LAPLACE, Pierre Simon (Laplace)

Pierre Simon Laplace was born March 23, 1749 in the town of Beaumont-en-OJ (Normandy) in the family of a poor peasant.

Pierre Simon graduated from the Benedictine school and was left there, in Beaumont, a military school math teacher. In the seventeen years he wrote his first scientific work.

In 1766 he went to Paris. There he obtained a position teaching mathematics at the Military School of Paris ..

. In 1773, Laplace became an associate, and in 1785 a full member of the Paris Academy.

. In 1784 Laplace made by the examiner of the Royal Corps gunners
. May 8, 1790 the French National Assembly commissioned the Academy of Sciences to create a system of weights and measures "at all times and for all peoples". Chairman of the House of weights and measures was named Laplace.

After the popular uprising in 1793 in France established Jacobin dictatorship. August 8, 1793 decree of the Convention Academy of Sciences, among all the other royal institutions were abolished, while Laplace was dismissed from the Commission on Weights and Measures ..

. In 1795, instead of the Convent of the Academy of Sciences created the National Institute of Sciences and Arts
. Laplace became a member of the Institute and heads the Bureau des Longitudes, which was engaged in measuring the length of the terrestrial meridian.

. The day after the 18 Brumaire, Napoleon appointed Laplace Minister of Interior.

. In 1803, Napoleon made the Laplace Vice-President of the Senate, and a month - Chancellor
. In 1804 he received the Legion of Honor.

From 1801 to 1809 Laplace was elected a member of the Royal Society in Turin and Copenhagen, the Academies of Sciences in Gottingen, Berlin and Holland. October 13, 1802 Laplace was made an honorary member of the St. Petersburg Academy of Sciences.

"Analytical theory of probability" Laplace published three times during the life of the author (in 1812, 1814, 1820). To design he created the mathematical theory of probability Laplace introduced the so-called generating functions. He cited the results obtained by other scientists in a harmonious system, simplified methods of proof, which is widely applied transformation and proved a theorem about the rejection frequency of the event from its probability. Thanks to him, probability theory has become a finished look.

. In physics, Laplace derived a formula for the velocity of sound in air, created an ice calorimeter, was the barometric formula for calculating the change in air density with altitude, taking into account its moisture
. He performed a number of works on the theory of capillarity and established the law, which allows to determine the value of capillary pressure and thus record the conditions of mechanical equilibrium for the mobile (liquid) interfaces.

. His first work on celestial mechanics published in 1773
. It was called "The Origin of universal gravitation and the secular inequalities of the planets, which are dependent on it". In 1780 Laplace proposed a new method of calculating the orbits of celestial bodies.

Laplace proved the stability of the solar system. He showed that the average velocity of the moon depends on the eccentricity of Earth's orbit, and that, in its turn, is changing under the influence of gravity of the planets. By the inequalities of motion of the moon, he identified the value of compression of the Earth at the poles.

. Laplace had concluded that the ring of Saturn could not be continuous, otherwise it would be unstable; predicted compression at the poles of Saturn; established laws of motion of Jupiter's moons
. The results were published by Laplace in his most famous five-volume classic work "A Treatise on Celestial Mechanics" (1798-1825).

. Cosmogonic hypothesis of Laplace was published in 1796 in the annex to his book "The imposition of the World
. For her, the solar system formed from the nebula, consisting of hot gas and extends beyond the orbit of the farthest planet. The rotational motion of the cooling and contracting nebula condition its flattening. In the process, flattening occurred centrifugal force, which under the influence of the nebula on its edge to detach the ring of gas matter, then gathered in clumps and gave rise to the planets and their satellites.

. After the restoration of the monarchy Laplace enjoyed the favor of Louis XVIII
. The king made him a peer of France, and bestowed the title of Marquis. In 1817 Laplace was a member of the newly established French Academy, t. e. one of the forty immortals.

Scientist died after a brief illness March 5, 1827. His last words were: "What we know so insignificant compared to the fact that we do not know."