26 New Black Hole Candidates Found In Andromeda 57
William Robinson writes "Astronomers have discovered 26 new likely black holes in the neighboring Andromeda galaxy — the largest haul of black hole candidates ever found in a galaxy apart from our own. The central region of the Andromeda galaxy is chock-full of black holes, according to extensive observations with NASA's Chandra X-ray Observatory."
These 26 black hole candidates add to nine previously known for a grand total of 35.
Re:what happens (Score:4, Informative)
Hawking radiation [wikipedia.org]
Re:what happens (Score:5, Informative)
I suspect you're thinking about black hole evaporation [wikipedia.org]? It's a real phenomenon, at least theoretically, but the energy radiated in this manner from a typically-sized black hole is way less than the background radiation of the universe, so the mass/energy of the singularity continues to grow.
Incidentally, the evaporation phenomenon is also why you don't have to worry about the LHC ever producing a black hole that destroys the earth--any black hole it could create would radiate to nothing almost instantly.
Re:what happens (Score:5, Informative)
What? No... You're completely wrong. I don't even know where to start. Not even radiation can escape a blackhole. The radiation blackholes cause, is hawking radiation. Hawking radiation is rather simple, the theory is that the universe is a constant froth of matter/antimatter being created in pairs. Most of the time these pairs collide and destroy each other immediately. On the event horizon of a black hole however, it's possible for the pairs to be come into being with 1 of the particles inside the event horizon and the other outside. So one escapes while the other is trapped. Since the trapped particle is the opposite of the free particle, it's "As if" the black hole emitted radiation, because the particle trapped has the negative effect on the blackhole that the escaping particle has. But it was NOT emitted. After BILLIONS of years this effect can eventually cause the blackhole to, for lack of a better word, evaporate. But this is not because it's giving off any radiation. Blackholes can not, nor will they ever, give off any type of radiation or matter. And the effect of Hawking radiation is so slow that the singularities will be the last things that exist in this universe for a very, very, very long time after all of our stars have run out of fuel.
Lastly, blackholes warp space and time. By the time matter passes the blackholes event horizon it's been torn to elementary particles by gravity. But even those elementary particles never reach the singularity. The warping of space-time is so great that time slows to nearly the point of stopping. They are in a perpetual free-fall towards the singularity but will never arrive. If you were falling backwards into a blackhole, and somehow had some magical device that allowed you to survive the decent, you would watch the end of time before your eyes. Granted it would be warped into a single point of light that would just snuff out, but you get the idea.
Re:what happens (Score:5, Informative)
little problem is that Hawking radiation is only theoretical, we don't know if it exists. also, your description of fate of infalling matter or view from that reference frame is not known for certain because black holes are where quantum mechanics meets general relativity meets whatever the mechanism of gravity (quantum?) is. we just don't know.
Re:what happens (Score:5, Informative)
By the time matter passes the blackholes event horizon it's been torn to elementary particles by gravity. But even those elementary particles never reach the singularity. The warping of space-time is so great that time slows to nearly the point of stopping. They are in a perpetual free-fall towards the singularity but will never arrive. If you were falling backwards into a blackhole, and somehow had some magical device that allowed you to survive the decent, you would watch the end of time before your eyes.
You got this all backwards unfortunately. First off, the event horizon is not really a special location to local observers. You could be torn up to pieces way before the event horizon for a small black hole, or way after it for a very large one. For a local person in free fall, nothing special would happen at the event horizon.
Second, the time slowing down and taking forever to fall in would be what a distant observer sees. For the observer in free fall, they would reach the singularity in a finite amount of time. And for even large black holes, that finite time is actually quite short, so you would not see the whole universe evolve in front of you, you would very quickly reach a point where the stresses exceed any imagined material strength.