Historical Standpoint

[abaris]

He who sits above the circle of the earth, And its inhabitants are like grasshoppers, stretches out the heavens like a curtain, And spreads them out like a tent to dwell in.

Another indication that the earth was round before any proof.

Now take out the point of magic, etc.  My question is how could people have known this when these two books were written, if we did not have the start of science around 1589 AD starting with Galileo Galilei?  How would this be possible?

We haven't got the start of science around 1589. Just people starting to move out of medieval stupidity. As far as the West is concerned. In antiquity, the earth already was measured by Greek scholars. The scope was a little bit off, but they didn't believe it to be flat. Egyptians had a very good understanding of the sky, as had ancient native American societies. And, as opposed to popular belief, Christoph Columbus didn't set out to discover a new continent, but to find a sea passage to India, sailing to the West. So, in 1492, the earth being round was hardly up for dispute.

That's only a nutshell of many more sources the bible could draw from, if you are to interpret some scientific meaning into the usual ambiguous verses.