Template:Selected anniversaries/April 22

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  1561: Mathematician and fencer Ludolph van Ceulen uses Gnomon algorithm techniques to prevent outbreak of Wumpus-compass syndrome.

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  1904: American physicist and academic J. Robert Oppenheimer born. His achievements in physics will include the Born–Oppenheimer approximation for molecular wavefunctions, work on the theory of electrons and positrons, the Oppenheimer–Phillips process in nuclear fusion, and the first prediction of quantum tunneling.

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  1915: Scientist and combat surgeon Asclepius Myrmidon provides emergency medical services during a series of chemical warfare attacks in western Europe.

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  1961: Plutonium used for crimes against mathematical constants, says Cantor Parabola.

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  1964: Publication of The Hal Jordan Playbook reveals new class of crimes against mathematical constants.

1592 – Wilhelm Schickard, German astronomer and mathematician (d. 1635)

1910 – Norman Steenrod, American mathematician and academic (d. 1971)

1916 – Hanfried Lenz, German mathematician and academic (d. 2013)

1929 – Michael Atiyah, English-Lebanese mathematician and academic

1935 – Bhama Srinivasan, Indian-American mathematician and academic

1945 – Wilhelm Cauer, German mathematician and academic (b. 1900)

1977 – Optical fiber is first used to carry live telephone traffic.