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Why light fades over distance?

  1. Nov 26, 2008 #1
    According to our observation light fades over distance.
    Please explain to me why light fades over distance in space (type 1a supernovas are observed fainter when they occur farther). Why is that since every individual photon’s energy is constant through its movement through space? Am I right?
  2. jcsd
  3. Nov 26, 2008 #2

    Doc Al

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    Staff: Mentor

    While each individual photon's energy is constant, the number of photons per unit area diminish with distance according to an inverse square law. See: http://hyperphysics.phy-astr.gsu.edu/HBASE/vision/isql.html" [Broken]
    Last edited by a moderator: May 3, 2017
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