To borrow a choice of words from Aron-Ra:
Because it's flat out wrong about damn near everything.
The Bible makes lots of factual claims about the natural world, and a great many of them can be shown to be incorrect. For example, we know that the world is not flat (Isaiah 40:22), is not encased in a firmament (Genesis 1:6-8), and does not sit immobile on a foundation (Psalm 104:5), just to name a couple of examples.
Or, to put it another way, the Bible is NOT inerrant.
So there is no reason to believe anything simply because the Bible says so. If any claim that Bible makes is true, that claim could be verified by means or sources independent of the Bible.