Aristarchus of Samos was an ancient Greek astronomer who lived around the third century BCE, and he’s often considered one of the first people to propose that the Earth revolves around the Sun. At a time when most scholars believed Earth was the center of the universe, Aristarchus suggested a heliocentric model, placing the Sun at the center instead.
He also made early attempts to measure the size and distance of the Moon and the Sun using geometry and observations of eclipses. While his calculations weren’t perfectly accurate, they were remarkably advanced for his time and showed that the Sun was much larger than the Earth.
Despite the significance of his ideas, Aristarchus’s heliocentric theory didn’t gain traction in the ancient world, where the Earth-centered model remained dominant for nearly two thousand years. It wasn’t until the work of Copernicus in the 1500s that similar ideas would resurface and reshape our understanding of the cosmos.
