Caption:
Earth-centered universe, with orbits of moon, Mercury, Venus, Mars, Jupiter, Saturn, and the firmament in concentric circles, 1495. In astronomy, the Ptolemaic system, is a description of the cosmos where Earth is at the orbital center of all celestial bodies. This model served as the predominant cosmological system in many ancient civilizations such as ancient Greece. As such, they assumed that the Sun, Moon, stars, and naked eye planets circled Earth. The astronomical predictions of Ptolemy's geocentric model were used to prepare astrological charts for over 1500 years. The geocentric model held sway into the early modern age, but from the late 16th century onward was gradually superseded by the heliocentric model of Copernicus, Galileo and Kepler.