It's the theory of the creation of the universe that most scientists accept at the truth. Just google it and look up the details, but as you probably know, the idea is that some small ball of energy suddenly exploded and out came tons of elements and gasses. Over time these came to for planets, stars, and even life. Evidence for the theory includes the fact that the universe is still expanding (from the explosion). Alternative to the theory is Creationism, or Intelligent design.
