There are a Bazillion of Them

Ginormous Neutrino

We think of fundamental particles as being very small, but “relic” neutrinos left over from the big bang could be big. Really big. According to the 22 May Physical Review Letters, the quantum wave describing one could be billions of light-years across, a good fraction of the observable universe. Such a large wave raises questions about how a quantum particle interacts with gravity at the scale of galaxies and galaxy clusters–questions that remain unresolved.