Detectors zero in on Earth's heat

摘要

A window on the deep Earth opened unexpectedly in 2011, when Japan's nuclear reactors were shut down after the Fukushima disaster. Before the closure, an underground particle detector called Kam-LAND based in Kamioka, Japan, was monitoring a torrent of neutrinos streaming from dozens of nearby nuclear reactors, seeking clues to the nature of these hard-to-catch subatomic particles. After those plants fell silent, KamLAND scientists could see more clearly a signal that had largely been obscured: a faint trickle of neutrinos produced inside the planet.