Uploaded September 2021 | Updated September 2026, 3 weeks ago
Earth’s radius can be checked with independent methods that rely on different observations. This video compares Eratosthenes shadow geometry, Al-Biruni’s horizon-dip method, hidden-height measurements with refraction corrections, and great-circle distances calculated with the Haversine formula, showing that the results converge on the same physical scale.
Earth’s radius can be checked with independent methods that rely on different observations. This video compares Eratosthenes shadow geometry, Al-Biruni’s horizon-dip method, hidden-height measurements with refraction corrections, and great-circle distances calculated with the Haversine formula, showing that the results converge on the same physical scale.
