Physical process Experimental tool Theoretical model Explains/predicts Gravitation Radio telescopes Self-gravitating system Emergence of a star system Nuclear fusion Spectroscopy Stellar evolution How the stars shine and how metals formed The Big Bang Hubble Space Telescope, COBE Expanding universe Age of the Universe Quantum fluctuations Cosmic inflation Flatness problem Gravitational collapse X-ray astronomy General relativity Black holes at the center of Andromeda Galaxy CNO cycle in stars