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

B Light constant for what?

  1. Oct 21, 2016 #1
    Is the light constant (3*10^8 m/s) the maximum speed for a beam of light or its photons which travel in waves?
  2. jcsd
  3. Oct 21, 2016 #2


    Staff: Mentor

    There are a number of apparent misconceptions lurking beneath your question. Rather than try to disentangle them, it would be better for you to give more information about why you want to know. What specific problem or scenario are you interested in? What sources are you using to understand the subject?
  4. Oct 22, 2016 #3


    Staff: Mentor

    The best way to understand the issue is to actually forget about light - its real basis is symmetry:

    Light when radiated travels at exactly the same speed regardless of the speed of the source in a vacuum (the speed of the source does not enter into Maxwell's equations) so must travel at the constant speed derived above being the only speed constant in all frames.

    IMHO its better to derive Maxwell's equations from relativity so no confusion can result:
    http://cse.secs.oakland.edu/haskell/Special Relativity and Maxwells Equations.pdf

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted