The idea of the neutrino was put forward in 1930 by Wolfgang Pauli in a desperate attempt to preserve energy conservation in nuclear beta decay. Soon Enrico Fermi exploited the idea to create a theory of the weak interactions that laid the foundation for the now-standard model of particle physics. Because of the putative neutrino’s small interaction cross section, Pauli dubbed it “the particle that cannot be detected.” But in 1956 Frederick Reines proved him wrong. Reines realized that one could compensate for the tiny cross section with a large detector and a copious neutrino source. After toying with the idea of an atomic bomb as the source, Reines settled on a nuclear reactor and discovered the neutrino with a detector that would look familiar today: a 200-liter liquid scintillator target monitored by photomultiplier tubes. 1
Reines has said that the idea of the neutrino as an astronomical messenger came...
