In the very first phase after the big bang, when the Universe was about a microsecond old, space was filled with____.
A) high-energy photons
B) protons and antiprotons
C) protons, neutrons, electrons, and positrons (anti-electrons)
D) electrons, and positrons (anti-electrons)
E) protons, neutrons, electrons

Question

Quizplus · Accepted Answer

In the very first phase after the Big Bang, the Universe was extremely hot and dense, filled with high-energy photons.

In the Very First Phase After the Big Bang, When