Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The evolution of the universe describes the history and future of the universe according to Big Bang cosmology, the prevailing scientific model of how the universe came into being and developed over time. The best available measurements as of 2011 suggest that the initial conditions occurred about 13.7 billion years ago in an event known as the Big Bang. Observations have shown that since then the universe appears to be expanding at an accelerating rate, and a number of models have arisen to predict its ultimate fate. Learn more about the most popular theories of our universe started, evolved and how it will eventually end, in the following pages.