Watson, of the University of Copenhagen's Niels Bohr Institute (NBI), said in a statement. "This fundamentally changes determinations of the masses of black holes."
Supermassive black holes can contain as much mass as hundreds of millions, or even several billion, suns.
The researchers used the twin Keck telescopes in Hawaii to measure the angle the dust ring makes in the sky — just 12 millionths of a degree. They combined the light collected by both telescopes, using a technique called interferometry. The method resulted in a resolution about 100 times greater than that achieved by NASA's Hubble Space Telescope, researchers said.
The team could then calculate the distance to the Eye of Sauron using geometry. The distance from the black hole to the dust ring forms the base of an isosceles triangle, whose twin long legs are the distance from Earth to either side of the ring; with the angle of the sharp point of the triangle known, the legs' distance can be computed.
The team calculated the distance to NGC 4151 to be 62 million light-years, with an uncertainty of just 13.5 percent or so. This improved precision will help researchers estimate the true heft of supermassive black holes, Watson said.
"The calculations of the mass (weight) of the supermassive black holes at the heart of galaxies depends on two main factors: the rotational speed of the stars in the galaxy and how far it is from the black hole to the stars," he said. "The rotational speed can be observed, and the distance from the black hole out to the rotating disc of stars can now be calculated precisely using the new method."
Initial indications suggest that supermassive black hole masses have been underestimated by perhaps 40 percent. Researchers hope to extend their measurements to other active galaxies; the technique could eventually help astronomers better understand the rate at which the universe is expanding, study team members said.
The new study was published online today (Nov. 26) in the journal Nature.www.space.com/27873-supermassive-black-hole-mass-eye-of-sauron.html
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Post by swamprat on Feb 26, 2015 9:55:33 GMT -6
Of course, "visit" is a misnomer. Once you come, you're stayin.......
......and make sure you go feet-first; you'll see more...... What Would Happen If You Fell into a Black Hole?by Natalie Wolchover, LiveScience
Black holes are without question some of the strangest places in the universe. So massive that they hideously deform space and time, so dense that their centers are called "points at infinity," and pitch- black because not even light can escape them, it isn't surprising that so many people wonder what it would be like to visit one. Black holes are without question some of the strangest places in the universe. So massive that they hideously deform space and time, so dense that their centers are called "points at infinity," and pitch- black because not even light can escape them, it isn't surprising that so many people wonder what it would be like to visit one. It's not exactly a restive vacation spot, as it turns out.
If you were to take a step into a black hole, your body would most closely resemble "toothpaste being extruded out of the tube," said Charles Liu, an astrophysicist who works at the American Museum of Natural History's Hayden Planetarium.
Liu said that when an object crosses a black hole's "event horizon" — its outer boundary, or point of no return — the same physics that causes Earth's ocean tides begins to take effect. Gravity's strength decreases with distance, so the moon pulls on the side of the Earth closer to it a bit more vigorously than the side farther from it, and as a result, Earth elongates ever so slightly in the direction of the moon. The land is sturdy, so it doesn't move much, but the water on Earth's surface is fluid, so it flows along the elongated axis. "That's the tidal interaction," he said. Rising tides are about as calming a scene as there is. A human toeing the line of a black hole? Not so much.
Near a black hole roughly the size of Earth, tidal forces are magnified off the scale. Swan-diving into one, the top of your head would feel so much more gravitational pull than the tips of your toes that you would be stretched, longer and longer. "[The British astrophysicist] Sir Martin Rees coined the term 'spaghettification,' which is a perfectly good way to put it. You eventually become a stream of subatomic particles that swirl into the black hole," Liu told Life's Little Mysteries.
Because your brain would dissociate into its constituent atoms almost instantly, you'd have little opportunity to soak in the scenery at the threshold of an Earth-size black hole.
However, if you're dead-set on visiting a space-time singularity, we recommend going big; bigger black holes have less extreme surfaces. "If you had a black hole the size of our solar system, then the tidal forces at the event horizon … are not quite that strong. So you could actually maintain your structural integrity," Liu said.
In that case, you would get to experience the effects of the curvature of space-time, predicted by Einstein's general theory of relativity, firsthand.
"First of all, you approach the speed of light as you fall into the black hole. So the faster you move through space, the slower you move through time," he said. "Furthermore, as you fall, there are things that have been falling in front of you that have experienced an even greater 'time dilation' than you have. So if you're able to look forward toward the black hole, you see every object that has fallen into it in the past. And then if you look backwards, you'll be able to see everything that will ever fall into the black hole behind you.
"So the upshot is, you'll get to see the entire history of that spot in the universe simultaneously," he said, "from the Big Bang all the way into the distant future." Not such a bad way to go, in the grand scheme of things.
www.livescience.com/19683-happen-fall-black-hole.html?cmpid=514636_20150226_41103506&adbid=10152589719971761&adbpl=fb&adbpr=30478646760
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Post by swamprat on Dec 23, 2015 11:07:17 GMT -6
How big can black holes grow?Black holes could grow as large as 50 billion suns, before the ‘food’ that makes them grow crumbles into stars, says new research.
