I it bad that I think my best friend is an idiot? I Just found out he doesn't believe in global warming, evolution, and gravity.
How do you feel about him after learning this?
I can't trust his judgment anymore.
Even though your friend is very misguided it's not nice to call him an idiot. Try to educate him on these matters instead.
Nah, I'm going to just ignore him now.
I understand being frustrated with your friend not believing in basic science, but ignoring him won't help him. You should spend some time to try to show him why he is wrong. That way, he can better understand these things and you can remain friends.