What are Cosmic rays?

Cosmic rays are electro magnetic waves of extremely short wave length. Origin of cosmic rays is from outer space or the cosmos. These rays consists positively charged particles coming from various galaxies outside the solar system and comprise mainly of protons, alpha particles and positive ions of some heavy elements.

Sun is a poor source of cosmic rays. The distant galaxies are the storehouses of charged particles. The high electric and magnetic fields present in these galaxies act as natural accelerators of these particles. The high velocities and the charged nature of these particles attribute the wave nature of these particles. Before entering into the atmosphere, the cosmic rays consist of 89 per cent protons, 9 per cent helium nuclei and the remaining 3 per cent heavy nuclei. The thick atmosphere around us is a natural blanket protecting us from harmful cosmic rays.

Millikan and Anderson first stated about cosmic rays on balloon flights. The intensity of these rays has been found to vary with altitude, latitude and depth under the sea. The primary cosmic rays interact with the molecules of the atmosphere giving rise to secondary particles like electrons, positrons and mesons. Antiproton was discovered during cosmic ray studies.