Contrary to popular belief the
sky is not blue because of
refraction.
Refraction is not a
significant enough
effect to have this sort of
affect although it can change the
apparent position of the
sun
The
real reason why the sky is blue
is due to a phenomenon known as
Rayleigh Scattering whereby blue light is absorbed by gaseous molecules in the
atmosphere ( ie air ) and then re-emitted in a random direction.
Thus as
white light from the
sun travels through the atmosphere the
blue light is scattered away from its original direction of travel, and some of it is scattered down towards
us which causes us to
perceive the sky as blue.
This is also the reason
why the sun is yellow.
No offence Sporus but the reason it wasn't printed is probably because it's piffle