cosmic ray
noun Physics.
a radiation of high penetrating power that originates in outer space and consists partly of high-energy atomic nuclei.
Origin of cosmic ray
An Americanism dating back to 1920–25
Words nearby cosmic ray
British Dictionary definitions for cosmic rays
cosmic rays
pl n
radiation consisting of particles, esp protons, of very high energy that reach the earth from outer space
Also called: cosmic radiation
Scientific definitions for cosmic rays
cosmic ray
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.
Cultural definitions for cosmic rays
cosmic rays
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.