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This question already has an answer here:

I was hoping to get some technical answers to this question, and was really asking because I thought it'd be a fun question. Have at it folks.

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marked as duplicate by John Rennie general-relativity Jun 1 '17 at 15:18

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ I think this is too large a question. There are solutions in GR with closed timelike curves, including ones in which those curves are not censored. So the question is: can such solutions arise from physically-plausible initial conditions? As far as I am aware the answer to this is that we don't know but there is a strong presumption that they can't. However my knowledge on this is about 30 years out of date now. $\endgroup$ – tfb May 28 '17 at 11:19
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Yes, time travel is compatible with the general theory of relativity. This could be achieved, for example, with wormholes or Alcubierre drive. Krauss's The Physics of Star Trek book provides a popular exposition of some of these ideas.

However, GR is not the only physics at play, and there's reason to believe that when quantum effects are taken into account, these time travel mechanisms will cease to be possible. But until we have a quantum theory of gravity we won't know for sure.

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  • $\begingroup$ Could you be more specific about what you mean in your second paragraph? I'm curious exactly how quantum effects play into this. $\endgroup$ – probably_someone May 28 '17 at 9:20
  • $\begingroup$ @probably_someone I refer you to this paper or you could ask a separate question (others here are better qualified than I am to discuss this topic). $\endgroup$ – lemon May 28 '17 at 9:38

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