A new measurement finds the universe’s teensiest particles weigh no more than one-millionth the mass of an electron.
Physicists have placed a new limit on how big the elusive neutrino can be—one of the universe’s smallest known particles—a limit that makes other subatomic particles look as big as black holes by comparison.
In a new result published this week in Science, researchers have put a new upper limit on the mass of this itsy-bitsy particle: no more than 0.45 electron volts (eV). For context, that’s less than one-millionth the mass of an electron, which clocks in at a comparatively gargantuan 511,000 eV. So, yeah—neutrinos are ridiculously lightweight.
Trillions of neutrinos pass through your body every second, but they are so small and so weakly interacting that you don’t feel a thing.
Neutrinos are the only known elementary particles whose mass remains unknown, though questions remain about how well those elementary particles cooperate with the Standard Model.
