Abstract:
Starting from the main postulates of General Relativity and an introduction to the basic theoretical tools of experimental gravitational physics, we discuss the principles of operation of the very long baseline radio interferometry (VLBI) and the American VLBI network. We then give an outline of experiments for testing General Relativity which have been previously conducted with the VLBI. We will particularly focus on the theory and results of the recent Jovian-Quasar experiment that measured the ultimate speed of gravity, and thus confirmed one of the main postulates of Einstein about the compatibility of special and general relativity.