(Polish, Mikotaj Kopernik). Born Feb. 19, 1473, in Torun; died May 24, 1543, in Frombork (Frauenburg). Polish astronomer, creator of the heliocentric system of the world.

Copernicus was the son of a merchant. After his father’s death in 1483, he was raised by his uncle, Lucas Waszenrode, bishop of the diocese of Warmia. (Warmia was an age-old Polish terri-tory, extending along the Vistula River from the city of Torun to the Baltic Sea.) Copernicus studied at the University of Krakow from 1491 to 1495. At the age of 24 he was elected a canon. He continued his education at the universities of Bologna, Padua, and Ferrara in Italy, where in addition to astronomy he studied medicine and law. Upon returning to his native country in 1503, he became his uncle’s secretary and physician and lived until his uncle’s death in the bishop’s residence in the city of Lidzbark Warminski (Heilsberg). In 1512 he moved to the city of Frombork, where he lived for more than 30 years in one of the towers of the fortress wall surrounding the cathedral. The tower also served as his observatory and has been preserved to this day.

Copernicus was active in Warmia’s affairs and in the struggle for its independence. Among contemporaries he was known as a statesman, a skillful physician, and a profound authority on astronomy. When the Lateran Council (1512–17) organized a committee for calendar reform, Copernicus was invited to Rome to take part in the committee’s work. He argued that the reform was premature, since the duration of the year was not known with sufficient accuracy.

The creation of the heliocentric system of the world was the result of many years of work. Copernicus began with attempts to improve the geocentric system described in Ptolemy’s Almagest. Numerous works before Copernicus had attempted this, but they amounted to either a more accurate determination of the elements of the deferents and epicycles with the aid of which Ptolemy represented the motions of celestial bodies or the addition of new epicycles. Having understood the relationship between the observed motions of the planets and the sun (well known even to Ptolemy), Copernicus used it as the foundation of the heliocentric system. This system provided the correct explanation for a number of observed laws of the motions of planets that could not be understood from the geocentric point of view. Tables compiled by Copernicus were much more accu-rate than Ptolemy’s; this was of great importance for marine navigation, which at that time was developing rapidly. The wide-spread use of Copernicus’ tables aided the dissemination of the heliocentric system.

Copernicus summarized the results of his work in the treatise De revolutionibus orbium coelestium (On the Revolutions of Heavenly Spheres), published in 1543 shortly before his death. The appearance of this work “marks the start of the chronology of the liberation of natural science from theology” (F. Engels, Dialektikaprirody, 1969, p. 8). Copernicus developed new philosophical ideas only to the degree required by the immediate practical needs of astronomy. He preserved the concept of a finite universe bounded by a sphere of fixed stars, although the need for this no longer remained (the existence and the finite dimensions of the sphere of fixed stars were only inescapable consequences of the idea of an immovable earth). Copernicus’ primary concern was to make his work as complete a handbook for solving all problems of astronomy as Ptolemy’s Almagest. Therefore, he concentrated his efforts on improving Ptolemy’s mathematical theories. Of great importance are Copernicus’ contributions to the development of trigonometry (plane as well as spherical). The chapters of his treatise dealing with trigonometry were published separately in 1542 by his sole disciple, G. J. Rhäticus (Rhaeticus).

The philosophical significance of the heliocentric system consisted in a changed view of the earth’s importance: the earth, formerly considered the center of the universe, was now rele-gated to the status of a mere planet. A new concept of the unity of the world arose in which the “heavens” and the “earth” are governed by the same laws. The revolutionary nature of Copernicus’ views was understood by the Catholic Church only after Galileo and others developed the philosophical consequences of his teachings. In 1616 the Inquisition decreed that Copernicus’ book be placed on the Index “until corrected”; it remained prohibited until 1828.