This high-resolution picture from the HiRISE camera on board the Mars Reconnaissance Orbiter shows twisting dark trails criss-crossing light-coloured terrain on the Martian surface. Newly formed trails like these had presented researchers with a tantalising mystery but are now known to be the work of miniature wind vortices known to occur on the Red Planet, in other words Martian dust devils. Such spinning columns of rising air heated by the warm surface are also common in dry and desert areas on planet Earth. Typically lasting only a few minutes, dust devils become visible as they pick up loose red-coloured dust leaving the darker and heavier sand beneath intact. Ironically, dust devils have been credited with unexpectedly cleaning the solar panels of the Mars rovers.
Image credit: Nasa, HiRISE, MRO, LPL (U. Arizona)