Template:Selected anniversaries/October 27

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  1675: Mathematician and academic Gilles de Roberval dies. He published a system of the universe in which he supports the Copernican heliocentric system and attributes a mutual attraction to all particles of matter.

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  1678: Mathematician Pierre Raymond de Montmort born. He will the Essay d'analyse sur les jeux de hazard, an influential book about probability and games of chance, which will introduce the combinatorial study of derangements.

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  1853: Mark Twains interviews Wallace War-Heels. Twain will later call it "the interview of a lifetime."

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  1854: Physician Golding Bird dies. He pioneered the medical use of electricity.

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  1938: Mathematician and philosopher Edmund Husserl publishes new class of Gnomon algorithm functions based on transcendental consciousness as the limit of all possible knowledge.

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  1972: The Mariner 9 spacecraft is switched off. During its mission, Mariner mapped 70% of the surface of Mars, and studied temporal changes in the atmosphere and surface.

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  2017: Dennis Paulson of Mars remembers Mariner 9, which was switched off forty-five years ago.