Place of work

• Normal school [d]
• Bureau of Longitudes

Pierre-Simon, Marquis de Laplace(French Pierre-Simon de Laplace; March 23 - March 5) - French mathematician, mechanic, physicist and astronomer; known for his work in the field of celestial mechanics, differential equations, and one of the creators of probability theory. Laplace's merits in the field of pure and applied mathematics and especially in astronomy are enormous: he improved almost all sections of these sciences.

Laplace was a member of six academies of sciences and royal societies, including the St. Petersburg Academy (1802), and a member of the French Geographical Society. His name is included in the list of the greatest scientists of France, placed on the first floor of the Eiffel Tower.

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  Born in peasant family in Beaumont-en-Auge, in Normandy. He studied at the Benedictine school, from which he emerged, however, as a convinced atheist. Wealthy neighbors helped the talented boy enter the University of Caen (Normandy).

  He advanced linear algebra far; in particular, Laplace gave an expansion of the determinant in minors.

  Laplace expanded and systematized the mathematical foundation of probability theory and introduced generating functions. The first book of "Analytical Theory of Probability" is devoted to mathematical foundations; Probability theory proper begins in the second book, as applied to discrete random variables. There is also a proof of the limit theorems of Moivre-Laplace and applications to the mathematical processing of observations, population statistics and “moral sciences”.

  Astronomy

  Laplace proved the stability of the solar system, which consists in the fact that due to the movement of the planets in one direction, small eccentricities and small mutual inclinations of their orbits, there should be an invariability of the average distances of the planets from the Sun, and the fluctuations of other elements of the orbits should be contained within very tight limits.

  Laplace proposed the first mathematically substantiated cosmogonic hypothesis for the formation of all bodies in the Solar System, called after him: the Laplace hypothesis. He was also the first to suggest that some nebulae observed in the sky are actually galaxies similar to our Milky Way.

  Before Laplace's discoveries, many scientists tried to explain the deviations of the theory from observations by the movement of the ether, the final speed of gravity and other non-Newtonian factors; Laplace buried such attempts for a long time. He, as Clairaut had earlier, proclaimed: in celestial mechanics there are no forces other than Newtonian ones, and he substantiated this thesis with arguments.

  Laplace discovered that the acceleration in the movement of the Moon, which perplexed all astronomers ( centuries-old inequality), is also a periodic change in the eccentricity of the lunar orbit, and it occurs under the influence of the attraction of large planets. The displacement of the Moon under the influence of these factors that he calculated was in good agreement with observations.

  Using inequalities in the motion of the Moon, Laplace clarified the compression of the Earth's spheroid. In general, the studies carried out by Laplace on the movement of our satellite made it possible to compile more accurate tables of the Moon, which, in turn, contributed to solving the navigation problem of determining longitude at sea.

  Laplace was the first to construct an accurate theory of the motion of the Galilean satellites of Jupiter, whose orbits, due to mutual influence, constantly deviate from Keplerian ones. He also discovered a relationship between the parameters of their orbits, expressed by two laws called “Lapplace’s laws.”

  Having calculated the conditions for the equilibrium of Saturn's ring, Laplace proved that they are possible only when the planet rotates rapidly about its axis, and this was indeed proven later by the observations of William Herschel.

  Actually predicted black holes:

  Physics

  Philosophical views

  The dialogue between Laplace and Napoleon is widely known:

  M. Arago assured me that Laplace, who was warned shortly before his death that the story was about to be published in a biographical collection, asked him to demand the publisher to remove it. It was necessary to either explain it or remove it, and the second way was the simplest. But, unfortunately, it was not removed or explained.

  Laplace was a supporter of absolute determinism. He postulated that if some intelligent being could capture all the particles in the world at some point, it could predict all world events with complete accuracy. Such a hypothetical creature was subsequently called Laplace's demon.

  Laplace was one of the outstanding figures of French Freemasonry. He was honorary

  Pierre Simon Laplace

  Laplace Pierre Simon (1749-1827), French astronomer, mathematician, physicist, foreign honorary member of the St. Petersburg Academy of Sciences (1802). Author of classic works on probability theory and celestial mechanics (dynamics of the Solar system as a whole and its stability, etc.): the works “Analytical Theory of Probability” (1812) and “Treatise on Celestial Mechanics” (vol. 1-5, 1798-1825) ; many works on differential equations, mathematical physics, capillarity theory, heat, acoustics, geodesy, etc. Proposed (1796) cosmogonic hypothesis(Laplace hypothesis). A classic representative of mechanistic determinism.

