Kepler showed that planetary orbits were actually ellipses, not circles as proposed by Copernicus.
Chat with our AI personalities
The only part of Copernicus's theory that Kepler retained was the idea that the Sun is at the centre of the Solar System.
Nothing. Copernicus died years before Kepler was born.
Johannes Kepler
Kepler formulated laws of planetary motion, while Copernicus merely(!) proposed that the sun was the center of the solar system rather than the earth.
studying astronomy and physics