Answer to Question #69707 in Astronomy | Astrophysics for SANJAY

Question

Ques. What is cosmic background radiation? Explain why it is so important to the debate
between evolving and a steady-state universe.

Answer 1

Cosmic background radiation is electromagnetic radiation (i.e. light) with the spectrum of black body with the temperature of about 2.72 K.
The existence of the cosmic background radiation is one of the most powerful arguments that there was an epoch of our universe, when the temperature of matter was high. Then the light had no opportunity to propagate. But our universe expanded, and one day it became cold enough to let the light propagate. The properties of this primordial light were the same over the whole universe. Then this light cooled to the present temperature.
If the universe is steady-state then there is no reason to existence of isotropic light.