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

There it looks for cascades of thousands of electrons and other particles, debris unleashed by cosmic rays or gamma rays crashing into Earth’s atmosphere.

From Popular-Science

“Our Earth gets bombarded by cosmic rays, galactic cosmic rays all the time,” he says.

From MIT Technology Review

The particles form when cosmic rays from space crash into Earth’s atmosphere, producing a shower of muons.

From Science News

Galactic cosmic rays coming from outside the solar system can cause harm, too.

From Singularity Hub 

The Auger Observatory and the Telescope Array in Utah have also detected smaller, subtler cosmic ray “hot spots” in the sky — presumably the locations of nearby sources.

From Quanta Magazine

Cosmic ray observations are more challenging than many other forms of astronomy.

From The Daily Beast

Due to their varying origins, they carry a variety of energies, which is called the cosmic ray spectrum.

From The Daily Beast

At the end of the second day after their trouble with the cosmic ray field, they stopped for observation.

From Project Gutenberg

The X-ray is high on the scale and even the cosmic ray is far above its lower limit of detection.

From Project Gutenberg

And he pointed to the cosmic-ray skiagraph of the Moon on the curved glass dome overhead.

From Project Gutenberg

It was relux, and he knew it, but he knew what would happen when that cosmic ray hit it.

From Project Gutenberg

Arcot shot out a cosmic ray himself, and swept the Thessian with it thoroughly.

From Project Gutenberg