The Michelson-Morley experiment tested whether Earth's motion through a proposed light-carrying ether would change the measured travel of light. Krishna Choudhary and Lester Nare discuss its unexpected null result and the challenge it posed to that picture of light propagation. The segment places the experiment in the history leading toward special relativity.
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The experiment used interference to compare light traveling along different directions.
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The expected evidence of an ether wind did not appear.
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Its result challenged ether-based explanations of light propagation.
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24:15The first American Nobel Prize was actually Teddy Roosevelt in peace for um, bartering the peace between Japan and Russia in their war. The first one in science was by Albert Michaelelsson and his assistant Edward Morlay. It was conducted in the Case School of Applied Science in Cleveland, Ohio. Now it's called Case Western University because it merged with Western University also in Cleveland, Ohio. This is the famous interferometer experiment that proved that the speed of light is constant no matter what you do. It's also known colloquially as the most famous failed
24:56experiment in all of physics because they were out there trying to figure out what is the speed of something called the ether. Okay, the ether is like this thing that light moves around, right? Sound moves through air and water. Light has to move through something. People thought there's got to be an ether. So Michaelelsson was like, well, if there's an ether, we can use the Earth's rotation to figure out what is the speed of the ether in one way or the other. And he figured out there is no ether because light just kept going the same way regardless of whether the earth was rotating this way or over here or 6 months later it's we're on the other side of the sun. Whatever we do the speed of light is exactly the same. And the main thing is he said my error bar
25:37is now so small that I can rule out any effect of this mysterious substance. This is what led to Einstein's revolution with the theory of special relativity in 1905. The ether is non-existent. 1893, founding of the physical review, which we've covered in the pod on multiple occasions. Yes, another great journal from America. Um, several papers we've