Nothing. His model actually fit the data worse than epicycles. He just thought it was a more sensible approach that matched the Pythagorean opinion. It wasn’t

Nothing. His model actually fit the data worse than epicycles. He just thought it was a more sensible approach that matched the Pythagorean opinion. It wasn’t until Kepler that a geocentric model involving ellipses actually was more predictive. Might be worth returning to the Pythagorean interpretation (which Bohr discussed): All is number. The world is made of math, not stuff.