The Demon Core, Ghost Hoaxers, and the Accidental Origins of Pasteurization

This episode of The Weirdest Thing I Learned This Week brings together three stories that each reveal something about how dangerous knowledge gets handled—sometimes recklessly, sometimes theatrically, sometimes with world-changing consequences. The throughline is less about the facts themselves than about the human tendency to push boundaries, whether those boundaries are nuclear criticality, social order, or scientific orthodoxy.

Tickling the Dragon's Tail

The "demon core" was a 14-pound plutonium sphere, just three and a half inches in diameter—roughly softball-sized—that was originally intended as the core for a third atomic bomb to be dropped on Japan in August 1945. When Japan surrendered before the third shot could be used, the core was repurposed for Operation Crossroads, the nuclear testing program at Bikini Atoll.

Between those two missions, the core killed two scientists in separate accidents. The first victim, Harry Daglian, was working alone in 1945 when he accidentally dropped a tungsten carbide brick—a neutron reflector—directly onto the core. The brick caused the core to go briefly critical, delivering a fatal dose of ionizing radiation. He died 25 days later.