cosmic background radiation

noun, Astronomy

electromagnetic radiation coming from every direction in the universe, considered the remnant of the big bang and corresponding to the black-body radiation of 3 K, the temperature to which the universe has cooled.

Also called cosmic microwave background.

Contemporary definitions for cosmic background radiation

noun

microwave radiation in the universe, produced during the Big Bang and subsequently thinned and cooled as the universe expanded; also called background radiation

Usage Note

science

cosmic background radiation in Science

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.