Err, that SciAm author misunderstood that research... what they wrote is exactly backwards. The neutrino observations they're talking about disproved the natura

Err, that SciAm author misunderstood that research... what they wrote is exactly backwards. The neutrino observations they're talking about disproved the natural nuclear reactor hypothesis. There is no antineutrino signal from the Earth of the type a nuclear fission process would emit. https://arxiv.org/abs/1909.02257 https://arxiv.org/abs/1909.02257 ("Comprehensive geoneutrino analysis with Borexino") What Borexino found was about 25 terawatts of radioactive decay occurring inside the Earth—alpha decay of 238U and 232Th. But, no nuclear fission. If there are fissioning critical masses inside the Earth, the total amount, constrained by neutrino counts, is no more than 2.4 terawatts (and consistent with 0).