SOMETHING has moved boulders on Mars, causing curious clumps near the northern ice cap. Now it seems the culprit is not Martians, but winter.
You would expect boulders to be randomly sprinkled across the Martian surface. But images from NASA’s Mars Reconnaissance Orbiter showed them clustered at the edges of polygon-shaped cracks in the soil. A team led by Travis Orloff at the University of California, Santa Cruz, suggests what may have moved them.
The polygons are thought to contract and expand each winter and summer. The boulders are encased in a layer of carbon dioxide frost during winter. As…
