Michelson-Morley Experiment

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Michelson-Morley Experiment

The Michelson-Morley experiment disproved absolute motion.

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Absolute motion

  • In the past, there was no concept of relative motion.
  • Scientists believed that everything must move relative to a fixed object or origin.
    • This fixed object was called the ether.
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Michelson-Morley experiment

  • Michelson and Morley tried to find the absolute speed of the Earth using an interferometer.
  • They used two mirrors and a partial reflector to send a beam of light in two perpendicular directions.
    • These beams are reflected back, and recombined to form an interference pattern.
  • Based on the shift in the interference patterns when the experiment is run in different orientations, the speed of the Earth should have been calculated.
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  • Michelson and Morley repeated the experiment, but could never find any results from their interference patterns.
  • They concluded that:
    • Absolute motion is impossible to detect.
    • The speed of light is equal for all observers.

Jump to other topics

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4Mechanics & Materials


6Further Mechanics & Thermal Physics (A2 only)

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8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

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