Light in a rainbow is polarized along the length of the arc. The top of the arc is horizontally polarized. The secret to a perfect cleave is to apply enough tension such that the speed of sound in the glass is faster than the speed of crack propogation. Because of CD players, there's a laser in almost every house. It is dark inside our bodies until a fiber optic illuminator is inserted.
Light can travel for billions of years at the same speed without losing energy.
Color is not an inherent property of light. That photon giving you a tan left the sun 8.3 minutes ago. Isaac Newton believed that light traveled faster in glass than in air. Christian Huygens straightened him out. Most people need 50 - 150 light quanta at 550 nm to see the light.