"Over The Rainbow" was written specially for the 1939 film "The Wizard of Oz" with music by Harold Arlen and lyrics by Yip Harburg. It has been recorded many times - most notably perhaps by Eva Cassidy but this post will finish with Israel Kamakawiwoʻole's version. Hawaiians knew him as Iz and its his ashes that are lovingly cast into the Pacific Ocean at the end of the video.
Scientists may be able to explain why rainbows happen but the bottom line is that they are magical and human beings have forever glimpsed at their passing, simple beauty with wonder. They come and they go. Briefly arching over us like a protective arm. And lord knows we need one of them right now.