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Travel to the Past

  1. Aug 19, 2013 #1
    Assuming (Big assumption I know) you could create a wormhole, and using either of the relativities created the time effect needed to travel in the past, is there any way where the traveler could go beyond the inception of the wormhole. So if we made the time machine today, how could I get to the Roman Empire?

    Is the only way through a natural blachole/wormhole and hope I land back on Earth in the past?
  2. jcsd
  3. Aug 19, 2013 #2


    Staff: Mentor

    As far as I know, the definitive paper on using wormholes as time machines is still this one by Morris, Thorne, and Yurtsever:


    There's a lot there for a short paper, but the key point for your question is that, even if you were able to make a wormhole into a time machine, you couldn't use it to go back in time to any event to the past of when the wormhole first became a time machine. So if you made the time machine today, you couldn't use it to travel back to the Roman Empire.

    (Thorne also has a layman's discussion of this in his book Black Holes and Time Warps.)
  4. Aug 19, 2013 #3
    From all my readings that seems to be the consensus. So my next question is that if I want to into the black hole and use it as a bridge to another white hole, will time stop for me (the travelers) once I'm past the event horizon?

    Time would continue normally for me the traveler correct? The real problem is not being ripped apart.
  5. Aug 19, 2013 #4


    Staff: Mentor

    Yes. But the relationship between your time and time in the outside universe can get pretty weird.

    Yes, tidal gravity is still going to be there, and it will be much too large for any material we're currently familiar with to survive the trip unless the wormhole is extremely large (and the larger the wormhole, the more difficult it is to make it and hold it open in the first place).
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