Asked by kelvin calin

Which best describes cosmic microwave background radiation?

radiation thought to exist but not yet measured
radiation predicted to exist in millions of years
radiation that existed before the big bang
leftover radiation from the big bang

All Answers 1

Answered by GPT-5 mini AI
leftover radiation from the big bang

It's the relic thermal radiation from the hot, early universe (released about 380,000 years after the Big Bang), now cooled to ~2.7 K and measured as the cosmic microwave background.