A Modification of the Newtonian Dynamics - Implications for Galaxy Systems

I consider the implications of a modification of the Newtonian dynamics to galaxy systems. Masses and mass-to-light ratios are re-derived, on the basis of existing data, for binary galaxies, small groups, clusters of galaxies, and the Virgo Supercluster. For each type of galaxy system, the average M/L values come out to be a few solar units. These results eliminate the need to assume large amounts of hidden mass in galaxy systems, if the modified dynamics applies.