Dark Matter: the Problem of Motion

Abstract

Dark matter (DM) may be studied through the motion of objects following nongeodesic trajectories either due to the existence of an extra mass as a projection of higher dimensions onto lower ones or as motion of dipolar particles and fluids in the halos of spiral galaxies. The effect of DM has been extended nearby the core of the galaxy by means of the excess of mass appearing in the motion of fluids in the accretion disc. Nongeodesic equations and those of their deviation are derived in the presence of different classes of bimetric theories of gravity. The stability of these trajectories using the geodesic deviation technique is investigated.