COPERNICUS, NICOLAUS

COPERNICUS, Nicolaus: translation

With On the Revolutions of the Celestial Spheres, Nicolaus Copernicus ini­tiated a shift in scientific thinking often now described as the ''scientific revo­lution.'' Although the details of the heliocentric theory of the universe were disproved long ago, its central claim that the earth is but one of many objects orbiting the sun without a doubt changed the theory and practice of astronomy and physics within the course of a single century.

The son of prosperous parents from Torun in Poland, Copernicus was edu­cated early both at home and elsewhere. At the age of twelve, following the deaths of his parents, he became the ward of his uncle Lucas Waczenrode, the bishop of Varmia. He first attended the cathedral school and later entered the University of Cracow in 1491. Upon the urging of his uncle, Copernicus was elected a canon to the cathedral chapter at Frombork in 1497. An eight-year educational sojourn in Italy solidified his training in law, medicine, mathematics, and astronomy. After study at the Universities of Bologna, Padua, and Ferrara, Copernicus returned to Varmia for good around 1504 and served the cathedral chapter with distinction for his remaining years.

Most of Copernicus's life was occupied by duties having little to do with his scientific achievements, but he is justly renowned for his heliocentric under­standing of the universe: ''The earth moves while the sun stands still.'' His scholarly output was limited, and even though he made no secret of his views, he opposed publication of his theory, bowing to the pressure of his friends only in the last years of his life. His delay can hardly be attributed to fear. He circulated a draft report of his new system as early as 1514, and by 1533 Pope Clement VII approved publication of his views. On the Revolutions of the Ce­lestial Spheres was complete by 1540, and the work appeared in 1543, the year of the author's death.

Although some ancient philosophers had posited heliocentricity, Copernicus was the first to elaborate upon it systematically.He did so in the face of sig­nificant resistance, since the strength of tradition and academic habits secured the dominant positions of Aristotle and Ptolemy within astronomy. In the second century, Ptolemy described a geocentric model of the universe by relying upon the basic tenets of Aristotle's Physics. Accordingly, the earth was the fixed center of the universe, and all bodies fell ''naturally'' to the earth. Since the heavens did not fall, they were of a qualitatively different substance than the earth, one that exhibited the qualities of perfection, not the least of which was perpetual and, therefore, circular (rather than linear) motion. But the problem for Aristotle was that the heavenly bodies displayed disturbingly irregular behavior to the observer on earth. They sometimes moved at different rates of speed or displayed varying degrees of brightness, and, in particular, they some­times moved in a retrograde fashion, that is, they sometimes went backward. Ptolemy elegantly tackled this problem in a theory that posited the existence of large and small circles. The planets moved first along the small circles positioned around imaginary points in space (equants) that were themselves moving along the large circles. Although inaccurate, this model, minus the equants, is in es­sence how modern astronomers understand the movement of moons around planets, in small orbits, and the sun, in large orbits. But centuries of observations had eroded the reliability of ancient thought on the heavens. The problem of explaining the speed, brightness, and retrograde motion of the planets remained.

Copernicus's own observations, along with those of others, led to his dissat­isfaction with received wisdom and to his desire to replace it with something simpler and more accurate. His central argument can be easily summarized, although the mathematics used to justify its claims cannot be. The earth rotated daily around an axis; furthermore, it circled annually around the sun. By impli­cation, the sun was the center of the universe around which the other heavenly bodies moved.

The chief significance of Copernicus's views lies not so much in his own conclusions as in the implications they raised—new problems that other astron­omers set themselves to solving. Copernicus was clearly right about the cen-trality of the sun, but he produced a model that was hardly less complex and barely more accurate than the accepted one. But he had vigorously attacked the Ptolemaic system and seriously challenged the physics of Aristotle underlying it. He had broken the traditional paradigm. In the following decades, like-minded philosophers of the natural world would follow. The empirical work of Galileo* would lay bare the physical nature of the heavens, and the theoretical work of Johannes Kepler* would accurately describe the complexities of planetary mo­tion. Both rightly acknowledged their debts to Copernicus.

