In the geocentric model for the solar system developed by Ptolemy, to what does the word "epicycle" refer?
A) small circle about which a planet moves while the center of this circle moves around Earth
B) large circle (orbit) that carries the planet around Earth while the planet itself is moving in a smaller circle
C) complete cycle of planetary motions after which the motions repeat themselves (almost) exactly
D) length of time from when the planet is farthest from Earth to the next time it is farthest from Earth

Question

Quizplus · Accepted Answer

An epicycle in Ptolemy's geocentric model refers to a small circle about which a planet moves, while the center of this circle moves around Earth. This concept was used to explain the complex movements of planets, including retrograde motion, within the framework of a Earth-centered universe.

In the Geocentric Model for the Solar System Developed by Ptolemy