Fizeau Precisely Measures Speed of Light
Detailed Account
Armand Fizeau obtains the first precise terrestrial measurement of c = 315,000 km/s using a toothed wheel. This begins the refinement process that would eventually yield c = 299,792,458 m/s exactly — the number that matches the Great Pyramid's latitude to 9 significant figures. Fizeau had no knowledge of the pyramid coordinate connection.
Geographic Context
Location
Paris, France
Latitude
48.856600° N
Longitude
2.352200° E