cosmic ray

noun

Physics.

1. a radiation of high penetrating power that originates in outer space and consists partly of high-energy atomic nuclei.

cosmic ray

1. A ray of radiation of extraterrestrial origin, consisting of one or more charged particles such as protons, alpha particles, and larger atomic nuclei. Cosmic rays entering the atmosphere collide with atoms, producing secondary radiation, such as pions, muons, electrons, and gamma rays. Cosmic rays (and secondary radiation) can be easily seen in a cloud chamber.

Word History and Origins

Origin of cosmic ray¹

An Americanism dating back to 1920–25

Example Sentences

New work from astrophysicists at Michigan State University may help resolve a scientific question that has lingered for more than a century: where do galactic cosmic rays come from?

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Other theories propose that cosmic rays start the process because the charged particles they produce accelerate within existing electric fields.

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Researchers long suspected that the feature reflects the highest energies that cosmic ray sources can reach, marking a shift in the spectrum from one power-law behavior to another.

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But when the Cold War propelled the U.S. to seek technological dominance on Earth and beyond, it was JPL that developed the U.S.’ first successful satellite, Explorer 1, designed to study cosmic rays.

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Since extreme temperatures and cosmic rays break down rubber or turn it to a brittle glass, metal alloys and high-performance plastic are chief contenders for airless space tyres.

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