Hope for Titan Ocean Evaporates into Ice Desert

first_imgSaturn’s moon Titan is a desert of sand made of ice grains mixed with hydrocarbons.  These grains form large fields of wind-driven dunes found over much of the planet-sized moon.  “Titan’s Seas Are Sand,” reported a press release from U of Arizona based on a paper in the May 5 issue of Science (see Perspective by Nicholas Lancaster1 and paper by Lorenz et al.2).    “Until a couple of years ago, scientists thought the dark equatorial regions of Titan might be liquid oceans,” the press release states.  “New radar evidence shows they are seas – but seas of sand dunes like those in the Arabian or Namibian Deserts,” as shown in the “cat scratches” soon detected on radar scan images.  The grains are probably eroded from the water-ice mountains as infrequent downpours of liquid methane roar down the slot canyons onto the plains.    Another surprise is that a moon this far from the sun could have enough solar energy to produce dune-sculpting winds.  The answer is that Saturn sets up strong enough tides in Titan’s atmosphere to do the work.  Though only on the order of one mile an hour, the winds in the thick atmosphere are able to transport the coffee-ground-size particles into familiar looking linear dunes.    Today also some exciting visuals came from the Cassini and Huygens teams.  New dramatic animations, based on actual photos, of the descent of the Huygens probe onto the surface (01/15/2005, 01/21/2005) give the viewer a probe-eye view of what it must have been like to ride the craft all the way to the dry lakebed.  Go to: JPL Cassini or U of Arizona Lunar and Planetary Lab.  Our favorite: JPL “Titan Descent Data Movie with Bells and Whistles” (you might want to provide your own blockbuster movie soundtrack to replace the electronic sounds representing the image sequence and signal strength).  For a higher-res version of this information-filled wild ride, see the ESA Huygens site.  For sheer drama and beauty of the descent, with Beethoven music to match, watch movie #3 at the DISR site.  Some versions of the movies add captions and narration and are available in WMV and Quicktime formats, and there are high-res stills also.  The bloggers at Unmanned Spaceflight are impressed.1Nicholas Lancaster, “Linear Dunes on Titan,” Science, 5 May 2006: Vol. 312. no. 5774, pp. 702 – 703, DOI: 10.1126/science.1126292.2Lorenz et al., “The Sand Seas of Titan: Cassini RADAR Observations of Longitudinal Dunes,” Science, 5 May 2006: Vol. 312. no. 5774, pp. 724 – 727, DOI: 10.1126/science.1123257.What an incredible finish to one of the biggest adventures in interplanetary exploration.  The world’s strangest moon, one that long-age scientists were convinced had to be covered with a liquid ocean, is dry.  Despite Titan’s bizarre color, orange you glad Huygens was a smashing success?(Visited 9 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img

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