Today marks the birthday of Nicolaus Copernicus, he was born February 19, 1473 (and died May 24, 1543). Although he was a cleric in the Church and practiced law as his “day jobs”, he is known today for the first well-known heliocentric (Sun-centered) model of the Solar System. We know him by his Latinized name (which he selected himself, in the scholarly custom of the time) that appears on the cover of his famous book, and while both German and Polish nationalists claim him as their own, neither Germany nor Poland existed as nations at that time, so Copernicus himself wouldn’t have thought of himself that way. (I sometimes commit the oversimplification of referring to him as Polish from modern geography; if you can find a History of Science confessor, I will say my mea culpas and be done.)
Copernicus worked in the era before telescopes, and looking at his heliocentric model with modern eyes, it’s easy to see that he was very much a man of his time. Which is to say: he wasn’t a modern scientist. A striking thing anyone reading his work today will notice is that the model of Copernicus is wrong. Yes, he places the Sun at the center of the Solar System, with planets orbiting it (while the Moon is the only body left orbiting Earth), but the orbits are circular. To fit the known data, each planet traces a smaller circle known as an epicycle, a holdover from the old geocentric system. In many ways, Copernicus’ system was not an immediate improvement over the standard model of his day.
That’s often the case when we look at new ideas in the history of science (or newish, since Copernicus wasn’t the first to propose a heliocentric model). What Copernicus offered was not a direct overthrow of geocentric thinking, but the beginnings of a new path that ended up requiring the gradual rise of modern science to fully understand. Galileo had his telescope, his moons of Jupiter, and his phases of Venus, but his model of the Solar System was even worse than Copernicus’ in fitting the data, since he left out the epicycles yet kept circular planetary orbits. Nevertheless, both models (along with the bizarre but interesting Tychonic model) were moves in the right direction; Kepler and Newton, respectively an astrologer and an alchemist, provided the improvements that we still teach today.
Science is often incremental, messy, wrong, and glacier-like: four steps forward may be counteracted by three steps back. Yet I’m not saying we should be harsh or dismissive to Copernicus: it’s always a mistake to judge scientists of the past by the standards of the present. Taken over a viewpoint of centuries, most of what we take as true and given will change, and a lot of what we think is correct today may be “wrong” in some sense in the future’s eyes. Heliocentrism will stand, evolution will last, the “big cosmos” view will endure, but the details? Who can tell what will change? The Copernican Revolution may have been more like a pebble that started an avalanche than a sudden convulsive change to the scientific consensus, and certainly if Copernicus had not written his book, someone else would have come along sooner or later with similar ideas. Nevertheless, I honor the man all the more because he wasn’t a giant, but because he was a real person, trying as we all do to figure out our wonderful universe. Long live his revolution!