Dark Sand Cascades on Mars Credit: HiRISE, MRO, LPL (U. Arizona), NASA
They might look like trees on Mars, but they're not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The above image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks -- streaks that might appear at first to be trees standing in front of the lighter regions, but cast no shadows. Objects about 25 centimeters across are resolved on this image spanning about one kilometer. Close ups of some parts of this image show billowing plumes indicating that the sand slides were occurring even when the image was being taken.
Lines in the Sand. Credit: NASA/JPL/University of Arizona #
Large Central Uplift of an Impact Crater. Credit: NASA/JPL/University of Arizona #
Dunes. Credit: NASA/JPL/UA/C&EP;
Tyrrhena Terra Crater with Central Uplift and Hydrated Minerals. Credit: NASA/JPL/University of Arizona #
CRISM observations of this region of the Noctis Labyrinthus formation have shown indications of iron-bearing sulfates and phyllosilicate (clay) minerals. Credit: NASA/JPL/University of Arizona #
Eroded Layered Deposits Near Ismenius Lacus Credit: NASA/JPL/University of Arizona #
Intersecting swirling trails left by the earlier passage of dust devils across sand dunes, as they lifted lighter reddish-pink dust and exposed the darker material below. Also visible are darker slope streaks along dune edges, formed by a process which is still under investigation. (NASA/JPL/University of Arizona)
Gullied Crater Wall. Credit: NASA/JPL/University of Arizona #
Context for MOC Image E13-01405 View of Gullied Crater. Credit: NASA/JPL/University of Arizona #br>
USGS Dune Database Entry Number 0419-449. Credit: NASA/JPL/University of Arizona #
Dune Monitoring. Credit: NASA/JPL/University of Arizona #br>
Exposure of South Polar Layered Deposits. Credit: NASA/JPL/University of Arizona #
Victoria Crater at Meridiani Planum, Mars. Credit: NASA/JPL/University of Arizona #
Mars Fresh Impact Crater, 17 January 2009. Credit: NASA/JPL/University of Arizona #
Cratered Cones Near Hephaestus Fossae, Mars. 18 November 2006. Credit: NASA/JPL/University of Arizona #
Large Cluster of Small Craters Near Maadim Vallis, Mars. 26 January 2009. Credit: NASA/JPL/University of Arizona #
Winslow Crater, Mars. 16 March 2009. Credit: NASA/JPL/University of Arizona #
Zumba Crater: Fresh 3-Km Crater, Mars. 04 May 2007. Credit: NASA/JPL/University of Arizona #
Crater Ejecta in Utopia Region, Mars. 21 September 2008. Credit: NASA/JPL/University of Arizona #
Two Craters South of Sirenum Fossae, Mars. 05 May 2009. Credit: NASA/JPL/University of Arizona #
Nilosyrtis Dichotomy Boundary Scarp or Crater, Mars. 01 April 2009. Credit: NASA/JPL/University of Arizona #
Dome and Crater, Mars. 30 January 2009. Credit: NASA/JPL/University of Arizona #
Very Well-Preserved 9-Kilometer Crater, Mars. 02 February 2009. Credit: NASA/JPL/University of Arizona #
Mars Global Surveyor data creates a view of weather on Mars, with blue-white ice clouds apparent. Credit: NASA/JPL/Malin Space Science Systems #
East Wall of Ritchey Crater, 04 February 2009. Credit: NASA/JPL/University of Arizona #