cosmic ray


Definition of cosmic ray

: a stream of atomic nuclei of extremely penetrating character that enter the earth's atmosphere from outer space at speeds approaching that of light

Examples of cosmic ray in a Sentence

Recent Examples on the Web Additionally, galactic cosmic rays try to flow into our solar system, but only 30 percent of these rays actually reach Earth. Jennifer Leman, Popular Mechanics, "We Finally Know What Happened When Voyager 2 Reached Interstellar Space," 4 Nov. 2019 Because the events that create gamma rays also spawned the cosmic rays Hess detected, your eyes led us back to the sites of two former stellar explosions. Liz Kruesi, National Geographic, "Dear Fermi: What it means to see the universe's extremes," 11 June 2019 Designed to operate for just three years, the AMS proved longer lived than expected, detecting more than 145 billion cosmic rays during eight-and-a-half years of operation. William Harwood, CBS News, "Astronauts to perform "open heart surgery" on cosmic ray detector in complex spacewalk," 15 Nov. 2019 Changes are due to sunspots/galactic cosmic rays Sunspots are storms on the sun’s surface that come with intense magnetic activity and can be accompanied by solar flares. Mark Maslin, Teen Vogue, "5 Climate Change Myths Debunked," 18 Sep. 2019 After a burst of cosmic rays from deep space threatens life on Earth, Roy must venture to the outer reaches of the solar system to find the source, where clues about his father's disappearance may also lie. Thomas Page, CNN, "James Gray on 'Ad Astra,' little green men and firing Brad Pitt into space," 16 Sep. 2019 If the nucleus recoils with enough vigor, and if the atoms that are perturbed are then buried deep in the earth (to shield the sample from cosmic rays that can muddy the data), then the recoil track could be preserved. Wired, "Dark Matter Hunters Are Looking Inside Rocks for New Clues," 13 Jan. 2019 Without the magnetic protection, particles from space called cosmic rays relentlessly bombard the moon’s surface and produce gamma radiation, some of which escapes. Kelso Harper, Scientific American, "Flashing Neurons, Invisible Moonlight and Adorable Squid Babies: The Week’s Best Science GIFs," 23 Aug. 2019 For now, the researchers are turning to sunspots and cosmic rays for an explanation. Alex Fox, Science | AAAS, "The world’s strongest lightning hits—not in summer—but from November to February," 9 Sep. 2019

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

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First Known Use of cosmic ray

1925, in the meaning defined above

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Time Traveler for cosmic ray

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The first known use of cosmic ray was in 1925

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Statistics for cosmic ray

Last Updated

6 Dec 2019

Cite this Entry

“Cosmic ray.” The Dictionary, Merriam-Webster Inc., Accessed 12 December 2019.

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More Definitions for cosmic ray

cosmic ray


English Language Learners Definition of cosmic ray

technical : a stream of energy that enters the Earth's atmosphere from outer space

cosmic ray


Kids Definition of cosmic ray

: a stream of very penetrating particles that enter the earth's atmosphere from outer space at high speed

More from Merriam-Webster on cosmic ray

Rhyming Dictionary: Words that rhyme with cosmic ray Encyclopedia article about cosmic ray

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