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How do solar sails work?

  1. Dec 6, 2008 #1
    I briefly researched this and all i found out was that the light pushes the sail as it is reflected off of its surface.

    So i am left wondering how this is possible because photons apparently have no mass therefor they can't push anything. I'm sorry if this is ignorant i am no physicist. Thanks!

    and if this belongs in a different area just let me know.
    Last edited: Dec 6, 2008
  2. jcsd
  3. Dec 6, 2008 #2


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    Staff: Mentor

    Even though photons have no mass, they do carry momentum. Even in classical electromagnetism (in which photons do not appear), electromagnetic waves carry momentum and energy. All you need to explain the operation of a solar sail is conservation of momentum.
  4. Dec 6, 2008 #3
    Thank you! sort of how magnets push each other i'd assume.
  5. Dec 6, 2008 #4
    When a light source emits light, if the light has momentum, does this mean that there is a resultant force in the opposite direction for the light emitting object?
  6. Dec 6, 2008 #5
    yes i think so because one plan to aid pushing the solar sail was to mount a laser on it to push the sail along
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