Lunar Reconnaissance Orbiter Camera

Tender Tendrils

Wispy flows down the wall of crater Hiccarchus G.

Beautiful granular flows on the wall of Hipparchus G crater brought fresh debris from the rim down the walls, downslope is to the left. Image width is ~1 km, and North is up; LROC NAC image M183474839L [NASA/GSFC/Arizona State University].


Hipparchus G is a high reflectance crater with a diameter of 13.7 km, it formed on the rim of the much older and degraded Hipparchus crater. While these streamers may look like mudslides, they are actually dry solids that underwent fluidized flow; these features are called debris flows and are seen in many craters on the Moon.

Why do these flows look like tendrils? As the debris was flowing downhill, in some places it encountered obstacles, such as a rougher surface or large boulders. If the flow had enough energy it found its way around the obstacle, as seen by the curved path taken by these streams, if the obstacle was too large and the debris was too thin, it came to a halt.

These flows really stand out from the rest of the crater wall material because they have a higher reflectance. Higher reflectance indicates that this material has been exposed to less space weathering than the crater wall, so this flow happened long after the formation of this crater.

LROC WAC context image of crater Hipparchus G.
LROC WAC context image of crater Hipparchus G.  The solid red outline is the full NAC image, which you can explore below, and the dashed red box roughly outlines where today's Featured Image is located.

Explore these whimsical features and more below:


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