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visits member for 1 year, 8 months
seen 22 hours ago

May
30
asked Momentum of particle in a box
May
29
answered Gauss's Law understanding
May
28
answered Gauss's Law - Electric Field outside a Shell?
May
11
answered Why is $r'/r^2 = -1/r$?
May
11
answered Mass in special relativity
May
10
comment Why can't you escape a black hole?
There are already several detailed explanations posted answering this question. If you want another one, surfaces of constant radius inside a black hole are spacelike, therefore to turn around you would need to travel faster than the speed of light, therefore you can't escape.
May
10
comment Why can't you escape a black hole?
There is no such point inside a black hole where you would need to travel at less than c to escape, so you're answer is still completely wrong. Once you enter a black hole, you can't even turn around, much less escape.
May
10
comment Why can't you escape a black hole?
I'd like to downvote but don't want to lose points. Anyway, this answer is completely wrong.
May
1
awarded  Teacher
Apr
29
answered How is the hamiltonian a hermitian operator?
Mar
27
accepted Can you enter a timelike hypersurface?
Mar
27
comment Can you enter a timelike hypersurface?
Ah, ok I see, that was silly. The normal part will contribute positively to the norm of the vector, but the tangential part will make it overall negative.
Mar
27
asked Can you enter a timelike hypersurface?
Mar
27
comment Diving into a charged (Reissner-Nordstrom) Black hole
Yes, that helps, thanks. When you say you arrive in a new spacetime patch upon exiting the black hole, do you mean he is in a different universe, or just not where in spacetime he was before? For someone observing something leaving the black hole, is it still a black hole for him? or is it just a white hole, so that he can't get in? The diagram seems to suggest it is a different universe...will two people following a similar path necessarily end up in the same universe, or is this even possible to say?
Mar
26
revised Diving into a charged (Reissner-Nordstrom) Black hole
added 1 characters in body
Mar
26
accepted Future light cones inside black hole
Mar
26
asked Diving into a charged (Reissner-Nordstrom) Black hole
Mar
22
awarded  Commentator
Mar
22
comment Future light cones inside black hole
That's a pretty good answer, though I still don't see how you can see this from the Schwarzschild metric.
Mar
22
comment Future light cones inside black hole
I see, however I don't see why the coordinate that gets a negative sign in the metric necessarily implies you can only move in one direction in that coordinate. On the other hand, can't I apply the same reasoning as you did to the time coordinate to infer that inside a black hole you can freely travel back and forth in time?