A Dust Storm on Mars
Occasional globe-encircling storms distribute dust all over Mars. A soil sample analyzed in October 2012 by the Chemistry and Mineralogy (CheMin) instrument on NASA's Curiosity rover is likely a blend of globally distributed dust and larger sand-sized particles derived from local sources.
Full image and caption: http://hubblesite.org/newscenter/archive/releases/2001/31/image/a/
Image credit: NASA/Cornell/SSI/STScI/AURA