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tags: #physics #relativity #history-of-science

The Michelson-Morley experiment, performed in 1887, was designed to detect the "aether wind"—the motion of the Earth through the stationary Luminiferous Aether.

The Setup:
An interferometer was used to split a beam of light, send the two beams along perpendicular paths, and then recombine them. If the Earth were moving through the aether, one beam should have been slowed down by the "aether wind" more than the other, causing a shift in the interference pattern when the beams were recombined.

The Result:
No matter how the experiment was oriented or when it was performed, no significant shift in the interference pattern was ever detected. The result was null.

The Conclusion:
The experiment's failure to detect the aether wind was a major puzzle for classical physics. It strongly suggested that the speed of light is constant for all observers, regardless of their motion. This "failed" experiment directly contradicted the established principles of the time and became a key piece of evidence that led Albert Einstein to develop his theory of Special Relativity, which does not require an aether.

Reference

Coursera, "Question Reality: Matter"