Aristarchus of Samos

Aristarchus of Samos was an ancient Greek astronomer and mathematician who presented the first known heliocentric model of the universe. This model placed the Sun at the center, with the Earth revolving around it annually and rotating on its axis daily. He also supported the idea that the Sun was merely another star. Born in Samos around 310 BC, he likely moved to Alexandria and studied under Strato of Lampsacus. Aristarchus's work included estimating the relative sizes and distances of the Sun and Moon. His finding that the Sun was significantly larger than Earth led him to believe it was the natural center of the universe. Influenced by Philolaus, Aristarchus arranged the planets in their correct order around the Sun. His heliocentric ideas, however, were largely rejected in favor of geocentric models proposed by Aristotle and Ptolemy. While Nicolaus Copernicus knew of Aristarchus's 'moving Earth' theory, it's debated if he was aware it was heliocentric. Aristarchus's work, though not fully preserved, laid foundational concepts for later astronomical models.