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Galilean Invariance and the Special Principle of Relativity

  1. Mar 19, 2012 #1
    To what extent is the PoR an extension of the galilean PoI?

    A stated consequence of the Galilean PoI is that inertial observers cannot determine by experiment if they are "in motion" or "at rest", with a similar consequence being mentioned for the PoR - to what extent to these differ, does anyone know?

    Does the special PoR extend the Galilean PoI to accelerating reference frames also?

    In general, to what extent are the two principles the same and different?
  2. jcsd
  3. Mar 19, 2012 #2


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    I think it would be helpful for you to read the wikipedia article on the History of Lorentz Transformations. There you will see that PoI is based on the Galilean Transformation and was accepted as fundamental for massive bodies up until the time of Einstein while the Lorentz Transformation was applied only to light. Thus, in effect, they had two different PoR's in operation at the same time because they didn't know how to reconcile them. Einstein's great contribution was to apply a single PoR to both massive bodies and to light, which is the reason for the name of his 1905 paper, "On the Electrodynamics of Moving Bodies".

    Einstein's PoR in Special Relativity does not extend to accelerating frames--General Relativity takes care of that.
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