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Time 101

  1. Jul 31, 2009 #1
    I'm hoping someone is willing to help me with this question.

    Time is well explained when observed at point between absolute rest and c. The faster an object travels through the dimension of space, the slower that object travels through the dimension of time. Fair enough.

    Does this mean that the dimension of time only pops into existence when an objects that has mass moves at a rate somewhere between absolute rest and c? Is the dimension of time "absent" at both extremes (absolute rest and c)?
  2. jcsd
  3. Jul 31, 2009 #2


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    You are forgetting that velocity is a relative concept. Something can only be at rest relative to something else, or moving at velocity v with respect to something else. Your statement:
    Applies with repsect to an observer in a different frame of reference. However, an observer in the same frame as the object obviously experiences time to move at the same rate. The only velocity that is truly irrespective of observers is c, since it is measured the same for all of them.

    I think this should clear up whatever questions you have about this.
  4. Jul 31, 2009 #3
    wow, that was fast - and thank you. So everything that has mass is in motion and experiences time. Differences in time and speed are relative to the frame from which they are being observed. So is asking about absolute rest sort of like asking about the beginning of time? Or like asking what’s north of the north pole again ;)
  5. Jul 31, 2009 #4


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    Well asking about an object which is absolutely at rest is actually a meaningful question with a meaningful answer. Simply put, nothing can be absolutely at rest because there always exists a reference frame such that this object is in motion.

    I'm not sure where you're going with the beginning of time bit, but it seems a little irrelevant to the discussion here.
  6. Jul 31, 2009 #5
    You’re right of course. The beginning of time comment isn’t relevant. What I meant to say is that there’s no point in me wondering about perspective from reference frame of absolute rest because, as you helped me understand, everything with mass is in motion from at least one other reference frame. As an amateur, I was trying to imagine how time and space might be perceived from an object that was in a true state of absolute rest. You’ve helped me understand why there's no such thing.
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