Aristotle (384 - 322 BCE)
Believed that the Earth is fixed at the center of the solar system and that everything revolves around it
Added to his model the four known elements of the universe (fire, air, water, earth)
His model proved that the earth is spherical; believed that all stars are fixed points which rotate on a single celestial sphere; has 56 spheres
Prime mover : drives the motion of the planets, In conjunction to Eudoxus' model
In conjunction to Eudoxus' model, he added 3 spheres to Jupiter and Mars; 4 spheres to Sun, Moon, Venus, and Mercury