Elusive geoneutrinos help map Earth's radioactive interior

The SNO+ detector in Canada's Creighton mine reported the first geoneutrino measurements in the Western Hemisphere, capturing particles from uranium, thorium and potassium decay in Earth's mantle. The results hint that the mantle may not be uniformly mixed.

• SNO+ holds 780 tons of scintillator and nearly 10,000 light detectors 2 km underground
• Only a few hundred geoneutrinos have been detected since 2005
• In November 2025 SNO+ added about 50 new events
• Differing fluxes may hint at a non-uniform mantle