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Redshift - does energy fade or get absorbed?

  1. Oct 7, 2006 #1
    Is it possible that redshift, though correct in it's theory, is not what we are viewing in terms of expansion of the universe?

    Is it possible that what we think is redshift is actually the strength of the light/energy fading, being absorbed or blocked over hundreds of millions of light years?

    I ask this because it seems to me that in the vast chasms of space between the observer and the observed, there have to be a large number of free-roaming particles of dust that would diminish the light, if only by a minescule amount at a time. Thus the light becomes dimmer, or darker.

    Is there any possibility that the universe is not actually expanding like we think it is based on the Redshift theory?

    Help me please because I'm a bit thick.
  2. jcsd
  3. Oct 7, 2006 #2
    The redshift is not the only reason that we know the universe is expanding. When Albert Einstein worked out Relativity and predicted how gravity works his calcultions indicated that the universe must be expanding, he didn't believe it was and so adjusted his calculations to compensate. It was Hubbard who convinced him that the universe really was expanding that his calculations were correct.
  4. Oct 7, 2006 #3


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    Tzemach is right. In addition you can actually calculate the results of this "tired light" theory, and those calulations don't agree with the observed numbers. So that theory has been falsified. So goes science, then we try another theory.
  5. Oct 7, 2006 #4

    Nuff said, thanks for your help folks.

    I go away slightly less in the dark than when I arrived.


    What about the effect of miniscule particles though, surely they cannot be calculated, and we observe their effect on white light on the horizon.
    Last edited: Oct 7, 2006
  6. Oct 7, 2006 #5
    If you mean the color of sunset, it appears redder only because much of the blue light has been blocked (scattered out giving that colour to the day sky elsewhere). The astronomical redshifts are where individual photons have all changed uniformly in colour. It might be hard to tell the difference for white light, but some of the atoms in these sources always produce lots of light at several very specific frequencies (so we can compare those lines in different stars spectra).
  7. Oct 8, 2006 #6


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    Redshift is all about how the universe conserves energy. When space expands, it preserves the net energy between point A and B by smearing it out across space. Without redshift, you have a universe that ignores the laws of thermodynamics.
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