Uploaded December 2021 | Updated September 2026, 3 weeks ago
A simple Eratosthenes-style experiment uses the length of a vertical object and its solar-noon shadow near the equinox to measure solar angle, latitude, Earth’s circumference, and Earth’s radius. Comparing simultaneous measurements from Michigan and Hawaii also tests whether sunlight behaves like parallel rays from a distant Sun rather than rays from a small nearby source.
A simple Eratosthenes-style experiment uses the length of a vertical object and its solar-noon shadow near the equinox to measure solar angle, latitude, Earth’s circumference, and Earth’s radius. Comparing simultaneous measurements from Michigan and Hawaii also tests whether sunlight behaves like parallel rays from a distant Sun rather than rays from a small nearby source.
