Map of global neutrinos shows nuclear activity

MIT Technology Review : Neutrinos were first detected in 1959 at the Savannah River nuclear power plant in Georgia. That observation led to the idea that measuring neutrino emissions could provide evidence of nuclear activity. Now William McDonough of the University of Maryland, College Park, and his colleagues have created a map of Earth that shows global neutrino emission levels. The map is based on data collected from neutrino detectors in Italy and Japan and on information about the density of Earth’s crust and the location of nuclear reactors. Dark areas highlight the reactors as well as naturally occurring areas of nuclear decay, such as the Himalayas. Neutrino detectors are more useful for monitoring known reactors than detecting hidden ones, because reactors are easily detected by the heat they give off. The detectors can also be useful for distinguishing uranium from plutonium, which is the primary fissile material used in nuclear weapons.