A stream of energetic particles, called cosmic rays, constantly bombards earth from space. It is kept from reaching the ground by earth’s atmosphere and magnetic field. Scientists know that cosmic rays come from the centres of large galaxies and from the explosive deaths of massive stars, or supernovae, based on detectors fit on satellites.
Scientists have also detected cosmic rays coming from the direction of the sun, which is because the star’s magnetic field has deflected them towards earth. Sometimes, particles in the cosmic rays interact with the sun’s atmosphere to produce gamma rays, which scientists study as solar gamma rays.
