Who hasn't looked up at the star-studded night sky and wondered, "Where did everything come from?" There are many ways to address this question. It was Edwin Hubble whose telescopic observations of galaxies in 1929 led to the major discovery that the universe is expanding, and that the rate of expansion is proportional to how far the galaxies are from one another. The farther apart they are, they faster they are going. This result implies there was a time about 13.75 billion years ago when the universe began in an event we now call the Big Bang. The evidence suggests...