[X] My Assistant

[belleraphon1]

All.....

http://saturn.jpl.nasa.gov/news/press-rele....cfm?newsID=816

"Roger Clark of the U.S. Geological Survey in Denver goes further, saying, "We see the same spectral signature on all the moons that have coatings of dark material." Clark is lead author of one of the new papers, which focuses on Saturn's moon Dione. His team found the dark material there to be extremely fine-grained, making up only a very thin layer on the moon's trailing side. Its distribution and composition, as measured by the Cassini visual and infrared mapping spectrometer, indicate that the dark material is not native to Dione. And scientists see many of the same signatures there that appear on the moons Phoebe, Iapetus, Hyperion and Epimetheus, and also in Saturn's F-ring.

As for where this material comes from and what the dark material is, Clark said, "It's a mystery, which makes it intriguing. We're still trying to find the exact match." The visual and infrared spectrometer detected unique absorption bands in the dark material within the Saturn system, which scientists have not seen anywhere else in the solar system. "The data keep getting better and better," he said. "We're ruling things out and figuring out pieces." So far, the team has identified bound water and, possibly, ammonia in the dark material.

Clark's team reports tentative evidence to support the hypothesis presented earlier this year that Dione is still geologically active. In one series of observations, the infrared spectrometer detected a cloud of methane and water ice encircling Dione in its orbit within the outer portions of Saturn's E-ring."

And

"A paper led by Frank Postberg of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, says there are traces of organic compounds or silicate materials within the water ice-dominated E-ring, close to Enceladus. "

Lost my online access to Icarus.... darn!!!!!

Craig

[tasp]

I note the 'coloration shift' from east to west on Iapetus, to me, implies in situ 'processing' of a 'feedstock' material of exogenous origin.

That this 'feedstock' material can 'leak' (in relative to Iapetus, minute quantities) out of the primary transport mechanism to Iapetus and appear in traces on other moons doesn't, upon reflection, to seem too surprising.

Not sure the extra deep craters of Hyperion are 'burned into it's carcass', but rather existing craters have been sites were the processing of the exogenous materials is enhanced. That the (distant) sun's rays are 'focused' onto the crater floors virtually globally on Hyperion, and the object is believed to 'chaotically' change its' orientation to the sun over time, again, to me, strongly suggests a 'catalytic' property of the solar efflux on this exogenous material in 'darkening' (or 'developing' to borrow a word from the folks at Kodak) it for us to then study.