Why is the sky blue?

It's sad because no-one here knows the real reason.

Same as the last 90,000+ times this has been asked. Rayleigh scattering.

Rayleigh Scattering.

scattering of sunlight by air molecules, don't know why people are getting thumbs down for writing right answer

http://spaceplace.nasa.gov/blue-sky/en/
An interesting read

Rayleigh Scattering.

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.

Because it's sad. No, because of sky blue because of refraction.