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

Evidence of Special Relativity

  1. Aug 19, 2014 #1
    I know that the example of time dilation and length contraction due to Special Relativity is usually given as the mountain top / sea level decays of muons created by cosmic rays but what is the evidence for mass change?
  2. jcsd
  3. Aug 19, 2014 #2


    User Avatar
    Gold Member

    Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.
    Its only that linear momentum and kinetic energy are different for different inertial observers which is like Newtonian mechanics just the transformation is different.
  4. Aug 19, 2014 #3


    User Avatar

    Staff: Mentor

  5. Aug 23, 2014 #4
    When designing particle accelerators the designers need to take the relativistic mass increase into account. See the outreach page at the Large Hadron Collider at
    UCSB Science Line sq test
    See also

    Where did you get the idea that they never use it? Just look above. I've also seen many other examples of it. For example; A simple relativistic paradox about electrostatic energy, Wolfgang Rindler, Jack Denur, Am. J. Phys., 56 (9), September 1988, page 795.
  6. Aug 23, 2014 #5
    Correct me if I'm wrong, but I though mass change had been derived in the late 1800s. The example I seem to remember is change in mass when the energy in a spring changes.
  7. Aug 25, 2014 #6
    Thomson, Joseph John (1893), Notes on recent researches in electricity and magnetism on Internet Archive, Oxford: Clarendon Press

    [p. 21] "When in the limit v = c, the increase in mass is infinite, thus a charged sphere moving with the velocity of light behaves as if its mass were infinite, its velocity therefore will remain constant, in other words it is impossible to increase the velocity of a charged body moving through the dielectric beyond that of light."
    Last edited: Aug 25, 2014
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook