Happy Birthday to Nicolaus Copernicus, born this day 540 years ago. Though his work on orbits still left us with epicycles (Kepler would succeed in eliminating them with his elliptical orbits replacing Copernicus’ circular ones) he nonetheless moved the science of astronomy and cosmology forward by his placement of the Sun at the centre of the system. He had the good sense to hold off from publication until near his death, but this didn’t prevent various theologian-astronomers of a more Aristotelian bent from damning him later. It is the fate of innovators to be chastised by the gatekeepers of the times it seems – no matter how right they are. As Jerome Ravetz said to me recently: “The difference between a crank and a rebel may become clear only in retrospect. Which was Galileo? He spent a huge part of his working life on a theory that anyone could have told him would never succeed.”
Copernicus’ major theory was published in De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), in the year of his death, 1543, though he had formulated the theory several decades earlier.
“1. There is no one center of all the celestial circles or spheres.
2. The center of the earth is not the center of the universe, but only of gravity and of the lunar sphere.
3. All the spheres revolve about the sun as their mid-point, and therefore the sun is the center of the universe.
4. The ratio of the earth’s distance from the sun to the height of the firmament (outermost celestial sphere containing the stars) is so much smaller than the ratio of the earth’s radius to its distance from the sun that the distance from the earth to the sun is imperceptible in comparison with the height of the firmament.
5. Whatever motion appears in the firmament arises not from any motion of the firmament, but from the earth’s motion. The earth together with its circumjacent elements performs a complete rotation on its fixed poles in a daily motion, while the firmament and highest heaven abide unchanged.
6. What appear to us as motions of the sun arise not from its motion but from the motion of the earth and our sphere, with which we revolve about the sun like any other planet. The earth has, then, more than one motion.
7. The apparent retrograde and direct motion of the planets arises not from their motion but from the earth’s. The motion of the earth alone, therefore, suffices to explain so many apparent inequalities in the heavens.”
Under strong pressure from his student, Rheticus, and having seen the favorable first general reception of his work, Copernicus finally agreed to give De revolutionibus to his close friend, Tiedemann Giese, bishop of Chełmno (Kulm), to be delivered to Rheticus for printing by the German printer Johannes Petreius at Nuremberg (Nürnberg), Germany. While Rheticus initially supervised the printing, he had to leave Nuremberg before it was completed, and he handed over the task of supervising the rest of the printing to a Lutheran theologian, Andreas Osiander.
Osiander added an unauthorised and unsigned preface, defending the work against those who might be offended by the novel hypotheses. He explained that astronomers may find different causes for observed motions, and choose whatever is easier to grasp. As long as a hypothesis allows reliable computation, it does not have to match what a philosopher might seek as the truth.
Tolosani recognized that the Ad Lectorem preface to Copernicus’ book wasn’t actually by him. Its thesis that astronomy as a whole would never be able to make truth claims was rejected by Tolosani, (though he still held that Copernicus’ attempt to describe physical reality had been faulty), he found it ridiculous that Ad Lectorem had been included in the book (unaware that Copernicus hadn’t authorized its inclusion). Tolosani wrote “By means of these words [of the Ad Lectorem], the foolishness of this book’s author is rebuked. For by a foolish effort he [Copernicus] tried to revive the weak Pythagorean opinion [that the element of fire was at the center of the Universe], long ago deservedly destroyed, since it is expressly contrary to human reason and also opposes holy writ. From this situation, there could easily arise disagreements between Catholic expositors of holy scripture and those who might wish to adhere obstinately to this false opinion. We have written this little work for the purpose of avoiding this scandal.” Tolosani declared “Nicolaus Copernicus neither read nor understood the arguments of Aristotle the philosopher and Ptolemy the astronomer.” He wrote that Copernicus “is very deficient in the sciences of physics and logic. Moreover, it appears that he is unskilled with regard to [the interpretation of] holy scripture, since he contradicts several of its principles, not without danger of infidelity to himself and the readers of his book.