  Laplace Pierre Simon (1749-1827) - French scientist, mathematician and astronomer. In his philosophical views he was a mechanistic materialist and an atheist. Proved that the solar system is stable and... therefore, it does not require periodic intervention from the creator to restore the disturbed balance. An important contribution to the development of materialism and atheism was his mathematical proof of the origin of the solar system from the primordial nebula. L. also owns the classical formulation of mechanical determinism, which is often called Laplace’s, the development of some provisions of the theory of probability, etc. Main works: “Exposition of the World System” (1795), “Analytical Theory of Probability” (1812).

  Philosophical Dictionary. Ed. I.T. Frolova. M., 1991, p. 215.

  Laplace Pierre Simon (1749-1827) - French scientist, astronomer, physicist, mathematician, founder of probability theory. Son of a Norman peasant. From 1785 - member of the Paris Academy of Sciences, from 1790 - chairman of the Chamber of Weights and Measures. L. developed (1796) a hypothesis about the origin of the solar system from the “primary” nebula, which was in slow uniform rotation and spread beyond the boundaries of the solar system that later emerged from it. The substantiation of the cosmogonic hypothesis in L.'s works was accompanied by a restructuring of the foundations of science: the static Newtonian picture of the world was replaced by an evolutionary mechanical picture of the world ("Exposition of the World System", vols. 1-2, 1795-1796). New probabilistic and statistical methods for studying evolutionary processes and mass events were introduced ("Analytical Theory of Probability", 1812). A new categorical apparatus was being formed to describe the change of states of large systems (“probability”, “change of states”, “determination”, etc.) (“Experience in the Philosophy of Probability Theory”, 1814). Rebuilding the foundations of science, L. relied on philosophical ideas Leibniz and French materialists of the 18th century, in particular, on the concept Holbach about the universal causal connection of bodies in the Universe. In the history of science, the concept of causal explanation of evolution and change large systems According to rigid unilinearly directed dynamic laws, it received the name Laplace determinism. Historical significance Laplace's determinism was that it became a logical means of scientific explanation of evolutionary processes and mass events in the mechanical picture of the world, replacing the analytical element-by-element form of causal explanation with a synthetic vision of intertwined causal series in the universe. Laplace determinism became a common name for the mechanistic methodology of classical physics.

  E.V. Petushkova

  Newest philosophical dictionary. Comp. Gritsanov A.A. Minsk, 1998.

  

  IGDA/G. Dagli Orti
  PIERRE SIMON LAPLACE

  Mathematician, physicist and astronomer

  LAPLACE, PIERRE SIMON (Laplace, Pierre Simon) (1749–1827), French mathematician, physicist and astronomer. Born March 23, 1749 in Beaumont-en-Auge (Normandy). Studied at school monastic order Benedictines, but in his youth he became a convinced atheist. In 1766 he came to Paris. For the next three years he studied mathematics, publishing his work in a mathematical journal founded by J. Lagrange. In 1771, on the recommendation of d'Alembert, he became a professor at the Military School in Paris. He actively participated in the reorganization of the education system, in particular in the creation of the Normal and Polytechnic schools. In 1790 he was appointed chairman of the House of Weights and Measures. After Napoleon came to power, he held the post of Minister of the Interior in 1799, received the title of count, but during the restoration he was also awarded many honors. Laplace's main astronomical works relate to the field of celestial mechanics. This term was first used by Laplace himself in the title of the five-volume fundamental work Treatise on Celestial Mechanics (Trait de Mcanique cleste, 1798–1825). He did almost everything that his predecessors failed to explain the movement of celestial bodies on the basis of the law of universal gravitation: he solved complex problems of the movement of planets and their satellites, in particular the Moon; developed a theory of perturbations of the trajectories of the planets, the Sun and the Moon; suggested new way calculations of their orbits; proved the stability of the solar system for a very long time; discovered the reasons for the acceleration in the movement of the Moon. In the history of the development of cosmology, the most important place is occupied by Laplace’s famous hypothesis about the formation of the Solar system from a rotating gas nebula (nebular hypothesis), which he formulated in his essay Exposition of the world system (Exposition du systme du monde, 1796).

