[X] My Assistant

[ngunn]

We discussed this briefly before in the "Equatorial Sand Seas" thread, posts 252 to 257, so I will understand if there are few further comments, but drawing from some recent abstracts there is now more to say so I thought I'd start a separate thread. First the neutral assessment of the issue that concluded those earlier deliberations:

QUOTE (rlorenz @ Feb 9 2008, 02:59 PM)
I dont see a strong case yet for any large-scale re-orientation (don't see a case against it either)

To summarise the issue as I see it:

The surface of Titan (like some other moons) is thought to be mechanically decoupled from the interior by a subsurface ocean. Unlike the other 'ocean' moons, Titan has highly active surface processes including fluid flow and solid mass redistribution. Deposition of material from the atmosphere is thought to favour the polar regions. We observe regional slopes, large scale lake basins, mountain chains (with preferential E-W orientation) and possible faults that could in part be maintained by migration of the entire crust with respect to the rotation axis. A testable prediction can be made: Titan's surface formations will be found to include some that originated far from their present latitude.

Now, what's new?:

http://www.cosis.net/abstracts/EGU2008/101...008-A-10189.pdf
Lorenz, R.; Stiles, B.; Kirk, R.; Zebker, H.; Callahan, P.; Radarteam, T.C.
Geophysical Results at Titan from Cassini RADAR : Topography and Spin State Overview

Note the last paragraph. Even the wind could be 'torqeing the surface around'.

Also relevant though not specific to Titan:

http://www.cosis.net/abstracts/EGU2008/013...008-A-01318.pdf
Harada, Y.
True polar wander due to surface mass loading: Interaction between rotation and deformation through pole tide

I'll leave it there for now to see if others have comments.

[ngunn]

The attached article (via Jupiter List - thanks!) is about Europa, but it's relevance to this thread is obvious:

Attached File(s)

 _jupiter_list__Wandering_Poles_Left_Scars_on_Europa.doc ( 3.63K ) Number of downloads: 206

 

[DrShank]

The attached article (via Jupiter List - thanks!) is about Europa, but it's relevance to this thread is obvious:

The sitation listed is poorly written version that leaked out before it was edited. the better draft can be found at

http://www.lpi.usra.edu/features/europa/cropCircles/

cheers
paul

[rlorenz]

Interesting stuff! The headline 'Global mapping of unusual large circular features on the ice-covered ocean world of Europa has revealed that Jupiter’s curious icy moon is even more unstable than previously thought.' seems a
bit strong - makes it sound like the whole place is about to blow..... if only that were true

The sitation listed is poorly written version that leaked out before it was edited. the better draft can be found at

http://www.lpi.usra.edu/features/europa/cropCircles/

cheers
paul

[DrShank]

Interesting stuff! The headline 'Global mapping of unusual large circular features on the ice-covered ocean world of Europa has revealed that Jupiter’s curious icy moon is even more unstable than previously thought.' seems a
bit strong - makes it sound like the whole place is about to blow..... if only that were true

"look out, its about to erupt!"

(anybody out there old enuf to recall the B-52s, who are still touring . . . ?)

of course, stability is not always a physical property, as any therapist will tell you.
so consider the author

[ugordan]

"The troughs and depressions are up to 500 meters (almost 1 mile) deep"

Luckily, this time there's no inbound orbiter that would rely on conversions such as this one.