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

Invariance of velocity ?

  1. Dec 28, 2012 #1
    does SR change the direction of light and if yes is it then possible to find a transformation keeping the velocity of light invariant and not only its speed ?
  2. jcsd
  3. Dec 28, 2012 #2


    Staff: Mentor

    I think just the identity transformation.
  4. Dec 28, 2012 #3


    Staff: Mentor

    Any Lorentz boost will leave invariant the direction of light beams that are directed along the same axis; but it will change the direction of light beams that are not directed along the same axis. So a Lorentz boost along the x axis would not change the direction of light beams traveling along the x axis; but it would change the direction of all other light beams.

    Also, even light beams whose directions are not changed by a Lorentz boost will have their frequency changed.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook