Description: The beautiful play of light in the everyday sky is due to bulk scattering of sunlight by water and dust particles in clouds, and air molecules in the atmosphere.

Original author: Jessie Eastland.

Modification: This image has been reframed and rescaled. Modification by Noumenon Multiphysics.

Original image: http://commons.wikimedia.org/wiki/File:Desert_Twilight.jpg.

License: This image is licensed under Creative Commons Attribution-Share Alike 3.0.