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Traveling into the future in order to travel back into the past

  1. Mar 2, 2008 #1
    Have physicists ever consider traveling into the future in order to travel back to the past? I know it sounds crazy, but one of the paradigms for time travel is Godel's closed time loop curve, where time I think is circular rather than linear. Special relativity permits travelers , if they travel at speeds closed the speed of light, to travel into the future. wouldn't travelers looped back into the past eventually as they are heading further and further into the future if time were circular?
     
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  3. Mar 2, 2008 #2

    JesseM

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    Godel's solution only works in a rotating Godel universe, but there's no evidence that our own universe is rotating (according to the linked article it can't be totally ruled out that the universe could have a small rotation rate sufficient to allow closed timelike curves, though measurements of the cosmic microwave background do rule it out if you accept certain cosmological assumptions).
     
  4. Mar 2, 2008 #3
    But if our universe were hypothetically rotating , then would we be able to travel into the future in order to travel back into the past
     
  5. Mar 2, 2008 #4

    JesseM

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    Yes, from what I understand this sort of thing would be possible in Godel's model. As the page I linked to said, "You enter a rocket, and you take a journey in the universe along a certain path. Then you will - after many billions of years - return to the starting point before you started."
     
  6. Mar 18, 2008 #5
    Uni

    I can agree more with you guys. Einstein's general relativity equations describes the possibility of time traveling into past and future. One thing though if one were to change the past that event has already happened. I believe that for the universe is very ease to compensate for any drastic changes we make if we were to travel into the past. People come with very absurd questions: what if I kill my father before I was born and other horrible
    ideas..The truth is that if one were to do so the universe would make it logical. Meaning that if you were to shoot your grandfather then the bullet will just go through him but not harm him. Or if you try stabbing him (grandfather) the knife would just go through him and you would vanish. It's like trying to stab your younger self, you would vanish but not your younger self. See how ease that is...., it's base on the laws of mass..."same mass can't occupy same space in time" Anyway, I would love hearing your argument or perspective about this....
     
  7. Mar 18, 2008 #6

    JesseM

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    You might be interested in the Novikov self-consistency principle, a hypothesis that history is constrained to be consistent so a time traveler would be unable to "change" history (though he could influence it in self-consistent ways). In the case of attempting to shoot one's grandfather, this principle would suggest that instead of miraculous violations of the laws of physics like the bullet passing right through the body without affecting it, instead the time traveler would simply fail to complete his mission--maybe he would change his mind, or the gun would jam, or he'd shoot the wrong man, or the time police would stop him, etc.

    But then there is also Stephen Hawking's chronology protection conjecture, which suggests that although general relativity seems to allow time travel, when quantum effects are incorporated into general relativity they will have the effect of making time travel impossible. No one can be confident whether this conjecture holds until physicists develop (and test) a theory of quantum gravity.
     
  8. Mar 31, 2008 #7
    Is anybody working on a time machine? or warm hole?
     
  9. Mar 31, 2008 #8
    You meant "worm hole" ... what you typed just opens the door for far too many bad jokes.:yuck:

    And no, no one is seriously working on such things because there is no solid theoretical basis for building one. The kinds of arguments referred to in this thread are far too speculative to start trying to engineer anything.
     
  10. Mar 31, 2008 #9

    DaveC426913

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    Well, not so much open the door, as ... relax it.
     
  11. Apr 1, 2008 #10
    But are there arguments that support a true development for a time machine anywhere in the world? Well I don't think time travel is impossible.
     
  12. Apr 2, 2008 #11
    Well, I have really deep personal reasons why I must think about building a time machine no matter what. If anybody wants to comment they are welcome to.
     
  13. Apr 2, 2008 #12

    DaveC426913

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    Just don't be changin' nothin'. Your grandfather might have died so that my grandfather could get his job and feed his kids. You change stuff and I'll regret it...
     
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