Adopting Pythagoras ’ view that the circle and sphere were perfect shapes, Aristotle believed that the heavens were a series of spheres within spheres, like layers of an onion.
Aristoteles võttis omaks Pythagorase idee, mille kohaselt ring ja kera on täiuslikud vormid. Sellest arendas ta oma maailmapildi, mille järgi taevad koosnevad üksteise sees olevatest sfääridest (paljudest kihtidest nagu sibul).