Michelson interferometer
  • (written as Michelson Interferometer)
    Device used in 1880 to show that the Earth does not move through an ether filling the universe. The Michelson-Morley Experiment which proved the absence of the ether shows that beams of light act in the same fashion even if they shine in different directions, so that the ether’s structure is not apparent and there is no medium present for light to travel through as there is, e.g., to carry waves through the ocean. This putative ether is not related to the organic chemical of the same name.
  • An interferometer which allows accurate measurements of electromagnetic radiation by varying the path length of one of the two beams. Once the incident beam is split, a fixed mirror and a moving mirror are utilized to produce the interference patterns.

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