The Greek Mathematician Who Built the Universe Out of Twenty-Seven Nested Rotating Spheres
[Eudoxus of Cnidus](/articles/eudoxus-of-cnidus) — Plato's contemporary and the founder of mathematical astronomy — proposed in the 360s BC that the apparent motions of the Sun, Moon, and five known planets could be explained by 27 concentric spheres rotating around the Earth at different rates and on different axes. The model was the best astronomical framework in the world for the next two centuries.
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