Scientists study the polygonal surface of Mars because these features help them understand the recent and past distribution of ice in the shallow interior, as well as provide clues about climatic conditions.
The HiRISE (High Resolution Imaging Science Experiment) camera on the Mars Reconnaissance Orbiter has seen a lot of polygons since 2006 when it entered Mars orbit.
The science team from HiRISE says that both water and carbon dioxide in the solid form of dry ice play a major role in sculpting the surface of Mars at high latitudes.
Water ice frozen in the soil divides the land into polygons. Then, dry ice rising from just below the surface as the ground warms in spring causes more erosion, creating channels around the polygon boundaries.
The polygons form over many years as the ice near the surface shrinks and expands seasonally.
But this polygon-covered region shows more activity in the spring, evidenced by the blue fan-shaped features. Scientists say the transparent layer of dry ice that covers the surface develops openings that allow gas to escape.
“The gas carries fine particles of material from the surface, further eroding the channels,” the team wrote on the HiRISE website.
The particles fall to the surface in a dark, fan-shaped sediment. Sometimes the dark particles sink into the dry ice, leaving shiny marks where the fans were originally deposited. Often the vent closes, then opens again, so we see two or more fans coming from the same place but pointing in different directions as the wind changes.”
Scientists are studying the polygonal surface on Mars because these features help them understand the recent and past distribution of ice in the shallow interior, as well as provide clues about climatic conditions.
And Mars isn’t the only place with polygons. It can be found in both the Arctic and Antarctic regions of Earth, and a 2015 flyby of the New Horizons spacecraft revealed the presence of polygons on Pluto as well.