Why does the Big Bang theory predict that the cosmic background radiation should have a perfect thermal radiation spectrum?
A) The background radiation came from the heat of the universe, with a peak corresponding to the temperature of the universe.
B) The spectrum of pure hydrogen gas must be a perfect thermal radiation spectrum.
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 cosmic background radiation is the afterglow of the hot, dense early universe that was filled with photons. As the universe expanded and cooled, these photons lost energy and their wavelengths stretched, ultimately reaching the microwave region of the electromagnetic spectrum. The cosmic background radiation should be a perfect thermal radiation spectrum because it originated from the heat of the early universe, with a peak corresponding to the temperature of the universe at that time.

Why Does the Big Bang Theory Predict That the Cosmic