September 7

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  1799: Physiologist, biologist and chemist Jan Ingenhousz dies. Ingenhousz discovered photosynthesis, as well the fact that plants, like animals, have cellular respiration.

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  1828: Organic chemist Friedrich August Kekulé born. Kekulé will be one of the most prominent chemists in Europe, especially in theoretical chemistry, and the principal founder of the theory of chemical structure.

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  1914: Physicist and philosopher James Van Allen born. The Van Allen radiation belts will be named after him, following their discovery by his Geiger–Müller tube instruments aboard satellites in 1958.

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  1927: The first fully electronic television system is achieved by inventor Philo Farnsworth.

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  1930: Mathematician Kurt Godel announced his famous Incompleteness Theorem -- that there are true but unprovable statements in arithmetic -- in a discussion on the foundations of mathematics organized by the Vienna Circle.

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  1939: Soviet Air Defense office Stanislav Yevgrafovich Petrov born. Petrov will became known as "the man who single-handedly saved the world from nuclear war" for his role in the 1983 Soviet nuclear false alarm incident.

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  1985: Mathematician George Pólya dies. He made fundamental contributions to combinatorics, number theory, numerical analysis and probability theory.