The Ammonia Connection and Mode 3

In 1972, a Soviet spacecraft detected ammonia in the clouds of Venus at concentrations so high they couldn't be explained by any known chemistry. The scientific community dismissed it within two years, and the finding sat untouched for half a century. Then a team of researchers built a model showing that ammonia isn't just present in those clouds — it may be actively remaking the chemistry of the entire cloud layer, neutralizing the acid, altering the particle composition, and explaining a set of unrelated atmospheric mysteries all at once. This episode lays out that model, introduces the strange large cloud particles known as Mode 3, and asks a question that becomes harder to dismiss the more you look at it: what could possibly be producing that much ammonia on a planet with no obvious source?