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Time reversal symmetry doesn’t say that you can time reverse system A while not time reversing system B, if systems A and B interact. The time reverse of a particle falling into a black hole is not a particle emerging from a black hole, it’s a particle emerging from the time reverse of a black hole.
The time reverse of a black hole would not violate GR per se, but there are other reasons (thermodynamic, cosmological, causal complications) that suggest such things probably don’t exist in the real universe.
Greg Egan /
npub1qq…j5nhv
2024-11-25 07:16:30
in reply to nevent1q…7gej
Author Public Key
npub1qqm7nu2qf25xd3mw6y6cyp4v2wr7ktf43ymp5wqz4u8jvz76ymtsjj5nhvPublished at
2024-11-25 07:16:30Event JSON
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