How can time stop at the event horizon?
The stronger the gravity, the greater the curvature of space, and the slower clocks run. From what we know about general relativity: if you watch something approach a black hole’s event horizon, you see its time is slowed to a stop, and the redshift of light it emits also approaches infinity. So you will see the object hover at the edge of the event horizon forever (although actually it will be emitting light of wavelength so redshifted that you can’t detect it, so actually you wouldn’t really “see” anything after a while!) The stuff we do see coming from black holes is emitted from highly heated stuff that has not yet reached the event horizon. If you are the object falling in (assuming you haven’t been squished by the intense tidal forces), you think your clock runs normally… but you see time speeding up everywhere else in the universe (for gravitational redshift, the observers agree on whose clock is faster: the one for which the gravitational field is stronger runs slower).
