Atheists the burden of proof is on you.(this is long)?
For one thing, the theory placed the creation event at less than 20 billion years ago (modern data now suggest a 12 to 13 billion year range); this was simply not enough time to accomodate the origin of life by random chance processes. For another, there is the question of what caused the Big Bang. This particular question became more pressing with the publication in the late 1960's of the Space-Time Theorem, by cosmologists Stephen Hawking, Roger Penrose, and George Ellis. This theorem uses general relativity to prove that matter, energy, space, and time all had their origins in a singularity (a geometric point of zero size). If space and time had a beginning, then whatever caused the Big Bang must have transcended space and time. Moreover, the Space-Time Theorem states that the amount of matter and energy in the universe is finite, imposing limits on how many times the dice can be thrown.
A further difficulty concerns black holes. A black hole is a collapsed star which is so dense that, if one is sufficiently close to it (the "event horizon"), nothing can escape from it, not even light. Using general relativity, one can prove that it takes an infinite amount of energy to remove a single particle from inside the event horizon of a black hole. The problem, of course, is that if the entire universe was originally squashed into a singularity, then that singularity was the granddaddy of all black holes. Whatever caused the Big Bang must have had infinite energy.
Moreover, the many-worlds hypothesis, even if true, does not solve the central problems of the origin of time and the need for infinite energy to cause the Big Bang. It also fails to get around the fact that the laws of physics seem tailor-made for life to exist. It is very easy, through slight manipulations of the physical laws, to construct universes which have only neutrons, which have only hydrogen, or which are otherwise unsuited for life.
For instance, if the electrostatic force, which is inversely proportional to distance squared, instead were inversely proportional to distance to the power 2.00001, electrons would fly off into space and atoms would never form. The hypothesis does, however, make a dent in the amount of time required for the origin of life by chance processes, since the dice could theoretically be thrown infinitely many times. But since there seems to be no motivation to accept the hypothesis, depending on it to explain the origin of life is as much an article of faith as believing in God.
Please prove that the Big bang theory actually happened. I have studied encyclopedias and they state it "controversial" why don't we have proof.