An international group of scientists announced Monday that they were on the way to determining that neutrinos have mass, a finding that could overturn the current understanding of the universe.
Neutrinos are elementary subatomic particles thought to be behind the "dark matter" theory used to account for mass thought missing from the universe.
The scientists fired a neutrino beam from Tsukuba, Ibaraki Prefecture, through 250 km of solid rock to hit the Super Kamiokande subatomic particle detector, a 50,000-ton water-filled chamber sitting under a mine in Kamioka, Gifu Prefecture.