Definition
Aristarchus was an ancient Greek astronomer and mathematician. He proposed a heliocentric model of the solar system, with the Sun at the center. Imagine him as the original 'sun-believer' way before Copernicus. His ideas were revolutionary but not widely accepted at the time. He also made estimations of the sizes and distances of the Sun and Moon. While not entirely accurate, they were ingenious for his time. His work laid the foundation for later astronomical discoveries.