Looking back ad fontes to classical antiquity, he found that in the third century BCE, Aristarchus of Samos had suggested that the planets revolved around the sun and that the Earth revolved on its own axis. He discovered that the Pythagoreans believed that mathematics rather than physics was the key to any understanding of the natural world, and that Philolaus, one of Pythagoras’s pupils, thought that the Earth, planets, and sun all revolved around a central, cosmic fire.
