Question: what are neutrinos?

Pierre Lasorak answered on 8 Nov 2014:

Hello
Neutrino are fundamental particles, this means we can’t break them in smaller pieces. Neutrino have this particularity that they interact very weakly. There are 4 known way of interacting for fundamental particles: gravitation (pulls you on earth), electromagnetic (charges your phone), “weak interaction” (produces energy in nuclear reactor), and “strong interaction”. All the particles undergo one or more of this interactions, and basically neutrino is the only one who interact through the weak interaction.
The fact that it is interacting weakly mean two things for us if we want to do experiment: we need to have a lot of neutrinos (something like 10 with 12 zeros behind) and huge detectors (tons and tons of water for example) if we want to have the chance to see 1 neutrino.
Neutrinos also have this strange property: They are like Superman and Clark Kent! Clark Kent interact with person, he speaks… But when Clark Kent wants to travel, he becomes Superman! But now neutrino are even more crazy and it would be as if Clark Kent interacts and speaks somewhere, then travels as Superman for miles across the mountains, and then when he interacts again he is not Clark Kent, but has changed and he became somebody else, say John Lennon. The travelling changed him! This is called neutrino oscillation and it is a lot of experiment are measuring right now.