1543

Copernicus’s De Revolutionibus

Nicolaus Copernicus (1473–1543)

After nearly a thousand years of stagnation, the Renaissance in western Europe was truly an awakening—of art, music, culture, and science. With the founding of universities in Bologna, Oxford, Cambridge, Paris, Padua, and elsewhere, and learned clergy, such as John of Sacrobosco, introducing the advances in astronomy made by Arabic, Chinese, and Indian scholars during Europe’s Dark Ages (and reintroducing the work of the Greeks and Romans), the stage was set for European science to flourish.

The first, and in some ways most important, Renaissance scientist to take that stage was Nicolaus Copernicus, a Polish canon (his uncle, who was also his patron, was a bishop), doctor, lawyer, economist, and part-time astronomer. As a community leader in Frombork, in northwestern Poland, Copernicus assumed many legal, administrative, and economic responsibilities as his nominal vocation. But he also made the time to conduct astronomical observations and to analyze his data, to read the classical and contemporary astronomical literature, and to ruminate on problems that he had had—ever since he was a student at Kraków and Bologna—with what he regarded as the overly complex geocentric planetary orbit model of Ptolemy’s Almagest.

Painting of Copernicus by an unknown artist (1580).

By 1514 he was circulating the basic outline of an alternative paradigm, a solar system with the Sun fixed at the center, the Earth and the other planets spinning on their axes and orbiting the Sun, and the Moon orbiting the Earth. But it wasn’t until just before he died in 1543 that he finally published his theory as De Revolutionibus Orbium Coelestium (On the Revolutions of the Heavenly Spheres). Perhaps surprisingly, the book and its Sun-centered thesis did not generate much interest or controversy at the time. It would take more than 50 years and the supporting observations and interpretations of Brahe, Kepler, and Galileo (and Galileo’s telescope) to make it apparent that De Revolutionibus had started what became widely known as the Copernican revolution in cosmology.

Illustration of the Copernican model of the solar system, from Andreas Cellarius’s 1660 star atlas, Harmonia Macrocosmica.