Deborah Byrd Release Date: Dec 22, 2015
In recent decades, astronomers have come to believe that supermassive black holes probably lie at the hearts of most large galaxies. Our own Milky Way galaxy, for example, is thought to contain a central black hole as massive as four million suns, and the relatively nearby supergiant elliptical galaxy M87 is thought to have a black hole of 6 billion solar masses. Other distant galaxies are thought to have even more massive central black holes. How big can black holes grow? New research from the University of Leicester in England suggests that black holes at the hearts of galaxies could grow as massive as 50 billion suns before losing the disks of gas they need to sustain themselves. The paper – titled How Big Can a Black Hole Grow? – is published in the journal Monthly Notices Letters of the Royal Astronomical Society.
Astronomical theorist Andrew King led the research, which explores the regions of space around supermassive black holes, where the gas that feeds the hole settles into an orbiting disk. According to a December 18, 2015 statement from the University of Leicester:
"This gas can lose energy and fall inwards, feeding the black hole. But these discs are known to be unstable and prone to crumbling into stars."
Professor King calculated how big a black hole would have to be for its outer edge to keep a disc from forming, coming up with the figure of 50 billion solar masses.
The study suggests that without a disc, the black hole would stop growing, meaning 50 billion suns would roughly be the upper limit. The only way it could get larger is if a star happened to fall straight in or another black hole merged with it.
Professor King added:
"The significance of this discovery is that astronomers have found black holes of almost the maximum mass, by observing the huge amount of radiation given off by the gas disc as it falls in. The mass limit means that this procedure should not turn up any masses much bigger than those we know, because there would not be a luminous disc.
Bigger black hole masses are in principle possible – for example, a hole near the maximum mass could merge with another black hole, and the result would be bigger still. But no light would be produced in this merger, and the bigger merged black hole could not have a disc of gas that would make light.
One might nevertheless detect it in other ways, for example as it bent light rays passing very close to it (gravitational lensing) or perhaps in future from the gravitational waves that Einstein’s General Theory of Relativity predicts would be emitted as it merged."
Botton line: New research from theorist Andrew King of the University of Leicester suggests that black holes could grow as large as 50 billion suns, before the infalling gas that makes them grow crumbles into stars.
earthsky.org/space/how-big-can-blacks-hole-grow?utm_source=EarthSky+News&utm_campaign=d460b9bba3-EarthSky_News&utm_medium=email&utm_term=0_c643945d79-d460b9bba3-394368745
My son is a professor of physics at a university; I ask him this question: "Okay, the mass of 50 billion suns. My question is, what diameter would such a black hole be? How much would a cubic centimeter of it weigh?"
His answer:
"Ok. Since you asked, and I'm bored!
Using the Schwarzschild radius equation and assuming the black hole as zero angular momentum, the radius is ~1.5E11 km (1.5 with 11 zeros after it!). This is about 1000 AU (astronomical units, the average distance between the earth and sun). Pluto is on average about 40 AU from the sun, so the black hole is 25 times the diameter of the entire solar system at this mass.
The density is a tougher question. The black hole is like an atom. All the mass is concentrated over a very small volume, in this case a singularity, but the black hole itself, as defined by the Schwarzschild radius is much larger. Calculated over this large volume, the density turns out to be quite small, on the order of a few micrograms per cubic cm. The more mass you put in the black hole, the further out the Schwarzschild radius extends, but the mass is still concentrated at the center of the singularity, which itself is infinitesimal.
To up your density, you want the black hole to be rather small. If the black hole had say only four solar masses, then its Schwarzschild radius would be only 12 km (just over 7 miles). The density would be about 1E18 kg/cm^3. So each cubic cm would have a mass of 1E18 Kg, which is equivalent to 2.2E18 pounds or 1E15 tons (1 quadrillion tons).
Good stuff!"
OK, TEOR pals! Get your mind around THAT! 1 quadrillion tons per cubic centimeter!
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Post by swamprat on Feb 13, 2016 9:54:06 GMT -6
Well, so far, they've found one about half that big: Black hole is sleeping giantRelease Date: Feb 12, 2016
This image shows the elliptical galaxy NGC 4889 in front of hundreds of background galaxies, and deeply embedded within the Coma galaxy cluster. Well-hidden from human eyes, there is a gigantic supermassive black hole at the center of the galaxy. Image credit: NASA & ESA
At the center of distant galaxy NGC 4889, pictured in this NASA/ESA Hubble Space Telescope image released February 11, 2016, lurks one of the most massive black holes ever discovered.
