Titan: brown and blue

One of the things that's been clogging my email inbox (which is down to 250 items, so I've been making some progress) are a pile of articles about Titan from a special issue of the journal Planetary and Space Science that I requested from various scientists about three months ago. ESA issued a press release about these when they were published in June, and still I didn't get to them. With our website down yesterday, I was able to sit down and start doing some reading. Many of these represent the end product (or at least an end product) of work that I've written about before, when the researchers presented progress reports on their work at various conferences.

Larry Soderblom's name was first on two articles. One was on the topography and geomorphology at the Huygens landing site, which they are deriving by doing stereo analysis of images taken by Huygens' DISR imaging system. Reading this article, I was reminded of the extremes of luck that smiled upon -- and plagued -- Huygens. In the former category, Huygens was extremely fortunate in that as it drifted down to its landing site, it just happened to emerge from the haze right over a major boundary between Titan's bright and dark terrain, affording incredibly lucky views of drainage channels dissecting the bright highlands, emptying into a dry, dark basin. In the latter category, the loss of one of Huygens' two data channels, and the nearly vertical descent (rather than the horizontal drift predicted by Huygens' designers), resulted in there being very few pairs of images useful for stereo analysis. The paper presented some digital terrain models that were improved slightly from ones presented at past conferences, and also made the interesting point that the flat region in which Huygens landed has experienced runoff from those drainage channels but has also experienced what appears to be "major west-to-east floods across the plains with flow parallel to the highland-lowland boundary," an event that occurred in a wetter period in Titan's recent past.