Which of the following statements correctly describes the universe for the entire first 380,000 years of its life?
A) All of the fundamental forces were united into one force.
B) It was filled with free quarks (not confined inside neutrons or protons).
C) It was a sea of nuclear reactions occurring at a gradually decreasing rate.
D) It was opaque.

Question

Quizplus · Accepted Answer

The universe was filled with plasma, which caused it to be opaque, preventing light from traveling freely through it. It wasn't until 380,000 years after the Big Bang that the universe had cooled down enough for the plasma to recombine into atoms and become transparent. Choices A and B are incorrect as they describe conditions that existed only during the earliest fraction of a second after the Big Bang, before the universe had expanded and cooled enough for these conditions to change. Choice C also does not accurately describe the universe during this time period.

Which of the Following Statements Correctly Describes the Universe for the Entire