  Laplace's physical research relates to the areas molecular physics, heat, acoustics, optics. In 1821 he established the law of change in air density with altitude (barometric formula). In 1806–1807 he developed the theory of capillary forces and derived a formula for determining capillary pressure (Laplace's formula). Using the ice calorimeter he designed together with A. Lavoisier, he determined the specific heat capacities of many substances. He derived a formula for the speed of sound corrected for adiabaticity (1816).

  Laplace is the author of fundamental works in mathematics and mathematical physics, primarily the treatise Analytical Theory of Probability (Thorie analytique des probabilits, 1812), in which one can find many of the later discoveries of probability theory made by other mathematicians. It covers gambling, Bernoulli's theorem and its connection with the normal distribution integral, theory least squares; the "Laplace transform" is introduced, which later became the basis of operational calculus. Laplace's partial differential equation is widely known and is used in potential theory, heat and electrical conductivity, and hydrodynamics.

  Laplace astronomical system

  The pinnacle of the achievements of astronomy in the 18th century was the book of the French scientist Pierre Laplace (1749-1827) “Exposition of the World System” (1796), which preceded his multi-volume “Celestial Mechanics”. The main idea of ​​this book, which had a great influence on the worldview of scientists, is the idea of ​​​​the mechanical stability of the Universe. The son of the “age of reason,” Laplace moved far from the Newtonian idea of ​​the need for repeated intervention of God, periodically restoring the stability of the world. Advanced thinkers of the 18th century argued that the universe could be stable without any non-material influence. These proofs came from the consistent application of Newton's law of gravitation to an ever-increasing range of astronomical problems. Laplace’s “Exposition of the World System” is based on the belief in the indisputability of Newton’s law of gravitation and the possibility of deducing from it an explanation of all astronomical phenomena as a system of mechanical and mathematical problems.

  Laplace owns the image of a hypothetical creature who currently knows the coordinates and velocities of all particles of matter in the world and is able to predict with absolute accuracy any details of everything further development the world, including the events of human history. This is the ideal of mechanical natural science of the 18th century. Of course, the laws of development are not reducible to mechanical laws. The impact of Laplace's theory on the ideological development of society was significant, especially the conclusions drawn from mechanical science by Laplace himself in his famous response to Napoleon. This scientist, who became a minister after the 18th Brumaire and subsequently a count of the Empire and a marquis of the Restoration, when asked by Napoleon what role he assigned to God in the world system, proudly replied: “I did not feel the need for this hypothesis!”

  In all areas of differentiated natural science of the 18th century, the mechanical limitations of science led to the incorrect idea of ​​\u200b\u200bmotionless nature. But at the same time, the desire for the unity of the scientific picture of the world, the accumulation of physical, chemical and biological information made it possible for the emergence of theories depicting the real development of the Cosmos and the Solar System. The earth, the earth's crust, the surface of the globe and its inhabitants.

  Quoted from the publication: World history. Volume V. M., 1958, p. 687-688.

  Laplace Pierre Simon (March 23, 1749, Beaumont-en-Oge - March 5, 1827, Paris) - French mathematician, physicist, astronomer. Member of the Paris Academy of Sciences, honorary member of the St. Petersburg Academy of Sciences. During the Directory, he was Minister of the Interior. He made an outstanding contribution to the theory of probability and to the development of the Kant-Laplace cosmogonic hypothesis. In the fundamental work “Treatise on Celestial Mechanics” (Traité de mécanique céleste, v. 1–5. P., 1799–1825, a popular version is “Exposition of the World System”, Exposition du système du monde, v. 1–2. P ., 1796, Russian translation 1861) summarized all previous research in this area. Using the apparatus of mathematics and physics and relying on the law of universal gravitation, Laplace developed ideas about the origin of the solar system from a cooling nebula under the influence of rotation. “The Analytical Theory of Probability” (Théorie analytique des probabilités. P., 1812) and its popular presentation in “Essai philosophique sur les probabilités. P., 1814, Russian translation M., 1908” contain ideas about the complete determinism of all natural phenomena and about the probabilistic nature of the entire system of human knowledge. According to Laplace, every phenomenon is connected with the previous one on the basis of the principle of causality; the present state of the Universe must be considered as a consequence of its previous and the cause of its subsequent state; for the mind, if it knew all the forces of nature and, having subjected them to mathematical analysis, could embrace them in a single formula, there would be nothing left unknowable - neither in the future nor in the past. Laplace considered mechanics as a model of all science.

