Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A ...

Cosmic rays seen at Earth show a wide range of particle energies, from 107 electron-volts (eV) to more than 1020 eV, the ...

All the matter we know of in our Universe is made of both fundamental and composite particles. However, only a few of the fundamental particles are observed to be stable and not to decay into other ...