Neutrinos are emitted during the beta-decay process. Neutrinos definitely have spin. Do neutrinos have mass? Most texts say neutrinos have zero or negligible rest mass. But Neutrinos travel with the speed of light. So how can any particle with finite mass travel with the speed of light? If so how would it make neutrinos different from an electromagnetic wave? A neutrino has spin 1/2. An anti-neutrino also has spin 1/2. How is it possible to distinguish a neutrino from an anti-neutrino? Lastly, just out of curiosity , do neutrinos constitute the dark matter in the universe?