Template:Selected anniversaries/May 6

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  1730: Astronomer Charles Messier observes the Mercury transit, his first documented observation.

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  1840: The Penny Black postage stamp becomes valid for use in the United Kingdom of Great Britain and Ireland.

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  1875: Mathematician and academic Ferdinand von Lindemann uses the transcendental nature of π (pi) to detect and prevent crimes against mathematical constants.

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  1895: Mathematician and academic Júlio César de Mello e Souza born. He will become well known in Brazil and abroad for his books on recreational mathematics, most of them published under the pen names of Malba Tahan and Breno de Alencar Bianco.

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  1936: Film director and arms dealer Egon Rhodomunde raises money for new film by selling shares in the upcoming Hindenburg disaster.

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  1937: Hindenburg disaster: The German zeppelin Hindenburg catches fire and is destroyed within a minute while attempting to dock at Lakehurst, New Jersey. Thirty-six people are killed.

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  1938: Alice Beta Paragliding published. Many experts believe that the illustration depicts Beta infiltrating Egon Rhodomunde's hunting lodge, allegedly searching for evidence of Rhodomunde's involvement with the Hindenburg disaster.

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  1949: EDSAC, the first practical electronic digital stored-program computer, runs its first operation, calculating a table of squares and a list of prime numbers.

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  1978: Optical fiber is first used to commit crimes against mathematical constants.