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A question on time

  1. May 23, 2004 #1
    I know there are other posts about time, but I have a more specific question to pose. Is time real?

    I dont really know whether or not time is real. I am thinking that time is just a measurement concocted by the human mind that is used to measure the speed of which something gets from point A to point B, and to measure the natural cycles of the universe. However, it is not a governing FORCE that affects our lives.

    But then, some people speak of time travel and other things. I dont know if I believe that is possible. If time is just a system of measurement, then that would mean there really is no physical "past" or "future" to travel to. Say that you said, right now, that you wanted to go into the future five minutes. So you let five minutes elapse. You would not be in the "future" because it would be "now". But since the past is gone and not tanigible, and the future hasnt even happened and is not a guaranteed, then how could time exist?

    Its difficult for me to put my position on this subject into words, but I have done the best I can.

    I am just wondering what your thoughts are about this and whether or not there is scientific proof that time does or does not exist. Thank you.
  2. jcsd
  3. May 23, 2004 #2
    I think if time is 4th dimension and the information is recorded there as we travel in time, you can go back. If you change something in the past, you would change both the future and the past (according to you). No need for paradoxes. For example a ball moving on a straight line would look like a long stick in 4D, if you touch this stick both its past and future path would change. IMHO.
  4. May 23, 2004 #3
    time must be real. humans have taken time from it's home, nature, and made it a measurment for their own uses. a 'time slice' will be a particuler moment which it will be still, and will not have anything 'in between'. to be able to alter the past you must 'loop' time form it's direction (the future). you are time travelling now, because you are aging constantly.
  5. May 23, 2004 #4
    But it's funny how there is no analogue of this 'arrow of time' thing in spacial dimensions. For instance, in your picture can't you also change the past by changing the future? And does your picture sort out all paradoxes? For instance, what if you solve a maths problem and then go back in time to tell yourself the answer before you worked it out?

  6. May 23, 2004 #5


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    You might be interested to hear that there is a way of looking at why objects under the influence of only gravity have their particular trajectories. John Wheeler especially likes to look at things this way, which is called the Principle of Maximal Aging.

    Here is a website you might find amusing; it has a tiny bit of Japanese embedded in it.

    http://www.bun.kyoto-u.ac.jp/~suchii/extrem.aging.html [Broken]
    Last edited by a moderator: May 1, 2017
  7. May 23, 2004 #6
    Don't know about arrow of time,
    but according to what I said, while travelling back in time, if you remain 4 dimensional, you would be changing the past before you arrive there, so anything could happen to prevent paradoxes. Actually, if we are 4 dimensional right now, for example pushing a ball would change the past so that it was already coming from that direction and our memories would also be updated. :smile:
  8. May 25, 2004 #7
    You cannot measure Time.

    Any measurement you come up with is of Time Lapsed - not Time itself.
    A positive value of Time Lapsed would be the past and a negative value would be the future, but neither of them would be Time.

    As has already been said, Time is now.

    Any measurement of time will contain all the fluctuations in GR and SR your recording device is subjected to when taking the measurement.

    If I was reading a book and had reached page 100, all the previous 99 pages could be seen as pages that have already lapsed. The rest of the book could be seen as the future.
    Does this make the book a dimension ? After all it has a past, a now (current page) and a future.

    If all you can ever perceive is now, then measurements of time are fundementally of little use, except maybe as nostalgia. Even the future cannot be predicted exactly because of fluctuations in GR and SR.
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