The rainbow, is an interesting symbol. In old Germany, the Gauls referred to the rainbow as "the bridge to heaven". Certainly some people viewed the bow itself as somewhat of a bridge. And yet, the colors of the rainbow are more of a bridge between the worlds than the bow itself. The legends of the pot of gold at the end of the rainbow, actually refer to the ancient magick of the alchemy of color.
People can change the color of their aura ( See Al Manning's "A New Light of Help for You") and even to a small extent the etheric color of their world. Most are not aware of this control and so the slide towards red continues. There is less chance when one lives in the red energy (and even worse infrared) to realize ones connection to God/Goddess then in any of the other colors. Especially the muddy red color that most people live in.
Another source of information and help can be found in Infinity Ultima Thule Forms of Yellow Remember.
An Example of a Muddy Aura 
He only had a cold!
Next: Environmental Infulences