Pierre Laplace Pt. 2

Pierre-Simon marquis de Laplace was a very prominent mathematician and physicist in France during the eighteenth and nineteenth century. A resource compiled by Rachel Still.

Early Life and Schooling

Pierre-Simon marquis de Laplace was born on March 23,1749 in Beaumont-en-Auge, Normandy, France. His father, Pierre Laplace, was well off in the cider trade and a small farmer. His mother, Marie-Anne Sochon, was from a prosperous farming family. While relatively well off, little education was apparent in the family, only Pierre-Simon’s uncle received an education. There is little known about Pierre-Simon’s early life. From a young age, Pierre-Simon attended a military academy, where he showed early promise with mathematical abilities. When he was sixteen, Pierre-Simon attended the University of Caen. His father always wanted him to make a career in the church, so he originally enrolled to study theology, before he realized his passion. Pierre-Simon did not stay at the University of Caen very long, only about two years, before he decided to leave without a degree. Receiving a letter of degree from his teachers for established mathematician Jean d’Alembret, Laplace made his way from the University in Caen to Paris.

The blue dot is Beaumont-en-Auge, Normandy, France. Caen and Paris are noted in pink.

Career

Papers Written

Within five years of accepting his job at École Militaire, he had already written thirteen scientific papers regarding various things, such as integral calculus, physical astronomy, and mechanics. Laplace’s first paper to read, but not published, by Académie de Sciences in Paris was in March 1770. The paper expanded on Lagrange’s (another famous mathematician of the time) methods of maximas and minimas of curves. His first paper that was actually published was in 1771, which was about integral calculus. Laplace also published another one that included equations important to mechanics and physical astronomy. Two of his most influential books were “The Exposition” and “Traité de Mécanique Celeste”, each with 5 volumes. “The Exposition” covered various topics such as motion of the sea and apparent motion of celestial bodies (book 1), actual motion of celestial bodies (book 2), force and momentum theories (book 3), universal gravitation theory and the shape of the Earth (book 4), and the historical account of astronomy and his famous Nebular Hypothesis (book 5). (See Scientific Discoveries and Contributions for more on the Nebular Hypothesis) Another one of his most famous books, “Traité de Mécanique Celeste” was considered his greatest work of all time. The book mainly focused on physics concepts, such as equilibrium and the motion of solids and fluids. It also focused on the motion of bodies in the solar system in accordance to the Law of Universal Gravitation. Throughout his career, Laplace applied his ideas to write papers that explain many phenomenons, such as double refraction, velocity of sound, capillary action, theory of heat and elastic fluids. Laplace had a strong infatuation with the study and movement of fluids, and even continued to write about them past the age of seventy years old.

Positions Held

After Laplace was accepted under d’Alembret’s wing, he was given his first job at École Militaire from 1769-1776. While he was there, he taught classes, did a lot of his beginning research there, and wrote many papers. After many years of teaching, Laplace moved to Académie de Sciences after had reading thirteen papers to them in less than three years. During his time there, he served on many different committees, and even held a senior position, beginning in 1785. During this time, he also was an examiner at the Royal Artillery Corps and did various things there, such as writing reports on cadets and even passing Napoleon Bonaparte, which made him well known to many powerful people in France at the time. After leaving Paris for a short time, due to political instability, Laplace helped find the École Normal school, which aimed to teach school teachers. Laplace taught there as well, but the school was only opened fourteen months. After the school closed, he helped to find the Bureau and the Paris Observatory. He also helped to lead the Institut National des Sciences et des Arts, which was basically a reopening of the Académie de Sciences, after it was closed. It was considered the height of his influence when he and several others founded the Société de Arcueil in 1805. The society was composed of several French scientists who met just south of Paris, in Arcueil, and wanted to take leading roles in the study of physics. Unrelated to his scientific career, he was also briefly the chancellor of the Senate.

Scientific Discoveries and Contributions

Pierre-Simon marquis de Laplace made unbelievably significant advances in the scientific community. Some of his major contributions were advances in calculus, especially in differential equations, which he applied to make discoveries in mathematical astronomy. These discoveries included the stability of the solar system, the relationship between planets and their moons, and the tendencies of planets and their orbits. Within the field of mathematics specifically, Laplace also studied a concentration of statistics and probability. Another key part of Laplace’s research is the study of physics related concepts, especially on theories of heat toward the end of his career, which through he discovered respiration is a form of combustion. In the later part of his career, Laplace sought to establish that almost all of nature can be explained by being reduced to actions between molecules. Another one of his most important contributions was he was on one of the committees in the Académie de Sciences that worked to standardize all measurement. Laplace even was the one that advocated for the metric system and decimal base.

Famous Nebular Hypothesis

This is one of Laplace’s most famous contributions to the scientific society at the time. This theory states that the solar system was originally created from the contracting and cooling of a incandescent gas that was very flat and slowly rotating. It is one of the mostly widely accepted theories of the evolution of the solar system. Although another scientist had had the idea before Laplace had, Laplace had proposed this idea independently sometime later.

Laplace's Equation

Although Laplace’s Equation was named after him, it was not in fact discovered by him. It is named for him though because of his studies related to the mathematic field. Laplace gave credit of the equation in his book “Mécanique Céleste”, fittingly to his haughty personality. The equation is a twice differentiable equation of all the coordinates of the Cartesian system such that they equal zero. It is known as a simple example of an elliptic partial differential equation.

Personal Life

Although Laplace was commonly considered the “Newton of France”, he ran into many difficulties because of his attitude and lack of humbleness. Early in his career, he began to have rocky relationships with his colleagues, because of his inability to give credit where it was due and to be humble. Even though he was, Laplace considered himself the best mathematician in France and if he would make an error in a paper, he would blame it on the printer, rather than as his mistake. He had a wife and two children, the daughter died during childbirth and the son never had children. Laplace was often known for commonly changing his beliefs and opinions to match those that were popular of the time, another characteristic that made him unpopular with his colleagues. Yet, this also seemed to prove successful sometimes with people of power, as he was named a marquis in 1817. Laplace lived during a very politically turbulent time in France, frequently having to leave and come back to Paris, dealing with such things as the “Reign of Terror”, which affected his life and career choices greatly. Pierre-Simon marquis de Laplace died on March 5th, 1827 by causes unknown.