rob, The Rema (Toras HaOlah 1:2) wasn’t written in the last century. See previous comment.
No one, myself included, said the Gedolim of this or previous generations are infallible.(*) We are talking about Chazal. So focus your comments/response regarding infallibility on Chazal. As I understand it, you say Chazal is infallible on halachic matters but not scientific matters, while I strongly dispute your denial of their infallibility on scientific matters whilst agreeing with your understanding of Chazal’s infallibility on halachic matters.
cherrybim, I am not saying anything other citing the Vilna Gaon in response to your characterization that “it’s silly” to say a Godol would have been even greater had he forgone secular study. If you have questions on the interpretation of what the Gra said, see your local Ultra-Orthodox Talmid Chachom.
(*)Although it is important to note that the Gedolim are closer to infallibility than you or I. And if there is an issue of disagreement between you and a Godol, the very strong likelihood is the Godol has a better idea of what Hashem wants.