  L.A. Mikeshina

  New philosophical encyclopedia. In four volumes. / Institute of Philosophy RAS. Scientific ed. advice: V.S. Stepin, A.A. Guseinov, G.Yu. Semigin. M., Mysl, 2010, vol. II, E – M, p. 373-374.

  Essays:

  in Russian Transl.: Exposition of the world system. L., 1982.

  Literature:

  Vorontsov-Velyaminov B.A. Laplace, 2nd ed. M., 1985.

  

  Peasant's son

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

  Pierre Simon graduated from the Benedictine school and was left there, in Beaumont, as a mathematics teacher at a military school. At the age of seventeen he wrote his first scientific work.

  In 1766 he went to Paris. There he received a position as a mathematics teacher at the Military School of Paris.

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

  In 1784, Laplace was made examiner of the royal corps of artillery. On May 8, 1790, the French National Assembly instructed the Academy of Sciences to create a system of weights and measures “for all times and for all peoples.” Laplace was appointed Chairman of the Chamber of Weights and Measures.

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

  In 1795, instead of the Academy of Sciences, the Convention created National Institute sciences and arts. Laplace becomes a member of the Institute and heads the Bureau of Longitudes, which was engaged in measuring the length of the earth's meridian.

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

  In 1803, Napoleon made Laplace vice-president of the Senate, and a month later - chancellor. In 1804 he received the Legion of Honor.

  From 1801 to 1809, Laplace was elected a member of the royal societies in Turin and Copenhagen, and the academies of sciences in Göttingen, Berlin and Holland. On October 13, 1802, Laplace became an honorary member of the St. Petersburg Academy of Sciences.

  Laplace's "Analytic Theory of Probability" was published three times during the author's lifetime (in 1812, 1814, 1820). To develop the mathematical theory of probability he created, Laplace introduced the so-called generating functions. He brought the results obtained by other scientists into a coherent system, simplified the methods of proof, for which he widely used transformation and proved a theorem about the deviation of the frequency of occurrence of an event from its probability. Thanks to him, the theory of probability acquired a complete form.

  In physics, Laplace derived a formula for the speed of sound in air, created an ice calorimeter, and obtained a barometric formula for calculating changes in air density with height, taking into account its humidity. He carried out a number of works on the theory of capillarity and established a law that allows one to determine the value of capillary pressure and thereby write down the conditions of mechanical equilibrium for moving (liquid) interfaces.

  His first work on celestial mechanics was published in 1773. It was called "On the cause of universal gravitation and the age-old inequalities of the planets that depend on it." In 1780, Laplace proposed a new way to calculate the orbits of celestial bodies.

  Laplace proved the stability of the solar system. He showed that average speed The movement of the Moon depends on the eccentricity of the Earth's orbit, which, in turn, changes under the influence of the gravity of the planets. From the inequalities of the Moon's motion, he determined the amount of compression of the Earth at the poles.

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

  Laplace's cosmogonic hypothesis was published in 1796 as an appendix to his book The Superimposition of the System of the World. According to her solar system formed from a nebula consisting of hot gas and extending beyond the orbit of itself distant planet. The rotational motion of the cooling and contracting nebula caused its flattening. In the process of this flattening, a centrifugal force arose, under the influence of which rings of gaseous matter were separated from the nebula along its edge, which then gathered into lumps and gave rise to 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 granted him the title of marquis. In 1817, Laplace became a member of the newly created French Academy, that is, one of the forty immortals.

  The scientist died after a short illness on March 5, 1827. His last words were: “What we know is so insignificant compared to what we don’t know.”

  Materials used from the site http://100top.ru/encyclopedia/

  Read further:

  World-famous scientists (biographical reference book).

  Literature:

  Laplace P. Exposition of the world system. L., 1982

  Vorontsov-Velyaminov B.A. Laplace. M., 1985

  LAPLACE (Laplace) Pierre Simon de (23.3.1749, Beaumont-en-Auge, Lower Normandy - 5.3.1827, Arceuil, near Paris), French astronomer, mathematician, mechanic and physicist, member of the Paris Academy of Sciences (1785), member of the French Academy (1816), honorary member of the St. Petersburg Academy of Sciences (1802), member of the Royal Society of London (1789).

