Which statement CORRECTLY describes the universe for the entire first 500,000 years of its life?
A) The universe was filled with free quarks (not confined inside neutrons or protons).
B) All the fundamental forces of nature were unified into one force.
C) The universe was a filled with a sea of nuclear particles undergoing violent reactions.
D) The universe was opaque.

Question

Quizplus · Accepted Answer

The universe was filled with high-energy radiation and was opaque for the first 500,000 years, meaning that light could not travel through it. It was only after the universe cooled down enough that atoms could form and the radiation was able to travel freely, making the universe transparent. Option A is incorrect because quarks were confined inside protons and neutrons during this time. Option B is incorrect because the forces of nature did not unify until much later in the history of the universe. Option C is also incorrect because the universe was not filled with a sea of nuclear particles undergoing violent reactions, but rather a sea of high-energy particles, such as photons and leptons.

Which Statement CORRECTLY Describes the Universe for the Entire First