Aristarchus of Samos (c. 310–230 BC), a Greek astronomer and mathematician, proposed the first known heliocentric model, placing the Sun at the center of the universe. His work, On the Sizes and Distances of the Sun and Moon, employed geometric techniques to calculate the dimensions of celestial bodies, though his heliocentric views remained largely unaccepted in his time.
Scholars such as Sir Thomas Heath mention his training under Strato of Lampsacus, while Plutarch and Herodotus refer to Samos in historical narratives. Although Copernicus later credited his "moving Earth" theory, Aristarchus’s groundbreaking ideas were eclipsed by geocentric models until modern astronomy rekindled his influence. His observations on stellar parallax and the vastness of the cosmos provided a foundation for future developments in celestial mechanics.