January 2, 2016
NASA’s Mars Reconnaissance Orbiter (MRO) took a picture of an impact crater filled with frozen sediments. With time, as sediments froze and thawed over and over again, they have created polygonal cracks that make up a striking pattern. Near the north pole on Mars, formation of these polygons is common, due to low temperatures and freezing. However, few are as notable as the one pictured here.
Close to the edge of the crater, cracks form a pattern resembling spokes and rings. As you look closer to the centre of the crater, polygons have more rectangular pattern. Almost at the centre, many polygons have polygons inside them, creating a natural fractal.
Frost in the cracks highlights the polygons that formed as sediments on Martian surface went through cycles of freezing and thawing. This process probably lasted for millions of years and still hasn’t stopped.
The crater itself is located near the north pole of the planet, at 69 degrees latitude. It is about 5 kilometres wide. It was created by an asteroid impact early in Mars’ history.
The image above was taken by MRO’s High-Resolution Imaging Science Experiment (HiRISE) camera from the altitude of 314 km. HiRISE camera is capable of resolving details on Martian surface to about a meter in size, either in visible or near-infrared light.
The MRO satellite was launched in August 2005 and has been taking high-resolution images of Mars since March 2006. Images from its HiRISE camera are managed by University of Arizona’s Lunar and Planetary Laboratory.