5 ms·
> It's true that infalling observers will experience outside time speeding up, and conversely outside observers will see infalling objects slow down. And the i
by lamontcg 3y ago
> It's true that infalling observers will experience outside time speeding up, and conversely outside observers will see infalling objects slow down.
And the infinite passage of all external time is observed in a finite time by the infalling observer. All of the communication from the external observer is going to become a high frequency chirp at the event horizon, and the last message the infalling observer could send will take nearly an infinite amount of time to reach the external observer. And in the next instant of subjective time by the infalling observer they will be past the event horizon and unable to communicate any more.
- gnramires 3y agoSure, but it seems this is unphysical if this passage occurs after essentially an infinite time for an outside observer. Before crossing the event horizon, the infalling person sees the whole history of the universe. But the problem is, if crossing the horizon takes infinitely long, how could the horizon form in the first place? That's what I've never seen addressed to a satisfactory degree.
- lamontcg 3y agoWell elsewhere in this thread I've pointed out that the black hole evaporates before the infalling observer ever crosses the event horizon. If you have a classical black hole and you don't bother yourself with how it forms, though, there's no paradox, the paradoxical effects arise because the areas of space-time become completely unreachable and you're using coordinate systems which are not local.