The CBR contains photons left over from the epoch in the universe's history when electrons recombined with nuclei.

Question

Quizplus · Accepted Answer

The Cosmic Microwave Background Radiation (CBR) is made up of photons that were produced approximately 380,000 years after the Big Bang when electrons and protons combined to form neutral atoms in a process called recombination. These photons have been traveling through space ever since, and make up the CBR that we can observe today.

The CBR Contains Photons Left Over from the Epoch in the Universe's