ABSTRACT
Once upon a time, people believed the earth was smack dab in the middle of everything and that all the planets revolved around it. Then came Copernicus, who argued that if this were true, something was deeply wrong with the rest of the universe because the observed motions of all the planets just didn’t add up. After considerable head scratching, Copernicus concluded that the earth was not at the center of things and the sun was. Knowing this didn’t actually change the universe, of course, but it did allow all of its movements to suddenly make sense.
