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When a particle drops into Earth, it hits the ground and rebounds, if time reverse, it is equivalent to another particle moves with same speed but opposite direction.

But at the case that a particle drops into black hole, if time reverses, that means a particle is come out from a black hole, but in theory no matter can escape from black holes once pass through event horizons, that means even the dropping particles in black hole can reverse its travel direction immediately, it still fails to escape from black holes, is it true? If it is true, is time symmetry is not applicable in the case that particles drops into black holes?

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    $\begingroup$ what is your definition of time reversal here ? $\endgroup$ – user46925 Feb 1 '16 at 2:52
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    $\begingroup$ That's a yes, but... as you can see from classical mechanics, electrodynamics etc... time reversal invariance of the equations doesn't mean a thing for the existence of time-reversed solutions, which are suppressed for statistical reasons. $\endgroup$ – CuriousOne Feb 1 '16 at 2:55
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The answer to this relies on knowing about the extended solutions for the Schwarzschild solution, namely the Kruskal solution. In this solution, there is not just a black hole, but a pair of a black hole and a white hole. Particles move from the white hole in the distant past, and then eventually fall into the black hole.

Therefore, the time-reversed particle falling into the black hole, becomes a particle "falling" out of a white hole.

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