webexhibits.orgFull text - Nicholas Copernicus, "De Revolutionibus (On the Revolutions)," 1543 C.E.Full text - Nicholas Copernicus, "De Revolutionibus (On the Revolutions)," 1543 C.E. The text of: Nicholas Copernicus De Revolutionibus (On the Revolutions), 1543 C.E. Nicholas Copemicus (1473-1543) That Nicholas Copernicus delayed until near death to publish De revolutionibus has been taken as a sign that he was well aware of the possible furor his work might incite; certainly his preface to Pope Paul III anticipates many of the objections it raised. But he could hardly have anticipated that he would eventually become one of the most famous people of all time on the basis of a book that comparatively few have actually read (and fewer still understood) in the 450 years since it was first printed. Copernicus was bom into a well-to-do mercantile family in 1473, at Torun, Poland. After the death of his father, he was sponsored by his uncle, Bishop Watzenrode, who sent him first to the University of Krakow, and then to study in Italy at the universities of Bologna, Padua and Ferrara. His concentrations there were law and medicine, but his lectures on the subject at the University of Rome in 1501 already evidenced his interest in astronomy. Returning to Poland, he spent the rest of his life as a church canon under his uncle, though he also found time to practice medicine and to write on monetary reform, not to mention his work as an astronomer. In 1514, Copernicus privately circulated an outline of his thesis on planetary motion, but actual publication of De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres) containing his mathematical proofs did not occur until 1543, after a supporter named Rheticus had impatiently taken it upon himself to publish a brief description of the Copernican system (Narratio prima) in 1541. Most of De revolutionibus requires a great deal of the modem reader, since sixteenth century methods of mathematical proofs are quite foreign to us; this is evident in the section of Book VI that is included. However, Book I and Copernicus' preface are more readily accessible. It must be noted that the foreword by Andreas Osiander was not authorized Copernicus, and that Osiander, who oversaw the book's printing, included it without the author's knowledge and without identifying Osiander as its author. http://www.webexhibits.org/calendars/year-text-Copernicus.html (1 of 41)11/30/2008 11:50:06 AMFull text - Nicholas Copernicus, "De Revolutionibus (On the Revolutions)," 1543 C.E.NICHOLAS COPERNICUSOF TORUÑSIX BOOKS ONTHE REVOLUTIONS OF THE HEAVENLYSPHERESDiligent reader, in this work, which has just been created and published, you have the motions of the fixed stars and planets, as these motions have been reconstituted on the basis of ancient as well as recent observations, and have moreover been embellished by new and marvelous hypotheses. You also have most convenient tables, from which you will be able to compute those motions with the utmost case for any time whatever. Therefore buy, read, and enjoy [this work].Let no one untrained in geometry enter here.NUREMBERG JOHANNES PETREIUS 1543XIXFOREWORD BY ANDREAS OSIANDERTo the Reader Concerning the Hypotheses of this Work There have already been widespread reports about the novel hypotheses of this work, which declares that the earth moves whereas the sun is at rest in the center of the universeHence certain scholars, I have no doubt, are deeply offended and believe that the liberal arts, which were established long ago on a sound basis, should not be thrown into confusion. But if these men are willing to examine the matter closely, they will find that the author of this work has done nothing http://www.webexhibits.org/calendars/year-text-Copernicus.html (2 of 41)11/30/2008 11:50:06 AMFull text - Nicholas Copernicus, "De Revolutionibus (On the Revolutions)," 1543 C.E.blameworthy. For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study. Then he must conceive and devise the causes of these motions or hypotheses about them. Since he cannot in any way attain to the true causes, he will adopt whatever suppositions enable the motions to be computed correctly from the principles of geometry for the future as well as for the past. The present author has performed both these duties excellently. For these hypotheses need not be true nor even probable. On the contrary, if they provide a calculus consistent with the observations, that alone is enough. Perhaps there is someone who is so ignorant of geometry and optics that he regards the epicyclc of Venus as probable, or thinks that it is the reason why Venus sometimes precedes and sometimes follows the sun by forty degrees and even more. Is there anyone who is not aware that from this assumption it necessarily follows that the diameter of the planet at perigee should appear more than four times, and the body of the planet more than sixteen times, as great as at apogee? Yet this variation is refuted by the experience of every age. In this science there are some other no less important absurdities, which need not be set forth at the moment. For this art, it is quite clear, is completely and absolutely ignorant of the causes of the apparent nonuniform motions. And if any causes are devised by the imagination, as indeed very many are, they are not put forward to convince anyone that are true, but merely to provide a reliable basis for computation. However, since different hypotheses are sometimes offered for one and the same motion (for example, eccentricity and an epicycle for the sun's motion), the astronomer will take as his first choice that hypothesis which is the easiest to grasp. The philosopher will perhaps rather seek the semblance of the truth. But neither of them will understand or state anything certain, unless it has been divinely revealed to him. Therefore alongside the ancient hypotheses, which are no more probable, let us permit these new hypotheses also to become known, especially since they are admirable as well as simple and bring with them a huge treasure of very skillful observations. So far as hypotheses are concerned, let no one expect anything certain from astronomy, which cannot furnish it, lest he accept as the truth ideas conceived for another purpose, and depart from this study a greater fool than when he entered it. Farewell. XX LETTER OF NICHOLAS SCHÖNBERGNicholas