Well, I somehow doubt rainbows were first invented for the ark. And as I mentioned, the biblical ark story was based on a Babylonian myth. Given that the bible is so easily contradicted by history, archaeology and even within itself, why should any of it be believed? Add that the fact that it has been edited a few times in the process. A big edit came around the 3rd century, there were more changes with the King James vs Catholic bible and more. The old testament can be traced to 3 groups who pretty much wrote the entire thing, none of whom had any connection to the actual events. Of course, not a word of the new testament was written within 3 generations of the supposed events. So, what can you possibly point to as absolute fact? I'd say absolutely none of if.