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Ole Roemer speed of light

 While collecting Jupiter’s Moon Io orbital data Ole Roemer was the first to accurately measure the speed of light in 1676 Scientists had assumed that the speed of light was to fast to measure or instantaneous. The prevalent view, argued by the French philosopher Descartes, was that light had an infinite speed. Galileo suggested that tables of the orbital motion of Jupiter’s satellites would provide a type of clock.

 So how did Roemer calculate the speed of light? He never actually gave a value for the speed of light but it was calculated using his data,

 Roemer did know light traveled farther when the Earth and Jupiter are on opposite sides of the Sun and estimated that light took twenty-two minutes to cross the diameter of the Earth’s orbit. The speed of light could then be found by dividing the diameter of the Earth’s orbit by the time difference. 131,000 miles per second.