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Is the CMBR a relic from the big bang or an image from background galaxies?

  1. Sep 23, 2012 #1
    Some time ago there was a thread which suggested that there was a logic / papers that demonstrated why the the CMBR could not be the result of ligh from background objects / galaxies. Unfortunately, I have not been able to locate the thread or associated material. Is this correct, and could anyone give me references to related material?

    (I apprecialte that I am not / unlikely talking about light or resibual light from visible galaxies.)

    Regards,

    Noel.
     
    Last edited: Sep 23, 2012
  2. jcsd
  3. Sep 23, 2012 #2

    mfb

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    It is correct that the CMBR cannot be light from galaxies or similar objects. It could not explain its spectrum and the tiny angular variations of the temperature.
    I do not know of any papers discussing this - it is just too far away from observations, I think.
     
  4. Sep 23, 2012 #3
    Thanks MFB. I was reading a paper by Molnar & Birkinshaw on Contributions to the Power Spectrum of Cosmic Microwave Background from Fluctuations Caused by Clusters of Galaxies (ArXiv 0002271) and it reminded me of the thread - I probably just mis-remember!

    Regards,

    Noel.
     
  5. Sep 23, 2012 #4

    mfb

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    The paper discusses how light of the CMB gets influenced by galaxies which formed later - they are in the path of the existing light and can influence it.
     
  6. Sep 23, 2012 #5
    Thanks MFB.

    Regards,

    Noel.
     
  7. Sep 23, 2012 #6
    If you go back into the late-1960's and early-1970's you'd find plenty of papers. The idea that CMB was the result of diffuse galaxies was the "last stand" of the steady state model.

    http://adsabs.harvard.edu/abs/1968Natur.217..339S

    The problem with that explanation of the CMB was that you should see small fluctuations due to the individual galaxies, and you don't.....

    http://adsabs.harvard.edu/abs/1973ApJ...181..243B
    http://adsabs.harvard.edu/abs/1973ApJ...182L..61C

    One thing that happens a lot in astrophysics is that people come up with an idea, it gets killed, and then people forget why it got killed. Also looking at astrophysics history is interesting. The way it gets presented in textbooks, was that in 1965 when the CMB was discovered people immediately moved to support the big bang. In fact it took a few years, because the steady state people were able to come up with explanations for CMB, and the first set of measurements from sounding rockets actually went against the BB.

    By the early 1970's, it was obvious that there were problems with the sounding rocket data, and that balloon and satellite data pretty clearly confirmed the big bang by showing that the spectrum was extremely smooth, and couldn't come from difuse galaxies.
     
    Last edited: Sep 24, 2012
  8. Sep 24, 2012 #7
    Thanks TwoFish. That makes sense.

    Regards,

    Noel.
     
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