Explanation: An important threshold on Mars has now been crossed. Landing in mid-2012, the Curiosity rover is searching for clues of whether life could ever have existed on the red planet . Recent findings of Curiosity include evidence for an ancient (but now dried) freshwater lake , and the non-detection of the biomarker methane in the Martian atmosphere. To continue its investigation, the car-sized rover is on an expedition to roll up Mt. Sharp , the central peak of the large crater in which it landed . Life might have shown preference for water that once ran down the Martian mountain. Two weeks ago, to avoid more dangerous and rocky terrain , Curiosity was directed to roll across a one-meter high sand dune that blocked a useful entrance to Mt. Sharp. Just after the short trip over Dingo Gap was successful, the robotic rover took the above image showing the now-traversed sand mound covered with its wheel tracks .

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