Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Velocity of a photon from its own reference frame

  1. Dec 15, 2011 #1
    So what will it see it self as?? At rest or moving a velocity c? Either way it seems to be a contradiction, so does that mean a photon can't be reference frame?
  2. jcsd
  3. Dec 15, 2011 #2

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Exactly. See our FAQ, [thread]511170[/thread].
  4. Dec 15, 2011 #3
    Hmm, shouldn't that be an assumption in Special relativity as well, along with equivalence of all inertial frame, and the light speed one.


    does it mean that a photon reference frame simply doesn't and cannot exist
  5. Dec 15, 2011 #4


    User Avatar
    Science Advisor
    Gold Member

    Extra assumption not needed. Definition of reference frame of an (inertial) observer: frame in which observer is at rest. Axiom of relativity: light moves at c in all reference frames. Then the reference frame of a photon requires it to simultaneously be at rest and move at c. Contraction. Such a frame is excluded without additional assumptions.
  6. Dec 15, 2011 #5
    yes, I see it now
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook