Discovered by Ernest Rutherford around 1900. Nuclei are composed of protons and neutrons. The mass of the total products of the reaction is less than the original mass. Fission is a nuclear reaction in which large, heavy nuclei such as those of uranium or plutonium are split into smaller nuclei plus byproducts. Again, the total mass of the products is less than that of the original nuclei, and the mass difference is converted into energy.
Nuclear fission occurs in atom bombs, and in controlled nuclear reactors.
Neutrinos can pass right through the Sun, and so it should be possible to detect the neutrinos coming from the fusion reaction at the core of the Sun. This document was last updated July 3, 1999.