Why is the sky blue

Question

I know that we have Oxygen, Carbon dioxide and Nitrogen in the air with Sunlight, but what is the reactions that take place to get Blue Skies?

Answer 1

As an aside, the Earth’s atmosphere is composed of the following molecules: nitrogen (78%), oxygen (21%), argon (1%), and then trace amounts of carbon dioxide, neon, helium, methane, krypton, hydrogen, nitrous oxide, xenon, ozone, iodine, carbon monoxide, and ammonia. Lower altitudes also have quantities of water vapor.

Note it's mostly N and O.

 

Jim

Answer 2

There are 2 answers to this question

1. Scientific: http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html
2. Philosophical: Because it's not green!

There is also a fascinating lecture on rainbows at http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/video-lectures/lecture-31-rainbows/  

It runs 50 minutes but covers a lot of ground.