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Light propulsion

  1. May 3, 2008 #1


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    I saw a program along time ago where a very light piece of material was caused to move using a laser beam. I know that there would of been a lot of energy because it was a vary intense beam of blue light, but photons have no mass so how do they move anything. If photons can move objects with mass could the have a slight effect on every day actions?
  2. jcsd
  3. May 3, 2008 #2
    Photons have energy as well as momentum. When they fall on objects, they undergo absorption, transmission, reflection, scattering etc. These processes involve transfer of energy as well as momentum. Photons do not have rest mass. One can interpret their energy as a measure of their relativistic mass( according to Einstein's theory)
  4. May 4, 2008 #3
    You don't even need to think about photons, since the effect is totally explained by classical electrodynamics: electromagnetic radiation carries momentum, as given from Poynting vector EXH.
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