What significant event occurred about 500,000 years after the start of the Big Bang?
A) All the galaxies we see today formed.
B) Electrons and nuclei combined to form neutral atoms.
C) Quarks became confined.
D) The formation of helium stopped.

Question

Quizplus · Accepted Answer

About 500,000 years after the start of the Big Bang, the temperature of the universe had cooled down enough for electrons and nuclei to combine into neutral atoms, which allowed light to travel freely through space, resulting in the formation of the cosmic microwave background radiation. This is a significant event in the timeline of the universe's history.

What Significant Event Occurred About 500,000 Years After the Start