Nicolaus Copernicus

The Polish astronomer Nicolaus Copernicus (1473-1543) was the founder of the heliocentric ordering of the planets.

Nicolaus Copernicus was born on Feb. 19, 1473, in Torun about 100 miles south of Danzig. He belonged to a family of merchants. His uncle, the bishop and ruler of Ermland, was the person to whom Copernicus owed his education, career, and security.

Copernicus studied at the University of Cracow from 1491 to 1494. While he did not attend any classes in astronomy, it was during his student years there that Copernicus began to collect books on astronomy and mathematics. Some of these contain marginal notes by him dating back to that period, but it remains conjectural whether Copernicus had already made at that time a systematic study of the heliocentric theory.

Copernicus returned to Torun in 1494, and in 1496, through the efforts of his uncle, he became a canon at Frauenburg, remaining in that office for the remainder of his life. Almost immediately Copernicus set out for Bologna to study canon law. In Bologna, Copernicus came under the influence of Domenico Maria de Novara, an astronomer known for his admiration of Pythagorean lore. There Copernicus also recorded some planetary positions, and he did the same in Rome, where he spent the Jubilee Year of 1500.

In 1501 there followed a brief visit at home. His first official act as canon there was to apply for permission to spend 3 more years in Italy, which was granted him on his promise that he would study medicine. Copernicus settled in Padua, but later he moved to the University of Ferrara, where he obtained in 1503 the degree of doctor in canon law. Only then did he take up the study of medicine in Padua, prolonging his leave of absence until 1506.

Upon returning to Ermland, Copernicus stayed in his uncle's castle at Heilsberg as his personal physician and secretary. During that time he translated from Greek into Latin the 85 poems of Theophylactus Simacotta, the 7th-century Byzantine poet. The work, printed in Cracow in 1509, evidenced Copernicus's humanistic leanings. At this time Copernicus was also mulling over the problems of astronomy, and the heliocentric system in particular. The system is outlined in a short manuscript known as the Commentariolus, or small commentary, which he completed about 1512. Copies of it circulated among his friends eager to know the "Sketch of Hypotheses Made by Nicolaus Copernicus on the Heavenly Motions," as Copernicus referred to his work. In it, right at the outset, there was a list of seven axioms, all of which stated a feature specific to the heliocentric system. The third stated in particular: "All the spheres revolve about the sun as their midpoint, and therefore the sun is the center of the universe." The rest of the work was devoted to the elaboration of the proposition that in the new system only 34 circles were needed to explain the motion of planets.

The Commentariolus produced no reaction, either in print or in letters, but Copernicus's fame began to spread. Two years later he received an invitation to be present as an astronomer at the Lateran Council, which had as one of its aims the reform of the calendar; he did not attend. His secretiveness only seemed to further his reputation. In 1522 the secretary to the King of Poland asked Copernicus to pass an opinion on De motu octavae spherae (On the Motion of the Eighth Sphere), just published by Johann Werner, a mathematician of some repute. This time he granted the request in the form of a letter in which he took a rather low opinion of Werner's work. More important was the concluding remark of the letter, in which Copernicus stated that he intended to set forth elsewhere his own opinion about the motion of the sphere of stars. He referred to the extensive study of which parts and drafts were already very likely extant at that time.

Copernicus could pursue his study only in his spare time. As a canon, he was involved in various affairs, including legal and medical, but especially administrative and financial matters. In fact, he composed a booklet in 1522 on the remedies of inflation, which then largely meant the preservation of the same amount of gold and silver in coins. For all his failure to publish anything in astronomy, to have his manuscript studies circulate, or to communicate with other astronomers, more and more was rumored about his theory, still on the basis of the Commentariolus.

Not all the comments were flattering. Luther denounced Copernicus as "the fool who will turn the whole science of astronomy upside down." In 1531 a satirical play was produced about him in Elbing, Prussia, by a local schoolmaster. In Rome things went better, for the time being at least. In 1533 John Widmanstad, a papal secretary, lectured on Copernicus's theory before Pope Clement VII and several cardinals. Widmanstad's hand was behind the letter which Cardinal Schönberg sent in 1536 from Rome to Copernicus, urging him to publish his thoughts, or at least to share them with him.

It was a futile request. Probably nobody knew exactly how far Copernicus had progressed with his work until Georg Joachim (Rheticus), a young scholar from Wittenberg, arrived in Frauenburg in the spring of 1539. When he returned to Wittenberg, he had already printed an account, known as the Narratio prima, of Copernicus's almost ready book. Rheticus was also instrumental in securing the printing of Copernicus's book in Nuremberg, although the final supervision remained in the care of Andrew Osiander, a Lutheran clergyman. He might have been the one who gave the work its title, De revolutionibus orbium coelestium, which is not found in the manuscript. But Osiander certainly had written the anonymous preface, in which Copernicus's ideas were claimed to be meant by their author as mere hypotheses, or convenient mathematical formalism, that had nothing to do with the physical reality.

The printed copy of his work, in six books, reached Copernicus only a few hours before his death on May 24, 1543. The physics of Copernicus was still Aristotelian and could not, of course, cope with the twofold motion attributed to the earth. But Copernicus could have done a better job as an observer. He added only 27 observations, an exceedingly meager amount, to the data he took over un-critically from Ptolemy and from more recent astronomical tables. The accuracy of predicting celestial phenomena on the basis of his system did not exceed the accuracy achieved by Ptolemy. Nor could Copernicus provide proof for the phases of Mercury and Venus that had to occur if his theory was true. The telescope was still more than half a century away. Again, Copernicus could only say that the stars were immensely far away to explain the absence of stellar parallax due to the orbital motion of the earth. Here, the observational evidence was not forthcoming for another 300 years. Also, while Ptolemy actually used only 40 epicycles, their total number in Copernicus's system was 84, hardly a convincing proof of its greater simplicity.

Still, the undeniable strength of Copernicus's work lay in its appeal to simplicity. The rotation of the earth made unnecessary the daily revolution of thousands of stars. The orbital motion of the earth fitted perfectly with its period of 365 days into the sequence set by the periods of other planets. Most importantly, the heliocentric ordering of planets eliminated the need to think of the retrograde motion of the planets as a physical reality. In the tenth chapter of the first book Copernicus made the straightforward statement: "In the center rests the sun. For who would place this lamp of a very beautiful temple in another or better place than this wherefrom it can illuminate everything at the same time."

The thousand copies of the first edition of the book did not sell out, and the work was reprinted only three times prior to the 20th century. No "great book" of Western intellectual history circulated less widely and was read by fewer people than Copernicus's Revolutions. Still, it not only instructed man about the revolution of the planets but also brought about a revolution in human thought by serving as the cornerstone of modern astronomy.


Further Reading on Nicolaus Copernicus

A popular modern account of Copernicus's life is A. Armitage, The World of Copernicus (1947). In Thomas Kuhn, The Copernican Revolution (1957), Copernicus's theory is discussed in the framework of the process leading from ancient to modern science through the medieval and Renaissance centuries. For a rigorous discussion of Copernicus's theory the standard modern work is A. Koyré, The Astronomical Revolution: Copernicus, Kepler, Borelli (1969).