Romer First Measures the Speed of Light
Detailed Account
Danish astronomer Ole Romer makes the first measurement of the speed of light by observing the moons of Jupiter — estimating ~220,000 km/s (26% low). This is the first time humanity measures the constant that would later be found encoded in the Great Pyramid's latitude. The fact that the speed of light is a finite, measurable constant was itself a revolutionary discovery.
Geographic Context
Location
Paris, France
Latitude
48.856600° N
Longitude
2.352200° E