Petrov Day, nuclear risk, and related discussions

40 years ago today, Stanislav Petrov might have prevented a nuclear war. To mark Petrov Day, we're hosting "Ask Me Anything" sessions with Andy Weber (U.S. Assistant Secretary of Defense from 2009-2014) and Christian Ruhl (senior global catastrophic risk researcher at Founders Pledge), and featuring some other related discussions. 

On September 26, 1983, the Soviet missile defense warning system “Oko” seemed to indicate that the US had launched five intercontinental ballistic missiles. Instead of following procedure and reporting the alarm, the engineer on duty Stanislav Petrov decided to wait for corroborating evidence — apparently following his intuition that the US is unlikely to start a war with only five missiles. He told his commanders that it was a false alarm. (It later turned out that the sun’s reflection off the clouds had confused a satellite.)

Petrov’s actions are believed to have prevented a retaliatory strike from the USSR, which would likely have started an all-out nuclear war. He was reprimanded for his actions. Petrov died in 2017. (For more: here’s a Vox article on Petrov and a Washington Post article.)