Cosmic rays

Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are protons, almost 10% are helium nuclei (alpha particles), and slightly under 1% are heavier elements and electrons (beta minus particles).^[1]The term ray is a misnomer , as cosmic particles arrive individually, not in the form of a ray or beam of particles.