In 1939 a four-year-old boy at the New York World’s Fair watched a time capsule being buried for a civilization thousands of years away. That boy grew up to send humanity’s own time capsules into interstellar space. This episode traces Carl Sagan’s worldview from a Depression-era Brooklyn childhood shaped by an analytical mother and an empathetic father, through the library book that revealed stars are distant suns, to early admission to the University of Chicago at 16 and mentorship under Gerard Kuiper.

We cover his involvement in Project A119, the classified plan to detonate a nuclear weapon on the moon, his correct predictions of a 900-degree Venus, oceans under Europa, and organic lakes on Titan, the 1968 Harvard tenure denial and move to Cornell, the Pioneer plaques and Voyager Golden Record, the Pale Blue Dot photograph, Cosmos reaching half a billion viewers, and how a wormhole request for the novel Contact spurred Kip Thorne’s research. The episode also explores his baloney detection kit, climate testimony to Congress in 1985, the TTAPS nuclear winter model, the Mr. X essay, and Ann Druyan’s reflection after his death in 1996.

• How back-of-the-envelope calculations separate science from science fiction
• Why the mid-century academic establishment distrusted a public-facing polymath
• What went on the Golden Record and why its real audience was Earth
• Extraordinary claims require extraordinary evidence and the warnings that anticipated today’s misinformation
• Clashes with Edward Teller and arrests at nuclear test protests