.jpg)
"The little neutral ones" as Fermi had called them, neutrinos may actually span billions of light years through the universe.
During the big bang very large numbers of 'relic' neutrinos were produced. These neutrinos are quantum-mechanical superpositions of three mass-energy states. All these states would have moved almost at the speed of light in the early universe.
But, in a Physical Review Letters paper, George Fuller and Chad Kishimoto of the University of California, San Diego state that in their calculations the most massive of the states in the quantum-mechanical superpositions of 'relic' neutrinos, slowed down as the universe expanded, which stretched them across the universe.
This could mean that only one of the neutrino's states would be liable to fall into a black hole and it is not clear what would happen to the other states if this occured.