In short, Pierre Simon Laplace is a scientist famous in scientific world as a 19th century mathematician, physicist and astronomer. He contributed decisive contribution into the theory of planetary motion. But Laplace is best remembered as one of the greatest scientists of all time and is called the “French Newton.” In his writings, he applied Isaac Newton's theory of gravity to the entire solar system. His work on probability and statistics is considered groundbreaking and influenced an entirely new generation of mathematicians.

Childhood and education

ABOUT early childhood Very little is known about the outstanding French scientist. short biography Pierre Laplace's story from birth to college is covered in a few lines and does not allow us to understand how certain views of the future genius were formed in his adolescence. It remains to be assumed that there were some unknown patrons, people with advanced views for their time, who may have helped him become familiar with the latest literature.

So, Laplace was born on March 23, 1749 in the city of Biemont-en-Og, Norway. He was the fourth of five children of Catholic parents, and was named after his father. The family was of average income: the father was a farmer, and the mother, Marie-Ann Sohon, came from a fairly rich family. Pierre's father really wanted his son to become an ordained priest, since in primary school He set out his special divine ideas in an essay on theology. But the father’s dream was not destined to come true. While studying in high school at the Benedictine monastic order, the guy developed atheistic views on world formation.

University and military academy

The biography of Pierre Simon Laplace preserved information for posterity about his universities, works, discoveries and hypotheses. In 1765, when he was only 16 years old, he was sent to the University of Caen. After a year of rhetoric at the College of Art, he began to study philosophy, but soon became interested in mathematics. She captivated him so deeply that Pierre Laplace began publishing his works in mathematical publications.

In 1769 he went to Paris with letter of recommendation from Le Canu to meet one of the most influential mathematicians of the time, Jean-le-Ronde d'Alembert. The mathematician became convinced of Laplace's abilities after reading his work on inertia. Thanks to D'Alembert, Pierre Laplace received a position as professor of mathematics at the Royal Military Academy, as well as an annual salary and housing at the school. Five years later, Laplace had already written 13 scientific papers on integral calculus, mechanics and physical astronomy, which became famous in scientific community and recognition throughout France.

First achievements in science

Laplace became adjutant of the Paris Academy of Sciences in 1773. At this time, he and D'Alembert were engaged in heat research, and their work became the basis future science, whose name is thermochemistry.

In 1778, changes occurred in the biography of Pierre Laplace personal life. He marries Charlotte de Courti, who a year after her marriage gave her husband a son and then a daughter.

Since 1785, Laplace has been an active member of the Academy of Sciences. His responsibilities include the reorganization of the education system in France. In 1790 he was appointed chairman of the House of Weights and Measures. At this time their collaboration with d'Alembert, but in the field of standardization. They solve the problem of measures, motley and confusing in France. Thanks to a specially appointed commission, which includes Pierre Laplace, the French Academy of Sciences is standardizing measures of weight and length, leading it to decimal system. The Commission accepted the developed standard, which stated that it was not derivative and did not belong to any of the nations. The kilogram and meter were adopted as standards.

The versatility of Laplace's talent

In 1795, Pierre became a member of the mathematics department of the new Institute of Sciences and Arts, of which he would be appointed president in 1812. In 1806, Laplace was elected a foreign member of the Royal Swedish Academy of Sciences.

Laplace's analytical mind could not help but be carried away by statistics - this game of blind chance. Laplace took up calculations and began to look for ways to subjugate random events, trying to bring them into the framework of patterns, as happens in movement celestial bodies. He coped with the task set for himself. His 1812 work, The Analytical Theory of Probability, contributed to significant study of the subjects of probability and statistics.

In 1816 he was elected to the French Academy. In 1821 he became the first president Geographical Society. In addition, he becomes a member of all major scientific academies in Europe.

