«Sunlight controls the length of our day. It also determines what objects we can see, the colors they display and how far away we can see them. In addition, sunlight is responsible for a variety of optical effects.» (Sunshine, Visibility and Optical Effectes - www.unc.edu)
may I also say, in addition, sunshine is responsible for inner rainbows, as an optical effect, of course!
figure: refraction of light through a tear... ops... I mean water, through a water drop, creating a rainbow
is this post tacky or what?
* from The Tempations song