Was (wer) ist Rainbow - definition
![A circumhorizontal arc (bottom), below a [[circumscribed halo]]](https://commons.wikimedia.org/wiki/Special:FilePath/A Double Rainbow Halo on June 1, 2014, at 1-57 PM.jpg?width=200 "A circumhorizontal arc (bottom), below a [[circumscribed halo]]")
![Depiction of the rainbow in the [[Book of Genesis]]](https://commons.wikimedia.org/wiki/Special:FilePath/Joseph Anton Koch 006.jpg?width=200 "Depiction of the rainbow in the [[Book of Genesis]]")
![Yosemite Fall]]](https://commons.wikimedia.org/wiki/Special:FilePath/Moonbow at lower Yosemite fall.jpg?width=200 "Yosemite Fall]]")
![supernumerary bows]] inside the primary bow.](https://commons.wikimedia.org/wiki/Special:FilePath/Regenbogen über dem Lipno-Stausee.JPG?width=200 "supernumerary bows]] inside the primary bow.")
![Eruption of [[Castle Geyser]], [[Yellowstone National Park]], with double rainbow seen in the mist](https://commons.wikimedia.org/wiki/Special:FilePath/Steam Phase eruption of Castle geyser with double rainbow.jpg?width=200 "Eruption of [[Castle Geyser]], [[Yellowstone National Park]], with double rainbow seen in the mist")
![High dynamic range]] photograph of a rainbow with additional supernumerary bands inside the primary bow](https://commons.wikimedia.org/wiki/Special:FilePath/Supernumerary-rainbows-jb.jpg?width=200 "High dynamic range]] photograph of a rainbow with additional supernumerary bands inside the primary bow")
![Image of the end of a rainbow at [[Jasper National Park]]](https://commons.wikimedia.org/wiki/Special:FilePath/WhereRainbowRises.jpg?width=200 "Image of the end of a rainbow at [[Jasper National Park]]")
Wikipedia
A rainbow is an optical phenomenon that can occur under certain meteorological conditions. It is caused by reflection, refraction and dispersion of light in water droplets resulting in an effect similar to a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the Sun.
Rainbows can be full circles. However, the observer normally sees only an arc formed by illuminated droplets above the ground, and centered on a line from the Sun to the observer's eye.
In a primary rainbow, the arc shows red on the outer part and violet on the inner side. This rainbow is caused by light being refracted when entering a droplet of water, then reflected inside on the back of the droplet and refracted again when leaving it.
In a double rainbow, a second arc is seen outside the primary arc, and has the order of its colours reversed, with red on the inner side of the arc. This is caused by the light being reflected twice on the inside of the droplet before leaving it.
