Sunset

The other night at sunset we were on our way to swim practice and captured a really cool sunset on our digital camera. So, that prompted us to investigate why sunsets are multi-colored. At sunset, it is daylight on the horizon to the west. The distant clouds and dust create a diffuse white glow called a Mie scattering. This includes all wavelengths of light. As the daylight travels east, the blue colors are scattered toward to ground and this is called Rayleigh scattering. Sun rays have to travel long distances through the dense parts of the atmosphere to reach the observer. This layer of the atmosphere is more than 30 times longer at sunset compared to the midday when the sun is directly above the observer so the violets and blues are lost leaving various shades of yellows, reds, and purples.