⏰ when
When was the first direct measurement of the speed of light made?
Quick Answer
It was first measured in a modern scientific way in 1676 by Ole Rømer.
The Full Story
Ole Rømer made the first convincing quantitative measurement of the speed of light in 1676. He did this by observing the timing of eclipses of Jupiter's moon Io and noticing delays as Earth moved in its orbit. His estimate showed that light takes time to travel, overturning the idea that it moved instantaneously. Later experiments refined the value, but Rømer's work was the breakthrough.
Key Facts
1.Measured in 1676
2.Done by Ole Rømer
3.Used Jupiter's moon Io
YouTube Angle
Suggested video title for this topic:
"How astronomers proved light is fast, but not instant."
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