•Plato 427 – 347 B.C. Simple motion using spheres Perfection
of the heavens,
•Eudoxus 390
– 337 B.C. Retrograde
motion
•
•Aristotle 384 – 322 B.C. Shape of Earth, Multiple Spheres
•
•Eratosthenes
~200 B.C. Size of the
Earth
•
•Ptolemy ~150 A.D. Models for planetary motion