2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/195654We discuss the motivation for high accuracy relativistic gravitational experiments in the Solar System and complementary cosmological tests. We focus our attention on the issue of distinguishing a generic scalar-theory of gravity as the underlying physical theory from the usual general relativistic picture, where one expects the presence of fundamental scalar fields associated, for instance, to inflation, dark matter and dark energy.10 pages, International Journal of Modern Physics D style. Talk presented at the International Workshop ``From Quantum to Cosmos: Fundamental Physics Research in Space'', 22-24 May 2006, Warrenton, Virginia, USA; updated referencesAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext