Alexis-Claude Clairaut Biography

A child prodigy, Alexis Claude Clairaut studied calculus at age 10, wrote mathematical papers at 13, and published a mathematical work on the gauche curve at age 18. Clairaut surpassed even Isaac Newton in his analysis of the effects of gravity and centrifugal force on a rotating body such as Earth, now known as Clairaut's theorem.

Clairaut was born in Paris, France, on May 7, 1713. His father, Jean-Baptiste, was a mathematics teacher who recognized his child's precociousness and guided his studies. Clairaut received his entire education at home; his father tutored him in algebra and geometry.

His mother, Catherine Petit, gave birth to 20 children, but most of them did not survive. Clairaut never married, but led an active social life. He and several other young mathematicians formed a society that served as a mathematical training ground for its members, and he often assisted his friends with their studies. He also visited and corresponded with most of the leading mathematicians of the age, including Leonhard Euler and Johann Bernoulli, and members of the Académie Royale des Sciences.

Clairaut's book, Théorie de la figure de la terre , which he published in 1743, was said to be responsible to a great degree for the acceptance of Isaac Newton's gravitational theories. The book was the result of Clairaut's journey to Lapland in 1736, where he assisted Pierre Louis Moreau de Maupertuis, director of the exploration, in measuring the curvature of the Earth inside the arctic circle. Their successful attempt at a meridian arc measurement proved Newton's theory that the Earth's shape was an oblate ellipsoid. Clairaut demonstrated, through an experiment which timed the swings of a pendulum, how the Earth's shape could be determined.

Clairaut was also interested in celestial mechanics. This field of study resulted in the first accurate determination of the size of the planet Venus (two-thirds the size of Earth). His studies of that planet also calculated its gravitational effects on the Earth as compared to the moon. Clairaut's work enabled him to determine a new figure for the size of the moon in relation to the Earth. He also was able to predict how close to the sun Halley's cometwould come in its orbit, and correctly predicted the comet's return in 1759.

Clairaut was elected to the Académie Royale des Sciences in 1731, when he was 18 years old. The Académie awarded him a prize for his work on tides in 1740, and he became associate director of the Académie in 1743. He was also made a Fellow of the Royal Society of London in 1737, the Académie's counterpart in England.

A prolific writer, Clairaut published the first complete book on solid analytical geometry, Recherches sur les courbes à double courbure , in 1731at age 18. In addition to Théorie de la figure de la terre, he also published books on motions of the moon (Théorie de la lune, 1752; Tables de la lune, 1754) and the comets (Théorie du mouvement des cométes, 1760). Clairaut died at age fifty-two on May 17, 1765, following a brief illness.