Ptolemaic System

The Ptolemaic system, articulated by the ancient Greek astronomer Claudius Ptolemy, is a geocentric model of the universe that places Earth at its center. In this model, the Sun, Moon, planets, and stars revolve around Earth in circular orbits, often explained using complex epicycles—small circles that planets move along while also orbiting Earth. This view dominated astronomical thought for over a millennium until the heliocentric model by Copernicus, which positioned the Sun at the center, gained acceptance. The Ptolemaic system exemplifies early attempts to understand the structure of our solar system and the cosmos.