Tuesday, July 26, 2005

Press Release: Close Cassini Flyby Hints at Unusual Tectonic Activity on Enceladus

CICLOPS has now posted some initial results from images taken during last week's flyby of Saturn's strange icy moon Enceladus. Whereas the previous two encounters highlighted features seen in the equatorial regions of Enceladus, this encounter focused on terrain near the south pole of Enceladus. Previous images of the region taken by Cassini showed some interesting features, but it wasn't until now that these features were seen at geologically useful resolutions.

From the press release:
New detailed images taken by NASA's Cassini spacecraft of the south polar region of Saturn's moon Enceladus reveal distinctive geological features, and the most youthful terrains of any seen on Enceladus. These findings point to a very complex evolutionary history for Saturn's brightest, whitest world.

Cassini's flyby on July 14 brought it within 175 kilometers (109 miles) of the surface of the icy moon. The close encounter revealed a landscape near the south pole littered with house-sized ice boulders, carved by tectonic patterns unique to Enceladus, and almost entirely free of impact craters. These features set the southerly region apart from the rest of the moon.
Several lines of evidence are discussed that point toward a youthful age for Enceladus. While absolute ages have yet to be determined due to a lack of understanding of the cratering function for the Saturnian system, circumstantial evidence such as the lack of craters larger than 1 km and the paucity of craters smaller than that and the rough appearance at very high resolution, including building-sized boulders, the lack of fine grained material. Enceladus should be an interesting but challenging world to geologically map, but Enceladus has thrown us a bone. Many of the geologic regions are topographically and morphologically distinct, such as the south polar region with its wavy boundary with several y-shaped features filled with folded terrain. Dr. Paul Helfenstein suggests that suggest that such a boundary, located at around 60 degrees South latitude, could be the result of changes in the global stress pattern due to despinning. Such geologic features he contends "may tell us a very interesting story about the way Enceladus has evolved over time and what might have provided the energy to power the geologic activity that has wracked this moon".

UPDATE 12:30 pm: Usually I post links to news articles of news organizations covering releases like this. Unfortunately, I have found that only spaceref.com even has a copy of the press release, let alone did a story of their own. Everything today is about the Shuttle launch.


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