NGC 4889, the brightest and largest galaxy in the above image, is located about 300 million light-years away in the Coma Cluster. The giant elliptical galaxy is home to a record-breaking supermassive black hole. Twenty-one billion times the mass of the sun, this black hole has an event horizon — the surface at which even light cannot escape its gravitational grasp – with a diameter of approximately 130 billion kilometers. This is about 15 times the diameter of Neptune’s orbit from the sun. By comparison, the supermassive black hole at the center of our Milky Way galaxy is believed to have a mass about four million times that of the sun and an event horizon just one fifth the orbit of planet Mercury.
earthsky.org/space/black-hole-is-sleeping-giant?utm_source=EarthSky+News&utm_campaign=4d46306ec9-EarthSky_News&utm_medium=email&utm_term=0_c643945d79-4d46306ec9-394368745
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Post by Deleted on Feb 13, 2016 12:56:08 GMT -6
In the coma berenices cluster...canes venatici hosts jewels nearby...
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Post by auntym on Apr 13, 2016 14:23:37 GMT -6
www.space.com/32549-bizarre-group-of-distant-black-holes-are-mysteriously-aligned.html?cmpid=514648_20160413_60477906&adbid=720310674094559232&adbpl=tw&adbpr=15431856 'Bizarre' Group of Distant Black Holes are Mysteriously AlignedBy Ian O'Neill, Discovery News April 12, 2016 This is an image of the deep radio map covering the ELAIS-N1 region, with aligned galaxy jets. The image on the left has white circles around the aligned galaxies; the image on the right is without the circles. Credit: Andrew Russ Taylor A highly sensitive radio telescope has seen something peculiar in the depths of our cosmos: A group of supermassive black holes are mysteriously aligned, as if captured in a synchronized dance. These black holes, which occupy the centers of galaxies in a region of space called ELAIS-N1, appear to have no relation to one another, separated by millions of light-years. But after studying the radio waves generated by the twin jets blasting from the black holes' poles, astronomers using data from the Giant Metrewave Radio Telescope (GMRT) in India realized that all the jets were pointed in the same direction, like arrows on compasses all pointing "north." This is the first time a group of supermassive black holes in galactic cores have been seen to share this bizarre relationship and, at first glance, the occurrence should be impossible. What we are witnessing is a cluster of galaxies, that all have central supermassive black holes that have their axes of rotation pointed in the same direction. "Since these black holes don't know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe," said Andrew Russ Taylor, director of the Inter-University Institute for Data Intensive Astronomy in Cape Town, South Africa. Taylor is lead author of the study published in the journal Monthly Notices of the Royal Astronomical Society. In other words, though each of these galaxies are currently independent from one another, they likely originated from the same small-scale mass fluctuation, shortly after the Big Bang, and therefore used to have some commonality on a quantum scale. These objects were all spawned in the same compact region of primordial space some 13.8 billion years ago that, as the universe expanded, drifted apart into the mature galaxies we see today in that distant volume of space. CONTINUE READING: www.space.com/32549-bizarre-group-of-distant-black-holes-are-mysteriously-aligned.html?cmpid=514648_20160413_60477906&adbid=720310674094559232&adbpl=tw&adbpr=15431856 Supermassive Black-Hole Jets Found Aligned in Same Direction --"Bizarre! Not Based on Current Understanding of Cosmology"www.dailygalaxy.com/my_weblog/2016/04/supermassive-black-hole-jets-found-aligned-in-same-direction-bizarre-finding-not-based-on-current-un.html
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Post by patsbox7 on Apr 14, 2016 0:32:25 GMT -6
Radio telescopes have spotted a curious cosmic alignment. Several black holes, 7 billion light-years from Earth, seem to be spinning and pointing in the same direction. South African researchers discovered that this alignment extends over 60 million light-years across, but they are still not exactly clear how it formed. The astronomers looked at 65 radio galaxy jets and noticed that a large fraction of them were aligned along a filament of about 1°. They looked at the probability of this being a random event and found a less than 0.1 percent chance of it. "Since these black holes don’t know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe," Professor Andrew Russ Taylor, principal author of the study, said in a statement. In the instants after the Big Bang, the universe went through a phase of exponential growth called cosmic inflation. As the universe expanded, primordial quantum fluctuations were stretched to macroscopic scales; these fluctuations generated small differences between the distribution of matter in the universe, and over time they grew into what we see in the cosmos today – the so-called cosmic web. The cosmic web indicates that galaxies are distributed in clusters with filaments stretching between them and large voids around them. Within the web, according to the main theories of cosmology, galaxies can be aligned as they please, so this finding was clearly not expected. The paper, published in the Monthly Notices of the Royal Astronomical Society, suggests potential explanations for this phenomenon. For example, a cosmic magnetic field could push the black holes, and their jets, to align; another explanation includes fields associated with exotic particles, or even peculiar cosmic strings as the cause for the alignment. flip.it/BP07X
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Post by Deleted on Apr 17, 2016 8:29:02 GMT -6
Have you ever noticed a particular pattern in the Hubble deep field ? How about other images of galactic clusters ? It's a mind blower when you consider rotation, distance , time,cosmic expansion, etc.
