Question

What is the cosmic background radiation?

the light emitted by supernova explosions
the radio noise from hot gas in rich galactic clusters
the light-energy remnants of the explosion in which the universe was born
the faint glow of light across the night sky

Answer 1

[AI-generated answer — Bot GPT 3.5]

The cosmic background radiation is the faint glow of light across the night sky that is the light-energy remnants of the explosion in which the universe was born. This radiation is also known as the cosmic microwave background radiation and is one of the strongest lines of evidence supporting the Big Bang theory.