I have experienced time and again people dismissing the data because they think MOND is wrong, so I am very consciously drawing a red line between th… - Stacy McGaugh

The concordance model of cosmology, ΛCDM, provides a satisfactory description of the evolution of the universe and the growth of large scale structure. Despite considerable effort, this model does not at present provide a satisfactory description of small scale structure and the dynamics of bound objects like individual galaxies. In contrast, MOND provides a unique and predictively successful description of galaxy dynamics, but is mute on the subject of cosmology. … it is far from obvious that the mass spectrum of galaxy clusters or the power spectrum of galaxies can be explained in MOND, two things that ΛCDM does well. Critical outstanding issues are the development of an acceptable relativistic parent theory for MOND, and the reality of the non-baryonic dark matter of ΛCDM. Do suitable dark matter particles exist, or are they a modern aether?

My gut reaction to all these questions is negative. But it appears that one set or the other must be answered in the affirmative. Either way, we are missing something fundamental about the nature of our universe.

A long standing prediction (Milgrom 1983) of MOND is that rotating galaxy curves will fall on a single mass-velocity relation with slope 4: M_b <math>\propto</math> V_f⁴. This prediction is realized in multiple independent data sets. Gas rich galaxies fall where predicted by MOND with no free parameters. There are not many predictions in extragalactic astronomy that fare so well a quarter century after their publication. … a physical understanding for why galaxy formation in the context of ΛCDM should pick out the particular phenomenology predicted a priori by MOND remains wanting.