Neutrinos (meaning "small neutral one"; ) are elementary particles that often travel close to the speed of light, are electrically neutral, are able to pass through ordinary matter almost undisturbed and are thus extremely difficult to detect. Neutrinos have a minuscule, but nonzero mass. They are denoted by the Greek letter ν (nu). Neutrinos are created as a result of certain types of radioactive decay or nuclear reactions such as those that take place in the Sun, in nuclear reactors, or… (More on Neutrino)