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When astronomers speculate the distance of galaxies are they talking about its

  1. Mar 27, 2012 #1
    When astronomers speculate the distance of galaxies are they talking about its....

    When astronomers speculate the distance of galaxies are they talking about its distance now or when the light was emitted? Since things are moving and the universe is expanding the distance from the object now is much different then were the object is currently....
     
  2. jcsd
  3. Mar 27, 2012 #2

    russ_watters

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    Staff: Mentor

    Er, well, "now" is not a well-defined concept. The distance is is measured "now" for us here. It is how far the galaxy currently appears to be, which doesn't include any motion since the light we currently see was emitted.
     
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