2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/3739We present a five-dimensional gravitational theory in a space-time-velocity Riemannian manifold. The equations of motion of a star moving around a galaxy are shown to be the Tully-Fisher law. The problem of the cosmological constant is discussed, and a new formula for the cosmological redshift is derived.27 pages LaTeX, to be publishedAstrophysicstext