simple balck hole question

[tolbiny]

Black holes are so dense that even light cannot escape, yet we can detect radiation from black holes (we can right?) how does the radiation escape?

[Metric]

[ QUOTE ]
Black holes are so dense that even light cannot escape, yet we can detect radiation from black holes (we can right?) how does the radiation escape?

[/ QUOTE ]
The radition doesn't escape from within the event horizon. What we "see" (for example in active galactic nuclei) is radiation from superheated gas which is about to fall in, but is still outside of the horizon.