One of the most effective theories for dark matter is Milgrom’s Modified Newtonian Dynamics, where a modified law of gravity based on a fixed acceleration scale a0 is postulated that provides a correct description of the gravitational fields in galaxies. However, the significance of a0 is unknown, and the whole theory is generally viewed as a phenomenological description of the observations. Based on Newton’s gravitational law as applied to a uniform continuous mass we posit a non-homogeneous distribution of mass at cosmological scales that would give rise to a constant acceleration that agrees with MOND’s a0. The implications for MOND as a viable theory of dark matter and for the problem of dark energy are discussed. In particular, relativistic high rotational velocities would be achieved at the border regions of the universe that would generate a transverse Doppler redshift that scales linearly with distance and migh provide an alternative explanation for the observed redshifts and expansion.