Atheist Pig said it a while ago: "If god needs humans to act on his behalf, Then It Ain't No God."
What we do know today is that matter is never destroyed, it just becomes another form of energy. The old idea that the universe came out of nothing is as wrong as saying that god always existed. Apparently the universe was very compact at one time according to theory, but even Lawrence Krauss says that "something was there when we say nothing." Believers call it their god. More rational people call it dark matter. We cannot see dark matter and it makes up a giant portion of the universe. At least we have gotten that far now. Dark matter is the new big mystery.
As for the mythical Noah and his Ark, it's all an impossible story. Finis Jennings Dake used to muse on whether the giants in the earth in those days helped Noah build the Ark. A recent blogger told me that the waters did not cover the entire earth. What does he mean? He's trying to explain that dove coming back with the olive leaf. The water only came up "this high" some apologist told them. We find that 40 days and 40 nights, 7 days, etc. all have religious meaning but not to an actual story. That doesn't stop believers from changing things repeatedly to try and keep these old myths believable. Instead, they sound more ridiculous.
The justification for a god killing everyone on earth is only that "they had become exceedingly wicked." Noah was the exception and the rest of his family was spared only because they were in "his family." This is the point where the story should have been recognized as only a story. It would make no sense in reality, at least not today. While believers cannot figure out why you don't believe it too, I'm wondering who would want to worship a god that drowned everybody? Certainly there is some sort of fear involved. Women want "god fearing" men and we are taught that we should "fear god." This sure sounds like love to me.
It gets totally whacked when believers that knew me before my atheism ask "who do you worship?" They cannot accept that you worship nothing and nobody. It flies over their heads.
I had a lot less trouble with the story of Noah's ark when I learned that there were hallucinogens in ancient times.
Shades of John of Patmos, eh? Supposed to be LOTS of magic mushrooms where he hung out!