It appears, from all that precedes, reasonably certain that if there be any relative motion between the earth and the luminiferous ether, it must be small; quite small enough entirely to refute Fresnel's explanation of aberration.
Concluding that there is no stationary ether with respect to which the earth moves while orbiting around the sun. On the Relative Motion of the Earth and the Luminiferous Ether by Albert Abraham Michelson and Edward Morley. American Journal of Science, 1887, 34 (203): 333–345.
Now, the velocity of wave propagation can be seen, without the aid of any mathematical analysis, to depend on the elasticity of the medium and its density; for we can see that if a medium is highly elastic the disturbance would be propagated at a great speed.Albert Abraham Michelson