Physicists looking at large galaxy structure are becoming unsatisfied with Dark Matter/Dark Energy explanations, so they’ve had a bit of a think about how gravity works.
Jacob Bekenstein’s relativistic covariant theory of gravity (TeVeS for TEnsor VEctor Scalar with a Hebrew flavour) looks like a good fit, because it seems to explain the same things as MOND (MOdified Newtonian Dynamics) but without tripping over factors like gravitational lensing. It also allows for fast growth of density variation from small disturbances during recombination, & has many other useful properties.
So. . . we might have a new theory of gravity (different at large scales) to deal with, shortly. The only constant thing is change?