Saturday, February 5, 2011

Long-term forecast for northern Mars: wind and shifting sands

Image Credit: NASA/JPL-Caltech/University of Arizona
Space scientists – who until now believed the sand dunes of northern Mars were frozen in time – now realize the martian sands are changing with both sudden and gradual motions. NASA’s Mars Reconnaissance Orbiter has been peering down at this part of Mars – an area the size of Texas – over a period covering two Martian years, or about four Earth years. The orbiter’s camera observed these dune fields in a band around the planet at the edge of Mars’ north polar cap. Three images of the same location taken at different times on Mars show seasonal activity causing sand avalanches and ripple changes on a Martian dune. Time sequence of the images progresses from top to bottom. Each image covers an area 285 meters (312 yards) by 140 meters (153 yards). The crest of a dune curves across the upper and left portions of the image. Article here

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