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Asked by monkey to Tom, Matt, Antonia on 15 Jun 2010 in Categories: General.
Question: what is a black hole?
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Matthew Hurley answered on 15 Jun 2010:
A black hole is made of, well…nothing! It’s a gap in spacetime made by something very dense. Everything is absorbed even light (hence it being Black) but it emits Hawking radiation (named after Stephen Hawking, who did the maths).
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Tom Hardy answered on 15 Jun 2010:
A hole that is black! Kidding… it is a part of space that is considered a deformation and is believed to be caused by densly compacted mass. Nothing can escape from a block hole, not even light! That is where the name ‘black’ comes from!
Comments
Douglas commented on :
A black hole is a dead star to start with. But it can grow bigger and bigger by sucking in other stars and planets. At the centre of most galaxies including our own is a giant black hole. It’s no danger to us though cos we’re way out in a spiral arm nowhere near it.
What happens is stars stay the same shape for millions of years as long as they’ve got fuel to burn and can give off light and heat. You’ve got gravity trying to pull the star in and the light and heat pushing out. They’re in balance.
But when a star runs out of fuel it stops pushing out and gravity make it shrink. What happend next depends how massive the star is. Small ones stop shrinking and become white or brown dwarfs.
Bigger star become neutron stars. Their gravity is strong enough to crush all atoms, when the fuel runs out, and you end up with a small ball of matter that’s made of nothing but neutrons. A teaspoon of this would weigh as much as a fleet of battleships.
With bigger stars even the neutrons are not strong enough to stop gravity and they get crushed down to nothing. The whole star shrinks to a point. But the gravity is still there and very strong.
It’s so strong that nothing that falls into the black hole can get out, not even light. That’s why they’re black.