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

The Luminiferous Aether (or ether) was a hypothesized medium that was thought to permeate all of space. 19th-century physicists proposed its existence to explain how light, an electromagnetic wave, could propagate through the vacuum of space.

Just as sound waves need a medium like air or water to travel, it was believed that light waves must also travel through some kind of invisible, massless, and frictionless substance. This aether was thought to be the absolute rest frame of the universe, the stationary background against which all motion could be measured.

The properties required of the aether were contradictory: it had to be incredibly rigid to support the high speed of light, yet offer no resistance to the planets moving through it.

The concept of the aether was a logical extension of the physics of the time, but it was ultimately disproven by the Michelson-Morley Experiment, which failed to detect any evidence of its existence. This "failed" experiment became one of the most important results in the history of physics.

Reference

Coursera, "Question Reality: Matter"