  Farmer's son. He studied at the school of the Benedictine monastic order, then at the local military school and the University of Caen. Early on he showed extraordinary abilities in mathematics, abandoned his initial intention of becoming a priest, and in his youth set the goal of reaching the top in the sciences and social position. In 1771, on the recommendation of J. D'Alembert, he received a position as a professor at the Military School in Paris. Participant of reforms in the field of education and science in France: one of the founders of the Normal and Polytechnic schools (in the first he was a professor of mathematics), the Bureau of Longitudes (1795, from 1799 president), the Chamber of Weights and Measures (1790, in 1795-99 chairman). During the Great french revolution was a Republican; after Napoleon Bonaparte came to power, he served as Minister of the Interior in 1799 and received the title of Count. After the restoration, Bourbon received a peerage and the title of marquis. Highest officer of the Legion of Honor.

  Basic scientific works dedicated to celestial mechanics, theoretical mechanics, higher mathematics, physics. Developing the results of L. Euler, J. D'Alembert and others, he completed (along with J. Lagrange) the creation of the foundations of classical analytical celestial mechanics as a theory of the perturbed motion of bodies of the Solar system under the influence of universal gravitational forces. Explained (1773) the secular changes in the speeds of the orbital motion of Jupiter and Saturn as periodic effects (the so-called secular inequalities), determining (1787) their period to be 929.5 years. Showed (1787) that secular changes in the eccentricity of the Earth's orbit cause periodic changes in the speed of the Moon. Justified (1787) the stability of the solar system for a sufficiently long period of time. Based on the theory of the motion of the Moon, for the first time he calculated with great accuracy the compression of the Earth at the poles and the value of the astronomical unit. Built the first complete theory disturbed motion of the satellites of Jupiter (1789); these studies contributed to solving the navigation problem of determining geographic longitude. He discovered resonances in the motion of the Galilean satellites of Jupiter and determined the libration period of these satellites. Developed the first dynamic theory of tides, the theory of the figures of celestial bodies; gave new method determination of planetary and cometary orbits (1780); laid the foundation for the study of the movement of the poles on the surface of the Earth, as well as the theory of the movement of a body of variable mass. Laplace combined the main results in the 5-volume work “Treatise on Celestial Mechanics” (“Traité de Mécanique сéleste”, 1798-1825), where he introduced the very name for the new science.

  Laplace made a significant contribution to the development mathematical methods astronomy and physics, in the theory of series and the theory of differential equations, introduced spherical functions (see Spherical functions) into the mathematical apparatus for solving special problems in the theory of gravity. The partial differential equation obtained by Laplace (Laplace equation) is used in potential theory, to describe the phenomena of thermal conductivity, in electrostatics and hydrodynamics. A linear differential operator (Laplace operator) is named after Laplace. Made a significant contribution to the development of probability theory: he proved simplest option central limit theorem (the so-called Moivre-Laplace theorem), obtained a double exponential continuous distribution of a random variable (Laplace distribution), developed the theory of errors and the least squares method, introduced a transformation that transforms a function of a real variable into a function of a complex variable (Laplace transform). Laplace's classic work, Theory analytique des probabilités, was published three times during his lifetime - in 1812, 1814 and 1820.

  Together with A. Lavoisier, he studied thermal conductivity, latent heat of fusion, invented an ice calorimeter, and studied the processes of respiration and combustion. He derived (1809) a formula for determining the speed of sound in air, established (1821) the law of change in air density with height above the earth's surface (barometric formula). Developed a theory of capillary phenomena, which received wide application in technology, and established a law that determines the value of capillary pressure (Laplace's law). Laplace was the first to try to solve the problem of the nature of comets based on the theory of heat. In 1796, he calculated at what mass and density of a body the speed required to overcome its gravity would be greater than the speed of light, and concluded that the most massive stars should be invisible (in fact, he expressed the idea of ​​​​the existence of black holes).

  In the essay “Exposition of the World System” (“Exposition du système du monde”, vol. 1-2, 1796), he put forward and developed the nebular cosmogonic hypothesis (Laplace’s hypothesis). This hypothesis, according to which the Solar System formed from a vast hot gaseous nebula - the atmosphere of the forming Sun, was rejected in the late 19th century. However, in the mid-20th century it stimulated a new beginning, modern stage development of planetary cosmogony.

  In philosophy he was a convinced determinist, a supporter of mechanistic materialism. He considered the process of knowledge endless, his last words were: “What we know is not much; what we don’t know is enormous.”

