background radiation


Definition of background radiation

: the microwave radiation pervading the universe that exhibits a corresponding blackbody temperature of 2.7 K and that is the principal evidence supporting the big bang theory

called also cosmic background radiation

Examples of background radiation in a Sentence

Recent Examples on the Web Many factors contribute to errors in quantum systems, including the environment, noise from internal components, background radiation, cabling, and even noise caused by qubits themselves. Paul Smith-goodson, Forbes, 15 June 2021 The needle jumps, showing a reading 50% higher than the already elevated background radiation. Gavin Blair, The Christian Science Monitor, 26 Feb. 2021 The aircraft belong to the Energy Department’s National Nuclear Security Administration, which is testing naturally occurring background radiation levels ahead of the 2021 presidential inauguration. Gabriel T. Rubin, WSJ, 23 Oct. 2020 The federal helicopter survey was originally supposed to fly above parts of the Bay Area as part of a research project to study background radiation levels. Cynthia Dizikes,, 3 Sep. 2020 That means, Martens said, that there’s about a 2 in 10,000 chance that random background radiation produced the signal as opposed to solar axions themselves. Rafi Letzter, Scientific American, 17 June 2020 But all detectors, no matter how well-shielded, experience noise from sources such as background radiation. Daniel Garisto, Scientific American, 9 June 2020 Peebles and his colleagues had predicted this background radiation, a result of when the universe, about 400,000 years after the Big Bang, cooled off enough for hydrogen and helium atoms to form., 9 Oct. 2019 Further such tests, and more refined observations of other cosmological features (such as the remnant microwave background radiation generated when the universe was young), might still someday find flaws in general relativity. Tom Siegfried, Scientific American, 21 Jan. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'background radiation.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of background radiation

1968, in the meaning defined above

Keep scrolling for more

Learn More About background radiation

Time Traveler for background radiation

Time Traveler

The first known use of background radiation was in 1968

See more words from the same year

Dictionary Entries Near background radiation

background projection

background radiation


See More Nearby Entries 

Statistics for background radiation

Cite this Entry

“Background radiation.” Dictionary, Merriam-Webster, Accessed 17 Sep. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon


Test Your Vocabulary

Dog Words Quiz

  • shiba puppy more or less demanding cuddles
  • Which of the following animals has a dog in its etymology?
Spell It

Can you spell these 10 commonly misspelled words?

 AlphaBear 2

Spell words. Make bears.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!