>>Others use other sources. For some, a book written around 3-4000 years ago to explain things to nomadic shepherds will suffice to explain things.<<
Some things, yes. It does not speak to every nook and cranny of creation. That is why man invented "science" and "mathematics". It is also why God gave us the ability to do just that.
"Some things, yes. It does not speak to every nook and cranny of creation."
There was no need for it to. Of what use would information regarding the evolution of, say, the marsupials be to nomadic shepherds?
No, Genesis gives a neat explanation of how things happened...enough to more than satisfy nomadic shepherds. It's very useful that way, just as are the creation stories in all ancient scriptures. Hinduism has several, depending on which of the many creations are being addressed.
We're less easily satisfied today. We do know a lot of things. We've visited some nearby moons and planets, either in person or via robotics. We have the tools to see things as small as individual atoms.
No, Genesis doesn't do as a good explanation for us today. It was adequate when it was written, though. I'm sure none of the nomadic shepherds questioned it at the time. They'd have no reason to, nor any interest in doing so.
The time of Moses was a long, long time ago. It was the bronze age, but many living in that time still used stone tools, since they were less costly. The population of the world known to the Israelites was small, and an entire people could cross the desert and come to a new territory to claim as their own.
Genesis is a great book. It's one of our earliest records of a culture. It has survived, intact, because it was a religious text. Indeed, only religious texts have survived that long, but there are a few others of the same age. All have similar characteristics, particularly in their creation stories.
I'm of the opinion, though, that the turtle theory is the best one. It is, indeed, turtles...all the way down.