Big Bang Theory! Where The Ball Came From?

Have you heard of the Big Bang? Not the big Ben in London but in the universe? Once there was a ball and it exploded and created our universe. Since then the universe is expanding and every thing is further away from each other! However, the big and crucial question where this ball came from at the first place. It can't came from nothing.
Of course it was the genius of Albert Einstein who came the relativity theory that the universe came about from a big bang theory. Never the less he just solved a part of the puzzle albeit very crucial and a major leap frog forward.