Why doesn't light escape a black hole?

It's because, in very, very simple layman's terms, the black hole bends spacetime around it so the light beam cannot escape. General relativity says that the closer you move the speed of light, the slower time appears to move around you. This is what the black hole uses, in a slightly roundabout way. Basically, the singularity in the centre of the black hole is such that any object falling into it would appear to an outside viewer to slow down more and more, until it was totally stopped and took an infinite amount of time to reach the centre.

Think of it this way: you have two clocks, really accurate atomic clocks. They're set to the same time. Now you throw one of them into a black hole and keep the other. (This is purely theoretical because the in reality, as light can't escape a black hole, you wouldn't be able to see it - but just for the sake of the thought experiment.) The clock which has just been thrown in will gradually slow down, until it gets to the very middle of the hole at which case it just stops. Weird, I know, but that's Einstein for you. The same happens with light: the light beam's "internal time" is slowing down until it just "stops", at which point so does the light beam itself.

If this hasn't helped, try here: http://stason.org/TULARC/science-engineering/astro... and here http://www.star.le.ac.uk/~sav2/blackholes/theory.h...

site from which this came from in the source

To understand fully why a black hole can trap light but the light still always travels at constant velocity requires an understanding of the General Theory of Relativity, but the essential point is that the black hole curves spacetime back on itself, so that all paths in the interior of the black hole lead back to the singularity at the center, no matter which direction you go (an analogy in two dimensions is that no matter which direction you go on the surface of the Earth in a "straight line" (what mathematicians call a "geodesic" or a "great circle"), you never escape the Earth but instead return to the same point. Imagine extending that analogy to the 4 dimensions of spacetime and you have a rough explanation for why light travels at light speed, but cannot escape the interior of a black hole.

Space is warped by gravity and the path of a beam of light is bent by the warp. The mass of a black hole is such that the warped space turns back on itself at the event horizon.

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light can be slowed down in a given frame of reference.

http://www.news.harvard.edu/gazette/1999/02.18/lig...

besides the time dilation effects that u all seem to be missing