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Time dialation

  1. Sep 2, 2010 #1

    I'm looking for any resources explaining time dialation at the atomic level.
    I can't find anything on it sooo If anyone could please refer me that would be helpful.

    kind regards
  2. jcsd
  3. Sep 2, 2010 #2


    Staff: Mentor

    What does that mean?
  4. Sep 2, 2010 #3
    For instance, if an explosion occurs, particles move very energetically. Would the speed of these particles create a time dialation relative the the size of those particles? Also, gravitys affect (or the lack thereof) on particles, would this create an opposite effect to time dialation occuring around stronger gravity?
  5. Sep 2, 2010 #4


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    Hi rhyshanan,

    it's time dilation, not 'dialation'. This is a relativistic effect that happens to other peoples' clocks. Atoms are not observers and so it's not very meaningful to ask about time dilation at the atomic level as you've described it.

    It is true that if we observe an atomic, or sub-atomic particle travelling at a great speed wrt to us, we can detect (time) dilation of the particles half-life, for instance.
  6. Sep 2, 2010 #5

    thanks very much for the response.
    sorry for my spelling and thanks for the correction.
    However, time dilation at the atomic level (as an observer) is meaningful for a theory i'm tinkering with.
  7. Sep 2, 2010 #6
    Time dilation for particles is pretty much the same as for larger objects like rockets, although particles are much more resilient to extreme acceleration and much cheaper to accelerate. Although you can not have observers at the atomic level, you can have "hypothetical" observers. Fortunately, some particles have built in clocks in the form of their decay half lives (as Mentz mentioned) so that is how we know they behave pretty much the same as larger particles. If you are talking about interactions between sub atomic particles at the nuclear level then things get much more complicated, but if if you are talking about individual particles far in space, then things are pretty straight forward. Gravity affects particles pretty much the same as larger objects too and in fact the calculations are simpler for particles because for a large object parts of the object are significantly nearer the source of gravity than other parts of the same object. Quite often when talking about large objects we treat them as if they are a point particle as an approximation because it makes things simpler to calculate.
  8. Sep 3, 2010 #7
    I completely disagree with this notion.

    How would you explain the Hafele–Keating experiment if atoms cannot observe anything?
  9. Sep 3, 2010 #8


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    What are you talking about ? Atoms don't have eyes or consciousness and so they can't be observers.

    Clearly we have a different understanding of the word 'observer'.
  10. Sep 3, 2010 #9


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    The time dilation experienced by particles interacting with each other will depend only on their relative velocities. Their own contribution to the gravitational field will be too small to be noticeable. They would all be equally affected by a gravitational field, unless the curvature was of the same order as atomic dimensions which would require an extreme field.
  11. Sep 3, 2010 #10
    The general definition of an observer requires the obsever, not necessarily sentient, to be or possess a system of clocks and rods with which to assign, or at least in theory being so able, spatial and temporal coordinates to events. I think the latter part rules out atoms or even lumps of rock, planets or galaxies unless such things have a coordinate system attached to them.

  12. Sep 3, 2010 #11


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    If you had a nuclear explosion in space, the high energy neutrons released (10 MeV) traveling at ~0.15c would be able to travel an average of 1% further before decaying, due to time dilation. I don't think this experiment has ever been performed, however a similar effect is that high energy pions, created by cosmic rays in the upper atmosphere, can manage to reach detectors on the ground even though their half-life is too short to make that distance, due to time dilation/length contraction.
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