Instead of attributing the excess gravitational pull to an unseen, undetectable dark matter, MOND suggests that gravity at low accelerations is stronger than would be predicted by a pure Newtonian understanding.
In addition, MOND made a bold prediction: the internal motions of an object in the cosmos should not only depend on the mass of the object itself, but also the gravitational pull from all other masses in the universe — called “the external field effect” (EFE).
Milgrom said the findings, if robustly confirmed, would be “the smoking gun proving that galaxies are governed by modified dynamics rather than obeying the laws of Newton and of general relativity.”