Black Holes

[debrakevin]

When physicists say that the gravity in a black hole can actually warp time, do they mean ACTUAL time (such as past, present and future) or do they mean it warps all our perception, understanding and measurement of time?
Likewise, when they talk about space being distorted, do they mean "space" itself, or just everything that's within that space?

[MarkRae]

Generally speaking, time is constant according to the observer. Two things can alter that: travelling near to or at the speed of light, and immense gravity.

I would suggest you read Prof Hawking's "A Brief History of Time" where he explains this properly.

[beso]

Time and Space are warped in any gravitational field not just near black holes. Likewise travelling at any speed has an effect on the passage of time as seen by external observers.

It is just that the effects are small until the speed or masses involved is very large.
The force of gravity is really a distortion of Time and Space such that masses experience what looks like a force that attracts them toward each other as they travel through time.

Inside the black hole the notion of time and space have no meaning.

[fragrant_vagrant]

The observed effects of black holes is that they bend light around them (if it didn't you wouldn't notice it was there!)... so the time taken to travel between two points is larger in the vicinity of black holes (imagine two dots on a balloon skin then stretching the balloon out) Time then is the period it takes to travel between two points. Obviously in the centre of a black hole the gravitational pull is so great that not even light can escape ... light heading in this direction would be 'stretched' out before disappearing.
The definition of space is not settled at the moment as physicists propose, argue and experiment with theories of 'dark matter'

[jezter]

Hi debrakevin. I asked myself the same question a couple of years ago and it spured me onto read read up about this stuff. Einstien's theory of special relativity is about how time can be different for different observers. Actually different - not just our perception of time. A clock zipping around will run slower than one staying 'still'. This is because the faster you move in space the slower intime and vis versa.

And the theory of general relativity is that space is warped by mass - space itsel not just things in it. So the space aroun the sun is warped so that light from a distant star passing close to the sun bends around the sun with the warping of the space. You warp space - but so insignificantly that we cant detect it.

Both of these theories have been tested - clocks run slower and light is bent. Amazing stuff.

Jez