Could CMB Mass Reveal Insights About Dark Matter?

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Discussion Overview

The discussion revolves around the potential relationship between the Cosmic Microwave Background (CMB) and dark matter, specifically whether the mass of the CMB could correspond to dark matter. Participants explore the implications of this idea and the characteristics of both the CMB and dark matter.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants express skepticism about the idea that dark matter could correspond to the mass of the CMB, questioning the meaning of "CMB mass corresponding."
  • One participant emphasizes that dark matter is not ordinary matter or photons, noting that its composition remains unknown.
  • Another participant argues that dark matter is unevenly distributed in space, mapped through weak lensing effects, and collects around galaxies, contrasting with the nearly uniform distribution of CMB photons.
  • It is suggested that any proposed correspondence would need to account for the significant difference in the amount of dark matter compared to the CMB, implying a need for an exotic mechanism that has not been described.
  • A later reply introduces the concept of the CMB power spectrum, indicating that it may favor the existence of dark matter, and provides a link to further reading.

Areas of Agreement / Disagreement

Participants generally disagree on the potential correspondence between CMB mass and dark matter, with multiple competing views presented regarding their characteristics and distributions.

Contextual Notes

Participants express uncertainty about the definitions and implications of terms used in the discussion, particularly regarding the relationship between CMB and dark matter.

Ignition
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I heard that dark matter could be the CMB mass corresponding, but I am not satisfied from that.
What about this?
 
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Ignition said:
I heard that dark matter could be the CMB mass corresponding, but I am not satisfied from that.
What about this?

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.
 
Ignition,
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.
 
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
 
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