During the First One-Ten-Thousandth of a Second (10^-4 S) of the Life

Multiple Choice

During the first one-ten-thousandth of a second (10^-4 s) of the life of the universe, antiprotons were very common. For every billion antiprotons, how many protons were there?

A) exactly 1 billion since protons and antiprotons were created in equal numbers
B) slightly more than 1 billion, thus producing the matter seen today
C) totally unknown number since the early universe was opaque and astronomers cannot see what conditions were like then
D) 10 billion, thus producing the dark matter seen today