A comet astronomer also invented the math behind your life insurance
In 1693, Edmond Halley analyzed birth and death records from Breslau to build one of the first rigorous life tables, showing how to calculate the probability of surviving to any given age. His method let insurers price annuities based on real mortality data instead of guesswork, helping found modern actuarial science. It's the same Halley who predicted the return of the comet that now carries his name.