COPERNICUS, or KOPPERNIGK, Nicolaus, Polish astronomer: b. Thorn, Poland, 19 Feb. 1473; d. Frauenburg, East Prussia, 24 May 1543. His father was a Pole and his mother a German. From a school at Thorn Copernicus wtnt to Cracow,.where he studied medicine, theology, mathematics and astronomy. The fame of Peurbach and Regiomontanus, the restorers of astronomy in Europe, excited his emulation. In 1496, at the age of 23, he went to Italy, and at Bologna resided two years, study ing canon law and astronomy. In 1497, while m Italy, he was appointed a canon of the cathedral of Frauenburg. In 1500 he went to Rome, where he lectured on mathematics and as tronomy. Subsequently he studied medicine at Padua, and canon law at Ferrara, where he graduated as doctor in this subject. He re turned to Prussia in 1505, and lived for some years at Heilshem, but his subsequent life was mostly spent at Frauenburg.
He now applied his whole strength to the study of astronomy, which at this time was dominated by the system of Claudius Ptolemy. Copernicus doubted whether the motions of the heavenly bodies could be so confused and so complicated as this hypothesis would make them. He found that some of the ancient Greelcs had thought of the possibility of a motion of the earth. This induced him to examine the subject more fully, and he came to the following conclusions: That the sun was the centre of the system; that the earth was a planet like Mars and Venus; and that all the planets revolve round the sun in the following order: Mercury id 87 days, Venus in 224, the Earth in 365, Mars in one year and 321 days, Jupiter in 11 years and Saturn in 29 years. Although Copernicus knew that the planetary orbits are not circles having the sun in the centre, he was not able to determine exactly their form. This was reserved for Kepler, who completed what may be called the natural his tory of the subject, and stated his three cele brated laws in the end of the 16th century. Thus Copernicus stands, as it were, upon the boundary-line of a new era. He commences his labors at a tittle when the belief in the immo bility of the earth is universal He conceives the idea of its motion, and pursues it with un wearied diligence, not for a few years, but through the greater part of his life, constantly comparing it with the appearances in the heavens. He at last confirms his idea, and
thus becomes the founder of a new system of astronomy. All this he did a hundred years before the invention of telescopes, with im perfect wooden instruments on which the lines were often only marked with ink. His great countryman, Kepler, has described his character in the followtng words: °Copernicus, vir maximo ingenio, et quod in hoc exercitio magni momenti est, animo In his celebrated work, dedicated to the Pope, Paul III, (De Orbitim coelestium Revolutionibus,' libro vi (completed in 1530, although first published at Nuremberg 1543, folio; later editions appeared at Basel 1566, at Amsterdam 1617, at Warsaw in 1851, at Berlin in 1873), his system is developed.
Besides his principal work, we have also by him a work on trigonometry, (De Lateribus et Angulis Triangulorum.) The first biography of Copernicus was written by the mathematician Gassendi (1654), and for 200 years this work served as the basis of all subsequent biographies of the great astronomer; but in more recent times the labors of Prowe and others have helped us to a better acquaintance with the facts of his life. Count Sieralcowski erected a monument to his rnemory in Saint Anne's Church at Cracow, with this inscription: °Sta, sol, ne movearep (Stand, Sun, do not move). Thorwaldsen, one of the greatest sculptors of our time, executed a colossal statue of Co pernicus for the city of Cracow, which is one of the noblest specimens of modern art. An other statue of him by F. Tieck has been erected in his native town. Consult Ber trand, 'Les foundateurs de l'astronomie moderne) (Paris 1865) • Bryant, (History of Astronomy' (London 1407); Curtze, (Nicolaus Copernicus' (Berlin 1899) ; Czynslci, (Kopernik et ses travaux) (Paris 1847) ; Flammarion, (Vie de Copernic) (ib. 1872) ; Gassendi, 'Vita Nicolai Copernici) (The Hague 1652) ; Muller, (Nilcolaus Copernicus, der Altmeister der neueren Astronomie (Freiburg 1898) ; Prowe, (Nicolaus Copernicus) (3 vols., Berlin 1884), the standard biography; Wolf, ‘Geschiehte der Astronomie (Munich 1877); id., 'Handbuch der Astronomie, ihrer Geschichte und Littera tur' (2 vols., Zurich 1893).