December 19, 2018

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Originally published October 10, 2009 LPOD-Oct10-09.jpg
Apollo 12-51-751 image from Apollo Image Atlas, LPI

With no result yet from LCROSS - other than that no one saw a plume - it's time to find a great image from an earlier mission. This ancient view from Apollo 12 is dramatic and illustrates a number of types of landforms. The long serrated shadows emphasize small irregularities in Encke's rim. The biggest is due to the crater that cuts the rim, and the others are more minor undulations. Even with this oblique view the polygonal nature of the rim is still noticeable. Encke is a floor-fractured crater, with an uplifted ring of mountains and hills. Below the crater in this image is a large swell that seems to be anchored around a bright mountain. Swells are probably gentle uplifting of the mare surface by magma that rises under but doesn't erupt onto the surface. I wonder if the uplifted floor of Encke and the uplifted and inflated swell are related? A very sharp-edge and relatively straight rille on the right side of Encke connects to a smaller and more curved rille that cuts the swell. Finally, the linear thing at bottom center is not a defect, but a beautiful string of overlapping secondary craters.

Chuck Wood

Technical Details

Related Links
Rükl plate 30

Yesterday's LPOD: A Final Pre-Impact View & an Update!

Tomorrow's LPOD: Give Truth a Chance


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