Why is the sky blue?

My first published, long writing is titled, Rayleigh Scattering. The main character is Margaret (Maggie) Rayleigh. As I was finishing the novella, I was flipping through the dictionary searching for a word when I happened upon the term "Rayleigh Scattering", a phenomenon which accounts for the colors of the sky and the predominance of blue. The description also describes the transformation that the protagonist experiences and much of the imagery of the novella focuses on how things appear in a given light.


So why is the sky blue? When one looks at the sky, rather than seeing the black of space, one sees light from Rayleigh scattering off the air. Rayleigh scattering is proportional to the inverse fourth power of wavelength, which means that the shorter wavelength of blue light will scatter more than the longer wavelengths of green and red light. This gives the sky a blue appearance. Conversely, when one looks towards the sun at sunset, one sees the colors that were not scattered away -- the longer wavelength, red light.

So this post is for Maggie, of the short wavelength and the immense scatter.