Is there a complete relativistic theory incorporating MOND?
There have been suggestions, such as Bekenstein’s Phased Coupled Gravity and Sanders’s Stratified Scalar-Tensor Theory. It is not obvious that either of these are satisfactory, but they do at least demonstrate that it is possible to construct theories which encompass both GR and MOND. This is a hard problem, especially conceptually. It took a long time to go from the inverse square law to the Poisson equation, and from special relativity to GR. If both GR and MOND are correct (as appears to be true empirically), then there must be a grander theory encompassing both. But don’t expect to derive it on the back of an envelope in a few minutes.
