Streams of high-energy particles that strike
the Earth’s atmosphere are called cosmic rays.
- most cosmic rays are deflected (pushed aside) by the Earth’s magnetic field or collide with particles in our Earth’s atmosphere long before they reach the ground..
- the study of cosmic rays provided scientists with most of their early knowledge about high-energy particles -these particle can only be made on Earth in huge machines (cosmic rays detection and arrays of detectors) called particle accelerators.
Energy Cosmic Rays level
- lowest-energy cosmic rays – come from the Sun or Galactic Cosmic Rays (GCRs) from outside the Solar System.
- medium-energy cosmic rays – come from sources within the Milky-Way, including powerful supernovae explosions.
- highest-energy cosmic rays – may come from outside the Milky-Way.
Galactic Cosmic Rays (GCRs)
- around 90% are nuclei of hydrogen atoms stripped of their electron. (see atom)
- most other CGRs are helium and heavier nuclei – there are also tiny positrons, electrons and neutrinos.
- neutrinos – so small that they pass almost straight through our Earth without stopping.