Travel 4000 years ago and ask the cientists of that time. They already knew the truth.
The Earth is motionless and the Michelson & Morley experiment proves this. This is corroborated by Airy's Failure experiment that also failed to detect any motion.
Airy's Failure suggests nothing of the sort. In fact "Airy's Failure" had a hand in the formulation of Einstein's own theories. Neither does the Michelson and Morley experiment.
What it directly proves is that if you split a beam of light into two and make the halves go on round-trip journeys along two equal-length arms at right angles, the difference in the times taken between the arms (nominally zero) does not change if you swap the positions of the two arms by rotating the apparatus.
The reason that's odd is that the earth is orbiting the sun at 30 km/s, and the sun is orbiting the center of the galaxy at 220 km/s, so the earth is presumptively moving through whatever it is that electromagnetic waves propagate through at at least 30 km/s and possibly much more. If light has to waste time chasing the apparatus, you can easily show that in the arm that's transverse to the earth's velocity the round-trip time should be increased by γ(v)γ(v) (the Lorentz factor), and in the other, longitudinal arm it should be increased by γ2(v)γ2(v).
Now for velocities much less than that of light, γ(v)≈1+v22c2γ(v)≈1+v22c2 and γ2(v)≈1+v2c2γ2(v)≈1+v2c2, for a difference of v22c2v22c2. That's pretty small but it ought to have been detectable with v=30 km/s and 1895 optical technology by rotating the apparatus and thereby flipping it from one arm to the other.
But no. The relativistic interpretation of this is two-fold. The nuts-and-bolts interpretation is that there is length contraction: whichever is the longitudinal arm at any particular time contracts by a factor of γ(v)γ(v) so as to make the times in the two arms equal. (The interpretation is also that both arms, as honorary light clocks, are then time dilated by γ(v)γ(v), but the MM version of the experiment is not sensitive to this - see instead the Kennedy–Thorndike experiment.)
The broader interpretation is that it's not just a one-off coincidence that the MM experiment failed to detect the velocity of the aether, it's a fundamental principle underlying the laws of physics, and that there must be whatever other effects are required to make the velocity relative to the aether systematically undetectable. The second new effect is of course time dilation: it must be the nature of an ideal clock to slow down by γ(v)γ(v) as for the arms of the MM experiment or you could do a combined experiment that would show the difference. And the third main new effect is relativistic mass increase. These have all now been confirmed in various combinations. Curiously you don't have to change a single thing about Maxwellian electromagnetism - it was right the whole time and Newtonian mechanics was wrong. Or in other words, the speed of light being constant is not a mysterious new property of light, it's a set of new properties of everything you could possibly measure light with.
And of course, what is systematically undetectable is presumptively non-existent. So we conclude that there never was an aether, it was just an artifact of thinking about EM in the context of the wrong theory of mechanics (and of time and space).
https://www.quora.com/What-did-the-Michelson-Morley-experiment-prove
