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Time Travel

  1. Jul 5, 2006 #1
    What do you think of this theory, time travel will never be created because if it was, then people in the future would have come back to the past and we would know about it by now. Unless of course a select few were able to go to the past, and told nor interacted with anyone.

    But my idea was that time travel isn't possible, because if it were, we would know about someone who was in the future that traveled back.
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  3. Jul 5, 2006 #2
    You mean we'd automatically know if anyone in the future had travelled back to now/sometime in the past? I don't really agree with that. That's just limited by their ability to disguise.

    I'd disagree with the above logic, partially. If one could create a wormhole, and travel at high speeds, then the relativistic effects would cause one end to be at a different time than the other. This time machine could never send anyone to before it had been created, and would send people a fixed amount of time back in the past (back 25 years, not back to 1980 for instance). The being-overrun-with-time-travellers logic breaks down for any such a time machine. Personally, I think that's the only kind which would be possible.
  4. Jul 5, 2006 #3


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    Do a search. There have been lots of threads about time travel. I've personally posted in some of them and I don't feel like repeating in this thread.
  5. Jul 6, 2006 #4

    Ivan Seeking

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    Yep, the problem is that if we have had visitors, we may not know it or even be capable of recognizing one... unless you can tell me what a practical time machine looks like and how to detect it.
  6. Jul 6, 2006 #5
    I time travel in my delorean. You must go at least 88mph though.
  7. Jul 6, 2006 #6

    Ivan Seeking

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    I know of a time machine that looks like a blue phone booth. :biggrin:
  8. Jul 6, 2006 #7
    Most excellent.
  9. Jul 6, 2006 #8
    I have a time machine. It tells the time. :cool:
  10. Jul 6, 2006 #9
    Its a police booth, where they can have a decent spot of Tea and a Scone at any time of day!

    Jolly good show
  11. Jul 6, 2006 #10


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    Nah, they look like this...

    http://img125.imageshack.us/img125/1156/timemachine0wq.jpg [Broken]

    I'm one of those that think if time travel is possible then we wouldn't know about it because it would have already happaened and therefore be part of our timeline anyway, or something like that...

    You'd never experience the first travel back because it must've happened before you first travelled back...

    < goes off to watch Back to the Future III again... >

    :confused: :confused: :confused: :confused: :confused:
    Last edited by a moderator: May 2, 2017
  12. Jul 6, 2006 #11
    Time travel has issues with free will too, unless there is a parallel universe:tongue:
  13. Jul 6, 2006 #12
    And that is an argument against time travel? :confused:
    Sorry but that is completely illogical.
  14. Jul 6, 2006 #13


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    Not really. If people travel back in time, the future will be predetermined, ie. it will evolve in such a way that ends in the world in which the time traveller travels back. Unless we are constantly branching to multiple universes and the time traveller is in only one...
  15. Jul 6, 2006 #14
    Yes and? :confused:
    So what if the future will be predetermined, how is that an argument against time travel?
    And how can one possibly deduce that "if the future will be predetermined" that that "ends the world".
    Last edited: Jul 6, 2006
  16. Jul 6, 2006 #15


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    Niven's Law of Time Travel: In any universe in which time travel is possible, it will never be invented.

    Niven's thesis runs approximately as follows: If time travel is possible, somebody will use it. Soon, someone will use it to edit the past. Eventually, things will get so bad that someone with access to a time machine will decide that the only worthwhile course of action is to go back in time and stop the inventor before he can develop time travel. This, of course, will edit the editor, and his own machine, out of the timeline.

    Heh heh. There's a story idea for all you budding authors: WikiTime.
  17. Jul 6, 2006 #16


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    There is a compromise that sidesteps this problem.

    A time machine might only be able to travel back as far as its first day of creation. Thus, if the time machine is activated today, it will never be able to visit yesterday.

    I believe this is in essence the way wormholes "work".
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