The Cosmic Microwave Background Radiation



If the universe began in an infinitely hot, infinitely dense state:

Expansion of the universe:


The Cosmic Microwave Background Radiation (CMBR) should appear as a (nearly) uniform "hiss" of microwave radiation on the sky and it should have a black body spectrum.


Observations of the CMBR:





Temperatures on the Earth (note the large range)









Temperature "Fluctuations" in the CMBR (Average Temp. = 2.73K)
blue = colder than average, red = hotter than average





Why should you care about the CMBR?


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