Thanks to its intense scientific activity Pierre Laplace had a great influence on the scientists of his time, especially on Adolphe Quetelet and Simeon Denis Poisson. He has been compared to the French Newton for his natural and extraordinary aptitude for mathematics. Several were named after him mathematical equations: Laplace equation, Laplace transforms and Laplace differential equations. He derives a formula that is used in physics to determine capillary pressure.

Research in Astronomy

Laplace is one of the first scientists to show great interest in the issue of long-term stability solar system. Complexity gravitational interactions between the Sun and known planets at that time did not seem to admit of a simple analytical solution. Newton had already sensed this problem by noticing disturbances in the motion of some planets; he concluded that divine intervention was necessary to avoid the dislocation of the solar system.

The works that Laplace wrote throughout his life are difficult to systematize. Pierre Laplace returned to some of the hypotheses put forward in his works more than once, refining them on the basis of new data obtained in experiments. These were hypotheses about black holes as astronomical objects, the existence of which was suggested by Laplace in the version classical physics And possible sources Universe.

Work on a five-volume book

For many years Laplace carried out research in the field of astronomy and published his five-volume treatise Traité de mécanique céleste (Celestial Mechanics).

His work on celestial mechanics is considered revolutionary. He found that small disturbances observed at orbital movement planets will always remain small, constant and self-correcting. He was the earliest astronomer to propose the idea that the solar system arose due to the compression and cooling of a large rotating and therefore oblate nebula of hot gas. Laplace published his famous work on probability in 1812. He gave his own definition probability and used it to justify fundamental mathematical manipulations.

Publication of a five-volume book

The first two volumes, published in 1799, contain methods for calculating planetary motions, determining their shapes, and solving tidal problems. The third and fourth were published in 1802 and 1805. They contain applications of these methods and various astronomical tables. The fifth volume, published in 1825, is mainly historical, but it gives results in an appendix latest research Laplace.

In his long-term work, Pierre Simon Laplace reveals the nebula hypothesis, according to which the Solar system is formed after the condensation of this nebula.

last years of life

At the age of 72, in 1822, Laplace was appointed an honorary member of the American Academy of Arts and Sciences. In 1825, his health deteriorated, he was forced to constantly stay at home, and met with students in his office. By the way, having fairly large incomes, the family lived modestly. This was most likely explained by the fact that Laplace was not sure about tomorrow, given the situation in the country in which he had to live during the reign of Napoleon and french revolution.

Having been engaged in science all his life, he was no stranger to art. The walls of the office were decorated with copies of Raphael's works. He knew many of the poems of Racine, whose portrait was on the wall of his office along with portraits of Descartes, Galileo and Euler. He liked Italian music.

Death

Pierre Simon Laplace died on March 5, 1827 at the age of 77 in Paris. The burial place of the outstanding scientist was the cemetery in Paris - Père Lachaise. In 1888, at the request of Laplace's son, his father's remains were reburied on the family estate along with the remains of his mother and sister.

Laplace's burial site, which contains a tomb in the form of a Greek temple with Doric columns, is located on a hill overlooking the village of Saint-Julien de Maillot, in Calvados.

About Pierre Simon Laplace it can be said that he was one of the 72 Frenchmen whose names were engraved on Eiffel Tower. As a tribute to his talent, one of the streets in Paris was named after him.

Pierre Simon Laplace(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, theory of capillarity, heat, acoustics, geodesy, etc. Laplace proposed (1796) cosmogonic hypothesis(Laplace hypothesis). A classic representative of mechanistic determinism.

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 1816, the scientist was appointed a member of the commission for the reorganization of the Polytechnic School. In 1817 Laplace became a member of the newly created French Academy, i.e. 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.”

Napoleon, who judged people very correctly, wrote about Laplace in his memoirs on the island of St. Helena: “The great astronomer sinned by considering life from the point of view of infinitesimals.”

