Ancient Humans Knew the Earth Was Round 2,000 Years Before NASA

Over 2,000 years before satellites existed, ancient Greek scholars had already calculated the size of the Earth — and they were off by less than 2%. No telescopes. No modern math. Just a stick, a shadow, and pure curiosity. In this video, we trace how humans figured out the Earth was round: from sailors watching ships vanish hull-first at the horizon, to Aristotle's observations during lunar eclipses, to Eratosthenes's legendary experiment at the Library of Alexandria using nothing but a well, a stick, and someone else's footsteps. We also bust the popular myth that "everyone thought the Earth was flat until Columbus" — a story that was actually invented centuries later to make history sound more dramatic than it really was. ⏱️ TIMESTAMPS: 0:00 - Introduction 0:24 - Ships and the Horizon 2:10 - Aristotle's Lunar Eclipse Clue 3:45 - Eratosthenes and the Well of Syene 6:30 - Verifying the Measurement 8:15 - The Truth About Columbus 9:50 - Why the Flat Earth Myth Exists 10:45 - Final Thoughts 📚 Sources and further reading in the pinned comment. #AncientHistory #Science #Eratosthenes #Astronomy #History #Education #LUMENOS