If you don’t love rainbows then there is something seriously wrong with you. The incredible light phenomenon is like nature painting the sky. No one has ever gazed upon a rainbow and not turned to the other people in the room or the car and said: “look, rainbow”. It simply has to be done as you have to share the wonderful piece of nature with everyone. While I have never been lucky enough to see a double rainbow in real life, I can barely imagine my reaction. Although I would try and contain my excitement a little bit more than the double rainbow guy from the viral video of 2010.
The science behind a rainbow and a double rainbow is well known, but it doesn’t make it any less fantastic. Essentially a rainbow is the result of light being refracted by raindrops. As raindrops pass through the sky, light enters and bounces off them. This divides the light into the colors of the rainbow and we get to see the wonder in the sky.
When it is a double rainbow the light is essentially bouncing more times in the raindrop. You can imagine it as if the second rainbow is the mirror image of the first. The second rainbow will always be much fainter and with the colors reversed. It is actually possible for more rainbows to occur yet the light becomes so faint that it can’t be seen by the naked eye. However, it is likely that you have seen a triple rainbow and not even known.
One final note of interest on the double rainbow is Alexander’s band. No this is not a Christian rock group, it is more science and may be useful for a quiz in the future. Alexander’s band is the strip of darkness between two rainbows. Alexander of Aphrodisias was the first to notice the dark strip between two rainbows and managed to get his name on it, even though he didn’t really understand it.