  We show that the current accelerated expansion of the Universe can be
explained without resorting to dark energy. Models of generalized modified
gravity, with inverse powers of the curvature can have late time accelerating
attractors without conflicting with solar system experiments. We have solved
the Friedman equations for the full dynamical range of the evolution of the
Universe. This allows us to perform a detailed analysis of Supernovae data in
the context of such models that results in an excellent fit. Hence, inverse
curvature gravity models represent an example of phenomenologically viable
models in which the current acceleration of the Universe is driven by curvature
instead of dark energy. If we further include constraints on the current
expansion rate of the Universe from the Hubble Space Telescope and on the age
of the Universe from globular clusters, we obtain that the matter content of
the Universe is 0.07 <= omega_m <= 0.21 (95% Confidence). Hence the inverse
curvature gravity models considered can not explain the dynamics of the
Universe just with a baryonic matter component.
