Born on Feb. 19, 1473, in Thorn (Torun), Poland, Nicolaus Copernicus was destined to become, through the publication of his heliocentric theory 70 years later, one of the seminal figures in the history of scientific thought. Copernicus study liberal arts at Bologna (1496-1501), medicine at Padua, and law at the University of Ferrara, from which he emerged in 1503 with the doctorate. Shortly afterward he returned to Poland and eventually settled permanently there. Copernicus not only faithfully performed his ecclesiastical duties, but also practiced medicine, wrote a treatise on monetary reform, and turned his attention to a subject in which he had long been interested—astronomy.
By May 1514 Copernicus had written and discreetly circulated in manuscript his Commentariolus, the first outline of those arguments eventually substantiated in On the Revolutions of the Heavenly Spheres, 1543. This classic work challenged the geocentric cosmology that had been dogmatically accepted since the time of Aristotle. Copernicus proposed that a rotating Earth revolving with the other planets about a stationary central Sun could account in a simpler way for the same observed phenomena of the daily rotation of the heavens, the annual movement of the Sun through the ecliptic, and the periodic retrograde motion of the planets.
In the midst of his radical reordering of the structure of the universe, Copernicus still adhered to the ancient Aristotelian doctrines of solid celestial spheres and perfect circular motion of heavenly bodies, and he held essentially intact the entire Aristotelian physics of motion. Moreover, with significant innovations, he clung to the Ptolemaic representation of planetary motion by means of complicated combinations of circles called epicycles. Although Copernicus realized that his theory implied an enormous increase in the size of the universe, he declined to pronounce it infinite.
These aspects of the Copernican treatise do not mitigate the novelty or the impact of the final theory, or the author’s firm conviction that his system was an accurate representation of physical reality. Rather, they indicate the scope of the work that lay ahead and that was effectively addressed in the next century when Kepler determined the ellipticity of planetary orbits, Galileo formulated his new concept of motion, and Newton espoused his theory of universal gravitation.
The enunciation of the heliocentric theory by Copernicus marked the beginning of the scientific revolution, and of a new view of a greatly enlarged universe. It was a shift away from the comfortable anthropocentrism of the ancient and medieval world. He died on May 24, 1543.
