What does «epiciclo» mean in Spanish?
- Orbit circle that was supposed to be described by a planet around a center that moved in another larger circle (called deferent), on which this center of rotation moves. This orbit was the basis of the geometric model devised by the Greeks that assumed the Earth at the center, which allowed to explain the apparent retrograde movements of the remaining planets, the Moon and the Sun. It is an astronomical term used since antiquity, first proposed by Apollonius of Perga at the end of the second century BC, then widely used in the second century BC by Hipparchus of Nicaea.