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Post by auntym on Apr 21, 2016 12:59:28 GMT -6
www.parentherald.com/articles/38495/20160421/stephen-hawking-talks-about-black-holes-can-work-as-portal-to-another-universe.htm Stephen Hawking Talks About Black Holes: It Can Work As Portal To Another UniverseBy Jonnalyn Carter Apr 21, 2016 Stephen Hawking gave a lecture at Harvard University on Monday. The physicist talked about black holes and its potential benefit to the people. The "A Brief History Of Time" author believes black holes can work as a portal to another universe. Talking About Black HolesAccording to the Boston Globe, Stephen Hawking visited the university to start a research center about black holes. The cosmologist described that black holes aren't an "eternal prison" like what people thought it is. "Things can get out of a black hole, both from the outside and possibly though another universe," Stephen Hawking told about 1000 students at Harvard. "So if you feel you're in a black hole, don't give up. There's a way out." Stephen Hawking explained it took him quite a while to find black holes do "exist" and release elements. In fact, Albert Einsten was apprehensive behind the reality of black holes. Black Holes As Part Of Science"Black holes are stranger than anything dreamed up by science fiction writers, but they are firmly matters of science fact," Stephen Hawking noted. He even asserted black holes don't gobble up everything that reach its surface. Stephen Hawking said it is like putting an encyclopedia on fire. However, the information inscribed into it won't be lost if one store its ashes but, it will be definitely hard to read. Daily Express reported Dejan Stojkovic, an associate professor of physics at the University of Buffalo, also disclosed the same claim by Stephen Hawking about black holes last year. "According to our work, information isn't lost once it enters a black hole. It doesn't just disappear." CONTINUE READING: www.parentherald.com/articles/38495/20160421/stephen-hawking-talks-about-black-holes-can-work-as-portal-to-another-universe.htm STEPHEN HAWKING SAYS BLACK HOLES COULD BE PORTALS TO OTHER UNIVERSES: www.ancient-code.com/stephen-hawking-says-black-holes-portals-another-universe/
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Post by swamprat on May 22, 2017 9:50:16 GMT -6
Slow Down! Researchers Spot Possible Speeding 'Renegade' Supermassive Black HoleBy Ian O'Neill, Space.com Contributor May 22, 2017
Astronomers have spied the possible aftermath of a colossal black hole collision that happened in the center of a galaxy far, far away.
Usually, researchers find supermassive black holes that are stationary objects, anchored in the cores of their galactic hosts. So astronomers became excited when they spotted a "renegade" supermassive black hole speeding through space, as reported in a new study.
The black hole, which is 160 million times the mass of Earth's sun, appears to be the result of a collision with another black hole in a galaxy 3.9 billion light-years away from Earth.
Theory suggests that when two galaxies merge, supermassive black holes in the two galaxies' cores orbit one another and eventually collide. The black hole pair may merge to create an even more massive supermassive black hole. But sometimes, the pair can violently recoil, and one of the black holes may be kicked in the opposite direction at great speed.The energy behind this powerful recoil is referred to as gravitational waves. As two black holes approach one other, they generate a lot of these ripples in space-time, and if the conditions are right, there might be a preponderance of gravitational waves blasted out in one direction, ejecting one of the black holes.
While searching through thousands of Sloan Digital Sky Survey (SDSS) observations in hopes of finding these recoiling black holes, the new study's researchers noticed a very bright X-ray source at the center of one galaxy. This is a telltale sign that a black hole is active and growing, the researchers said in a statement.
Then, using the Hubble Space Telescope, they discovered that the emissions were coming from two distinct objects. Further observations by NASA's Chandra X-ray Observatory and the Keck telescope in Hawaii revealed that one of the two black holes is not in the center of its galaxy and is traveling at a different speed than its surroundings.
These clues suggest the object is a recoiling black hole, and the host galaxy itself also carries evidence of the merger that could have instigated it, the researchers said. The galaxy is forming stars at a high rate, for example, which is a sign that interstellar gases have been compressed. Also, the outer regions of the galaxy show signs of a massive disturbance.
Although the data supports a bona fide recoiling black hole, the researchers said in the statement, further observations are needed to rule out other explanations.
Watch video: www.space.com/36931-moving-black-hole-possibly-spotted-in-far-away-galaxy-video.html
The study was recently accepted to The Astrophysical Journal and is available online on arXiv.org.
www.space.com/36932-renegade-speeding-supermassive-black-hole-spotted.html
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Post by swamprat on Feb 25, 2018 10:07:48 GMT -6
Time for another headache.....Some black holes erase your pastBy Robert Sanders/Berkeley News, EarthSky Voices in SPACE February 25, 2018
You can’t survive a passage into a black hole … or can you? A UC Berkeley mathematician says you could enter certain types of black holes, but your past would be obliterated and you’d have an infinite number of possible futures.
In the real world, your past uniquely determines your future. If a physicist knows how the universe starts out, she can calculate its future for all time and all space.
But a UC Berkeley mathematician has found some types of black holes in which this law breaks down. If someone were to venture into one of these relatively benign black holes, they could survive, but their past would be obliterated and they could have an infinite number of possible futures.
Such claims have been made in the past, and physicists have invoked strong cosmic censorship to explain it away. That is, something catastrophic – typically a horrible death – would prevent observers from actually entering a region of spacetime where their future was not uniquely determined. This principle, first proposed 40 years ago by physicist Roger Penrose, keeps sacrosanct an idea – determinism [cause and effect] – key to any physical theory.
