I see the Michelson-Morley experiment as an aether detector that didn't detect the aether.
It may be a fable, but I heard that Einstein, in response to the Experiment's negative result, called the aether a "ghost," and that its supposed fictional status prompted him to think through the nature of electromagnetic radiation (light), resulting in his Special and then General Relativity theories.
I'm aware of at least one similar experiment that attempted to detect dark matter (involving a deep underground chamber designed to isolate dark matter from other variables), and this experiment failed to detect dark matter.
Much like many contemporary scientists' response to the failed MM experiment (performed in the late 1800s), many current scientists' response to this dark matter detection failure has simply prompted a redoubled effort to think through a better experiment, or a better detector design for dark matter.
I heard a few years ago a public radio interview with some sort of scientific expert, wherein the expert was asked to identify some key issues still left for science to fully determine and understand, and I think they listed something like five things. One of those things was the nature of gravity itself, and I remember thinking that three of the remaining four things could very well be other facets of gravity .. the expert presumed that dark matter and dark energy were independent issues from gravity for instance.
The other tie-in here is the graviton. I've read where this particle could only be theoretically directly detected, if the detector was roughly the mass of the planet Jupiter.
So overall, my question is, is there some way in which perhaps within the nature of gravity itself, there is the explanation for why the galaxies arrange and move as they do? My layman intuition has fallen upon the "gravitation constant:" is it possible that it somehow changes when objects like galaxies are involved, but remains as we've determined it to be with smaller objects like stars and planets?
Clearly, I am way beyond my depth here, but I wondered if anybody had any light to shed upon these musings of mine.