A Revised Pythagorean System of the World Wherein, According to Copernicus, the Sun is Held to be in its Center

Abstract

Since, then, the Ptolemaic system presented so many incurable defects and unreasonable hypotheses, Nicolaus Copernicus of Torun, Doctor of Medecine and Canon of Frauenburg in Prussia, was moved about one hundred years ago to resurrect the system of Pythagoras of Samos, Philolaus, Aristarchus, and their followers, who were mentioned previously in Chapter 1. They had made the sun the center of the world and claimed that the earth, together with the other planets, rotated about it. (Even before the time of Copernicus, in about 1440, Cardinal Nicolaus of Kues also held firmly. to this conviction.) Copernicus assigned to the earth, therefore, the place previously occupied by the sun between the planets, Mars and Venus, thereby introducing a remedy for those difficulties and inconsistencies that arose from the Ptolemaic theory. His concept is illustrated in Plate II. In this diagram, the region of the fixed stars bounds the world and is completely without movement, and insofar as we can perceive, orbicular or spherical. The sun, moreover, is in the center of this heavenly vault and likewise appears stationary. With these two regions comprising immobile boundaries, as it were, the moving planets are arranged in the space between and carry out their various courses both around the sun and below the region of the fixed stars. First of all the planets, Mercury is situated nearest the sun with the result that it describes the shortest orbit of all about the sun and completes it most quickly, essentially within three months. Venus holds the second position. It has a larger orbit than Mercury and moves with greater speed than the more distant planets, thus completing its orbit within seven and a half months.