That is, given the past and present, the physical laws of the universe do not allow more than one possible future.
But, says UC Berkeley postdoctoral fellow Peter Hintz, mathematical calculations show that for some specific types of black holes in a universe like ours, which is expanding at an accelerating rate, it is possible to survive the passage from a deterministic world into a non-deterministic black hole.
"What life would be like in a space where the future was unpredictable is unclear. But the finding does not mean that Einstein’s equations of general relativity, which so far perfectly describe the evolution of the cosmos, are wrong," said Hintz. He said:
"No physicist is going to travel into a black hole and measure it. This is a math question. But from that point of view, this makes Einstein’s equations mathematically more interesting. This is a question one can really only study mathematically, but it has physical, almost philosophical implications, which makes it very cool."
Hintz and his colleagues published a paper describing these unusual black holes in January 2018 in the journal Physical Review Letters.
Beyond the Event Horizon Black holes are bizarre objects that get their name from the fact that nothing can escape their gravity, not even light. If you venture too close and cross the so-called event horizon, you’ll never escape.
For small black holes, you’d never survive such a close approach anyway. The tidal forces close to the event horizon are enough to spaghettify anything: that is, stretch it until it’s a string of atoms.
But for large black holes, like the supermassive objects at the cores of galaxies like the Milky Way, which weigh tens of millions if not billions of times the mass of a star, crossing the event horizon would be, well, uneventful.
Because it should be possible to survive the transition from our world to the black hole world, physicists and mathematicians have long wondered what that world would look like, and have turned to Einstein’s equations of general relativity to predict the world inside a black hole. These equations work well until an observer reaches the center, or singularity, where in theoretical calculations the curvature of spacetime becomes infinite.
Even before reaching the center, however, a black hole explorer – who would never be able to communicate what she found to the outside world – could encounter some weird and deadly milestones. Hintz studies a specific type of black hole – a standard, non-rotating black hole with an electrical charge – and such an object has a so-called Cauchy horizon within the event horizon.
The Cauchy horizon is the spot where determinism breaks down, where the past no longer determines the future. Physicists, including Penrose, have argued that no observer could ever pass through the Cauchy horizon point because they would be annihilated.
As the argument goes, as an observer approaches the horizon, time slows down, since clocks tick slower in a strong gravitational field. As light, gravitational waves and anything else encountering the black hole fall inevitably toward the Cauchy horizon, an observer also falling inward would eventually see all this energy barreling in at the same time. In effect, ALL THE ENERGY THE BLACK HOLE SEES OVER THE LIFETIME OF THE UNIVERSE HITS THE CAUCHY HORIZON AT THE SAME TIME, BLASTING INTO OBLIVION ANY OBSERVER WHO GETS THAT FAR.
You Can’t See Forever in an Expanding Universe Hintz realized, however, that this may not apply in an expanding universe that is accelerating, such as our own. Because spacetime is being increasingly pulled apart, much of the distant universe will not affect the black hole at all, since that energy can’t travel faster than the speed of light.
A spacetime diagram of the gravitational collapse of a charged spherical star to form a charged black hole. An observer traveling across the event horizon will eventually encounter the Cauchy horizon, the boundary of the region of spacetime that can be predicted from the initial data. Hintz and his colleagues found that a region of spacetime, denoted by a question mark, cannot be predicted from the initial data in a universe with accelerating expansion, like our own. This violates the principle of strong cosmic censorship. Image via APS/Alan Stonebraker.
In fact, the energy available to fall into the black hole is only that contained within the observable horizon: the volume of the universe that the black hole can expect to see over the course of its existence. For us, for example, the observable horizon is bigger than the 13.8 billion light-years we can see into the past, because it includes everything that we will see forever into the future. The accelerating expansion of the universe will prevent us from seeing beyond a horizon of about 46.5 billion light-years.
In that scenario, the expansion of the universe counteracts the amplification caused by time dilation inside the black hole, and for certain situations, cancels it entirely. In those cases – specifically, smooth non-rotating black holes with a large electrical charge, so-called Reissner-Nordström-de Sitter black holes – an observer could survive passing through the Cauchy horizon and into a non-deterministic world. Hintz said:
"There are some exact solutions of Einstein’s equations that are perfectly smooth, with no kinks, no tidal forces going to infinity, where everything is perfectly well behaved up to this Cauchy horizon and beyond."
Hintz noted that the passage through the horizon would be painful but brief.
After that, all bets are off; in some cases, such as a Reissner-Nordström-de Sitter black hole, one can avoid the central singularity altogether and live forever in a universe unknown.
