image credit: NASA JPL; image source; larger image
Why isn't the Martian sky blue like the Earth's?
The Martian sky is butterscotch, not blue like our own--the butterscotch color is produced by light scattering from dust particles blown into the atmosphere by the strong Martian winds. For more on the Martian sky, see this NASA Q & A.
(This feature was updated on July 28, 2011.)
Atmospheric Optics: Rays and Shadows
See pictures and detailed explanations of atmospheric phenomena at Atmospheric Optics: Rays and Shadows. Many of the optical effects are caused by scattering sunlight.