Geocentrism is an ancient astronomical theory that posits the Earth as the center of the universe. According to this model, all celestial bodies, including the Sun, Moon, and stars, revolve around the Earth. This view was widely accepted in many cultures, including those of the ancient Greeks and the medieval European scholars. The geocentric model was famously articulated by the Greek philosopher Aristotle and later expanded by the astronomer Ptolemy. It remained dominant until the Copernican Revolution in the 16th century, when the heliocentric model, which places the Sun at the center, gained acceptance through the work of astronomers like Nicolaus Copernicus.