Big Bang
The Big Bang is one of the accepted theories about the origin of universe, which probably occurred 15 billion years ago. It pretends to be an explosion of matter and energy that has been expanding till nowadays. That explains the way planets and other cosmic objects formed. Several scientist have studied this phenomenon, without proving its existence, leaving indefinite assumptions. The other curious things are 'the red shift' and the background radiation, whose importance was estimated with the Nobel Prize.