Indeed, everything that did not relate to science was infinitesimal for Laplace. Strict and demanding of himself when it came to science, in everyday life Pierre Laplace sometimes acted well, sometimes badly, depending on the circumstances, neglecting all this as if it were infinitesimal, in the name of the main cause of his life - scientific creativity. For the sake of science, he even changed his beliefs. Apparently, it is worth treating some moments in Laplace’s life as infinitesimal in comparison with the great and significant that the scientist created in astronomy, mathematics and physics. (Samin D.K. 100 great scientists. - M.: Veche, 2000)

More about Pere Laplace:

Pierre Laplace was born in peasant family in Beaumont, in the department of Calvados. Already in his early youth, Laplace had a remarkable memory and ability to understand, so that he easily received a position as a teacher in his hometown. The memoir “Sur le calcul integral aux differences infiniment petites et aux differences finies” of 1766, sent by him to Turin and published there, attracted the attention of scientists and Pierre Laplace was invited to Paris, where he was first made an examiner artillery school, and then, in 1773, was elected a member of the Academy of Sciences.

In general, P. Laplace devoted himself to quiet scientific activity and only a short time managed to force him into places of honor; so in 1799 Bonaparte appointed him Minister of the Interior, then he was Chancellor of the Protective Senate and even Count of the Empire. After the restoration, Louis XVIII made Laplace a marquis and peer of France.

The merits of Pierre Laplace in the field of pure and applied mathematics and especially in astronomy are enormous - he improved almost all departments of these sciences, and even created many again. He was distinguished by a remarkable ability to discover relationships and connections between objects and phenomena, apparently dissimilar, and was able with amazing clarity to deduce important consequences from such connections. P. Laplace proved the stability of the solar system, which consists in the fact that due to the movement of all 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 in very close limits.

Pierre Laplace discovered the causes of periodic inequalities in the movements of Jupiter and Saturn and the connection between the movements of the satellites of Jupiter, a connection expressed by two laws known as “Laplace's laws.” Having calculated the equilibrium conditions for the ring of Saturn, Laplace proved that they are possible only with the rapid rotation of the planet around its axis, which, in connection with the compression of Saturn, was indeed later proven by the observations of V. Herschel.

Laplace discovered that the reason for the acceleration in the movement of the Moon, which perplexed all astronomers, depends on periodic changes eccentricity lunar orbit and determined the compression of the earth's spheroid by inequalities in the motion of the Moon. In general, the research carried out by scientists on the movement of our satellite made it possible to compile more accurate tables of the Moon, which, in turn, had beneficial results in the matter of determining longitudes at sea.

Pierre Laplace developed the causes and phenomena of tides using twenty years of observations of sea level in Brest and proved the stability of the seas. Laplace also carried out many studies in physics, for example, on the phenomena of hairiness, the speed of sound, refraction, atmospheric pressure, etc.

Finally, Pierre Laplace compiled a cosmogonic hypothesis of the formation of all bodies of the solar system, called by his name and in general outline, unchanged to this day. Laplace's memoirs are published in the publications of the Paris Academy for the years 1772 - 1823. In addition, he published separately: "Mecanique Celeste" (5 volumes, 1799 - 1825 - a collection of all the studies of Newton, Clairaut, D'Alembert, Euler and Laplace himself, in which celestial mechanics was brought into a coherent system for the first time; “Exposition da systeme da monde” - a work that went through many editions (Russian translation by Khotinsky, 1861); a popular presentation of the previous one; “Theorie analytique des probabilites” and “Essal philosophique. sur les probabilites” - major treatises on the theory of probability - Now the Paris Academy has published L.'s "Oeuvres completes" in 13 volumes. (encyclopedic Dictionary Brockhaus and Efron) Sources - http://www.calend.ru/, http://to-name.ru/biography/per-simon-laplas.htm

Pierre-Simon Laplace is an outstanding French mathematician, physicist and astronomer who improved almost every section of these sciences. The main achievement of the scientist is the proposed nebular hypothesis, which states that the solar system is formed from large quantity rotating gas.

