Small Trough Network Spotted On Mars Could Become Martian 'Spiders'

NASA's Mars Reconnaissance Orbiter captured images showing a growth of branching network of troughs on the planet Mars. These were carved by thawing carbon dioxide in the span of more than three Martian years and could become the so-called Martian "spiders."

Spiders on #Mars? Erosion-carved troughs may be infant versions of larger features known as Martian “spiders”. Info: https://t.co/eoirKZvepG pic.twitter.com/VwUSueL7if

— NASA (@NASA) December 20, 2016

"Spiders" are geological features that are radially patterned channels and can only be found in the south polar region of Mars. These features indicate a related phenomenon as functions of the cycle of carbon dioxide (CO2) ice condensation and sublimation. The "spiders" are thought to be the result from thawing of seasonal carbon-dioxide ice that covers big areas near Mars' south pole during winter.

In the images taken by High-Resolution Imaging Science experiment (HiRISE) camera, the spiders range in size from tens to hundreds of yards or meters. There are multiple channels typically converge at a central pit, resembling the legs and body of a spider.

Ganna Portyankina from the University of Colorado, Boulder, said that they have seen for the first time these smaller features that survive and extend from year to year, and this is how the larger spiders get started. She further explained that these are in sand-dune areas, so they do not know whether they will keep getting bigger or will disappear under moving sand.

Meanwhile, Candice Hansen of the Planetary Science Institute and the co-author of the report said that much of Mars looks like Utah if one stripped away all vegetation. On the other hand, the "spiders" are a uniquely Martian landform.

NASA reports that the image also includes dark "fans" resulting from the same thawing process. The carbon dioxide ice also known as "dry ice," which does not occur on Earth, cover the surface of Mars during winter in areas near both poles. These include the south polar regions with the spidery terrain. Meanwhile, the dark fans are visible in these regions during spring.