Why Do Mountains Look Blue from Afar?

Imagine you're looking at a big blue crayon from far away, it looks gray or pale. That's what happens with mountains! When light travels through the air, tiny invisible particles called aerosols scatter the blue part of the light more than the red or yellow parts. So when you look at mountains far away, most of the blue light reaches your eyes, and that’s why they appear blue from a distance. It's like having a giant sky filter for the mountains.