Observational constraints on long-range modified models of gravity L. Iorio INFN-Sezione di Pisa The First Galileo-Xu Guangqi Meeting- THE SUN, THE STARS, THE UNIVERSE and GENERAL RELATIVITY Shangai, China, October 26-30, 2009 L. Iorio (INFN-Sezione di Pisa) Modified Gravities and Observations 1st Galileo-Xu Guangqi Meeting 1 / 27