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Dark matter

  1. Sep 5, 2008 #1
    I heard that dark matter could be the CMB mass corresponding, but I am not satisfied from that.
    What about this?
  2. jcsd
  3. Sep 5, 2008 #2


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    What does "CMB mass corresponding," mean?
    In any case the CMB consists of photons with a spectrum of about 2.7 deg. K. What dark matter is made up of is unknown. What is known is that it is NOT ordinary (baryonic) matter or photons.
  4. Sep 5, 2008 #3


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    mathman is right. There is no possible correspondence.
    Dark matter distribution is very uneven in space---it has been mapped using the optical distortion it causes (so-called weak lensing effect)

    the maps clearly show that it collects in large blob-shaped clouds around galaxies and clusters of galaxies. it tends to collect where there is already some matter to attract it gravitationally.

    by contrast, the CMB photons are distributed almost evenly throughout all space, they are going too fast to collect around galaxies or anything else, there are as many of them in a cubic light year in one place as in the same volume somewhere else----almost the same number everywhere

    also such a correspondence would not add up. dark matter represents much more stuff.
    or it would have to be a very exotic strange correspondence, by some mechanism that nobody I know of has described.

    if you have a link to where you read about it, we could have a look-see.
  5. Sep 5, 2008 #4


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    Perhaps a language barrier, ignition. It sounds like you are inquiring about the CMB power spectrum. It is true it favors existence of DM. Here is an article you may find interesting: http://www.sarahbridle.net/lectures/uclgrad07/lss_and_cmb.pdf [Broken]
    Last edited by a moderator: May 3, 2017
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