Philolaus
of Croton

The guy who said the Earth wasn’t the center — and meant it. Philolaus (fl. 5th century BCE) took Pythagorean thought and launched it into orbit, literally. He imagined a cosmos built on number and harmony, with a “Central Fire” (not the Earth!) at the heart of it all. Half philosopher, half astronomer, all mystery. His works survive in scraps, but his ideas echo loudly — especially in the minds of later revolutionaries with telescopes.