Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: 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.
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