  Works: Œvres complètes. R., 1878-1912. Vol. 1- 14; Experience in the philosophy of probability theory. M., 1908; Exposition of the world system. L., 1982.

  Lit.: Vorontsov-Velyaminov B. A. Laplace. 2nd ed. M., 1985.

  Pierre-Simon Laplace- outstanding French mathematician, physicist and astronomer.

  

  Laplace's discoveries in astronomy

  In addition to the mathematically substantiated cosmogonic hypothesis of the formation of all bodies in the Solar System, named after him: Laplace's hypothesis, he made many other discoveries in astronomy.

  Assumption of many galaxies

  He was the first to suggest that some nebulae observed in the sky are actually galaxies similar to our Milky Way.

  

  He developed perturbation theory and convincingly showed that all deviations of the planetary positions from those predicted by Newton's laws are explained mutual influence of planets, which can be taken into account using the same Newton laws. Back in 1695, Halley discovered that over the course of several centuries Jupiter gradually accelerates and approaches the Sun, while Saturn, on the contrary, slows down and moves away from the Sun. Some scientists believed that Jupiter would eventually fall into the Sun. Laplace discovered the reasons for these displacements ( inequalities) - mutual influence of planets, and showed that these are nothing more than periodic fluctuations, and everything returns to its original position every 929 years.

  He put forward and substantiated the thesis that in celestial mechanics there are no forces other than Newtonian ones.

  Laplace discovered that the acceleration in the movement of the Moon, which perplexed all astronomers ( centuries-old inequality), is also a periodic change in the eccentricity (a numerical characteristic of a conic section, indicating the degree of its deviation from the circle) of the lunar orbit and arises under the influence of the attraction of large planets. The displacement of the Moon under the influence of these factors that he calculated was in good agreement with observations.

  Using inequalities in the motion of the Moon, Laplace clarified the compression of the Earth's spheroid. The studies carried out by Laplace on the movement of the Moon made it possible to compile more accurate tables of the Moon, which, in turn, contributed to solving the navigation problem of determining longitude at sea.

  

  Laplace's laws

  Laplace was the first to construct an accurate theory of the motion of the Galilean satellites of Jupiter, the orbits of which, due to mutual influence, constantly deviate from Keplerian ones. Galilean satellites- these are the 4 largest satellites (of total number 67) Jupiter: Io, Europa, Ganymede and Callisto (in order of distance from Jupiter). They are among the largest satellites in the solar system and can be observed with a small telescope). The moons were discovered by Galileo Galilei on January 7, 1610, using his first ever telescope.

  He also discovered a relationship between the parameters of their orbits, expressed by two laws called “Lapplace’s laws.”

  About the movement of Saturn's rings

  

  The rings of Saturn have constantly excited the imagination of researchers with their unique shape. Kant was the first to predict the existence of the fine structure of Saturn's rings. Using his model of a protoplanetary cloud, he imagined a ring in the form of a flat disk of colliding particles rotating differentially around the planet according to Kepler's law. It is differential rotation, according to Kant, that causes the disc to separate into a series of thin rings. Later Simon Laplace proved the instability of a solid wide ring. And even earlier he proved that rings cannot be solid. After spending mathematical analysis, Maxwell became convinced that they could not be liquid, and came to the conclusion that such a structure could only be stable if it consisted of a swarm of unrelated meteorites. The stability of the rings is ensured by their attraction to Saturn and the mutual movement of the planet and meteorites.

  Having calculated the equilibrium conditions for the ring of Saturn, Laplace proved that they are possible only when the planet rotates rapidly about its axis, and this was indeed proven later by the observations of William Herschel.

  Dynamic theory of tides

  Laplace developed the theory of tides using twenty years of observations of sea levels in Brest (France). To calculate the tides, Laplace proceeded from the assumption that the entire Earth is immersed in a drop of the World Ocean, but took into account that the tidal forces in it change according to a periodic law, which is the sum of harmonic components with different phases.

  Laplace's "dynamic" theory of tides, published in 1775, eliminated main drawback Newton's statistical theory - a hypothesis about the static state of a phenomenon, which in reality is constantly changing.

  In dynamic theory tides are considered as wave movement of water particles in vertical and horizontal directions. Laplace, within the framework of this theory, obtained the equations for the motion of tides on a rotating Earth and gave their solution under the assumption that the ocean covers the entire Earth in an even layer.

