This is just BS extracted from the mind of nully, but, suppose there really is aether?
The only “proof” we have that there isn’t is the Michelson–Morley experiment, an experiment that has only been done on the surface of the Earth. Suppose the aether swirls like the eddies around an oar or water flowing down a drain?
Stuff accumulates in these eddies/vortexes, every planet, every star and every galactic feature is defined by these eddies. If you look at an eddies in the 2 dimensional water model you can see striations on the walls, these correspond to the 3 dimensional arms in galaxies.
Back to Michelson–Morley experiment, done on the surface of the Earth only. The mass accumulation and the rotational velocity mirror the rotation of the aether vortex. The revolution of the Earth around the Sun tracks the swirl of the aether spinning around the Sun. After billions of years the interaction of aether and matter more or less reach an equilibrium. Surface velocity on a massive object is more or less zero, exactly as Michelson and Morley found. In effect, the were attempting to measure the velocity of the wind from a balloon floating freely in and with the breeze.
Why do some galaxies show anomalous rotation? The centers of most galaxies have a black hole where space-time spirals in. Does the fabric of space-time have a yield strength?
If so, as the black hole continues to gain mass, the very fabric of space-time stretches as the gravity well gets deeper and deeper. If at any point the strain exceeds the yield stress of space-time the funnel tears in two at that depth. Everything below that tear falls off into a separate universe.
Everything above? It rebounds. More space pours out of the old event horizon, as the mass that was holding it in place has budded off and as far as this universe can tell, simply ceased to exist. All the matter on the sidewalls above the new event horizon barfs out along with the space and forms the central bar seen on so many galaxies. For a time the bottom of the gravity well looks flat, and this flat gravitational gradient allows the matter to rotate around the core at the same rate rather than faster towards the center (which no longer has a steeper slope) than the edge.
You see a similar effect if you abruptly close a drain valve.
However, astronomers have recently discovered galaxies which appear to have no dark matter.
Their center black hole simply hasn’t developed a steep enough stress gradient to bud off. Yet.
I like your theory. It could explain the Boötes void.
Also, I am not sure space IS ‘empty’ either.
If you take an empty cube of space, and shine a light through it, it comes out the other side- what exists inside the ‘space’ when the light is traveling through it?
This isn't an aether/oar question.