H. Blumenberg, The Genesis ofthe Copernican World, 1987.

O. Gingerich, The Eye of Heaven, 1993.

Copernicus, Nicolaus: translation

(1473-1543)

   Polish astronomer, best known for his theory of the universe that placed the sun, rather than the earth, at the center of the system. Born in the Polish city of Torún and orphaned at an early age, Copernicus was supported by an uncle who became a bishop. The uncle sent him in 1491 to the University of Cracow. Through his uncle's influence, he secured a lifetime appointment as one of the canons of the cathedral chapter at Frauenburg (Frombork). In 1496 the chapter sent him to the University of Bologna to study canon law, but he was also able to study astronomy there, and his first recorded astronomical observation was made there in 1497. After returning home to Frauenburg in 1501, he received permission to return to Italy in order to study medicine at Padua. He received a doctorate in canon law from the University of Ferrara in 1503 and also was qualified to practice medicine before returning to spend the rest of his life at Frauenburg.

   Copernicus became widely known as an expert astronomer and made a number of important astronomical discoveries, though his major achievement was not in discovering new data but in rethinking the theoretical foundations of astronomy. His Italian education gave him the competence in Greek that allowed him to publish Latin translations of Greek books and to consult the Greek text of Ptolemy's major astronomical work, the Almagest, a work not yet available in Latin.

   Copernicus' later fame rests on his book De revolutionibus orbium coelestium / On the Revolutions of the Celestial Spheres (1543), but he had worked for much of his life seeking to discover a view of the universe that challenged the complicated and self-contradictory system of the Hellenistic astronomer Ptolemy, the universally acknowledged authority in astronomy.As early as 1513 he wrote a short work, Commentariolus / Little Commentary, that put forward many of the ideas elaborated in De revolutionibus. His new system made a rather simple suggestion—that if one reversed the positions that Ptolemy and nearly all subsequent astronomers assigned to the earth and the sun, putting the sun instead of the earth at the center, many of the troublesome complications of astronomy were resolved.

   Yet since his proposal would challenge many philosophical and religious ideas associated with the idea that the earth was the center of the universe, Copernicus hesitated to publish his new system. His pupil Georg Joachim Rheticus, who had published a summary of his ideas under the title Narratio prima / Preliminary Account, finally persuaded Copernicus to publish his major treatise. The work was dedicated to Pope Paul III, and publication was arranged by a Lutheran minister, Andreas Osiander, who added a preface presenting Copernicus' new theory not as literally true but as a hypothesis useful in simplifying astronomical calculations.

   Although his book attracted considerable attention, most astronomers rejected it not just because it flew in the face of traditional learning but also because its theories raised certain objections that Copernicus himself could not explain. In particular, Copernicus' continued adherence to the Ptolemaic belief that the orbits of the planets must be perfectly circular prevented his system from providing the greater accuracy in the calculation of orbits that he anticipated. Though well known to professional astronomers, his ideas were rejected by most of them. In the long run, the importance of De revolutionibus is that it defined the problems that astronomers of the next four or five generations —Tycho Brahe, Johannes Kepler, Galileo Galilei, and Isaac Newton—would resolve as they developed a new science of astronomy based on his heliocentric theory.

Copernicus, Nicolaus: translation

(1473–1543)

The first developed heliocentric theory of the universe in the modern era was presented in De Revolutionibus Orbium Coelestium, published in the year of Copernicus's death. The system is entirely mathematical, in the sense of predicting the observed position of celestial bodies on the basis of an underlying geometry, without exploring the mechanics of celestial motion. Its mathematical and scientific superiority over the Ptolemaic system was not as direct as popular history suggests: Copernicus's system adhered to circular planetary motion, and let the planets run on 48 epicycles and eccentrics. It was not until the work of Kepler and Galileo that the system became markedly simpler than Ptolemaic astronomy.

Copernicus, Nicolaus: translation

Copernicus, Nicolaus

• Latinized form of Niclas Kopernik, the name of the founder of the heliocentric planetary theory; born at Torun (Thorn), 19 February, 1473, died at Frauenburg, 24 May, 1543

Catholic Encyclopedia.Kevin Knight.2006.