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26 New Black Hole Candidates Found In Andromeda

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.

2 of 57 comments (clear)

  1. Re:what happens by antimatt · · Score: 5, Informative

    It's far easier for astronomers to identify black holes by how nearby objects behave--especially by observing their orbits, and the gravitational lensing effects.

    I suspect you're thinking about black hole evaporation? 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.

  2. Re:what happens by Anonymous Coward · · 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.