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Record-breaking supermassive black hole found in heart of far-offgalaxy
A supermassive black hole — with the mass 21 billion times that of our
own sun — has been found at the heart of a distant galaxy. NGC 4889 is an elliptical galaxy. Rather than being the galaxy most people think of, elliptical galaxies look like they have no real structure, with their collection of stars looking more like blobs in space. The galaxy is about 300 million light years away, in the heart of a galaxy cluster known as the Coma Cluster. The black hole has an event horizon — a location where not even light can escape — with diameter of 130 billion km. That’s approximately the distance between the sun and Neptune, the last planet in our solar system. Comparatively, the black hole at the heart of our galaxy has an event horizon about one-fifth the orbit of Mercury, the closest planet to the sun and a mass of about four million times that of the sun. Astronomers believe that the black hole is no longer gobbling up matter. In fact, they believe that stars have begun to form in the surrounding region. http://globalnews.ca/news/2511541/re...ar-off-galaxy/ |
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Record-breaking supermassive black hole found in heart of far-offgalaxy
On 2/12/2016 10:21 AM, Yousuf Khan wrote:
A supermassive black hole — with the mass 21 billion times that of our own sun — has been found at the heart of a distant galaxy. NGC 4889 is an elliptical galaxy. Rather than being the galaxy most people think of, elliptical galaxies look like they have no real structure, with their collection of stars looking more like blobs in space. The galaxy is about 300 million light years away, in the heart of a galaxy cluster known as the Coma Cluster. The black hole has an event horizon — a location where not even light can escape — with diameter of 130 billion km. That’s approximately the distance between the sun and Neptune, the last planet in our solar system. Comparatively, the black hole at the heart of our galaxy has an event horizon about one-fifth the orbit of Mercury, the closest planet to the sun and a mass of about four million times that of the sun. Astronomers believe that the black hole is no longer gobbling up matter. In fact, they believe that stars have begun to form in the surrounding region. http://globalnews.ca/news/2511541/re...ar-off-galaxy/ Note, John Sefton, that black holes are not presented in GR as things that swallow everything in their vicinity, and that star formation in the region outside a black hole is perfectly consistent with general relativity. No matter what magazine article you think you might have read sometime that suggested to you otherwise. -- Odd Bodkin --- maker of fine toys, tools, tables |
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Record-breaking supermassive black hole found in heart of far-off galaxy
On Fri, 12 Feb 2016 10:26:28 -0600, Odd Bodkin wrote:
Note, John Sefton, that black holes are not presented in GR as things that swallow everything in their vicinity, and that star formation in the region outside a black hole is perfectly consistent with general relativity. How does that work? My limited understanding of the mechanism for black holes emitting matter via 'Hawking' radiation works best for black holes just barely big enough to hold thenselves together. Bigger ones would thus emit less. |
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Record-breaking supermassive black hole found in heart of far-offgalaxy
On 2/12/16 10:21 AM, Yousuf Khan wrote:
A supermassive black hole — with the mass 21 billion times that of our own sun — has been found at the heart of a distant galaxy. NGC 4889 is an elliptical galaxy. Rather than being the galaxy most people think of, elliptical galaxies look like they have no real structure, with their collection of stars looking more like blobs in space. The galaxy is about 300 million light years away, in the heart of a galaxy cluster known as the Coma Cluster. The black hole has an event horizon — a location where not even light can escape — with diameter of 130 billion km. That’s approximately the distance between the sun and Neptune, the last planet in our solar system. Comparatively, the black hole at the heart of our galaxy has an event horizon about one-fifth the orbit of Mercury, the closest planet to the sun and a mass of about four million times that of the sun. Astronomers believe that the black hole is no longer gobbling up matter. In fact, they believe that stars have begun to form in the surrounding region. http://globalnews.ca/news/2511541/re...ar-off-galaxy/ Thanks for posting this. -- sci.physics is an unmoderated newsgroup dedicated to the discussion of physics, news from the physics community, and physics-related social issues. |
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Record-breaking supermassive black hole found in heart of far-offgalaxy
On 2/12/2016 10:56 AM, Mike Duffy wrote:
On Fri, 12 Feb 2016 10:26:28 -0600, Odd Bodkin wrote: Note, John Sefton, that black holes are not presented in GR as things that swallow everything in their vicinity, and that star formation in the region outside a black hole is perfectly consistent with general relativity. How does that work? My limited understanding of the mechanism for black holes emitting matter via 'Hawking' radiation works best for black holes just barely big enough to hold thenselves together. Bigger ones would thus emit less. Because of the gravitational pull of the black hole, matter can accrete outside the black hole's event horizon WITHOUT being sucked in. This is for the same reason that the matter in the rings of Saturn accrete in those rings without falling into Saturn, and for the same reason the asteroid belt orbits the sun without falling into the sun. If the density of the accretion is high enough, you can seed stars. If the black hole has angular momentum, then you can also get effects that come from the rotation of the orbiting matter, such as magnetic fields and ejected jets along the axis. None of this has anything to do with Hawking radiation, which (as you say) is tiny, tiny, tiny for a supermassive black hole. -- Odd Bodkin --- maker of fine toys, tools, tables |
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Record-breaking supermassive black hole found in heart of far-off galaxy
Mike Duffy wrote:
On Fri, 12 Feb 2016 10:26:28 -0600, Odd Bodkin wrote: Note, John Sefton, that black holes are not presented in GR as things that swallow everything in their vicinity, and that star formation in the region outside a black hole is perfectly consistent with general relativity. How does that work? Very simple. An object has to *pass* the event horizon of a black hole in order to be “swallowed” by it. That does not happen if the object is far enough away from the event horizon and/or has an orbital speed that is high enough. For example, light can circulate forever around a black hole on a trajectory outside the event horizon called the “photon sphere”. Popular-scientific version: https://www.youtube.com/watch?v=eI9CvipHl_c Corresponding science: http://jila.colorado.edu/~ajsh/insidebh/ My limited understanding of the mechanism for black holes emitting matter via 'Hawking' radiation works best for black holes just barely big enough to hold thenselves together. Bigger ones would thus emit less. Hawking radiation – which AFAIK is yet to be detected – has nothing to do with this. https://en.wikipedia.org/wiki/Hawking_radiation X-Post & F'up2 news:sci.physics.relativity PointedEars -- Q: Who's on the case when the electricity goes out? A: Sherlock Ohms. (from: WolframAlpha) |
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Record-breaking supermassive black hole found in heart of far-off galaxy
Dear Thomas Lahn:
On Friday, February 12, 2016 at 5:37:45 PM UTC-7, Thomas 'PointedEars' Lahn wrote: .... Hawking radiation - which AFAIK is yet to be detected Starting with the Tevatron, energetic collisions produced massive composites that evaporated as "fireballs"... so lots of light. No claim of black holes being produced, but the evaporation mechanism appears to be sound. David A. Smith |
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