Ptolemaic astronomy

Ptolemaic astronomy, developed by the ancient Greek astronomer Claudius Ptolemy, describes the universe as Earth-centered, with planets, the Sun, and the Moon revolving around it in circular orbits. This geocentric model explains planetary movements through a system of "epicycles" (small circles) that account for the observed retrograde motion of planets. Although accurate for its time, it was eventually replaced by the heliocentric model of Copernicus, which positioned the Sun at the center. Ptolemy's work, particularly the "Almagest," greatly influenced medieval and Renaissance astronomy and laid the groundwork for future astronomical studies.