The greatest inaccuracy in Copernicus's theory of the solar system was
A) no allowance for retrograde motion.
B) placement of the planets on epicycles, the centers of which followed orbits around the Sun.
C) the assumption that the planets move in elliptical orbits with constant speeds rather than variable speeds.
D) placement of the planets in circular orbits.

Question

Quizplus · Accepted Answer

Copernicus's model inaccurately placed planets in circular orbits, whereas they actually move in elliptical orbits.

The Greatest Inaccuracy in Copernicus's Theory of the Solar System