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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.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
cosmic microwave background 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
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
cosmic microwave background in Culture

cosmic microwave background

The microwave radiation that arrives at the Earth from every direction in space. The detection of this radiation played an important role in acceptance of the Big Bang theory.

Note

This radiation is sometimes referred to as the “echo” of the Big Bang.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.