Epicycle
epicycle. noun. epi·cy·cle ˈep-ə-ˌsī-kəl. : a circle according to an early astronomy theory in which a planet moves and which has a center that is itself carried around at the same time on the circumference of a larger circle.[1]
Epicycle Media
The epicycles of the planets in orbit around Earth (Earth at the center). The path-line is the combined motion of the planet's orbit (deferent) around Earth and within the orbit itself (epicycle).
The basic elements of Ptolemaic astronomy, showing a planet on an epicycle (smaller dashed circle), a deferent (larger dashed circle), the eccentric (×) and an equant (•).
The complexity to be described by the geocentric model
The basic simplicity of the Copernican universe, from Thomas Digges' book
The deferent (O) is offset from the Earth (T). P is the center of the epicycle of the Sun S.
- ↑ Merriam-Webster