Alexis-Claude Clairaut

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Alexis-Claude Clairaut

French mathematician and physicist

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June 22, 2026

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Alexis-Claude Clairaut was an 18th-century French mathematician and physicist. He is known for developing Clairaut's equation, a type of differential equation. Clairaut also contributed to the understanding of Earth's shape, participating in an expedition to Lapland to measure a degree of the meridian. His work in Théorie de la figure de la terre connected surface gravity on a rotating ellipsoid to its compression and centrifugal force.1

Furthermore, Clairaut tested Isaac Newton's theory of universal gravitation. He was instrumental in accurately calculating the return of Halley's Comet, a feat that involved complex computations of gravitational perturbations. His work demonstrated the predictive power of Newtonian physics and advanced celestial mechanics.2

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Clairaut’s equation
…18th-century French mathematician and physicist Alexis-Claude Clairaut, who devised it. In 1736, together with Pierre-Louis de Maupertuis, he took part in an expedition to Lapland that was undertaken for the purpose of estimating a degree of the meridian, and on his return he published his treatise Théorie de la figure…
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…18th-century French mathematician and physicist Alexis-Claude Clairaut, who devised it. In 1736, together with Pierre-Louis de Maupertuis, he took part in an expedition to Lapland that was undertaken for the purpose of estimating a degree of the meridian, and on his return he published his treatise Théorie de la figure…
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analytic geometry
Analytic geometry of three and more dimensions
…Hermann and the French mathematician Alexis Clairaut produced general equations for cylinders, cones, and surfaces of revolution. For example, Euler and Hermann showed that the equation f(z) = x² + y² gives the surface that is produced by revolving the curve f(z) = x² about the z-axis (see the figure,…
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…Hermann and the French mathematician Alexis Clairaut produced general equations for cylinders, cones, and surfaces of revolution. For example, Euler and Hermann showed that the equation f(z) = x² + y² gives the surface that is produced by revolving the curve f(z) = x² about the z-axis (see the figure,…
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astronomy
Testing Newton’s theory
…1747 French mathematician and physicist Alexis-Claude Clairaut proposed a modification of Newton’s law of gravity. Instead of a pure inverse-square law, Clairaut proposed adding a small term, proportional to the inverse fourth power of the distance, in order to get the motion of the Moon’s perigee to come out correctly.…
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…1747 French mathematician and physicist Alexis-Claude Clairaut proposed a modification of Newton’s law of gravity. Instead of a pure inverse-square law, Clairaut proposed adding a small term, proportional to the inverse fourth power of the distance, in order to get the motion of the Moon’s perigee to come out correctly.…
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geoid
Ellipsoidal era
…America, the French mathematical physicist Alexis-Claude Clairaut deduced the relationship between the variation in gravity between the Equator and the poles and the flattening. Clairaut’s ideal Earth contained no lateral variations in density and was covered by an ocean, so that the external shape was an equipotential of its own…
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…America, the French mathematical physicist Alexis-Claude Clairaut deduced the relationship between the variation in gravity between the Equator and the poles and the flattening. Clairaut’s ideal Earth contained no lateral variations in density and was covered by an ocean, so that the external shape was an equipotential of its own…
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physical science
Impact of Newtonian theory
…return, the French mathematician Alexis Clairaut employed rather tedious and brute-force mathematics to calculate the effects of the gravitational attraction of Jupiter and Saturn on the otherwise elliptical orbit of Halley’s Comet. Clairaut was finally able to predict in the fall of 1758 that Halley’s Comet would reach perihelion in…
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…return, the French mathematician Alexis Clairaut employed rather tedious and brute-force mathematics to calculate the effects of the gravitational attraction of Jupiter and Saturn on the otherwise elliptical orbit of Halley’s Comet. Clairaut was finally able to predict in the fall of 1758 that Halley’s Comet would reach perihelion in…
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