Why is cosmic background radiation used as evidence of the big bang theory of the origin of the universe?
A.
It corresponds to the temperature predicted by the big bang theory.
B.
It is emitted from a black hole at the center of the universe.
C.
Its wavelength is getting shorter, so it must be very old.
D.
It is not very common, so it must be running out.
1 answer
A. It corresponds to the temperature predicted by the big bang theory.