Why are we limited to the water on Earth?
I mean, we are talking about God here. In order to cleanse the Earth, why wouldn't he just grab some spare available water kicking around in the neighborhood - say the 10 mile deep oceans on Europa or the martian ice caps and just precipitate those onto the Earth surface over 40 days. Once the cleansing was complete he could just as easily slowly move the water all back to it's original location. Or destroy it completely - perhaps that is where the supposed martian oceans went... God used them to cleanse the Earth and then got rid of it.
In fact, why are we worried at all about where the water came from? Why didn't God just create it? Certainly would be a lot simpler, wouldn't it?
I find the whole, "there isn't enough water" or "where did it come from" arguments about the flood extremely useless. Coming up with a simple, common material and dumping it on the Earth for a short period of time and then getting rid of it would be something easily within the capabilities of God.
The important questions that need to be answered about the flood is why didn't it leave any geologic/physical/biological evidence? There is no global sediment layer, no global population bottlenecks, no massive fossil layer with dinosaurs, mammals, birds, fish, amphibians all jumbled together, and..., and..., and... - the list goes on and on.
Again, there is a very simple solution to this and that is that God made it look the way it is. Once the Earth was cleansed, he wanted to hide and tamper with the evidence. This leads us to (as a former poster here put it) a trickster god that leaves us with a world that intentionally misleads us. In that case, how can we know that he didn't do the exact same thing last Thursday and none of us actually existed before then - how would we know?
It boggles my mind that so many people put so much emphasis on a series of books, written by men, over thousands of years, translated and copied many times and insist that it is completely, 100% factual.
Why can't people look at the 'books' supposedly created by God - the Earth and Universe - and read and interpret it?
That is what science does. They are arguably the true worshipers of God and his creation. Not some man written manuscript.