Imaggeo On Monday: Both Ends of the Rainbow

Imaggeo On Monday: Both Ends of the Rainbow

A double rainbow was captured when heading through the glaciated Benasque valley, located in the heart of the Pyrenees. The photo was taken just before the sunset, after heavy rainfall.

A rainbow is caused by reflection and dispersion of light in water droplets. Second rainbow arc results from one reflection more than in the first one, thus the rainbow colours are “reverted”. The geometry causes the region between arcs to be darker and the area below the primary arc lighter. The inter-arc area is sometimes called “Alexander’s dark band”, named after Alexander of Aphrodisias.


Description by Adam Ciesielski, after the description on


Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at

This guest post was contributed by a scientist, student or a professional in the Earth, planetary or space sciences. The EGU blogs welcome guest contributions, so if you've got a great idea for a post or fancy trying your hand at science communication, please contact the blog editor or the EGU Communications Officer to pitch your idea.

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