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Does the CMB move or is it static?

  1. Jan 24, 2012 #1
    If the CMB is quantum fluctuations of the primordial universe, I would expect it to move, not be static like a photograph. Quantum fluctuations do not hold still, nor has time itself seem to have dilated to the point where it would look constant.

    Can somebody take a movie of it and see? All that we see is the famous photograph, but no one has seen the motion picture.


  2. jcsd
  3. Jan 24, 2012 #2


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    At a distance of dozens of billions of light years, just how fast would any part of it have to be moving in order for us to see visible movement in the few decades we have been observing?

    Hint: it is difficult enough for us to visually detect movement of stars in our own galaxy, some millions of times closer.
  4. Jan 24, 2012 #3
    We are looking at CMB photons that were separated by by much closer distances, when the universe was only 380,000 years old. I would expect much more motion than the stars, which don't seem to move on day to day human time scales. How much motion, I don't know.
  5. Jan 24, 2012 #4


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    The point is, at a distance of 14 billion light years, things would have to be travelling at outrageous speeds for their motion to be visible at all over such a short time frame.

    What is the angle of a triangle whose short side is .5 light years wide and 14 billion light years long? That is the angle an object would subtend travelling at .5c over one year.
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