Skip to main content
19 votes

Is the universe macroscopically transparent to CMB? Is the fraction intercepted by stars and dust so tiny that it doesn't have a correction factor?

For the most part, the CMB photons travel directly to our telescopes from the surface of last scattering. Some corrections need to be made to determine the blackbody nature of the spectrum, but they ...
Eric Jensen's user avatar
  • 4,864
6 votes
Accepted

Is the universe macroscopically transparent to CMB? Is the fraction intercepted by stars and dust so tiny that it doesn't have a correction factor?

Let me add a minor addendum to Eric's excellent answer. The primary way in which CMB photons interact with matter is via scattering off of electrons in plasmas. After recombination (redshift $\sim ...
Peter Erwin's user avatar
  • 17.1k
5 votes
Accepted

Why does the first measurements of the thermal Sunyaev-Zel’dovich effect from ALMA show a temperature decrease and not an increase at the cluster?

Calling it a "temperature decrease" is kind of misleading. (Possibly this is a side effect of the tendency to use "brightness temperature" in radio astronomy to mean measured ...
Peter Erwin's user avatar
  • 17.1k
4 votes
Accepted

Non-thermal Sunyaev-Zel'dovich effect

The non-thermal S-Z effect is caused by inverse Compton scattering of the CMB photons from a non-thermal population of electrons - i.e. electrons that have high energies not because they are hot, but ...
ProfRob's user avatar
  • 153k

Only top scored, non community-wiki answers of a minimum length are eligible