Ben Levi,
When I say it’s a “fact” I mean that you cant write a fact like the length of the month if you do not know it. It’s not a “historical” narrative told after the fact by people with a clear agenda; which as you pointed out can be easily twisted. I asked for an example of something scientific that was known to Chazal and no one else and you provided me with something that chazal said that was already known by non Jews in the times of Chazal.