Geocentrism is based on the geocentric model of the cosmos (or universe), a model that was widely accepted for over a millennium and across ancient civilizations. It is also known as Ptolemaic model, after the great Greek mathematician and astronomer (among his other notable qualifications). According to this model, Earth is at the center of the universe and all the visible planets, stars (including our sun) and moon rotate around it on fixed circular paths. This model was supported by the fact that to a stationary observer on Earth, all the celestial bodies appear to 'rise' and 'fall' or move from one end to other through the day. The model was later renounced after the observations of Galileo and findings of Kepler and Copernicus. The currently accepted model is a heliocentric model in which Sun is the center of the solar system and Earth, along with other planets, move around it.
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