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Absolute or relative TIME

  1. Aug 21, 2009 #1
    According to Special Theory of Relativity nothing is absolute in this universe, but relative to each other. as we know that Einstein told me that speed of light is max. Now i'm little bit confuse if speed of light is absolute or relative i.e it may be max. for initial reference frame but for any other frame it may/should be change from the value of 3 X 108 m/s. can anyone give me the reason for this.
  2. jcsd
  3. Aug 21, 2009 #2


    Staff: Mentor

    That is not correct at all. There are many things which are absolute in SR. E.g. the spacetime interval, proper time, mass, the norm of the 4-acceleration, etc.
  4. Aug 21, 2009 #3


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    Staff: Mentor

    And it is probably more correct to say that the speed of light is a constant, not an "absolute" or a relative thing. Ie, it is a constant relative to any inertial observer.
  5. Aug 21, 2009 #4

    George Jones

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    Staff Emeritus
    Science Advisor
    Gold Member

    Actually the locally measured speed of light is constant relative to any observer, inertial or not, in both special and general relativity.
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