Dark Energy and Dark Matter or Gravity

Abstract: The knowledge of the Universe is essentially based on the theory of general relativity (GR). If from one hand, solar system data is in excellent agreement to the theory, available cosmological evidence on the other, is consistent with GR provided one assumes the existence of dark energy and dark matter. We shall discuss the evidence on the existence of these entities as well as on a putative interaction between dark energy to dark matter. We shall also present a new version of f(R) gravity models with a non-minimal coupling between curvature and matter and discuss some of its implications.