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COPERNICUS, NICOLAUS (1473–1543)

COPERNICUS, NICOLAUS (1473–1543), Polish astronomer, born in Thorn (Torun), West Prussia, a province subject to the king of Poland. In about 1485, after his father's death, Nicolaus came under the care and patronage of his maternal uncle, who shortly afterward became bishop of Varmia (Ermland).

EDUCATION AND CAREER

Beginning in 1491, Copernicus enrolled successively at the universities of Cracow, Bologna, and Padua, where he studied, respectively, mathematics and astronomy, canon and civil law, and medicine. He was elected a canon of the cathedral chapter of Varmia in 1497, providing him with a lifetime income. In 1503 he was awarded a doctorate in canon law from the University of Ferrara.

In 1610 Copernicus settled in Frauenburg (Frombork), near the Baltic Sea. There he carried out his canonical duties, practiced medicine, administered the holdings of the Varmia chapter, wrote on the problem of the debasement of the silver coinage of Royal Prussia, and continued to work intensively at improving the astronomical ideas he had begun to develop earlier.

As a student, Copernicus had become aware of the dichotomy between Aristotelian principles and the techniques employed by Claudius Ptolemy (c. 100–c. 170), the greatest astronomer of antiquity. For Aristotle (384–322 B.C.E.) the motionless Earth at the center of the universe was surrounded by uniformly rotating homocentric spheres carrying the Moon, Sun, and planets. The task of astronomy was to devise geometrical means for calculating the apparent positions of the celestial bodies, which neither moved uniformly nor maintained a constant distance from Earth. The planets, moreover, periodically moved with retrograde motion.

Some time after 1502, Copernicus circulated among a few individuals an anonymous treatise, subsequently titled Commentariolus (Brief commentary), an early stage in the development of his heliocentric system. He shortly afterward began De revolutionibus (On the revolutions), his detailed exposition of this system.

In 1539 Georg Joachim Rheticus (1514–1574) of the University of Wittenberg visited Copernicus. Impressed by Copernicus's theory, Rheticus tested the waters for the publication of Copernicus's almost completed work by publishing in 1540 his own account of it, Narratio prima (First account). Its reception encouraged Copernicus to publish his own work, a copy of which reached Copernicus as he lay dying in 1543.

Andreas Osiander (1498–1552), a Lutheran minister, oversaw the printing of the latter part of Copernicus's book and inserted an anonymous preface asserting, contrary to Copernicus's opinion, that the work represented only calculating devices and not the true constitution of the universe.

THE COPERNICAN SYSTEM

Copernicus's heliocentrism possessed several advantages over Ptolemaic astronomy. The apparent retrograde motions of the planets could now be accounted for by the revolution of Earth, dispensing with Ptolemaic astronomy's traditional geometric devices. Copernicus eliminated the Ptolemaic equant, a point not at the center of Earth about which the planets moved uniformly, and substituted a technique earlier used by a Muslim astronomer. Corrections to the apparent distances of the Moon also had Arabic roots. The relative distances of the planets from the Sun could now be determined as fractions or multiples of the distance from Earth to the Sun. Above all, Copernicus had created an integrated astronomical system, contrary to the independent sets of geometrical techniques for each of the planets characteristic of Ptolemaic astronomy. This was undoubtedly the prime consideration for the creation of his system.

Despite its advantages, heliocentrism was not without physical, observational, and theological problems. A revolving and rotating Earth violated several long-established Aristotelian principles, including the tendency of dropped bodies to fall to Earth at the center of the universe. Copernicus held that bodies fell because they tended to rejoin the spherical bodies of which they had been a part. For the Peripatetics, objects on a rotating Earth would be flung off, and objects thrown aloft should then land to the west of the point from which they were thrown. Copernicus responded that bodies on Earth or above it share in its circular motion. To the charge that observations made from an orbiting Earth should show stellar parallax, a change in the apparent position of the stars in the course of a year, Copernicus answered that a parallax could not be observed because the stars were much farther than had been believed.

RECEPTION AND INFLUENCE

In 1551 Erasmus Reinhold (1511–1553) published the Tabulae Prutenicae (Prutenic Tables) based on Copernicus's work. They were more accurate than the tables commonly in use, and they helped sustain interest in the Copernican theory. In particular, astronomers at the University of Wittenberg thought the Copernican theory was superior to that of Ptolemy in a number of respects, but they did not accept its heliocentrism. Throughout Europe a few astronomers were open to the validity of Copernicanism's fundamental hypothesis, but hardly any accepted it fully.

However, successive challenges to Aristotelian concepts, based on precise observations, began to remove some objections to Copernicanism. Tycho Brahe (1546–1601), whose astronomical observations were more accurate than any previously recorded, rejected heliocentrism, as did a few others, in favor of a geoheliocentric system, in which the planets circled the Sun, while the Sun revolved about the motionless Earth. Johannes Kepler (1571–1630), using Brahe's data, modified Copernicus's system significantly in 1609. Kepler placed the Sun in one of the foci of each of his elliptical planetary orbits, which were traversed with non-uniform motion. This led to a significant improvement in the prediction of planetary positions.

Galileo Galilei's (1564–1642) observations with the telescope beginning in 1609, as well as his subsequent publications on the nature of motion, were most important in the removal of Aristotelian objections to a moving Earth and to the size of the solar system. The placing of Copernicus's De revolutionibus on the Index of Prohibited Books in 1616 and Galileo's subsequent trial for heresy had little effect. With the work of Kepler and Galileo, as well as the influence of Cartesianism, heliocentrism became increasingly accepted; most astronomers were won over by the middle of the seventeenth century.

Copernicanism marked a turning point in the history of astronomy and provided a foundation for the remarkable achievements in related sciences in the seventeenth century. Copernicus's heliocentrism played a significant role in debates about the cause of planetary motion, and the nature of space, matter, and motion, and was thus a significant component of and stimulus to the scientific revolution.

See also Astronomy; Brahe, Tycho; Cartesianism; Galileo Galilei; Index of Prohibited Books; Kepler, Johannes; Scientific Revolution.

BIBLIOGRAPHY

Primary Sources

Copernicus, Nicolaus. Copernicus: On the Revolutions of the Heavenly Spheres. Translated by A. M. Duncan. Newton Abbot and New York, 1976. Translation of De revolutionibus orbium coelestium, 1543.

——. Three Copernican Treatises: The Commentariolus of Copernicus, The Letter against Werner, The Narratio Prima of Rheticus. Translated with an introduction by Edward Rosen. 3rd rev. ed. New York, 1971.

Secondary Sources

Armitage, Angus. Copernicus: The Founder of Modern Astronomy. New York and London, 1957. A general survey in the context of the history of astronomy.

North, John. "Copernicus' Planetary Theory." In The Norton History of Astronomy and Cosmology. Chapter 11. New York and London, 1995. A brief survey for the general reader.

Swerdlow, Noel M., and Otto Neugebauer. Mathematical Astronomy in Copernicus's De Revolutionibus. 2 parts. Berlin and New York, 1984. Has a substantial nontechnical introduction, including biographical details and the development of Copernicus's ideas.

WILBUR APPLEBAUM