Why the Sky is Blue (the first legitimate guide)

different frequencies of light exhibit different behaviors in similiar environments. for instance, molecules which are smaller than the wavelengths in the visible spectrum (700nm) will have a scattering effect on the particles of light. however, the amount of acattering at a given frequency (400nm-700nm) is approximately 1/λ^4, which means that if you double the wavelength, you decrease the scattering effect 16 times. so, blue and violet light at the bottom of the spectrum scatter almost 16 time more efficently than red and orange light at the top of the spectrum. since more blue light is scattered, blue light reaches our eyes, thus the sky appears to be blue.

this also explains why sunsets are red and orange. because the light travels through a lot more atmosphere, the red and orange light is scattered by the time it reaches our eyes, and thus we see the sky as orange.

but seriously, get a life.