A unique prediction of MOND One curious aspect of MOND as a theory is the External Field Effect (EFE). The modified force law depends on an absolute acceleration scale, with motion being amplified over the Newtonian expectation when the force per unit mass falls below the critical acceleration scale a ₀ = 1.2 x 10 ^-10 m/s/s. Usually we consider a galaxy to be an island universe: it is a system so isolated that we need