The future scientist was born in northern France in the small town of Beaumont-en-Auge (department of Calvados, Normandy) on March 23, 1749. Later, although Pierre received the titles of count and marquis, he continued to be ashamed of his humble origins, so about him youth practically nothing is known.

The peasant family was of average income, but an influential neighbor helped the smart boy get an education and sent him to study at a Benedictine school, and after graduation to enter the University of Caen. After graduating from school, Laplace became a convinced adherent of atheism.

He graduated from school with honors and an offer to stay in the city military school as a mathematics teacher. At the age of 17, Laplace wrote his first scientific work related to the theory gambling. Subsequently, the method used in the calculations became one of the most common in statistics.

The level of knowledge and opportunities in a small town did not suit the guy, so at the first opportunity in 1766 he moved to Paris, where for the first three years he intensively studied mathematics and published his works. After 5 years of living in the capital, friends helped him get a professorship at the Military School.

In 1778 he married Charlotte de Courti, who bore him two children.

Career

In 1773 he became an adjunct of the Paris Academy of Sciences for his study of the stability of planetary orbits. Since 1785 - an active member of the Academy of Sciences. 5 years after receiving membership in the academy, Laplace was elected Chairman of the Chamber of Weights and Measures, who was tasked with introducing new system measures

After the Jacobins came to power in 1793, the Academy of Sciences was abolished, and Laplace was dismissed from his position in the Commission on Weights and Measures. A year later, the Higher Normal and Polytechnic school, where the scientist became a professor. Instead of AN they created National Institute Sciences and Arts, where Pierre was invited as a member and head of the Bureau of Longitudes.

The new ruler of France, Napoleon, already on the second day after the revolution appointed Laplace Minister of the Interior. He was later promoted to member of the Senate. In 1803, the scientist became vice-president of the Senate, and later chancellor.

Major scientific achievements

First scientific achievements Laplace co-authored with Lavoisier. Their general work became the basis for the development new science called thermochemistry. Based on their research, scientists have proven that the amount of heat that is used to decompose a compound is equal to the amount of heat released during the formation of such a compound.

Laplace is a fairly versatile scientist. But most of it fundamental discoveries done in three directions - mathematics, physics and astronomy.

His main achievements in mathematics:

• Fundamental developments in the field differential equations;
• Introduction to the science of spherical functions;
• Developed methods of mathematical physics;
• Significantly expanded the foundation of linear algebra with a theorem on the representation of determinants by the sum of products of additional minors, probability theory - introduced generating functions;
• Developed the theory of errors and approximations using the least squares method.

Laplace achieved no less outstanding successes in physics:

1. He derived a formula for calculating the speed of sound in air.
2. Invented the ice calorimeter.
3. Established a law for capillary pressure.
4. He developed a barometric formula based on which air density can be calculated.

But, greatest number The scientist's research relates to celestial mechanics. Main work throughout his life bears a similar name - “Celestial Mechanics”. In his works, Laplace proved the stability of the solar system, which had previously been refuted.

In 1780, he proposed a completely innovative method for calculating the orbits of celestial bodies. Another important achievement scientist - in 1787 he showed that average speed Moon depends on eccentricity earth's orbit, changed under the influence of the gravity of the planets. Based latest theory The scientist determined the amount of compression of the Earth at the poles. He also developed and dynamic theory tides

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 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 writes one after another and sends them to Paris Academy sciences their works. 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 - full member academy.

P. Laplace, like no one else, knew how to highlight the main thing in the problem under consideration; knew how to imagine complex phenomena nature 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. Discovered the causes of periodic inequalities in the motion of Jupiter and Saturn and solved another one for this special case 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 universal gravity. Since then, mathematicians have succeeded in everything known phenomena reduce 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, combining together all the results on the equilibrium and motion of solid and liquid bodies, from which our solar system and similar systems spread out in the vastness of the universe are built, 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 the excellent work underlie theoretical astronomy, and the method of presentation serves as a model 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 the assessment of his personality and human dignity cannot be produced by 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, 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 from Emperor Napoleon count's title. 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.

