This is a new explanation of the experimental physics of mass, space, time, gravity, and Big Bang theory. It shows that Einstein's metaphysical assumptions of equivalence, massless photons, and relative motion are not necessary to explain the measured dynamics of matter, energy, gravity and the creation of the universe with a Big Bang. The principle of the Living Universe describes the evolution of matter and energy in the Cosmos from its beginning and resolves the many paradoxes and contradictions in Big Bang theory.