The Demon Core: A 6lb Ball of Death That Killed 2 Scientists

Added: 2026-06-02

[00:00:00]Did you know a softball size sphere killed two scientists and they kept experimenting with it? The demon core was 6 lb of plutonium used in the Manhattan Project. On August 21st, 1945, physicist Harry Daghlian was working alone late at night. He accidentally dropped a tungsten brick onto the core.

[00:00:17]The room filled with blue light.

[00:00:18]Daghlian had just received a lethal dose of radiation. He died 25 days later in agony. 9 months later, Louis Slotin made the same mistake during a demonstration.

[00:00:28]He died 9 days later. Both times, the core killed in seconds. Both times, they knew the [music] risks.