> Christians (well, members of other religions too, but I don't know as much about them) have a Bible which purports to be an account of the creation of the universe. The Bible contains and implies answers to the "why" questions of the way everything works, though the legitimacy of those answers is up to the beliefs of the individual. Other ideas exist too, of course, like the "scientific" theories that aren't really scientific at all. Like the Big Bang theory, which attempts to explain the origin of the universe but still doesn't answer any key "why" questions: after all, where did the original superdense particle come from prior to the Big Bang? Not to mention that the theory is not scientific by any means, but rather is just a hypothesis that will likely remain unproveable forever. Sorry for sounding snide, but that particular theory seems a little preposterous to me because it is based on so much raw, illogical, uninspired speculation. Also, its heavy reliance on faith makes it a true religion, despite heavy protests from all its proponents that it's NOT. But I digress...

We have evidence for the Big Bang in the form of residual background radiation, as well as many other details that are far easier to explain if the Big Bang happened than if the Universe was infinatly old. In fact, it's probably fair to say that we have as much evidence of the Big Bang as we do for some of the more unusual elementary particles.

In addition, modern brane theory seems to provide a decent explanation of the causes and physics of the Big Bang, but even that only really pushes the question back to "How did the very first universes come into being?".