Geocentric model In astronomy, the geocentric model considers the earth to be the centre of the solar system. The moon, the planets, the sun, and the stars rotate, in a uniform circular motion, around the earth (which stays still). These celestial bodies thus compose the heavens, which are considered in the model to be ethereal and unchanging. The most highly developed geocentric model was that of Claudius Ptolemy of Alexandria (2nd century AD), who designed his armillary sphere based on a flawed geocentric model of the universe.
