Astronomers (Ibata et al., 2013) have just managed to show that many of the satellite galaxies of the large Andromeda galaxy M31 are co-rotating en masse about it in a plane, just like the planets in the Solar system orbit the Sun. The satellite galaxies' orbits may also be aligned with the rotation of the Milky Way. There is no known way to explain this with standard models of galaxy formation. Their article is here:http://www.nature.com/nature/journal/v493/n7430/full/nature11717.html
These satellite galaxies are definitely in the regime of MiHsC, with a very low acceleration which makes me wonder. Are they orbiting like this to maintain their acceleration above the MiHsC minimum: 2c^2/Theta? Or, since they are some way from the mass of the Andromeda galaxy, is their inertial mass being influenced also by more distant matter? Is there an inertial interaction between galaxies that makes them align like magnets? Anyway, it is a nice anomaly to think about.