On what basis do you accept St. Augustine as an authority? Would you be inclined to accept everything he has written to be true, or just the things that comport with your version of reality?
Just seems that on this matter that he was able to make sense 1600 years ago of something that still confuses you today. The Bible isn’t a science textbook, and its truths are spiritual truths given by God to a primitive tribe many thousands of years ago, not scientific treatises.