When Copernicus first created his Sun-centered model of the universe, it did not lead to substantially better predictions of planetary positions than the Ptolemaic model. Why not?
A) Copernicus used perfect circles for the orbits of the planets.
B) Copernicus placed the planets in the wrong order going outward from the Sun.
C) Copernicus misjudged the distances between the planets.
D) Copernicus placed the Sun at the center, but did not realize that the Moon orbits the Earth.

Question

Quizplus · Accepted Answer

Copernicus still used perfect circles for the orbits of the planets, which did not accurately represent their elliptical paths around the Sun. It wasn't until later that Johannes Kepler improved upon the Copernican model by using elliptical orbits.

When Copernicus First Created His Sun-Centered Model of the Universe