Pierre-Simon Laplace (French Pierre-Simon Laplace; March 23, 1749 - March 5, 1827) - French mathematician and astronomer; known for his work in the field of celestial mechanics, differential equations, 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 departments of these sciences.

Born into a peasant family in Beaumont-en-Auge, in the Norman department of Calvados. 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).

What we know is limited, but what we do not know is infinite.

Laplace Pierre-Simon

The memoir “Sur le calcul integral aux differences infiniment petites et aux differences finies” (1766) that he sent to Turin and published there attracted the attention of scientists, and Laplace was invited to Paris. There he sent D'Alembert a memoir about general principles mechanics. He immediately appreciated the young man and helped him get a job as a mathematics teacher at the Military Academy.

Having settled his everyday affairs, Laplace immediately began to attack the “main problem of celestial mechanics”: the study of the stability of the Solar system. At the same time he published important work on the theory of determinants, probability theory, mathematical physics, etc.

1773: masterfully applied mathematical analysis, Laplace proved that the orbits of the planets are stable, and their average distance from the Sun does not change due to mutual influence (although it experiences periodic oscillations). Even Newton and Euler were not sure about this. However, it later turned out that Laplace did not take into account tidal friction, which slows down the rotation, and other important factors.

...I didn't need this hypothesis.
(About God)

Laplace Pierre-Simon

For this work, 24-year-old Laplace was elected member (adjunct) of the Paris Academy of Sciences.

1778: married Charlotte de Courty. They had a son, the future General Laplace, and a daughter.

1785: Laplace becomes a full member of the Paris Academy of Sciences. In the same year, during one of the exams, Laplace highly evaluates the knowledge of the 17-year-old applicant Bonaparte. Subsequently, their relationship was invariably warm.

IN revolutionary years Laplace took a leading part in the work of the commission on the introduction metric system, headed the Bureau of Longitudes (the name of the French Astronomical Institute) and lectured at the Ecole Normale. At all stages of the stormy political life In France of that time, Laplace never entered into conflicts with the authorities, who almost invariably showered him with honors.

Laplace's common origin not only protected him from the repressions of the revolution, but also allowed him to occupy high positions. Although he did not have any political principles (however, perhaps that is why).

1795: Laplace lectures on the theory of probability at the Ecole Normale, where he was invited as professor of mathematics, along with Lagrange, by decree of the National Convention.

1796: “Exposition of the System of the World” - a popular essay on the results later published in Celestial Mechanics, without formulas and vividly presented.

1799: the first two volumes of Laplace’s main work, the classic “Celestial Mechanics,” were published (by the way, it was Laplace who coined this term). The monograph describes the movement of the planets, their forms of rotation, and tides. Work on the monograph lasted 26 years: volume III published in 1802, volume IV in 1805, volume V in 1823-1825. The presentation style was too concise; the author replaced many statements with the words “it’s easy to see that...”. However, the depth of analysis and richness of content made this work reference book astronomers of the 19th century.

In Celestial Mechanics, Laplace summed up both his own research in this area and the work of his predecessors, starting with Newton. He gave a comprehensive analysis famous movements bodies of the Solar System on the basis of the law of universal gravitation and proved its stability in the sense of the practical invariability of the average distances of the planets from the Sun and the insignificance of fluctuations in the remaining elements of their orbits.

Along with the mass of special results concerning the movements of individual planets, satellites and comets, the figure of the planets, the theory of tides, etc., the most important was the general conclusion that refuted the opinion (which Newton also shared) that maintaining the present appearance of the solar system requires the intervention of some some extraneous supernatural forces.

In one of the notes to this book, Laplace casually outlined the famous hypothesis about the origin of the solar system from a gaseous nebula, previously expressed by Kant.

