Why does the Big Bang theory predict that the cosmic background radiation should have a perfect thermal radiation spectrum?
A)The spectrum of pure hydrogen gas must be a perfect thermal radiation spectrum.
B)The background radiation came from the heat of the universe, with a peak corresponding to the temperature of the universe.
C)The spectrum of 75 percent hydrogen and 25 percent helium must be a perfect thermal radiation spectrum.
D)The light from all the stars and gas in the sky averaged over the entire universe will be a perfect thermal radiation spectrum.
E)It doesn't predict that the cosmic background radiation should have a perfect thermal radiation spectrum.

Question

Quizplus · Accepted Answer

According to the Big Bang theory, the universe was once very hot and dense. As it expanded and cooled, it emitted radiation in the form of photons, which eventually became the cosmic microwave background radiation. This background radiation should therefore have a thermal radiation spectrum with a peak corresponding to the temperature of the universe at that time, which is predicted by the theory.

Why Does the Big Bang Theory Predict That the Cosmic