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How does the expansion of the universe affect redshift?

  1. Aug 12, 2009 #1
    does the expansion itself redshifts photons (if so, does the expansion affect the photon in his frame of referance?) or is it because the distant object that emits them is seemingly moving away from us (in cases where the expansion is much more dominant of course)? The latter doesnt makes much sense to me because the object isnt realy moving as fast as he seems.
  2. jcsd
  3. Aug 13, 2009 #2


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    Science Advisor

    Yes, the expansion itself redshifts photons. Basically, the wavelength of photons is increased by the same factor as the distances between galaxies is increased with expansion.
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