How did ancient Greeks accurately measure the size of our planet more than 2,000 years ago — without satellites, GPS, airplanes, or modern technology?
Around 240 BC, the Greek mathematician Eratosthenes used something remarkably simple: sunlight, shadows, geometry, and observations from two locations in ancient Egypt.
From the difference in the shadows, he was able to estimate the circumference of Earth — revealing the approximate size of our planet thousands of years before modern technology existed.
But how could a simple shadow reveal the size of an entire planet?
In this video, we explain the Eratosthenes experiment step by step and show how ancient mathematics was used to measure the Earth.
🌍 No satellites.
☀️ No GPS.
📐 Just sunlight, shadows, and mathematics.
The modern circumference of Earth is approximately 40,000 km (24,900 miles), making Eratosthenes' ancient calculation one of the most remarkable achievements in the history of science.
If you enjoy science explained, ancient science, mathematics, astronomy, geography, and fascinating scientific discoveries, subscribe to SciencEdAI.
#Eratosthenes #Earth #Science #AncientScience #HistoryOfScience
