Picard's arc measurement (La mesure de la Terre)
Medición del arco de Picard (La mesure de la Terre)
- Date
- 1669-1670 · confidence high
- Place
- Paris Observatory, Paris, France
- Credited to
- Jean Picard
- Field
- Cosmos & Earth
What was discovered
Measurement of a degree of meridian between Paris and Amiens with triangulation and telescopic sights with reticles, giving a degree of about 111 km. Its result was the value of the Earth's size used by Newton to check gravitation.
What it led to
- a precise size of the Earth for astronomy and celestial mechanics
- the basis of the Cassini map and French geodesy