File:PIA15295 Bridges 2-br2.gif

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Summary

DescriptionPIA15295 Bridges 2-br2.gif	English: Advancing Dune in Nili Patera, Mars. Back-and-forth blinking of this two-image animation shows movement of a sand dune on Mars. This discovery shows that entire dunes as thick as 200 feet (61 meters) are moving as coherent units across the Martian landscape. The sand dunes move at about the same flux (volume per time) dunes in Antarctica. This was unexpected because of the thin air and the winds which are weaker than Earth winds. It may be due to "saltation" - balistic movement of sand grains which travel further in the weaker Mars gravity. The lee fronts of the dunes in this region move on average 0.5 meters per years (though the selection may be biased here as they only measured dunes with clear lee edges to measure) and the ripples move on average 0.1 meters per year. ^[1].
Date	5 September 2012
Source	http://mars.jpl.nasa.gov/mro/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1220
Author	NASA / JPL

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