Admittedly, he said, charged black holes are unlikely to exist, since they’d attract oppositely charged matter until they became neutral. However, the mathematical solutions for charged black holes are used as proxies for what would happen inside rotating black holes, which are probably the norm. Hintz argues that smooth, rotating black holes, called Kerr-Newman-de Sitter black holes, would behave the same way. Hintz said:
"That is upsetting, the idea that you could set out with an electrically charged star that undergoes collapse to a black hole, and then Alice travels inside this black hole and if the black hole parameters are sufficiently extremal, it could be that she can just cross the Cauchy horizon, survives that and reaches a region of the universe where knowing the complete initial state of the star, she will not be able to say what is going to happen. It is no longer uniquely determined by full knowledge of the initial conditions. That is why it’s very troublesome."
Hintz’s paper has already sparked other papers, one of which purports to show that most well-behaved black holes will not violate determinism. But Hintz insists that one instance of violation is one too many. He said:
"People had been complacent for some 20 years, since the mid ‘90s, that strong cosmological censorship is always verified. We challenge that point of view."
Bottom line: A UC Berkeley mathematician suggests that there are some types of black holes in which the law of determinism breaks down.
earthsky.org/space/some-black-holes-erase-your-past?utm_source=EarthSky+News&utm_campaign=c1b04e44ef-EMAIL_CAMPAIGN_2018_02_02&utm_medium=email&utm_term=0_c643945d79-c1b04e44ef-394368745MY bottom line: This universe of ours is WEIRD!
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Post by swamprat on Apr 23, 2018 18:09:07 GMT -6
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Post by swamprat on Dec 18, 2018 11:05:06 GMT -6
Too bad Einstein and Hawking aren't around to discuss.Matter Sucked in by Black Holes May Travel into the Future, Get Spit Back OutBy Don Lincoln, Senior Scientist, Fermi National Accelerator Laboratory; Adjunct Professor of Physics, University of Notre Dame | December 18, 2018
Black holes may not have singularities at their center. Instead, the matter they suck in may be spit out across the universe at some time in the future, a new theory suggests. Credit: Shutterstock
Black holes are among the most mysterious places in the universe; locations where the very fabric of space and time are warped so badly that not even light can escape from them. According to Einstein's theory of general relativity, at their center lies a singularity, a place where the mass of many stars is crushed into a volume with exactly zero size. However, two recent physics papers, published on Dec.10 in the journals Physical Review Letters and Physical Review D, respectively, may make scientists reconsider what we think we know about black holes. Black holes might not last forever, and it's possible that we've completely misunderstood their nature and what they look like at the center, according to the papers.
The edge of Einstein’s physics Astronomers and physicists have long held that the idea of a singularity simply must be wrong. If an object with mass has no size, then it has infinite density. And, as much as researchers throw around the word "infinity," infinities of that kind don't exist in nature. Instead, when you encounter an infinity in a real, physical, science situation, what it really means is that you've pushed your mathematics beyond the realm where they apply. You need new math.
It's easy to give a familiar example of this. Newton's law of gravity says that the strength of the gravitational attraction changes as one over the distance squared between two objects. So if you took a ball located far from Earth, it would experience a certain weight. Then, as you brought it closer to Earth, the weight would increase. Taking that equation to the extreme, as you brought the object near to the center of Earth, it would experience an infinite force. But it doesn't.
Instead, as you bring the object close to the surface of Earth, Newton's simple law of gravity no longer applies. You have to take into account the actual distribution of Earth’s mass, and this means that you need to use different and more complex equations that predict different behavior. Similarly, while Einstein's theory of general relativity predicts that a singularity of infinite density exists at the center of black holes, this can't be true. At very small sizes, a new theory of gravity must come into play. We have a generic name for this new theory: It's called quantum gravity.
The name quantum gravity simply means "gravity at the smallest scales," but the phrase doesn't imply a specific theory. However, specific theoretical proposals have been made that would describe gravity as it is in the microcosm. One proposal is called loop quantum gravity.
Loop quantum gravity is well-defined mathematically, and it expresses the fabric of space-time as a lattice of spin networks, which evolve over time. Spin networks are just a mathematical formulation that describes how particles and fields interact. From a more practical point of view, loop quantum gravity predicts that space-time is quantized, with a smallest possible unit or piece of space and time, beyond which space-time cannot be subdivided further.
Loop quantum gravity is a difficult mathematical theory that has resisted the making of testable predictions inside black holes. However, Abhay Ashtekar and Javier Olmedo at Pennsylvania State University and Parampreet Singh at Louisiana State University have applied loop quantum gravity to the center of black holes. They claim that the result is not a singularity.
Their calculation predicts that space-time is curved very strongly near the center of the black hole. The result is that space-time continues into a region in the future that has the structure of a white hole. A white hole is like a black hole in reverse, meaning that unlike a black hole, which pulls matter in, a white hole shoots matter out.
There is perhaps another way to imagine what they are predicting. It is well-known that in strong gravitational fields, time slows down. And black holes contain the strongest gravitational fields in the universe. Because of this, one possible interpretation of this new work is that matter falls into a black hole and then "bounces," shooting the mass back across the cosmos. Because time is so slow near the center of a black hole, that process simply is taking an enormous amount of time. If the researchers are correct, in the very distant future, where there are now black holes, matter will be erupting, spreading matter throughout the cosmos.
As always in theoretical science, there are many interesting and provocative ideas that just aren’t true, and this may be one of them. So it's important to see if there is experimental support for theoretical ideas like these.
There are a few possibilities. Scientists have observed very high energy phenomena in space that have not been completely explained. One is the existence of very high energy cosmic rays that hit Earth’s atmosphere. Another is what are called "fast radio bursts," which is when a large amount of radio energy is observed in a very short amount of time. Both of those phenomena could, at least in principle, be the signature of a black hole transitioning to a white hole.
It is certainly premature to accept this interesting new idea. Instead, it would be prudent to see how ongoing calculations using loop quantum gravity unfold. If predictions improve and begin to look more like some of the unexplained observed astronomical phenomena, it could be that this new result will both explain how quantum gravity works and reshape our understanding of both the past and the future of our universe.
www.livescience.com/64332-black-holes-white-holes-quantum-gravity.html
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Post by swamprat on Jan 15, 2019 14:36:28 GMT -6
"Let me know if this works; then I'll follow you..."
The first astronaut willing to confirm this theory is going to be one brave soul.Rotating black holes as portals for hyperspace travelBy EarthSky Voices in HUMAN WORLD | SPACE | January 15, 2019
One of the most cherished science fiction scenarios is using a black hole as a portal to another dimension or time or universe. Is it possible? Maybe. But choose carefully. All black holes are not created equal.
Want to travel to another dimension? Choose your black hole wisely. Image via Vadim Sadovski/Shutterstock.com
One of the most cherished science fiction scenarios is using a black hole as a portal to another dimension or time or universe. That fantasy may be closer to reality than previously imagined.
Black holes are perhaps the most mysterious objects in the universe. They are the consequence of gravity crushing a dying star without limit, leading to the formation of a true singularity – which happens when an entire star gets compressed down to a single point yielding an object with infinite density. This dense and hot singularity punches a hole in the fabric of spacetime itself, possibly opening up an opportunity for hyperspace travel. That is, a short cut through spacetime allowing for travel over cosmic scale distances in a short period.
Researchers previously thought that any spacecraft attempting to use a black hole as a portal of this type would have to reckon with nature at its worst. The hot and dense singularity would cause the spacecraft to endure a sequence of increasingly uncomfortable tidal stretching and squeezing before being completely vaporized.
Flying through a black hole My team at the University of Massachusetts Dartmouth and a colleague at Georgia Gwinnett College have shown that all black holes are not created equal. If the black hole like Sagittarius A*, located at the center of our own galaxy, is large and rotating, then the outlook for a spacecraft changes dramatically. That’s because the singularity that a spacecraft would have to contend with is very gentle and could allow for a very peaceful passage.
The reason that this is possible is that the relevant singularity inside a rotating black hole is technically “weak,” and thus does not damage objects that interact with it. At first, this fact may seem counterintuitive. But one can think of it as analogous to the common experience of quickly passing one’s finger through a candle’s near 2,000-degree flame, without getting burned.
Hold your finger close to the flame and it will burn. Swipe it through quickly and you won’t feel much. Similarly, passing through a large rotating black hole, you are more likely to come out the other side unharmed. Image via mirbasar/Shutterstock.com.
My colleague Lior Burko and I have been investigating the physics of black holes for over two decades. In 2016, my Ph.D. student, Caroline Mallary, inspired by Christopher Nolan’s blockbuster film Interstellar, set out to test if Cooper (Matthew McConaughey’s character), could survive his fall deep into Gargantua – a fictional, supermassive, rapidly rotating black hole some 100 million times the mass of our sun. Interstellar was based on a book written by Nobel Prize-winning astrophysicist Kip Thorne and Gargantua’s physical properties are central to the plot of this Hollywood movie.
Building on work done by physicist Amos Ori two decades prior, and armed with her strong computational skills, Mallary built a computer model that would capture most of the essential physical effects on a spacecraft, or any large object, falling into a large, rotating black hole like Sagittarius A*.
Not even a bumpy ride? What she discovered is that under all conditions an object falling into a rotating black hole would not experience infinitely large effects upon passage through the hole’s so-called inner horizon singularity. This is the singularity that an object entering a rotating black hole cannot maneuver around or avoid. Not only that, under the right circumstances, these effects may be negligibly small, allowing for a rather comfortable passage through the singularity. In fact, there may no noticeable effects on the falling object at all. This increases the feasibility of using large, rotating black holes as portals for hyperspace travel.
Mallary also discovered a feature that was not fully appreciated before: the fact that the effects of the singularity in the context of a rotating black hole would result in rapidly increasing cycles of stretching and squeezing on the spacecraft. But for very large black holes like Gargantua, the strength of this effect would be very small. So, the spacecraft and any individuals on board would not detect it.
This graph depicts the physical strain on the spacecraft’s steel frame as it plummets into a rotating black hole. The inset shows a detailed zoom-in for very late times. The important thing to note is that the strain increases dramatically close to the black hole, but does not grow indefinitely. Therefore, the spacecraft and its inhabitants may survive the journey. Image via Khanna/UMassD.
The crucial point is that these effects do not increase without bound; in fact, they stay finite, even though the stresses on the spacecraft tend to grow indefinitely as it approaches the black hole.
There are a few important simplifying assumptions and resulting caveats in the context of Mallary’s model. The main assumption is that the black hole under consideration is completely isolated and thus not subject to constant disturbances by a source such as another star in its vicinity or even any falling radiation. While this assumption allows important simplifications, it is worth noting that most black holes are surrounded by cosmic material – dust, gas, radiation.
Therefore, a natural extension of Mallary’s work would be to perform a similar study in the context of a more realistic astrophysical black hole.
Mallary’s approach of using a computer simulation to examine the effects of a black hole on an object is very common in the field of black hole physics. Needless to say, we do not have the capability of performing real experiments in or near black holes yet, so scientists resort to theory and simulations to develop an understanding, by making predictions and new discoveries.
Gaurav Khanna, Professor of Physics, University of Massachusetts Dartmouth
Bottom line: Is it possible to travel through space and time via a black hole?
earthsky.org/space/rotating-black-holes-portals-for-hyperspace-travel
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Post by auntym on Apr 19, 2019 15:08:22 GMT -6
www.astronomy.com/news/2018/04/the-milky-ways-supermassive-black-hole-has-siblings?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter The Milky Way’s supermassive black hole may have a dozen nomadic siblings New research suggests that ‘wandering’ supermassive black holes are common within many types of galaxies — including the Milky Way.By Jake Parks / www.astronomy.com/authors/jake-parks Published: Friday, April 27, 2018 Like most galaxies, the Andromeda galaxy (pictured above) is thought to house a supermassive black hole at its core. According to new research, galaxies roughly the mass of the Milky Way also likely contain about a dozen more ‘wandering’ supermassive black holes. NASA/JPL-Caltech At the center of the Milky Way sits a dark and dangerous beast: Sagittarius A*. Located about 26,000 light-years from Earth, our galaxy’s only known supermassive black hole is roughly 4 million times as massive as the Sun, and its immense gravitational pull can nonchalantly annihilate any object that strays too close. Fortunately for us, Sagittarius A* is like a troll under a bridge — it does not leave its post. This tends to be the case for most supermassive black holes (SMBHs) found throughout the universe. However, sometimes a SMBH can be forced from the center of its host galaxy, particularly if it’s involved in a galactic merger with a bigger counterpart. For example, if a small galaxy merges with a larger one, the smaller galaxy’s SMBH will likely be thrown into a wide orbit around the newly formed galaxy, therefore becoming a ‘wandering’ supermassive black hole. Though astronomers have previously found evidence of these nomadic SMBHs on the outskirts of other galaxies, their overall prevalence is still largely unknown. But according to a new study published April 24 in The Astrophysical Journal Letters, wandering supermassive black holes may be quite common (and even observable) within many different types of galaxies — including the Milky Way. To carry out the study, the researchers took advantage of a new, state-of-the-art cosmological simulation called ROMULUS25. This N-body simulation uses an advanced supercomputer called Blue Waters to model how billions of individual particles interact and evolve over time. Though the ROMULUS25 simulation encompasses an astounding volume of over 15,000 cubic Megaparsecs (1 Megaparsec = 3 million light-years), it is still able to resolve the internal structure of galaxies and dwarf galaxies, as well as capture the orbital evolution of SMBHs following galactic mergers. A sample of the ROMULUS25 simulation at redshift z = 0.4. The three slices of the simulation are focused on the same central group of galaxies (about 10 times as massive as the Milky Way), and shows the distribution of dark matter (left), the distribution of stars color-coded by composition (center; red are metal poor, blue are metal rich), and the distribution of stars color-coded by age (right; red are old, blue are young). White dots mark black holes. N-Body Shop (University of Washington) By extracting a sample of Milky-Way-mass galaxies from the simulation, the researchers were able to determine that any galaxy roughly the mass of the Milky Way, regardless of its recent merger history or morphology, likely contains about a dozen supermassive black holes, with roughly five being located within 30,000 light-years of the galaxy’s center. Although this slew of meandering SMBHs may seem intimidating (especially considering they roam for at least a few billion years), according to the study, they pose little threat to our tiny corner of the cosmos. “It is extremely unlikely that any wandering supermassive black hole will come close enough to our Sun to have any impact on our solar system,” said lead author Michael Tremmel, a postdoctoral fellow at the Yale Center for Astronomy and Astrophysics, in a press release. “We estimate that a close approach of one of these wanderers that is able to affect our solar system should occur every 100 billion years or so, or nearly 10 times the age of the universe.” So, even though the supermassive black hole at the center of the Milky Way may have a dozen disenfranchised siblings, by the time they could pose a threat to Earth, the Sun will have likely already burnt out. In the meantime, astronomers will continue working hard to definitely prove these wandering Goliaths actually exist. And once they do, the real fun can begin. www.astronomy.com/news/2018/04/the-milky-ways-supermassive-black-hole-has-siblings?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter
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