History

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The decisions, accidents and people that shaped now.

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How a stick's shadow measured the whole Earth: Eratosthenes, a well and 5,000 stadia Two sticks, one shadow and one distance were enough for Eratosthenes to size the whole planet around 240 BC. On the summer solstice the noon Sun shone straight… History4 min read How Eratosthenes measured the whole Earth with a stick and a shadow Around 240 BC, Eratosthenes, head of the Library of Alexandria, measured the size of the whole Earth with a stick and a shadow. At noon on midsummer, sticks in… History4 min read