• 1941 – Plutonium was first chemically identified by chemist Glenn T. Seaborg and his team at the University of California, Berkeley.


• 1987 – Light from the supernova SN 1987A (remnant pictured) in the Large Magellanic Cloud reached the Earth.

• Red Army Day or Day of Soviet Army and Navy in the former Soviet Union, also held in various former Soviet republics.