  The differentiated equations derived by Laplace showed the possibility of expressing the variability of tides over time at certain points in the form of the sum of a series of simple harmonic oscillations. Thus, Laplace laid the foundation for the most general practical method pre-calculation of tides, called harmonic analysis . This method is still the main method for predicting tides for practical purposes.

  

  P. Laplace was born in the north of France into a peasant family. The boy's outstanding abilities prompted wealthy neighbors to help him graduate from the school of the Benedictine Order. It is difficult to say what knowledge P. Laplace took away from the institution of the Holy Fathers. But there is no doubt that it was after school that he became a convinced atheist. At the age of 17 he becomes a teacher high school V hometown Beaumont writes several mathematical articles.

  Then, having secured a letter of recommendation, he goes to Paris to J. d’Alembert. However, the famous mathematician was skeptical about provincial patronage. Then P. Laplace writes a work on the fundamentals of mechanics in a few days and sends it to J. d’Alembert again. Justice has prevailed; and soon the young ambitious man finds himself accepted into the teaching staff of the Paris High School.

  Having barely established himself, P. Laplace wrote one after another and sent his works to the Paris Academy of Sciences. Rare persistence combined with a certain mathematical talent led to the fact that at the age of 24 he became an adjunct, and at the age of 36 - a full member of the academy.

  P. Laplace, like no one else, knew how to highlight the main thing in the problem under consideration; was able to present complex natural phenomena in mathematical form, formulate the conditions of the problem and select original method her decisions.

  It is difficult to list the works of P. Laplace - there are so many of them, and they are so diverse. However, despite basic research in mathematics and physics, the bulk of his work relates to astronomy.

  P. Laplace proved the stability of the structure of the solar system, that is, the constancy of orbits and the invariability of the average distances of the planets from the Sun. He discovered the causes of periodic inequalities in the motion of Jupiter and Saturn and solved for this another special case of the famous “three-body problem.” Considering the theory of the motion of Jupiter's satellites, he derived the laws that received his name and significantly supplemented the lunar theory. We can say that P. Laplace actually completed it, giving a complete theoretical calculation of the movement of the Moon. Of course, he finished in the sense and at the level that the state of his contemporary science allowed.

  As a result of his astronomical works, one should name the five-volume “Treatise on Celestial Mechanics”, in which, in a sequential presentation, he combined the works of I. Newton, L. Euler, J. d'Alembert and A. Clairaut and in which P. Laplace himself gives a complete mathematical explanation of the movement of solar system bodies.

  “At the end of the last century,” he writes in the preface to the first volume, “I. Newton published his discovery of universal gravitation. Since then, mathematicians have managed to reduce all known phenomena of the universe to this great law of nature and thus achieve unexpected accuracy in astronomical theories and tables. My goal is to present from a unified point of view the theories scattered throughout various jobs, bringing together all the results on the equilibrium and motion of solid and liquid bodies from which our solar system is built and similar systems, spread out in the vastness of the universe, and in this way build celestial mechanics.”

  This treatise became a classic during P. Laplace’s lifetime. To this day, many of the ideas of this excellent work form the basis of theoretical astronomy, and the method of presentation serves as a model for the approach to solving theoretical problems. They say it last words before his death were: “How insignificant is what we know compared to the boundless area of ​​the unknown.” P. Laplace, of course, was an outstanding scientist, a great scientist, a great mathematician.

  What a pity that an assessment of his personality and human dignity cannot be made in the same words. P. Laplace had a very unpleasant character. Extremely vain, arrogant and rude towards people below him on the social ladder and towards his colleagues, he could not stand the delicate J. Lagrange and quarreled with A. Lavoisier. Perhaps, the only person at the academy, to whom he treated more or less decently, there was J. d’Alembert.

  P. Laplace supported the republic, extolling freedom, equality and fraternity. But when Napoleon became first consul, the astute mathematician begged him for the position of home secretary. Dismissed after six weeks for his inability to do this work, he was, as a consolation, appointed a member of the Senate. P. Laplace dedicated the third volume of his “Celestial Mechanics” to the “Heroic Pacificator of Europe”, having obtained the title of count from Emperor Napoleon. But several years later he voted for the deposition of his idol and joyfully welcomed the restoration of Louis XVIII. Ready to admit and deny anything for the sake of another order, he later received the title of Marquis and the peerage of France from the king.