What nationality was the man who determined that light has a finite speed?
Rømer's determination of the speed of light Rømer's determination of the speed of light was the demonstration in 1676 that light has a finite speed, and so does not travel instantaneously. The discovery is usually attributed to Danish astronomer Ole Rømer (1644–1710), who was working at the Royal Observatory in Paris at the time.
Pierre-Gilles de Gennes Pierre-Gilles de Gennes (] ; October 24, 1932 – May 18, 2007) was a French physicist and the Nobel Prize laureate in physics in 1991.