# Gravity of Black Holes

1. Mar 20, 2004

### Ghost of Progress

Recently someone told me that Black holes give off some sort of radiation and that this radiation, in escaping the black hole, must be traveling at faster than the speed of light.
The biggest thing that I'm unsure of is just how much a black hole bends space. Does it curve it just sharply enough so that light can't escape but,in theory, somthing going faster than light might be able to? Or does it curve space into itself so that if something was trying to move out from a black hole even at an infinate speed it could not do it.
then this brings up a second thought. If a black hole bends space back into itself wouldn't this make a closed sphere that nothing could enter.
And finaly - if it's true that there is some kind of radiation coming from black holes maybe instead of trying to figure out how it's going faster than light we could think that it's some particle that's unaffected by curves in 3D space.

2. Mar 20, 2004

### Ghost of Progress

Any answers on the question of just how much a black hole can curve space would still be appreciated - thanks.

3. Mar 20, 2004

### Janitor

Partial answer, and I'm shootinig from the hip.

I think it can fairly be said that the more massive the black hole, the less it bends spacetime at its event horizon. That may seem a little bit counter to your intuition.

4. Mar 20, 2004

### Tail

Well, a black hole bends space a lot. At the singularity the curvature of space is infinite or close to infinite, depending on which physicist you tend to agree more.

A black hole can roughly be defined as everything inside its event horizon. The event horizon is where light cannot escape anymore (hence the "black" hole). So, a particle moving faster than light should be able to escape the event horizon. However, I must remind you that the theory of relativity is based on the assumption that nothing can move faster than light.

Last edited: Mar 20, 2004