How Jupiter's Moons Showed Us the Speed of Light

Light travels through space as fast as anything in the universe possibly can, but before scientists could figure out light’s speed, they had to figure out whether that speed was even finite.

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Sources:
http://galileoandeinstein.physics.virginia.edu/lectures/spedlite.html
http://mathshistory.st-andrews.ac.uk/Biographies/Empedocles.html
https://interestingengineering.com/a-brief-history-of-the-speed-of-light
https://oll.libertyfund.org/titles/galilei-dialogues-concerning-two-new-sciences
https://www.pbs.org/wgbh/nova/article/brief-history-speed-light/
https://www-spof.gsfc.nasa.gov/stargaze/Sun4Adop1.htm
https://www.amnh.org/learn-teach/curriculum-collections/cosmic-horizons-book/ole-Rømer-speed-of-light
https://www.nbi.ku.dk/english/www/Rømer/Rømer/lysets_toeven/
https://web.pa.msu.edu/people/horvatin/Astronomy_Facts/planet_pages/Jupiters_moons.htm
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Images:
https://commons.wikimedia.org/wiki/File:Aristotle_Altemps_Inv8575.jpg
https://commons.wikimedia.org/wiki/File:Ole_R%C3%B8mer_(Coning_painting).jpg
https://www.spacetelescope.org/images/opo9630a/
https://commons.wikimedia.org/wiki/File:Christiaan_Huygens-painting.jpeg
https://commons.wikimedia.org/wiki/File:Frodsham_chronometer_mechanism.jpg