who proposed the geocentric theory
- The geocentric model of Plato could not explain the retrograde motion of the planets. Around 140 A.D. Ptolemy proposed his refined geocentric model. This model gives predictions on the positions of the planets within a few degrees from the actual positions. This was generally accepted and the Ptolemaic model dominated the western world for 1500 years. It was, in fact, superior to the Copernican system propsed in the 16th century.