microwave background

British

noun

a background of microwave electromagnetic radiation with a black-body spectrum discovered in 1965, understood to be the thermal remnant of the big bang with which the universe began

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

microwave background Scientific

See cosmic background radiation

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The second method looks at the early universe by studying the cosmic microwave background, the faint radiation left over from the Big Bang.

From Science Daily • Apr. 29, 2026

Arno Penzias at Bell Labs won the Nobel Prize in Physics for discovering “cosmic microwave background radiation” from the Big Bang.

From The Wall Street Journal • Mar. 29, 2026

They used measurements of the cosmic microwave background to estimate how matter was distributed shortly after the Big Bang.

From Science Daily • Mar. 6, 2026

They’ve measured the cosmic microwave background, or leftover radiation from the Big Bang, with extremely high precision to help paint a picture of the first nanoseconds of the universe.

From Salon • Jan. 17, 2025

This is consistent with the observations of the microwave background radiation, which show that it has almost exactly the same intensity in any direction.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023