Why do distance mountains seem blue viewed from distance?

Question

I know the answer, see who gets 10 points for a good answer

Oh yes, and how come the sun when setting seems red?

Answer 1

The same reason that the sky is blue, the atmosphere scatters the light from the sun and blue wavelengths are scattered the most because they are the shortest. The blue "haze" that you see comes from the increasing amount of air in between you and the mountain.

The sun seems red when it is setting because it the light is travelling through more air which filters out the short and medium wavelengths of light. The farther light travels, the more red it appears when it reaches Earth. This is called red-shift.