An extremely energetic (relativistic) charged particle.

Atomic nuclei (mostly protons) that are observed to strike the Earth's atmosphere with extremely high amounts of energy.

radiation originating in outer space and consisting mostly of high-energy atomic nuclei.

an energetic particle originating outside our solar system. cosmic radiation: a stream of cosmic rays

(n.) A rapidly moving atomic nucleus from space. Some cosmic rays are produced in the sun, whereas others come from interstellar space and probably originate in supernova explosions.

An extremely energetic (relativistic) charged particle.

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

An extremely energetic and relativistic charged particle. Galactic Cosmic Rays originate from outside the solar system and the Sun can produce "cosmic rays" during energetic proton events. definition courtesy of: NWS Space Weather Prediction Center

High energy charged particles traveling through interstellar space at nearly the velocity of light. Most are produced in supernova explosions.

High energy sub-atomic particles from outer space that collide with the earth's atmosphere to produce a shower of gamma rays (and other particles) at high energies.

An extremely energetic (relativistic) charged particle.

An energetic particle originating outside our solar system. Cosmic radiation: a stream of cosmic rays.