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Timon and Pumba on photons

  1. Aug 7, 2003 #1


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    Timon, Timon, I wonder howcome photons have no mass at rest and yet mass is their only property?
    Pumba, Pumba, you wonder - I know. There are no photons at rest!
    ha, ha, ha...ain't it funny?
  2. jcsd
  3. Aug 7, 2003 #2


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    What do mean by that? Photons have energy, travel at the speed of light, have spin 1, and other properties.
  4. Aug 8, 2003 #3


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    it is because...

    the energy of the photon is E=mcc
    the momentum p=mc
    if m=0 (there is no m) then
    E=0;p=0... too(there is no E,p...).
  5. Aug 14, 2003 #4
    Re: it is because...

    Doesn't work that way.


    If mass is 0, than energy is equal to momentum times c.

    Think relativistically!
    Last edited by a moderator: Aug 14, 2003
  6. Aug 18, 2003 #5


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    Re: Re: it is because...

    Ok, how much is the momentum then?
  7. Aug 18, 2003 #6
    Obviously then the photon must have mass ,right ? And if we follow this statement through to its conclusion it means that energy must have mass ?
  8. Aug 18, 2003 #7
    Why must a photon has mass? Look at the equations again. Energy approximately equates to momentum with a zero rest mass particle (mass disappears at c/c in the equation). So its MOMENTUM that relates to energy with the photon, not mass.
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