cosmic rays

British  

plural noun

1. Also called: cosmic radiation.  radiation consisting of particles, esp protons, of very high energy that reach the earth from outer space

---

cosmic rays Cultural  

1. Elementary particles, mainly protons, that are produced by the sun and other stars and then strike the upper atmosphere of the Earth. Some of these particles are absorbed, some help form the Van Allen belt, and some reach the Earth's surface, where they form a part of the background radiation that constantly surrounds us.

---

Example Sentences

The findings mark an important advance in understanding how cosmic rays are created and how they travel through the galaxy.

From Science Daily • May 14, 2026

A photography student at a university has created unique works of art using cosmic rays high above the earth.

From BBC • Apr. 29, 2026

Earth's magnetosphere offers some protection against radioactive cosmic rays and solar particles to the orbiting ISS, but no such cover on the Moon.

From Barron's • Apr. 10, 2026

They evaluated long-term exposure to cosmic rays, changes during magma evolution, and contamination from meteorites.

From Science Daily • Feb. 8, 2026

Carbon 14 is continually being generated in the atmosphere by cosmic rays.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond