Most people know Edmond Halley only for the comet that bears his name, but this deep dive argues that is a massive historical injustice. Born in 1656 to a wealthy London soapmaker, Halley arrived at Oxford with a 24-foot telescope, corrected the Astronomer Royal's tables as a student, then abandoned his degree to sail to St. Helena and catalog 341 southern stars. There he observed a transit of Mercury and realized planetary transits could be used with parallax to measure the distance from Earth to the Sun. King Charles II personally forced Oxford to grant him a degree, and he was elected to the Royal Society at 22.

The episode follows Halley into his most consequential role: the man who coaxed Isaac Newton into writing the Principia, then edited, proofread, and personally financed it after the Royal Society blew its budget on a book about f ...