Napoleon awarded Laplace the title of Count of the Empire and every conceivable order and position. He even tried it as Minister of the Interior, but after 6 weeks he chose to admit his mistake. Laplace introduced into management, as Napoleon later put it, “the spirit of the infinitely small,” that is, pettiness. Laplace changed the title of count, given to him during the years of the empire, shortly after the Bourbon restoration to the title of marquis and member of the house of peers.

1812: the grandiose “Analytical Theory of Probability”, in which Laplace also summarized all his and others’ results.

1814: “An Essay on the Philosophy of the Theory of Probability” (popular exposition), the second and fourth editions of which served as an introduction to the second and third editions “ Analytical theory probabilities." “An Experience in the Philosophy of Probability Theory” was published in Russian translation in 1908 and republished in 1999.

Contemporaries noted Laplace's goodwill towards young scientists and his constant readiness to help.

Named in honor of the scientist:
* crater on the Moon;
* asteroid 4628 Laplace;
* numerous concepts and theorems in mathematics.

Laplace was a member of six Academies of Sciences and Royal Societies, including St. Petersburg Academy(1802). His name is included in the list of the greatest scientists of France, placed on the first floor of the Eiffel Tower.

Scientific activity

Mathematics

When deciding applied problems Laplace developed methods of mathematical physics that are widely used today. Particularly important results relate to potential theory and special functions. The Laplace transform and the Laplace equation are named after him.

He's come a long way linear algebra; 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 Probability Theory” is dedicated to mathematical fundamentals; Probability theory proper begins in the second book, as applied to discrete random variables. There's proof right there limit theorems Moivre-Laplace and applications to the mathematical processing of observations, population statistics and the “moral sciences”.

Laplace also developed the theory of errors and approximations by the method of least squares.

Astronomy

Laplace proved the stability of the solar system, which consists in the fact that due to the movement of all 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 narrow 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 distant galaxies like our Milky Way.

He advanced perturbation theory far and convincingly showed: all deviations of the positions of the planets from those predicted by Newton’s laws (more precisely, predicted by the solution of the two-body problem) are explained by the mutual influence of the planets, which can be taken into account using the same Newton’s 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) - the mutual influence of the planets, and showed that these are nothing more than periodic oscillations, and everything returns to initial position every 929 years.

Before Laplace's discoveries, many scientists tried to explain the deviations of theory from observations by the movement of the ether, terminal speed 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 (secular inequality), is also a periodic change in the eccentricity of the lunar orbit, and it arises under the influence of gravity major planets. The displacement of the Moon calculated by him under the influence of these factors 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, the orbits of which, 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 equilibrium conditions for 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.

Laplace developed the theory of tides using twenty years of observations of sea level in Brest.

belongs to Laplace barometric formula, relating air density, altitude, humidity and acceleration free fall. He also studied geodesy and the theory of refraction, and invented an ice calorimeter.

Together with A. Lavoisier in 1779-1784. Laplace studied the theory of heat, invented the ice calorimeter, and struggled with the theory of phlogiston. Laplace published a number of works on the theory of capillarity and established Laplace's law for capillary pressure.

In 1809, Laplace dealt with problems of acoustics; he derived a formula for the speed of sound in air.

Laplace's important studies relate to hydrodynamics.

Philosophy

By philosophical views Laplace was an atheist and materialist; His dialogue with Napoleon is known:
- You wrote such a huge book about the system of the world and never mentioned its Creator!
- Sire, I did not need this hypothesis.

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

Pierre-Simon Laplace - photo

Pierre-Simon Laplace - quotes

...I didn't need this hypothesis. Explanation of the quote: Napoleon once asked: “Newton spoke about God in his book, but in your book I never came across the name of God.” Laplace replied: “Citizen First Consul, I did not need this hypothesis.”

What we know is limited, but what we do not know is infinite.