The Big Bang theory is a model that attempts to explain how the universe was formed. This theory suggests that the universe as we know it came into existence a little less than fourteen billion years ago and that everything started from a very dense, hot, state from which the universe as we know it began to expand. This theory is based on, and is consistent with, all of the current observations we have surrounding the known universe, such as the fact that it is expanding or that there exists a large abundance of light elements in the universe. The one thing left unexplained by this theory, though, which you may likely be wondering about, is how that initial state came to be in the first place. How did the first matter originate, and why was it all packed together in a very dense state? Unfortunately we cannot answer that one, and neither does the Big Bang theory. Rather, the Big Bang theory is only focused on explaining the evolution of the universe from that initial state to what it is today and to what it will become in the future.