On This Day

Leó Szilárd

Physicist and Inventor Leó Szilárd

Profession: Physicist and Inventor

Why Famous: Leó Szilárd was a leading figure both in the development of nuclear energy and as an activist calling for its peaceful use.

He began studying physics in Berlin in the 1920s, becoming close friends with Albert Einstein. He moved to England when Adolf Hitler came to power in 1933. There he was the first to develop the idea of a nuclear chain reaction.

Sensing war in Europe he moved to the United States where he continued his work on nuclear energy. In 1939 Szilárd drafted the 'Einstein letter' signed by Albert Einstein delivered to President Franklin D. Roosevelt about the possibilities of nuclear weapons. The result was the Manhattan Project. In 1942 Szilárd was part of the team that built Chicago Pile-1, the world's first artificial nuclear reactor. Both during and after WWII he strongly advocated for restraint in the use of nuclear weapons; it was his idea to install a 'Hot Line" between Moscow and Washington D.C.

After the war Szilárd became a prominent biophysicist and helped found the Salk Institute for Biological Studies.

Born: February 11, 1898
Birthplace: Budapest, Hungary, Austro-Hungarian Empire

Generation: Lost Generation
Star Sign: Aquarius

Died: May 30, 1964 (aged 66)
Cause of Death: Heart attack

Events in the Life of Leó Szilárd

  • 1930-11-11 Patent number US1781541 is awarded to Albert Einstein and Leó Szilárd for their invention of the Einstein refrigerator
  • 1933-09-12 Leó Szilárd, waiting for a red light on Southampton Row in Bloomsbury, conceives idea of a nuclear chain reaction
  • 1934-07-04 Hungarian physicist Leo Szilard patents the chain-reaction design for the atomic bomb
  • 1942-12-02 World’s 1st self-sustaining nuclear chain reaction occurs in Chicago Pile-1 (world's 1st nuclear reactor) at the University of Chicago, overseen by Enrico Fermi

External Biographies