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Aging of a spinning wheel

  1. Apr 9, 2013 #1
    One of the classical consequences of relativity is that if someone travels far away from Earth and comes back, he would have aged less than people here (acceleration and thus changing frames of reference being the reason.)

    So, why wouldn't this work also for shorter distances? If someone runs to the other side of an olympic stadium and back, he would have aged less than me, who stayed stationary. The difference in ages might be a staggeringly small fraction, but still non-zero.

    Smaller still, if we have a spinning wheel and look at one point in it, it will first traverse away from an observer and then towards it. Again, one would expect that point to have aged less than the observer.

    Therefore if we have a wheel and spin it fast enough, it should start aging measurably less than its surroundings. Is this hypothesis correct?

    Could this be theoretically measured?
  2. jcsd
  3. Apr 9, 2013 #2


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    Yes, the earth is such a spinning wheel and Einstein predicted exactly the effect you describe in his 1905 paper introducing SR at the end of section 4. Unfortunately, there are also effects due to gravity that compound the measurement but the contribution from the spinning earth is as predicted.
  4. Apr 9, 2013 #3
    As well some particle accelerators are circular, in effect the particle representing the " spinning wheel and look at one point in it".

    Yes, but because there are different velocities for the wheel (centre spins more slowly than outer edge) the wheels "age" becomes a little more difficult to name.
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