Dark matter proponents theorize that most of the known Universe is actually made of material that doesn’t interact with light, making it invisible and undetectable, but that this material accounts for much of the gravitational pull among galaxies. A counter explanation introduced by the Israeli physicist Mordehai Milgrom in 1983, the MOdified Newtonian Dynamics (MOND) theory, says this gravitational pull exists because the rules of gravity are slightly altered. 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 makes 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 — the so-called external field effect. Now, astrophysicists from South Korea, the United Kingdom and the United States report a detection of this external field effect in 153 disk galaxies from the Spitzer Photometry and Accurate Rotation Curves (SPARC) database.