I do not know if this has been discussed before, but it is one solution to Dark Matter, Can inertia even be quatised? arXiv:1709.04918 [pdf, other] Galaxy rotations from quantised inertia and visible matter only M.E. McCulloch Comments: 9 pages, 2 figures. Published in Astrophys Space Sci Journal-ref: McCulloch, M.E. Astrophys Space Sci (2017) 362: 149 Subjects: Astrophysics of Galaxies (astro-ph.GA) It is shown here that a model for inertial mass, called quantised inertia, or MiHsC (Modified inertia by a Hubble-scale Casimir effect) predicts the rotational acceleration of the 153 good quality galaxies in the SPARC dataset (2016 AJ 152 157), with a large range of scales and mass, from just their visible baryonic matter, the speed of light and the co-moving diameter of the observable universe. No dark matter is needed. The performance of quantised inertia is comparable to that of MoND, yet it needs no adjustable parameter. As a further critical test, quantised inertia uniquely predicts a specific increase in the galaxy rotation anomaly at higher redshifts. This test is now becoming possible and new data shows that galaxy rotational accelerations do increase with redshift in the predicted manner, at least up to Z=2.2.