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Space time travel theory

  1. Nov 22, 2007 #1
    the basic theory is that if you travel fast enough then time will go slower for you then the rest of the universe. doese anybody know if this is true or not?
  2. jcsd
  3. Nov 22, 2007 #2

    Chris Hillman

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    Are you asking about time dilation in str?

    Athrax, physics is complicated and misunderstandings can easily arise if you are not very careful to use technical terms correctly. There is a reason why physicists use all those funky words---- under some circumstances, nature doesn't work like everyday intuition might lead one to expect, so physicists have devised mathematical theories and technical words to discuss those theories. It's important, when you ask a question about effect E in theory T, to state the name of theory T and effect E, if at all possible.

    If I were to guess, I'd guess that you might be asking about "time dilation" in "the theory of special relativity" (str). Does that sound right? (My expectation is that this might jog your memory; if not, ask again and we'll try to figure out the question.)
    Last edited: Nov 22, 2007
  4. Nov 22, 2007 #3


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    There is some experimental evidence. Muons produced by cosmic rays have a longer half life than expected because they travel very fast.
  5. Nov 22, 2007 #4


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    The idea you are referring to comes from the theory of Relativity. The tricky bit to grasp is that to comprehend it, you need to do away with the notion of any absolute time. All you can talk about is how fast you observe time to be passing for someone else.

    If you were in a train moving at close to the speed of light past a station, you could look at your watch and see that compared to a clock sitting at the station, your watch 'ticks' faster. Therefore as far as you are concerned, time runs slower for people on the station.

    However this is not universal, so you can't say 'time goes slower on the station' but only that ' you observe time to run slower on the station'. This might seem pedantic, but it goes to the heart of relativity. To see why this is important, consider now that you are standing on the platform instead of the train. You could argue that it is you that is moving, not the train, and in fact it turns out that relative motion is the only thing you can talk about sensibly. In this case by the same logic, when you are on the platform your watch appears to run more quickly than a clock attached say to the front of the train.

    In both cases people on the train and the platform see each others time ticking slower than their own! This is why you can only talk about how things are seen by various observers, but not whether time runs fast or slow in some absolute sense.
  6. Apr 19, 2011 #5
    near a high mass object (a black hole for example) the incredible warping of space is so severe that time passes at a different rate to a state of inertia (no force acting on an object), so moving close to a heavier object means time will pass slower
  7. Apr 19, 2011 #6
    True. Simply put, a denser mass will have a more negative gravitational potential and will thus slow down any clock in its gravity field. One have to be careful in understanding the slowing down of clocksw stuff. One is put forward by special relativity where the proximity of a moving vehicle to the speed of light alters the ticking of clocks and the other has to do with general relativity which I first mentioned.
  8. Apr 21, 2011 #7
    Exactly!! Refer Roger Penrose's Emperor's New Mind..
  9. Apr 28, 2011 #8
    Since moving closer to the speed of light slows your time down wouldn't the clocks and people at the station appear to be moving quicker not slower?
    Last edited: Apr 28, 2011
  10. Apr 28, 2011 #9


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    I think you're missing the point. Moving fast does NOT slow down your time in any absolute sense. There IS no absolute sense. You and the train station observer BOTH see your own time and movement as perfectly normal and you both see the SAME apparent slowdown in the time being experienced by the other.
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