Cosmic ray

Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. The composition includes electrons, protons, neutrons, and atomic nuclei from a large region of the periodic table. The kinetic energies of these particles span over fourteen orders of magnitude. The wide variety of particle energies is reflected in the wide variety of sources. Cosmic rays originate from energetic processes on the Sun all the way to the farthest reaches of the visible universe.

Cosmic rays can be conceptually broken into different kinds:

• Solar cosmic ray
• Galactic cosmic ray
• Anomalous cosmic ray

Cosmic rays can have energies up to 10E¹⁴ MeV ₁

History of Cosmic Rays

Cosmic rays were initially considered to come from some source other than the Sun. This was because the Sun was thought to emit little but visible light, and, of course, cosmic rays are isotropic and would arrive at Earth from all directions.

References:

• 1 -- Introduction to Geomagnetically Trapped Radiation by Martin Walt 1994