I have been reading a lot about Cosmological experiments such as Planck or WMAP that aim to investigate the CMB's power spectrum. I am unclear though as to what theses sky surveys actually measure, is it the distance to regions of temperature fluctuations?
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They measure the spectrum of microwaves (with pretty good angular resolution) over the whole sky.
The spectrum represents the red-shifted black-body of the hot, early universe plus local contributions. They separate out the underlying black-body spectrum and that is the signal.
Much information can be extracted from the temperature- and angular-fluxuations of the signal.
answered Apr 11, 2013 at 19:34
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