Page "Luminiferous aether" Paragraph 44

Another, completely different, attempt to save " absolute " aether was made in the Lorentz-Fitzgerald contraction hypothesis, which posited that everything was affected by travel through the aether.

In this theory the reason the Michelson-Morley experiment " failed " was that the apparatus contracted in length in the direction of travel.

That is, the light was being affected in the " natural " manner by its travel though the aether as predicted, but so was the apparatus itself, canceling out any difference when measured.

Fitzgerald had inferred this hypothesis from a paper by Oliver Heaviside.

Without referral to an aether, this physical interpretation of relativistic effects was shared by Kennedy and Thorndike in 1932 as they concluded that the interferometer's arm contracts and also the frequency of its light source " very nearly " varies in the way required by relativity.