EFFECTIVE DARK MATTER AND DARK ENERGY FROM GENERAL RELATIVY

In this PhD thesis, we consider the idea that that some fraction of the dark matter and the dark energy can be explained as relativistic effects. We studied two different, not mutually exclusive models. The inhomogeneity matter generates gravitational distortions, which are general relativistically retarded. These combine in a magnification effect. Such non negligible effect on the averaged expansion of the universe contributes both to the estimations of the dark matter and to the dark energy, so that the parameters of the Cosmological Standard Model need some corrections. On the other hand, the fractal cosmology, now modelled with a Lemaitre-Tolman-Bondi (LTB) metric, results in distortions of the luminosity distances of SNe Ia, explaining the acceleration as apparent. In this work we extend the LTB metric to ancient times. We show that the evolution of such a inhomogeneity necessarily requires a dynamical generalization of LTB.