Enormous polygon patterns in rock lie dozens of meters below Mars’ surface, ground-penetrating radar data suggest. Similar patterns develop on the surface in Earth’s polar regions when icy sediments ...

NASA's Curiosity rover snapped this view of polygon-patterned bedrock on May 4. Mars is home to a lot of odd-shaped rocks that can look pretty random. Patterns, however, can catch scientists’ eyes.

Perfect circles of stones cover the ground in parts of Alaska and the Norwegian islands of Spitsbergen. Elsewhere in the far north, stones form other striking patterns on the ground: polygons, stripes ...