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Posted by: AlexBlackwell Feb 8 2007, 07:25 PM

http://www.space.com/scienceastronomy/070208_enceladus_albedo.html
By Ker Than
Staff Writer, Space.com
posted: 08 February 2007
02:03 pm ET

This refers to the following http://www.sciencemag.org/about/authors/prep/gen_info.dtl#categories in the http://www.sciencemag.org/content/vol315/issue5813/index.dtl:

Enceladus: Cosmic Graffiti Artist Caught in the Act
Anne Verbiscer, Richard French, Mark Showalter, and Paul Helfenstein
Science 315, 815 (2007)
http://www.sciencemag.org/cgi/content/abstract/315/5813/815
http://www.sciencemag.org/cgi/content/full/315/5813/815/DC1

Note: Unless one has pre-embargo access to Science, the abstract and SOM links above are not accessible yet.

Posted by: nprev Feb 8 2007, 08:48 PM

Heh, heh..."Cosmic Graffiti" would be an awesome name for a band, wouldn't it?

Seriously, though, I wondered about this before...seems like the cumulative accumulation of Enceladian "exhaust" on the other moons might become quite significant. In fact, given impacts, Titanian outgassing, etc., how much internecine materiel mixing must have occurred across Saturn's moons over time? Doubt that this is geologically significant, but definitely may be small-scale compositionally important.

Posted by: AlexBlackwell Feb 8 2007, 09:35 PM

QUOTE (AlexBlackwell @ Feb 8 2007, 09:25 AM)

Posted by: AlexBlackwell Feb 9 2007, 12:30 AM

http://www.virginia.edu/uvatoday/newsRelease.php?id=1461
University of Virginia News
February 8, 2007

Posted by: alan Feb 11 2007, 07:12 AM

So does this mean that Enceladus is responsible for the dichotomy between the hemispheres of Tethys, Dione and Rhea?

Posted by: ugordan Feb 11 2007, 03:37 PM

I'm starting to wonder as well. So far we had a theory where the trailing sides got darker due to magnetospheric plasma interactions or some other weird phenomena. This new insight might imply the trailing hemispheres are the only ones where old, dusty regolith appears exposed. All the other parts of the surface get a thin coating of fresh icy particles. The dark stuff could therefore be the "actual" surface of the moons. It might also explain why Tethys has smaller dark splat than Dione and Rhea as it's closer to Enceladus and material can coat a greater portion of the moon. It also fits the fact that after Enceladus, Tethys has the highest albedo in the system.

Posted by: nprev Feb 11 2007, 04:59 PM

By way of refresher & analogy, does anyone recall if Europa exhibits a similar hemispheric albedo dichotomy as a result of material deposited from Io? I know the situations & materials involved are very different, but perhaps there's something there to learn about Enceladus' effects on the other moons.

Posted by: ugordan Feb 11 2007, 05:24 PM

I always thought that was a given, nprev. Most likely Europa has its share of sulfur, but the surface deposits I always figured were sprayed on by Io. Sulfur inside Europa would be dissolved and probably not reddish, due to the presence of water.

Posted by: nprev Feb 11 2007, 05:32 PM

Argh, right; forgot for a moment that Europa's surface is dynamic, unlike Saturn's icy moons save Enceladus...too much mixing going on there for a permanent "stain", apparently.