On this day in 1932, the journal Nature published a letter by English physicist James Chadwick that detailed his possible discovery of the neutron.

See omnystudio.com/listener for privacy information.

On this day in 1917, the Original Dixieland Jass Band made the first jazz recording. 

See omnystudio.com/listener for privacy information.

On this day in 1870, Hiram Revels became the first African-American U.S. senator.

See omnystudio.com/listener for privacy information.

On this day in 1803, the landmark U.S. Supreme Court case Marbury v. Madison was decided, establishing judicial review.

See omnystudio.com/listener for privacy information.

On this day in 1954, Dr Jonas Salk's polio vaccine trials began.

See omnystudio.com/listener for privacy information.

On this day in 1943, White rose members Sophie Scholl, Hans Scholl, and Christoph Probst were executed for passing out anti-Nazi pamphlets. 

See omnystudio.com/listener for privacy information.

On this day in 1965, Black nationalist leader Malcolm X was assassinated in New York City. 

See omnystudio.com/listener for privacy information.

On this day in 1902, renowned photographer Ansel Adams was born.

See omnystudio.com/listener for privacy information.

On this day in 1942, FDR signed Executive Order 9066, which authorized military commanders to prescribe certain areas as "military zones," which made it legal to incarcerate Japanese Americans in US concentration camps.

See omnystudio.com/listener for privacy information.

On this day in 1930, junior astronomer Clyde Tombaugh discovered that Pluto was a planet. Learn even more about Pluto on the episode of Stuff You Missed in History Class, Pluto: The Demoted Dwarf Planet.

See omnystudio.com/listener for privacy information.