LAPLACE, Pierre-Simon. — Astronomer and mathematician, b. at Beaumont-en-Auge (Calvados) on 23 March 1749, d. at Paris on 5 March 1827. He began his career in teaching at the École Médicale, was an adherent of Bonaparte, and became first Minister of Public Instruction and later a senator. Opportunistic in his dealings with events, upon the Restoration he paid homage to Louis XVIII and was elected to the Académie Française.
His scientific activity began with a study of the mutual perturbations between Jupiter and Saturn; this was followed by research on the secular acceleration of the Moon, the discovery of the invariability of the mean distances of the planets, and the discovery of important theorems on determinants. He studied the attraction between spheroids, making use of the researches he had conducted on the partial differential equation Δφ = 0, which bears his name, and was the first to employ the method of perturbations, still so fruitful today, which consists in solving a problem in two stages: first, in a first approximation, abstracting from less important elements, and subsequently in a second approximation, taking into account the elements previously neglected.
In 1796 Laplace published the Exposition du système du monde, known as the Kant-Laplace theory on the formation of the universe; now outdated, it is nonetheless far from concluded. In 1812 he wrote the Théorie analytique des probabilités, perhaps the first systematic treatise on this important and delicate subject.
He was a believer, as is evident from an 1809 letter to his son, in which he wrote: «Je prie Dieu qu'il veille sur tes jours. Aie-Le toujours présent à ta pensée ainsi que ton père et ta mère», and from his Christian death. His complete works were published in 7 vols., at Paris 1843-47, and in 13 vols., ibid. 1878-1904.
LA PLATA, ARCHDIOCESE OF. — In Argentina, the city that is the capital of the province of Buenos Aires, is situated on the right bank of the river of the same name.
It extends over approximately 64,000 sq. km. and has a population of 3,500,000 inhabitants, of whom 2,740,000 are Catholics, distributed in 167 parishes, served by 317 diocesan priests and 375 religious, one seminary, 88 male religious communities and 273 female (Annuario Pontificio 1951, p. 240).
The diocese was created by Pope Leo XIII on 15 February 1897, with the bull In Petri cathedra, as a suffragan of Buenos Aires. Pope Pius XI, with the apostolic constitution Nobilis Argentinae nationis of 20 April 1934, elevated it to metropolitan status, assigning as its suffragans the dioceses of Bahia Blanca and Viedma (AAS, 27 [1935], pp. 257-63).
The cathedral is dedicated to the Immaculate Conception of the Blessed Virgin Mary.