Greek Astronomy

Pythagoras

Pythagoras and his followers, known for their mathematical insights, proposed a cosmos governed by numerical relationships. They believed that mathematical harmony underpinned the movements of celestial bodies, contributing to the idea that the universe could be understood through mathematical principles. This Pythagorean perspective established an early connection between mathematics and astronomy, a relationship that would become more prominent in later developments.

Plato and Aristotle

Plato, a prominent philosopher, presented a geocentric cosmology in his work "Timaeus." According to Plato, the Earth was a stationary sphere at the center of the universe, surrounded by nested celestial spheres carrying the planets and stars. Building on Plato's ideas, Aristotle developed a comprehensive geocentric model of the universe. According to Aristotle, the Earth was the central, motionless sphere, and celestial bodies moved in circular orbits on concentric spheres.

Eudoxus of Cnidus

Eudoxus, a mathematician and astronomer, made significant contributions by refining the geocentric model. He introduced a system of nested spheres, each carrying celestial bodies, providing a mathematical framework to account for observed planetary motions.

Aristarchus of Samos

Aristarchus proposed a heliocentric model, challenging the prevailing geocentric view. In his vision, the Earth and planets orbited the Sun. Despite facing skepticism and limited acceptance in ancient times, Aristarchus' heliocentric idea laid the groundwork for later thinkers who revisited and expanded upon this revolutionary concept.

Hipparchus

Hipparchus, often regarded as one of the greatest ancient astronomers, made substantial contributions to observational astronomy. He compiled a detailed catalog of stars, measured their positions, and introduced the concept of magnitude to quantify stellar brightness. Hipparchus' work laid the groundwork for later developments in stellar classification and observational techniques.

Ptolemy

Claudius Ptolemy, in the 2nd century CE, synthesized earlier Greek astronomical ideas in his monumental work "Almagest." Ptolemy proposed a geocentric model with epicycles to explain the observed retrograde motion of planets. This Ptolemaic system, incorporating elements from earlier Greek thinkers, dominated Western astronomy until the Copernican revolution in the Renaissance.