Hey Space Placers!
Check this out http://www.jpl.nasa.gov/news/news.cfm?release=2012-130.
WHat we are seeing are large scale changes in sand dunes on Mars! WHat makes this blinking sequence amazing is that it was thought that Mars' atmosphere was too thin to cause such large sacale changes - about the size of sand dunes here on earth.
The pics were taken in 2007 and 2010 by the Mars Reconnaissance Orbiter (MRO). We will have quite a one-two punch for exploring Mars between MRO and when Curiosity reaches the Red Planet in August of this year.
Sky Guy in VA