Dear PF Forum, I once read in several links just a couple of days ago, that the number of neutrinos exceeds the number of baryon in the universe by several orders of magnitude. 1. Is that true, that neutrinos are much more abundant than atoms? 2. Do neutrinos have mass? Not that they are catholic 3. If they have mass, I know I should have calculated it myself, which is more massive? Neutrinos or atoms in the universe? 4. Baryon asymetriy. Does that includes electron and neutrino? Thanks for any explanation.