Often revolutions are only recognized as such in the wake of their transformations. This was the case for the massive shift in human culture in accepting the fact that the earth orbits the sun rather than the other way around. Between the heliocentric model of Nicolaus Copernicus (d. 1543) and the Papacy’s condemnation of Galileo Galilei’s defense of it in 1632, many scholars and astronomers argued about how the cosmos functioned. The work you see here, by Christopher Clavius (d. 1612), was one of the most widely promoted astronomy works of the time, and yet today few of us know it.
Copernicus’ work didn’t cause a great stir in his time: he died shortly after it was published, for one thing. And for another, his was not the only new opinion. For instance, Girolamo Fracastroro in 1538 challenged the Ancient Ptolemaic model of the universe by declaring that his Ancient Greek ancestor Aristotle had things more correct: Aristotle argued for “homo-centricity”, or that all celestial bodies orbit the earth. (Ptolemy disagreed and argued that some bodies had epicycles, mini-orbits: these explained retrograde motion). Yet another scholar, Roberto Bellarmino (d. 1621), who infamously argued with Galileo, thought that the heavenly bodies above were floating in fluid, the planets thus swimming around the earth.
Christopher Clavius actually didn’t think of Copernicus as his major threat — after all, the Ancient Greek astronomer Aristarchus (d. 230 BCE) had also thought that earth and the other planets revolve around the sun, and that the stars were effectively other suns, just very far away. Copernicus’ model did not get rid of the need for epicycles (although it eliminated the need for many of them). In fact, Copernicus thought that the planets followed a completely circular path (of course, they follow elliptical orbits), which made his model fallible.
Christopher Clavius engaged with all of these astronomers’ ideas, and the _Commentary_ he wrote was hugely respected. He defended the Ptolemaic model of geocentrism, but he also valued his conversations with Galileo. Had he lived longer, perhaps he might have been persuaded to heliocentrism.
Copernicus’ work didn’t cause a great stir in his time: he died shortly after it was published, for one thing. And for another, his was not the only new opinion. For instance, Girolamo Fracastroro in 1538 challenged the Ancient Ptolemaic model of the universe by declaring that his Ancient Greek ancestor Aristotle had things more correct: Aristotle argued for “homo-centricity”, or that all celestial bodies orbit the earth. (Ptolemy disagreed and argued that some bodies had epicycles, mini-orbits: these explained retrograde motion). Yet another scholar, Roberto Bellarmino (d. 1621), who infamously argued with Galileo, thought that the heavenly bodies above were floating in fluid, the planets thus swimming around the earth.
Christopher Clavius actually didn’t think of Copernicus as his major threat — after all, the Ancient Greek astronomer Aristarchus (d. 230 BCE) had also thought that earth and the other planets revolve around the sun, and that the stars were effectively other suns, just very far away. Copernicus’ model did not get rid of the need for epicycles (although it eliminated the need for many of them). In fact, Copernicus thought that the planets followed a completely circular path (of course, they follow elliptical orbits), which made his model fallible.
Christopher Clavius engaged with all of these astronomers’ ideas, and the _Commentary_ he wrote was hugely respected. He defended the Ptolemaic model of geocentrism, but he also valued his conversations with Galileo. Had he lived longer, perhaps he might have been persuaded to heliocentrism.
Sources: www.pas.rochester.edu/~blackman/ast104/copernican9.html. “The Renaissance Mathematicus,” Feb 19, 2020, “The emergence of modern astronomy — a complex mosaic: Part XXX,” Jamie Bond, and Aug 13, 2009 “Syphilis and Comets”. Review: _Between Copernicus and Galileo: Christoph Clavius and the Collapse of Ptolemaic Cosmology_ by James M. Lattis, by William L. Hine, _Isis_, vol 88, no 2 (June, 1997), p. 331.
