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Posted by: AlexBlackwell Nov 25 2005, 05:15 PM

For what it's worth, a recent presentation by the Cassini RADAR Team (Rosaly Lopes et al.), entitled "The Surface of Titan as seen by the Cassini Radar Mapper," is now publicly available (http://saturn.jpl.nasa.gov/multimedia/products/pdfs/20051129_CHARM_RADAR.pdf).

Posted by: alan Nov 26 2005, 04:10 PM

Here is an new section of the T8 SAR from the pdf.

Posted by: scalbers Nov 26 2005, 04:41 PM

Interesting image that strikes me as a bit similar to the visible light Huygens images. We have lots of dark terrain interspersed with the brighter islands. Wonder how close this is to the Huygens landing site? Also shows a good example of the cat scratches flowing around the islands confirming the "fluid" flow relation.

Posted by: David Nov 26 2005, 04:53 PM

I'm astounded by the regularity of these "scratch" features (they really look more like the grooves on a record now), and how they extend for many miles (what's the scale?) parallel to each other before joining or splitting. Are there Earth (or Mars) dunes that show the same sort of extension? Or is this really a new type of landform?

Posted by: volcanopele Nov 26 2005, 05:05 PM

This is in the central portion of Belet, west of Adiri (Adiri's west edge can be seen in slide 27, right image).

In another thread, I eluded to possible topography in the cat scratches. Look at the scratches in slide 32, of the presentation above. in the top image on that slide, toward the lower left, you see scratches with bright top edges, and dark bottom edges, indicating topography (illumination from above). This would mean that they are not likely to be those grain size megadunes (seen in Antarctica), which have little topography.

Posted by: exoplanet Nov 28 2005, 03:00 AM

Back from a five day Thanksgiving vacation . . . Still think that these "dunes or drifts" are created tidally rather than by wind. Can you see the lower scratches curve around the lighter colored features in a sinuous way. I am astonished that they are exactly spaced between each other as well. They almost look <gasp> artificially made.

Posted by: David Nov 28 2005, 05:02 AM

It's true that in some cases the dunes seem to curve around the lighter [=rougher] areas, but in other places they seem to flow directly into them, as if the lighter areas were extensions or expansions of the lighter parts of the dunes.

Posted by: The Messenger Nov 28 2005, 05:18 PM

After looking at VP's images of similar structures on the Earth, IAOTO they are evidence that the winds that formed these dunes blows (or blew) consistently in one directional plane.

When I looked at this image, my first thought was of a man who killed a Native American near where I live, a century an a half ago. Terrified of a reprisal, to hide the body, he buried it, then spent the whole night plowing about a one acre field around where he dug the grave, so no one would be suspicious of the fresh mound.

Posted by: Olvegg Nov 28 2005, 07:22 PM

Another one section of RADAR swath from the presentation. This is a boundary between Belet and Adiri, around 230 degree WL. Looks like liquid lakes among the dune sea.
The grey homogeneous surface between the dark patches may be a shoal. The question is how transparent the liquid is for Cassini radar. The lack of dunes indicate that this surface is protected from winds (or has another makeup?)
There are also some river-like features on the light "shore".

Posted by: BruceMoomaw Nov 29 2005, 01:32 AM

From what I've read, Cassini's radar can punch through several dozen meters of liquid methane/ethane, so it's possible that even the radar-textured dark areas often hide shallow lakes.

Posted by: JonClarke Nov 30 2005, 12:06 AM

Terrestrial longitudinal dunes can be hundreds of km in length. Much of central Australia looks remarkably like Titan. Almost enough to feel at home!

See http://www.uow.edu.au/science/eesc/staff/gnanson/gn/aeoliandunes_centralaustralia/aeolduneca.html

http://www.diamantina-tour.com.au/outback_info/land_sys/dune_sys/dune_sys.htm

http://disc.gsfc.nasa.gov/geomorphology/GEO_8/GEO_PLATE_E-17.HTML

http://disc.gsfc.nasa.gov/geomorphology/GEO_8/GEO_PLATE_E-18.HTML

Jon

Posted by: ljk4-1 Dec 23 2005, 05:27 AM

These polar features on Mars remind me of Titan's cat scratches:

http://photojournal.jpl.nasa.gov/catalog/PIA03649

Any similarities possible?