|Main Entry:||cosmic background radiation|
|Part of Speech:||n|
|Definition:||microwave radiation in the universe, produced during the Big Bang and subsequently thinned and cooled as the universe expanded; also called background radiation|
|cosmic background radiation
Weak radio-frequency radiation traveling through outer space with equal intensity in every direction. It is thought to be residual radiation from a period shortly following the big bang, when the universe was very hot. Also called microwave background.