Where do the photons in the cosmic background radiation originate?
A)the moment of the Big Bang
B)the end of the Planck era
C)during the era of nucleosynthesis
D)the end of the era of nuclei
E)during the era of galaxy formation

Question

Quizplus · Accepted Answer

The photons in the cosmic background radiation originate from the end of the era of nuclei, also known as the recombination era, when electrons combined with protons to form neutral hydrogen atoms, allowing photons to travel freely through space.

Where Do the Photons in the Cosmic Background Radiation Originate