Michelson-Morley Experiment and Its Historical Impact

Introduction

• Michelson-Morley Experiment: Most famous physics experiment in history.
• Purpose: Detect the motion of the Earth through the luminiferous ether, a hypothesized medium for light propagation.
• Ether: Concept by 19th-century physicists to explain light transmission through space.

Physics Folklore

• Legend: Michelson-Morley experiment disproved ether; Einstein's theory of relativity explained the result.
• Experiment Date: 1887
• Location: Cleveland, Ohio at Case Institute of Technology
• Significance: Comparable to major historical scientific advancements in less recognized areas.

Albert Michelson

• View of Experiment: Considered it a failure despite its importance.
• Time Period: 1887, Victorian era, London as commercial capital.

Historical Context

• James Clark Maxwell: Electromagnetic radiation equations (23 years prior to 1887).
• American Context: Post-Civil War, peace, prosperity, and migration.
• 19th Century Concept: Physics was thought to be nearing completion/perfection.
• Ether Belief: Real with physical properties deduced through behavior.

Ether Concept

• Wave Propagation: Through various media (water, crystal, air); ether believed to facilitate light waves.
• Ether Characteristics: Non-viscous, incompressible fluid filling space.

Michelson and Morley's Experiment Design

• Interferometer: Designed by Michelson, splits light into beams to detect earth's motion through ether; expected small differences in beam travel times.
• Objective: Measure tiny differences in speed to prove ether's existence.
• Result: No difference found in light speed irrespective of direction; ether not detected.

Impact and Reactions

• Physicists' Efforts: Repeated experiments for 50 years; no ether found.
• Scientific Dilemma: Challenged existing physics understanding.
• Alternative Theories: FitzGerald-Lorentz contraction hypothesis; basis for Lorentz transformation.

Shift in Scientific Thought

• Relativity Principle: From Galileo, inertial frames (uniform motion = rest state).
• Einstein: Introduced special relativity, recognizing light's consistent speed across all frames of reference.

Einstein and Michelson's Legacy

• Nobel Prize: Michelson's accolades and contributions to experimental physics.
• Theory of Relativity: Transformation of space-time concepts.
• Historical Teaching: Often altered for pedagogical purposes.

Conclusion

• Historical Reality vs. Folklore: Discrepancies in historical narratives.
• Next Discussion: Exploration of Einstein's development of relativity theory.