2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/6381New measurements of the velocity dispersion of the globular cluster omega Centauri allow to trace its gravitational potential down to an acceleration of 8e-9 cm/s/s. It is found that the dispersion profile remains flat well inside the tidal radius as soon as the acceleration of gravity approaches a_0, a result that finds its simplest explanation within the contest of Modified Newtonian dynamics. A similar behavior is observed in the globular cluster M15 showing this is not a peculiar features of omega Centauri. This result is surprising and suggestive of a failure of Newton's law at low accelerations.Presented at the IAU220 symposium: "Dark matter in galaxies". Sydney, August 2003Astrophysicstext