Quarter 2 Astronomer Biography

Dictionary of Scientific Biography.  C. Gillispie, editor.  Charles Scribner's Son, publisher. 1981

Quarter Two Astronomer Biography

            Pierre Simon Laplace was born in Beumont-en-Auge, Normandy, France on March 23^rd, 1749.  His father, Pierre Laplace, was involved in the cider trade and did well for himself and his mother, Marie-Anne Sochon came from a farming family in Tourgeville.  Pierre Simon Laplace attended a Benedictine priory school in his home town of Beaumont-en-Auge between the ages of 7 and 16.  His father sent him to this school because he expected him to pursue a career in the Church.  When he was 16, Laplace enrolled in Caen University to study theology because he was still planning on a career in the Church.  But during his two years at the University of Caen, Laplace realized that he was gifted in the area of mathematics and how much he loved the subject.  This realization is accredited largely to two mathematics teachers at Caen: C Gadbled and P Le Canu.

            Laplace chose to leave Caen without his degree and went to Paris.  He was given an introduction letter to d’Alembert from Le Canu, his teacher.  Laplace was only 19 years old when he got to Paris but d’Alembert was very impressed by him and he began to direct his mathematical studies and found him a position as professor of mathematics at the Ecole Militaire.  Laplace began to produce many groundbreaking mathematical papers and the first was presented in the Academie des Sciences in Paris on March 28^th, 1770.  Laplace’s first paper to be published was one on the integral calculus which he translated into Latin and published at Leipzig in the Nova acta eruditorum in 1771.  On March 31^st, 1773, Laplace was elected an adjoint in the Academie des Sciences.  By the time he was elected, he had already read thirteen papers to the Academie in less than three years.  In 1780, Laplace and the chemist Lavoisier applied quantitative methods to a comparison of living and nonliving systems, with the aid of an ice calorimeter that they had invented, showed respiration to be a form of combustion.  In 1784, Laplace was appointed as the examiner at the Royal Artillery Corps.  Laplace was promoted to a senior position in the Academie des Sciences in 1785.  Laplace marries Marie-Charlotte de Courty de Romanges on May 15^th, 1788.  They had two children and their son, Charles-Emile, who was born in 1789, went on to a career in the military.  Before the 1793 Reign of Terror, Laplace and his wife and two children left Paris and lived 50 km southeast of Paris. He did not return to Paris until after July 1794. 

            Laplace presented his famous nebular hypothesis in 1796 in Exposition du systeme du monde, which looked upon the solar system as originating from the contracting and cooling of a large, flattened, and slowly rotating cloud of incandescent gas.  Exposition du systeme du monde was written as a non-mathematical introduction to Laplace's most important work Traité de Mécanique Céleste whose first volume appeared three years later.  Laplace had discovered the invariability of planetary mean motions.  In 1786 he had proved that the eccentricities and inclinations of planetary orbits to each other always remain small, constant, and self-correcting.  These and many other of his earlier results formed the basis for his second work.  Laplace became Count of the Empire in 1806 and he was named a marquis in 1817 after the restoration of the Bourbons.  Laplace continued to apply his ideas of physics to other problems such as capillary action (1806-07), double refraction (1809), the velocity of sound (1816), the theory of heat, in particular the shape and rotation of the cooling Earth (1817-1820), and elastic fluids (1821).  Laplace died on the morning of March 5^th, 1827.