A double rainbow is considered a symbol of transformation and is a sign of good fortune in eastern cultures. The first arc represents the material world, and the second arc signifies the spiritual realm. A double rainbow forms due to an optical illusion when sunlight enters a raindrop and creates two internal reflections before the rays exit the droplet.
In a single rainbow, sunlight spreads into a spectrum of colors from red to violet. But in a double rainbow, the colors are inverted, with red appearing on the inside and violet on the outside. According to Chinese mythology, red represents the feet, and violet symbolizes the head. Therefore, a single rainbow signifies a human descending from heaven to earth. A double rainbow, due to its reversal of colors, represents the movement from earth to heaven and is considered to be a sign of future success.
Rainbows are used symbolically in mythology, religion and the arts. It is said that the Irish leprechaun hid his pot of gold at the end of the rainbow, and in Genesis 9, a rainbow is part of Noah's story in which God promises never to create another destructive global flood. Rainbow flags have been used to symbolize hope and social change and are a symbol of gay pride.