Author Question: Before the decoupling, A) deuterium produced electrons and positrons. B) protons and electrons ... (Read 120 times)

RRMR · **on:** Jul 27, 2018

Before the decoupling,

A) deuterium produced electrons and positrons.
B) protons and electrons combined to form atoms.
C) the universe was opaque to radiation.
D) there was more helium than hydrogen.
E) the universe was transparent to radiation.

Question 2

Why don't stars less massive then type M exist?

What will be an ideal response?

popopong · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

C

Answer to Question 2

A body less massive than a type M star (about 8 the Sun's mass) will not get hot enough by gravitational collapse to start fusing hydrogen into helium.