Copernicus’ work De revolutionibus orbium coelestium.
Copernicus’ work De revolutionibus orbium coelestium caused uproar in ecclesiastical circles. Wikimedia

Copernicus the heretic

Nicolaus Copernicus is considered one of the founders of modern astronomy. His heliocentric planetary model unleashed an outcry in Reformation circles, especially in Switzerland.

Thomas Weibel

Thomas Weibel

Thomas Weibel is a journalist and Professor of Media Engineering at the Fachhochschule Graubünden and the Hochschule der Künste in Berne.

Polish-born Nicolaus Copernicus (1473-1543), original name Niklas Koppernigk, was a scientist in the broadest sense of the word. He had studied the seven liberal arts – grammar, rhetoric, logic, arithmetic, geometry, music and astronomy – and also added law, Greek, philosophy and medicine to his store of knowledge. Although he worked as a doctor and as a canon and administrator for the Prince-Bishop in the coastal town of Frauenburg (now Frombork in northern Poland), Copernicus’s real passions were mathematics and astronomy, in particular the study of planetary movements. At night he used primitive instruments to observe the star-studded sky, albeit with varying degrees of success. To his great annoyance (“because of the haze”) he never managed to observe Mercury, the innermost planet of the solar system, let alone determine its position.
Copernicus observes the heavens in Rome.
Copernicus observes the heavens in Rome. ETH Library Zurich
Increasingly, Copernicus’s observations caused him to have doubts about the prevailing view of the structure of the solar system. Scholars had been aware for nearly two millennia that Aristotle’s theory, postulated in the 4th century BC, that the sun and the planets revolved around the Earth, could not be entirely correct. For example, if we track the path of Mars across the night sky it can be seen that the planet’s movement periodically slows down, and even reverses. Not until 72 days later does the planet start moving from east to west again as usual – there is no hint of uniform movement. Classical astronomy had been able to resolve this obvious contradiction to some extent with what was known as the epicycle theory, but the more precise the observations became, the more discrepancies emerged.
Animation of the Copernican planetary model from De revolutionibus orbium coelestium. More information about the animation can be found at: thomasweibel.ch
Copernicus realised that an entirely new planetary model was needed to explain this – a model that he summarised in his 1543 book De revolutionibus orbium coelestium (On the Revolutions of Heavenly Spheres). At the centre of his new model, for the first time in history, was the sun. Copernicus believed that the Earth, for two thousand years the fixed point of all astronomical considerations, revolved around the sun like the other known planets Mercury, Venus, Mars, Jupiter and Saturn. The Revolutionibus was a scientific revolution, and it was the Reformation that condemned the work as delusional, if not outright heresy. Nowhere was the outcry louder than in Switzerland.
Manuscript of De revolutionibus orbium coelestium.
Manuscript of De revolutionibus orbium coelestium. At the centre of the planetary system is the sun, around which Mercury, Venus, the Earth and the moon, Mars, Jupiter and Saturn revolve. Wikimedia
This is somewhat surprising because the influential Reform leader Huldrych Zwingli (1484-1531) had founded the Hohe Schule in Zurich in 1525 and, as a scholar, was committed to science. The practical benefit of scientific observation, especially astronomy, was obvious: the stars, Zwingli preached, existed “to divide day and night, to serve as signs and times, and generally also to bring about fruitful growth, that times and signs should be known for our benefit, such as times for tilling the field, for reaping and for haymaking”. Despite his scholarly bent, however, for Zwingli science remained above all wonder at the miracle of creation; the “true and proper art of astronomy” and “the calculation and course of the stars” were seen by him primarily as an expression of divine works. “For just as the celestial body is a means and an instrument through which the divine power reveals itself and pours forth, so the knowledge of its course and its order is nothing other than a knowledge of the divine action.”
Portrait of Huldrych Zwingli.
Science yes, Zwingli thought, but only to a certain and practical extent. Swiss National Museum
Astronomy as a means of understanding divine creation, the Holy Scriptures as the basis of all science: it was inevitable that Copernicus’s writings would shake the Reformation to its foundations. Psalm 93 places the Earth immovably at the centre of the universe (“the world is established, so that it cannot be moved”), and according to Psalm 19, the sun indisputably revolves around the Earth (“Its rising is from one end of heaven, and its circuit to the other end”). In an inflammatory speech in 1549 Philipp Melanchthon, an associate of Martin Luther and a harsh critic of Copernicus, thundered: “But certain people have concluded, either out of a thirst for innovation or to show off their own sagacity, that it is the Earth that is moving. They claim that neither the eight spheres [the fixed stars] nor the sun revolve… It shows a lack of honour and taste to express such ideas publicly; it sets a dangerous example. It is the duty of a good Christian to accept the truth as revealed by God and to trust in it.” In Geneva, John Calvin went even further: “We see some people who are so insane (…) that they must everywhere show their unnatural nature and say that the sun is immovable and that it is the Earth that moves and turns.” Calvin left no doubt as to whom this comment referred: “Who will dare to place the authority of Copernicus above that of the Holy Spirit?”
Portrait of Niclaus Copernicus, 17th century.
Copernicus had many enemies. For example… Wikimedia
Portrait of Jean Calvin.
… John Calvin, who called him insane. Swiss National Museum
Copernicus, who himself had been in church service all his life, always knew he was unlikely to make any friends in the circle of Bible exegetes. By way of pre-empting the expected storm of protest, he dedicated the Revolutionibus to Pope Paul III himself with, among others, these words: “If perchance there shall be idle talkers, who, though they are ignorant of all mathematical sciences, nevertheless assume the right to pass judgment on these things, and if they should dare to criticise and attack this theory of mine because of some passage of Scripture which they have falsely distorted for their own purpose, I care not at all; I will even despise their judgment as foolish.” In the Pope’s case, to begin with these misgivings proved baseless: Copernicus’s calculations were even used as a basis for the Gregorian calendar reform in 1582. But when the deluge of writings in protest continued, Rome began to buckle under the pressure and established the Sacred Congregation of the Index of Prohibited Books; and when eventually even the polymath Galileo Galilei, in his conflict with the church, referred to the Copernican worldview, the Inquisition opened proceedings that culminated in a ban on the Revolutionibus. However, the verdict was a half-hearted one, because Copernicus’s model solved a whole swathe of existing astronomical and mathematical problems in one fell swoop. With a number of small amendments that emphasised its hypothetical character, Copernicus’s revolutionary work was finally allowed to continue to be printed and read.
Portrait of Pope Paul III, painted by Tiziano Vecellio, 1546.
Pope Paul III, here in a portrait by Tiziano Vecellio, 1546. Wikimedia
The sun as the centre, the Earth as a planet among other planets: in the decades that followed, observations and calculations by astronomers such as Galileo Galilei, Tycho Brahe and Johannes Kepler would show more and more clearly that the Bible was not an appropriate basis for explaining scientific findings, and in 1771 Switzerland’s first observatory was established in Geneva, the site of possibly the most violent resistance to the Copernican model. But the author of all this upheaval would not live to see the enormous influence of the Copernican scientific revolution and the concomitant major shift in worldview. Not long after the publication of the Revolutionibus, on 25 May 1543, Copernicus died in Frauenburg from the consequences of a stroke.

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