Edwin hubble is credited for the initial development of the big bang theory, an idea which to explain the formation of the universe over 15 billion years ago. which piece of evidence did hubble find that led him to begin the development of the big bang theory? a) the sun is the center of the universe. b) the universe is expanding in all directions. c) new universes are being made on a regular basis. d) all life appeared on earth about 3.5 billion years ago.