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Homework Help: How can light move at C?

  1. Mar 24, 2010 #1
    I've been reading alot about quantam physics and whatnot mostly for entertainment, but it suddenly hit me today that I didn't realize something. Why doesn't light get infinitely heavy, and therefore take an infinite amount of energy to move it? I've always accepted both the heavy, energy, and time factors of moving at the speed of light, but why isn't light itself affected by its movement? I must have missed something crucial. What further confused me is that light is affected by gravity, but not by its own speed.

    Here's the question (just for a recap)

    1. Why doesn't light get infinitely heavy, there fore taking an infinite amount of energy to move it?
  2. jcsd
  3. Mar 24, 2010 #2
    Photons are massless? Massless particles, if I am not wrong, only travel at c. We experimentally find them to be as massless as possible. They are affected by gravity because they travel in curved paths which are caused by masses as they bend spacetime.
  4. Mar 25, 2010 #3
    Ohhh! Now I think I get it. :-) Thanks for the answer!
  5. Mar 25, 2010 #4
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