The Geocentric Theory is an ancient astronomical model that posits the Earth as the center of the universe. According to this theory, all celestial bodies, including the Sun, Moon, and stars, revolve around the Earth. This view was widely accepted in many cultures, particularly in ancient Greece, where philosophers like Aristotle and Ptolemy contributed to its development. The Geocentric Theory was dominant until the 16th century, when the Copernican Revolution introduced the Heliocentric Theory, which placed the Sun at the center of the solar system. This shift marked a significant change in our understanding of the universe and laid the groundwork for modern astronomy.