Why is cosmic background radiation used as evidence of the big bang theory of the origin of the universe?

Question

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.

Answer 1

The correct answer is:

A. It corresponds to the temperature predicted by the big bang theory.

Cosmic background radiation, specifically the cosmic microwave background (CMB), is considered strong evidence for the Big Bang theory because it matches the temperature and properties that scientists predicted would exist if the universe started with a hot, dense state and has been expanding and cooling over time. The CMB is uniform and isotropic, with a specific temperature around 2.7 Kelvin, which aligns perfectly with theoretical predictions from the Big Bang model.