Kahil M.E.Harko T.Mathematics DepartmentModern Sciences and Arts UniversityCairoEgypt; Department of PhysicsCenter for Theoretical and Computational PhysicsUniversity of Hong KongPok Fu Lam RoadHong KongHong Kong2020-01-252020-01-2520092177323https://doi.org/10.1142/S0217732309028667PubMed ID :https://t.ly/mp3pAScopusWe investigate the possibility that the observed behavior of test particles outside galaxies, which is usually explained by assuming the presence of dark matter, is the result of the dynamical evolution of particles in higher dimensional spacetimes. Hence, dark matter may be a direct consequence of the presence of an extra force, generated by the presence of extra dimensions, which modifies the dynamic law of motion, but does not change the intrinsic properties of the particles, like, for example, the mass (inertia). We discuss in some detail several possible particular forms for the extra force, and the acceleration law of the particles is derived. Therefore, the constancy of the galactic rotation curves may be considered as an empirical evidence for the existence of the extra dimensions. � 2009 World Scientific Publishing Company.EnglishDark matterExtra dimensionsGeodesic motionArticlehttps://doi.org/10.1142/S0217732309028667PubMed ID :