Pictures taken by the camera on Nasa’s Mars Reconnaissance Orbiter have captured sand dunes forming oddly recognisable shapes.
In an extraordinary photograph by the High Resolution Imaging Science Experiment (HiRISE), the dunes appear to form a line of Morse code – the language system which humans often use to communicate from a great distance.
The dunes can typically tell us something about local wind direction by their shape and orientation, but in these peculiar images something is amiss.
Scientists predict that a circular depression on the planet’s surface, probably an old impact crater, has limited the amount of sand available for dune formation. The dots and dashes come from bi-directional winds moulding the sand into unusual shapes
Planetary scientist Veronica Bray has translated the code for Gizmodo, spelling out gibberish: