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Relativity Concerning Small Particles

  1. Jan 30, 2008 #1
    At what scale does time dilation manifest itself?

    Is time dilation dictated only by the velocity of entire large objects (people, watches)?

    Or is it based upon its component particles?

    For example if a clock is at rest with respect to a room, but its component atoms are vibrating at a speed of 1 km/s, is the latter speed used?

    Or is a much smaller scale used (objects vibrating on the Planck scale, etc.)?

    I would also like to know, just out of curiosity, what kinds of speeds are seen at the atomic or subatomic level. There is obviously very little net displacement, but I am wondering about the speeds at which objects "vibrate."
  2. jcsd
  3. Jan 31, 2008 #2
    If you could place or define clocks inside those little particles, you would really notice those little clocks going slower with respect to our common clocks. A common clock like a wrist watch, instead, is made up of a huge number of those vibrating little particles, so its average speed is very low for relativistic effects to appear. Other kinds of clocks works in a different way but they however consist of some physical effects which involve an entire system and not single particles only, so you should better says that the time measured is not the time of every particle of the system, but of the system as a whole thing.
  4. Feb 1, 2008 #3


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    What makes you think that time depends on scale at all?

    The standard belief, which appears to be consistent with experiment, is that atomic clocks keep the same sort of time as pendulum clocks. It's simply that the atomic clocks are better. There are two reasons for this: atoms are all the same, having no "manufacturing variation" as long as indentical isotopes are used. The second reason is a little more subtle. While both large and small clocks keep the same sort of time, the disturbing effects of motion on the larger clocks is more pronounced.

    This shows up in, for examle , the historical development of the naval chronometer. The evolution of the accurate clock has been from larger less accurate devices to smaller more accureate ones.
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