Tag Archives: Milky Way galaxy

What are Cosmic Rays?

Cosmic rays are very high energy atomic nuclei (mostly protons) traveling through space at close to the speed of light that strike the Earth’s atmosphere.

Cosmic rays are mostly pieces of atoms: protons, electrons, and atomic nuclei. The term “cosmic rays” usually refers to galactic cosmic rays, which originate in sources outside the solar system, distributed throughout our Milky Way galaxy.