The first detection of geoneutrinos, by an instrument in Japan called Kamland, was reported in 2005. In November 2025, SNO+ reported its first detection, bumping up the number of observed geoneutrinos by about 50. Geochemists have conventionally assumed that radioactive elements are distributed evenly throughout the mantle, because the flowing rock should mix everything together. “There may be deep Earth structures in the mantle that are not understood,” Chen said. Neutrinos could one day offer new insight into the still mysterious origin of these deep structures and, more broadly, the patterns in the mantle that underlie many aspects of the Earth system.