Early Academicians, for example, made enormous contributions to the field of astronomy. Plato’s friend Eudoxus devised a working model for showing the movement of the planets and the heavens. Heraclides, another Plato student, may have been the first person to propose that the earth rotated on its axis. He also used calculations of the orbits of Venus and Mars to show that they must be revolving not around the earth, but around the sun—literally an earthshaking hypothesis.‖
