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Force of gravity between photon and earth

  1. Apr 6, 2009 #1
    If I wanted to use F=(GMm)/(r^2) to find the force between a photon and the earth
    could I use E=hf and then find the energy the plug it into E=mc^2 then use the to find
    the mass equivalence and then plug it into the first equation.
    would this work.
  2. jcsd
  3. Apr 7, 2009 #2


    Staff: Mentor

    Not really, the observed deflection is twice that. That was one of the early tests of GR.
  4. Apr 7, 2009 #3
    so then how would we calculate it .
  5. Apr 7, 2009 #4
    Review the google websites discussing the famous Mossbauer Effect experiments by Pound and Rebka at Harvard in 1959, where they measured the energy gain of the 14 keV photons from iron-57 falling from the top of the physics building to the basement.
  6. Apr 7, 2009 #5


    User Avatar

    Staff: Mentor

    Bending Light gives both Newtonian and relativistic calculations.
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