When you look up at the night sky you see a lot of stars that, in relation to our own planet, haven't moved a whole lot in a very, very long time. But some of the stars in our home galaxy aren't so lucky and astronomers recently identified one, in particular, that is absolutely speeding its way out of the Milky Way and they think they know why.
The star, known by its label S5-HVS1, got a little too close to the supermassive black hole at the center of our galaxy around five million years ago. When it did, the black hole flung it away at an incredible speed and it's moving so fast that it's essentially been evicted from our galaxy.
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Black Hole Mergers: Cooking With Gas and a 112,000 MPH Kick
“With a light signature, astronomers could easily pinpoint the cosmic location of these mergers and study them in much more detail than is presently possible,” said paper author Barry McKernan, a research associate in the Museum’s Department of Astrophysics as well as a professor at the Borough of Manhattan Community College, CUNY, and a faculty member at CUNY’s Graduate Center.
Black holes form when massive stars die. Much like dense objects sinking into a river on Earth, black holes tend to sink into regions of galaxies where gravity is strongest. It is believed that large numbers of black holes build up in the centers of galaxies, where a much larger, single, supermassive black hole lurks.
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Remote objects: The properties of merging black holes can be calculated from the initial part of the signal waveform. | Photo Credit: LIGO
In September 2015, the LIGO detectors in the US made history by directly detecting for the first time the merging of two black holes. Since then, LIGO, joined by other detectors around the world, has gone on to detect eleven events of which one is the merger of two neutron stars and the remaining ten, of pairs of black holes (binary black holes).
Black hole: Supermassive black hole throws star out of Milky Way Galaxy at 3.7
Researchers, led by Sergey Koposov of Carnegie Mellon University's McWilliams Center for Cosmology as part of the Southern Stellar Stream Spectroscopic Survey (S5), spotted the star — known as S5-HVS1 — in the constellation Grus. According to a press release Tuesday, the star was traveling at just 29,000 light-years away from Earth, or "practically next door by astronomical standards."
Researchers said the "runaway" star was traveling at speeds about 10 times faster than most other stars in the galaxy. "The velocity of the discovered star is so high that it will inevitably leave the [Milky Way] and never return," said co-author Douglas Boubert of the University of Oxford.
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Bad Astronomy | Our local supermassive black hole shot a star right out of the galaxy
Hypervelocity stars are weird. They were first discovered a couple of decades ago, and like their name suggests, they are stars that are moving . Pretty much every star in the sky is orbiting the center of the galaxy, like the planets orbit the Sun, and those speeds can be fairly high in human terms (the Sun orbits at about 230 kilometers per second).
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Of these, the most brain-crushing is if the binary stars themselves get too close to the supermassive black hole in the center of the Milky Way, called Sgr A* (when spoken, "Sagittarius A star"). Over time the three objects interact, screwing with the binary stars' mutual orbits. After all, the binary stars might have masses a few times that of the Sun, but Sgr A* has a mass of over four million Suns. It wins, every time.
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Could Supermassive Black Hole at Center of Galaxy Harbor a Wormhole? | Digital Trends
Wormholes which bend the fabric of space-time are a staple of science fiction writing, but a team of theoretical physicists is working to see if they could have a place in reality as well.
Researchers from Case Western Reserve University, University at Buffalo College of Arts and Sciences, and Yangzhou University have come up with a technique for detecting traversable wormholes — theoretical tunnels in space-time which could allow objects to travel great distances across the galaxy or even the universe. They turned their attention to the supermassive black hole at the center of our galaxy, Sagittarius A* , to see if it could harbor such a wormhole.
Black Holes Orbiting Even Bigger Black Holes Might Also Be Eating Each Other - D-brief
Now, a group of researchers has proposed a new possibility. Black holes in the accretion disk surrounding a galaxy's central supermassive black hole might gather in similar orbits. This could lead black holes to go through multiple mergers, growing larger each time.
The researchers created simulations to show that this was possible and described their results in the journal Physical Review Letters .
One place where a black hole might swallow multiple other singularities is in an environment that's dense with stars. Globular star clusters, for example, pack lots of stars — and the black holes they sometimes form — into a relatively tight space. There, a black hole might meet and combine with other black holes multiple times.
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Black hole spit a star out of the Milky Way https://t.co/3s1XQOuHnu https://t.co/2q0GQInTNq nypost (from New York, NY) Fri Nov 15 19:35:31 +0000 2019
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