The answer to the question of how the universe started is not as much WHAT happened; the ultimate question is what CAUSED it to happen. Ex Nihilo, Nihil Fit - Out of nothing, nothing comes. If I have noting in my hand, what can you get? Nothing. Whatever begins to exist has a cause. The universe began to exist therefore it has a cause. The “big bang” requires that the universe began to exist, and is created, out of nothing. If out of nothing, nothing comes then how can the universe creating from nothing without a cause. “Nothing is what rocks dream about” - Aristotle

The details differ, but the essential elements in the astronomical and biblical accounts of Genesis are the same… This is an exceedingly strange development, unexpected by all but the theologians. They have always believed the word of the Bible. But we scientists did not expect to find evidence for an abrupt beginning because we have had, until recently, such extraordinary success in tracing the chain of cause and effect backward in time… At this moment it seems as though science will never be able to raise the curtain on the mystery of creation. For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.—Robert Jastrow (former director of NASA’s Goddard Institute for Space Studies)