Titan's topography, strange.... |
Titan's topography, strange.... |
Apr 12 2009, 12:44 PM
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#1
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Recent article in Science by Zebker et al.:
Zebker et al. Science in press, "Size and Shape of Saturn's Moon Titan". doi: 10.1126/science.1168905 (published online April 2, 2009) Link to abstract (pay-for article): http://www.sciencemag.org/cgi/content/abstract/1168905 Article on spaceref discusses this paper: http://www.spaceref.com/news/viewpr.html?pid=27912 Figure 3 from the Science article is a global elevation map relative to barycenter. Key points of article:
"Xanadu seems to be systematically lower than other parts of the equatorial belt, and not uplifted like most mountainous areas on Earth." (quote from Fig. 3 caption in article) -Mike -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Apr 16 2009, 11:38 AM
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#2
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
Possibly, but it also restores - or rather preserves - the credibility of the current 'official' hypothesis that the dune particles form in the atmosphere.
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Apr 16 2009, 07:47 PM
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#3
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Possibly, but it also restores - or rather preserves - the credibility of the current 'official' hypothesis that the dune particles form in the atmosphere. Yup. And if you invoke the sands being able to bounce easily across bright terrain (your item #2), it supports the atmospheric deposition hypothesis. Any atmospheric fallout that hits bright terrain could be blown off. But I'm not sure how this would explain the relatively dune-free W margins of the dune seas. A Xanadu depression makes some of my earlier speculations go bye-bye: it is hard to invoke an earlier sand-sea filling nitrogen ocean without filling in Xanadu as well. -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Apr 16 2009, 09:52 PM
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#4
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
sands being able to bounce easily across bright terrain (your item #2) That wasn't meant to be a serious suggestion. I take it as read that corrugated terrain would be harder for sand to cross than a flat plain. Neither was option 1. (What are we to imagine - critters lining the beaches and eating the stuff?) Option 3 was the serious one, though on reflection you could have a blend of 3 and 4, with a bright albedo obstacle like Xanadu temporarily arresting an inexorable eastward migration of the sands, only to be overwhelmed in a comparatively swift event when eventually the piling up of sand to the west of it becomes just too great and everything moves to it's next quasi-stable position. I have also been thinking about disposal of the atmospheric fallout that lands on Xanadu. In corrugated terrain perhaps not all of it blows clean away. Some could be trapped in pockets or fissures too small for current imaging to resolve and too small also to affect the overall albedo of the region. |
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