Cosmic rays are fast-moving ionizing particles from the Sun. The Earth’s magnetic field prevents them from reaching us because they would be very harmful. Solar flares (bursts of energy from the Sun) interfere with these satellite systems. Cosmic rays are not really rays at all, they are a stream of particles of ionised atoms. They can range from a single proton to the nucleus of an iron atom-or larger. Cosmic ray particles are travelling at speeds close to that of light and they have a lot of energy.