Gourdhead -- it applies to the event horizon.


Jeff Root -- I'm aware that time dialation is relative, and the infalling astronaut doesn't see his own time as running slower. I'm talking about an outside observer watching the infalling astronaut will see the infalling astronaut's time run slower, and will witness that it takes forever for the infalling astronaut to reach the event horizon.

But I think your wrong that the time dialation is only an illusion, and even though we don't see the astronaut ever cross the event horizion in reality he already has. Because consider that we watch him for 1000 years getting ever closer to the black hole. Then, he decides to turn around and come back (or perhaps he was on a trajectory that only had him orbit very close to the event horizon and then swing back). At any rate, the astronaut may have only experienced 3 or 4 seconds, but the rest of the universe has still aged 1000 years. It's not like the astronaut falls in, 3 seconds later turns around and comes back and only 3 seconds has passed for the rest of the universe even though we're still seeing an image of him falling into the black hole.

If you see him falling into a black hole, and 1000 years later you still see him falling into the black hole that's because he's still falling into the blackhole. He hasn't crossed the event horizon yet, in either your reference frame or his. So this doesn't invalidate my question.