At about what time after the Big Bang did the universe pass through the transition from being radiation-dominated to being matter-dominated?
A) at the Planck time, 10-⁴³ s
B) about 15 billion years, as stars began to form
C) 500,000 years
D) 30,000 years

Question

Quizplus · Accepted Answer

The universe transitioned from being radiation-dominated to matter-dominated approximately 30,000 years after the Big Bang.

At About What Time After the Big Bang Did the Universe