Large distinct Martian gully
Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on June 1, 2026 by the high resolution camera on Mars Reconnaisance Orbiter (MRO).
The object of focus is obviously that large gully, draining downhill about 5,000 feet to the northeast, over a distance of about three miles.
Gullies like this are found in many places in the Martian mid-latitudes. When first discovered scientists thought they might be related to the sublimation of underground ice. More recent research suggests they are formed by the seasonal dry ice frost cycle that in the high latitudes has carbon dioxide condense to fall as snow in autumn and then sublimate away in the spring.
This latter hypothesis however generally applies to a set of gullies on the interior rim of craters, all of which experience that cycle of freeze-thaw. In the case of this large gully the former hypothesis seems more likely, as it appears to be within a thick lobe of soft material that was a mass wasting event of glacial material off the crater wall (whereby a large section detaches and moves downward). Regardless, the near surface ice impregnated in the soil appears to be sublimating away, creating the gully.
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