Monday, November 17, 2008

A private tour of Enceladus

Planetary geologist Bill McKinnon from Washington University was sitting in front of me last night on a flight from Tucson to Denver. Bill and I know each other from the early '80s when we both were working on the Voyager mission to the moons of Jupiter. Bill's continued focusing on the structure and tectonics of icy satellites in the solar system.

He fired up his laptop and we spent much of the flight looking at images collected just a few weeks ago by the Cassini spacecraft from an altitude of only 15 miles. Resolution was as good as 10 m or so.

Enceladus is getting lots of attention because of jets of water blasting out of areas within certain sulci (levee-bound grooves) at the south pole. Bill pulled up infrared images showing hot streaks that looked like the magnetic stripes in the Earth's oceans. The similarity is not just coincidence. Bill's opinion is that the sulci may be spreading centers resulting from internal convection generated by tidal forces.

The picture above shows what we both agreed look like fold and thrust belts. Bill pointed out the shapes and patterns suggestive of transform faults - look at the bluish-green shading in the center of the photo above.

Unfortunately, we had to shut down the laptop as we came in for landing, but what a trip! One of the reasons I like geology is the exploration and sense of discovery. During my career I've seen the exploration of a good part of the solar system and amazing discoveries that just keep on coming.

[photo credit, NASA/JPL/Space Science Institute]

update 11-21-08: Scientific American has a feature story on Enceladus geology-tectonics in the November issue with a good set of photos.

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