A New Gully Channel in Terra Sirenum, Mars! This pair of before (left) and after (right) images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASAs Mars Reconnaissance Orbiter documents the formation of a substantial new channel on a Martian slope between Nov. 5, 2010, and May 25, 2013. Gully or ravine landforms are commonly found in the mid-latitudes on Mars, particularly in the southern highlands. These features typically have an alcove at the upper end, feeding into a channel and an apron of debris that has been carried from above. Researchers using HiRISE have discovered many examples of gully activity likely driven by seasonal carbon-dioxide frost (dry ice). The changes visible by comparing the 2010 and 2013 observations at this site formed when material flowing down from the alcove broke out of an older route, eroded a new channel and formed a deposit on the apron. Although this pair of observations does not pin down the season of the event, locations HiRISE has imaged more often demonstrate that this sort of event generally occurs in winter, when liquid water is very unlikely. Despite their resemblance to water-formed ravines on Earth, carbon dioxide may play a key role in the formation of many Martian gullies. Image credit: NASA/JPL-Caltech/Univ. of Arizona #mars #hirise #mro #planets #gully #water #science
Posted on: Wed, 19 Mar 2014 18:48:55 +0000
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