cosmic microwave background

noun

Examples of cosmic microwave background in a Sentence

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In contrast, measurements based on the cosmic microwave background, the faint afterglow of the Big Bang, indicate a slower expansion, as well as a slightly older Universe of about 14 billion years. Georgina Jedikovska, Interesting Engineering, 5 Mar. 2026 Penzias and Wilson had accidentally found the cosmic microwave background, or CMB, the leftover radiation from the big bang. IEEE Spectrum, 20 Jan. 2026 Having established that the cosmic microwave background is symmetric on large scales, variations in this relic radiation from the big bang have been found. Subir Sarkar, Space.com, 5 Jan. 2026 And there was even an anti-Big Bang argument put forth just a few months ago that the cosmic microwave background might not be of cosmic origin, but that it might merely be reflected light emitted from galaxies. Big Think, 12 Nov. 2025 See All Example Sentences for cosmic microwave background

Word History

First Known Use

1981, in the meaning defined above

Time Traveler
The first known use of cosmic microwave background was in 1981

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Cite this Entry

“Cosmic microwave background.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cosmic%20microwave%20background. Accessed 11 Mar. 2026.

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