Pet theory: "dark matter" is gravitation leaking from adjacent universes, in specific, from the juxtaposition of many divergent universes.
Most diverge in trivial ways, so dark matter concentration is correlated with where matter is in our universe.
Some relatively few diverge more drastically, so there is a background.
As someone outside the field I remain curious if there are reasons this is inconsistent with observations to date, for some models of the multi-world hypothesis.
Flying through hyperspace is not like flying over fields. Said one famous pilot doing the Kessel Run in less than 12 parsecs. Maybe Dark Matter is the real space shadow of stuff in hyperspace the same way real space stuff has shadows in hyperspace.
Seriously, I cannot judge this level of physics, or just understand them. It would make a nice addition to Star Wars lore so.
1. It would tend to imply dark matter having the same shape as the matter in galaxies. It doesn't. So it doesn't explain the galactic rotation curves, which is the whole reason we hypothesized dark matter in the first place.
2. It doesn't explain the Bullet Cluster.
3. It doesn't match why some galaxies have more dark matter than others.
4. It doesn't explain Baryon Acoustic Oscillations.
Most diverge in trivial ways, so dark matter concentration is correlated with where matter is in our universe.
Some relatively few diverge more drastically, so there is a background.
As someone outside the field I remain curious if there are reasons this is inconsistent with observations to date, for some models of the multi-world hypothesis.