An explanation for the spiral shaped gorges in the Martian polar ice caps has been presented.
The tilted planet causes ice on one side of a crack to heat and vaporize, deepening and widening the crack. Then the water vapor hits the shady, colder side of the growing canyon and refreezes.
Eventually, chasms more than a half-mile (1 kilometer) deep developed, and they cover hundreds of miles of the polar regions. But only on Mars, it seems.
Characteristics unique to the red planet -- its thin atmosphere, chilly climate and specific planetary tilt -- make it the only known place in the solar system where the ice spirals occur. They don't exist at Earth's poles, in part because temperatures are regulated somewhat by global ocean and air currents.
"On Mars, the surface temperature is strongly determined by the angle with respect to the Sun, because very little heat transport occurs in the thin atmosphere," Pelletier told SPACE.com .
"The troughs form by an instability in which areas on the ice cap that are slightly steeper towards the Sun begin to melt while nearby areas remain frozen," he said. "The steep areas get steeper, face even more directly towards the Sun, and further melt in a positive feedback."