All of our American fans (and anyone else that is familiar with our currency): please pull a dime from your pocket and hold it up for a second... guess what? About 150 billion tiny, nearly mass less particles called neutrinos just passed through it. You should really work on being more observant, I bet you didn't notice it at all. I guess i'll let it slide this time since they're invisible to the human eye 😉
A neutrino (which is one of the least understood fundamental particles that make up matter in the universe) is a type of lepton -- an electrically neutral, weakly interacting elementary subatomic particle with half-integer spin. There is much evidence acquired to suggest that neutrinos do in fact have mass but that their mass is tiny (even by the standards of subatomic particles), though we can't be sure, as their mass has not yet been measured accurately by physicists.
Scientists have found that they were created in great numbers during the big bang, but are also formed through processes like radioactive decay, interactions between cosmic rays and atoms and through nuclear reactions such as fusion in the cores of stars. The elementary particles come in three "flavors" (electron neutrinos, muon neutrinos and tau neutrinos. [The latter two are like electrons, only heavier] Each type also have a corresponding antiparticle) that are currently know and seemingly disappear just as quickly as they appear. Furthermore, it appears that they do NOT carry an electric charge, making them unaffected by electromagnetic forces that are known to affect charged particles like electrons and protons. However, they ARE affected by the weak subatomic force, which give them the ability to travel throughout the confines of the universe, through stars, planets and galaxies, without being fundamentally affected by it.
So, given the fact that trillions of these tiny particles pass through Earth on a daily basis without interacting with a single atom, how exactly do physicists detect them and study their properties? These images attached with the article are of a neutrino detector! How cool are they?