Nicholas Copernicus, Polish astronomer. Born in Torun, Poland, February 19, 1473.
He soon abandoned his early idea of taking holy orders, and went to the University of Bologna, where he studied canon law. He went next year to Padua, where he studied medicine and philosophy.
In 1505 he finally left Italy, and went to spend six years as his uncle's physician at the castle of Heilsberg. In 1512 Copernicus went to Frauenburg where he had been nominated canon of the cathedral in 1497. However, till the end of his life astronomy was his favourite study. His great theory was broached in 1543 in the De Revolutionibus Orbium Coelestium, Libri VI, published at Nuremberg and dedicated to Pope Paul III.
Copernicus brought about one of the great revolutions of thought in man's history by showing that the earth is not the center of the universe. Until the introduction of the Copernican theory, men believed that the planets, the sun, the stars, and all other heavenly bodies revolved about an unmoving earth. Copernicus showed that the earth is a planet like all the others and moves around the sun in much the same way. To explain the apparent movement of the stars, he assumed that the earth rotates daily on its own axis, despite the belief that such a rotation would cause a gigantic wind to arise on the earth. These features of the Copernican theory required great changes in man's accustomed way of looking at the world.
His work demonstrates the theory, already hinted at by the Pythagorean philosophers, that the Sun is the center of the planetary system, and that the Earth and the planets revolve round it. Where observational facts failed Copernicus found them himself, with an instrument of his own making, though he was essentially a thinker rather than an observer. De Revolutionibus represents a complete reformation of astronomy; the discovery of the true form of the planetary orbits by Kepler, and the conception of universal gravitation by Newton, would have been impossible without the preliminary heliocentric viewpoint which Copernicus established.
Copernicus explained the sun-centered theory in his treatise De revolutionibus orbium coelestium ("On the Revolutions of Heavenly Bodies"). He completed the treatise in 1529 but did not publish it until 1543, perhaps because he feared unfavorable reactions from scientists, philosophers, and the clergy. The Copernican system offered a fairly simple explanation of the observed movements of the planets and other heavenly bodies, but it conflicted with the Ptolemaic system, which was the popular theory of the time. The Ptolemaic system, named for the Greco-Egyptian astronomer Ptolemy, assumed that the earth is the motionless center of the universe and that all heavenly bodies revolve around the earth. Despite the general acceptance of the Ptolemaic system many influential men of science immediately recognized the significance and essential truth of the Copernican system.
Copernicus' ideas about the revolution and rotation of the earth were not entirely original. The Greek astronomer Aristarchus of Samos, for example, had presented a vague sun-centered theory in the 3d century B.C. Some of the works of other early theorists also contained ideas of a sun-centered universe and a moving earth. But Copernicus was the first to state these ideas clearly and to support them with detailed specifications of planetary motions.
Copernicus also made studies of the moon's motion and determined its size and distance from the earth. In addition, he calculated the distances of the planets from the sun.
Nicholas Copernicus died in Frauenburg, East Prussia (now in Poland), May 24, 1543.