Neutrinos are unimaginably numerous, but their infrequent interaction with matter make the particles a challenge to study. Neutrinos exist in three “flavors:” muon, electron and tau. The NOvA experiment aims to investigate one of the peculiar properties of neutrinos — their tendency to change flavors, or oscillate. NOvA is what the physicists call a long-baseline experiment, as the neutrinos travel more than 500 miles underground. “We make a beam of muon-type neutrinos at Fermilab, and then we detect those at Ash River, Minnesota,” Vahle explained. “We are looking for muon-type neutrinos to change into electron-type neutrinos. We also look for...