69: Solar Secrets & Nebulous Neutrinos

Fusion reactions in stars, including our Sun, produce huge amounts of neutrinos. These tiny elementary particles are almost impossibly hard to spot: ludicrous numbers of neutrinos are passing through you right now, without noticing your atoms at all. But they're one of the only ways we have to understand the inner workings of the Sun's core — and deep underground beneath an Italian mountain, astronomers have *finally* spotted neutrinos originating from the final piece of the stellar fusion puzzle, the CNO cycle.