Strange Mars Tree Illusion

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Naturally erupting dust clouds on Mars are creating structures that look surprisingly like trees near the planet's north pole. But don't be fooled ? it's just an optical illusion, NASA scientists say.

The Martian "trees" are actually dark basaltic sand pushed to the surface of sand dunes by sun-heated solid carbon dioxide ice, or dry ice, sublimating directly into vapor, explained Candy Hansen, a member of NASA's Mars Reconnaissance Orbiter (MRO) team at the University of Arizona.

The sand dunes form a nearly complete ring around Mars' north pole and are covered by a thin layer of reddish Martian dust and patches of dry ice. To date, there is no firm evidence of any type of Martian biology, past or present, plant or otherwise.

This new image of Mars taken by NASA's Mars Reconnaissance Orbiter shows an optical illusion. What appears to be trees rising from the Martian surface are actually dark streaks of collapsed material running down sand dunes due to carbon dioxide frost evaporation. The image was released in Jan. 2010.
CREDIT: NASA/JPL/University of Arizona.