Cosmic rays

High energy interstellar particles that travel at relativistic speeds. The 10 most abundant elements in cosmic rays are hydrogen, helium, oxygen, neon, nitrogen, magnesium, silicon, iron and sulphur. Cosmic rays emanate from many sources, including local stars, supernovae, and distant galaxies, and make life hazardous for forms of life in any unshielded habitat. Some cosmic rays even penetrate through planetary atmospheres.

See also

• cosmic background radiation