1930

The dwarf planet Pluto was discovered by American astronomer Clyde Tombaugh.

1970

The “Chicago Seven” defendants were found not guilty of conspiring to incite riots at the 1968 Democratic National Convention; five were convicted of violating the Anti-Riot Act of 1968.

2001

Auto racing star Dale Earnhardt Sr. died in a crash on the final lap of the Daytona 500; he was 49.

Veteran FBI agent Robert Philip Hanssen was arrested, accused of spying for Russia.