The Demon Core: Two Scientists Died From the Same Plutonium Sphere

Added: 2026-05-25

[00:00:00]Did you know two scientists died from the exact same piece of plutonium? They called it the demon core. August 1945, Los Alamos physicist Harry Daghlian was alone in a lab working with a 6-lb sphere of plutonium. He was stacking tungsten [music] bricks around it bringing it closer and closer to critical mass. One brick slipped from his hand. The moment it hit the core, the room filled with blue light.

[00:00:27]Daghlian had triggered a nuclear chain reaction with his bare hands. He died 25 days later from radiation poisoning.

[00:00:34]You'd think they'd destroy [music] the core after that. They didn't. Nine months later physicist [music] Louis Slotin was showing the same deadly sphere to colleagues. He used two screwdrivers to hold apart two metal [music] hemispheres around the core. His hand slipped. The screwdriver twisted.

[00:00:52]The hemispheres closed. Blue flash.

[00:00:55]Nuclear criticality. Again. Slotin died nine days later. His body [music] destroyed from the inside out. These weren't accidents. They were addiction.

[00:01:05]Scientists literally gambling with death using the world's most dangerous material as their poker chips. The demon core had claimed two lives and they kept playing.