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B Very simple question about GR

  1. Oct 17, 2016 #1
    Relativity say as an an object accelerates, time dilates and distances contract.

    It is my understanding that the shortest distance possible is a planck length, so as distance contracts, does the number of planck lengths decrease, or does a Planck length get shorter? It would seem the former, but I don't know. I've got only a pop sci education

    Is there a simple answer?
  2. jcsd
  3. Oct 17, 2016 #2


    Staff: Mentor

    Not in GR. In GR there is no shortest possible distance. The idea that the Planck length is the shortest possible distance comes from speculations about quantum gravity.

    In GR, an object that is one Planck length long in its rest frame will appear shorter than one Planck length in a frame in which it is moving.
  4. Oct 17, 2016 #3


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    Staff: Mentor

  5. Oct 18, 2016 #4
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