Subatomic particles called neutrinos—billions of which are whipping through you and the device you’re reading—were the subject of this year’s Nobel Prize in Physics, awarded on Tuesday. Neutrinos come in three types, or “flavours”, created in different nuclear processes. But because they very rarely interact with any other particles, learning much more about them has been difficult. The prize went to Takaaki Kajita of Japan and Arthur McDonald of Canada; each led experiments that found fewer neutrinos of one flavour than theory predicted, or too many of another. The only explanation was that neutrinos can flip their flavour on their travels. That, in turn, implied they have mass, a finding that put a significant crack in the Standard Model, the current-best theory of physics. Patching that crack could, among other things, resolve why the universe contains more matter than antimatter—that is, why you and your device are here at all.