A ray of radiation of extraterrestrial origin, consisting of one or more charged particles such as protons, alpha particles, and larger atomic nuclei. Cosmic rays entering the atmosphere collide with atoms, producing secondary radiation, such as pions, muons, electrons, and gamma rays. Cosmic rays (and secondary radiation) can be easily seen in a cloud chamber.
|an extraordinary or unusual thing, person, or event; an exceptional example or instance.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|