[X] My Assistant

[belleraphon1]

OK, here's the result of my queries, which I just posted in the blog:

Ralph replied that "I think [Wall] is referring to the porosity that may be indicated in the radiometry polarization data, which isn't published yet." He added that he had indeed talked about caverns on Titan -- in the form of karst terrain -- in his book Lifting Titan's Veil, and that the idea had "originated with Jonathan Lunine in the late 1980s, but that was based on some lab data that subsequently proved to be wrong. We discussed solution erosion on Titan (and showed it to be tiny) in "Erosion on Titan: Past and Present" (Lorenz and Lunine, 1995, PDF format), although we didn't mention caverns specifically."

Ralph had copied Steve Wall and Jonathan Lunine. Jonathan added that the lab data he'd based his original karst terrain speculation on weren't his, they were "somebody else's published in the refereed literature." He also pointed out that another researcher, David Stevenson, "argued in the early '90s for a porous crust to 'hide' an ethane-methane ocean. It was purely theoretical, and he had one piece of gray [unpublished] literature on this in which he at least speculated about big caverns."

Steve Wall commented that "I confess the language is loose. The reference to porosity is (as Ralph suggests) based on radiometry. Size of the 'pores', and if they extend to anything anyone would call caverns, is debatable."

--Emily

Thanks for the clarification Emily......

regarding the data the says methane/ethane liquids cannot significantly erode water ice....... we know that the surface on Titan is not just pure water ice....... aside from the hydrocarbon gook, the bedrock is probably a mixture of ices. I note that there are hints of CO2 in the Huygens GCMS surface data. Wonder if any studies have been done with the effect of these liquids on a mixture of ices?????? I can envision a water ice stratum with inclusions of CO2 and ammonia. If these other two materials erode more easily, than you have a recipe for karst terrains and caverns.

Again.... where are the VIMS people???? Have they managed to get a grip on their data and remove the haze contribution to get spectra that are from the surface?

Craig

[Guest_AlexBlackwell_*]

Again.... where are the VIMS people???? Have they managed to get a grip on their data and remove the haze contribution to get spectra that are from the surface?

Have you looked at any of the Europlanet #1 abstracts that I mentioned in another thread? Hint: Click here.

[remcook]

This also just came out:

Limits to the abundance of surface CO2 ice on Titan


Hartung, M.; Herbst, T. M.; Dumas, C.; Coustenis, A.
Abstract:
In the context of the Cassini/Huygens mission, we performed supporting ground-based observations to complement the results from the NASA/ESA/ASI space mission to the Saturnian system with particular focus on Titan. On the nights of 18 and 19 December 2004, we conducted adaptive optics observations with VLT/NACO to search for and map the distribution of CO2 ice deposits on the spatially resolved surface of Titan (65 mas resolution). This experiment became possible because (1) solid CO2 possesses two narrow and strong absorption lines at 2012 nm and 2070 nm that fall into the 2.05 μm window of Titan's atmosphere and (2) the width of these bands matches the band pass of the Fabry-Perot instrument installed in NACO. We do not detect this chemical compound, but we can derive firm limits on the abundance of CO2 ice on the surface of Titan at sub-Earth longitudes 284°W and 307°W. With a spatial sampling of 65 mas, we conclude that a partial surface coverage of segregated CO2 ice does not exceed 7% or 14% for bright or dark surface regions, respectively.

[belleraphon1]

This also just came out:

Limits to the abundance of surface CO2 ice on Titan


Hartung, M.; Herbst, T. M.; Dumas, C.; Coustenis, A.
Abstract:
In the context of the Cassini/Huygens mission, we performed supporting ground-based observations to complement the results from the NASA/ESA/ASI space mission to the Saturnian system with particular focus on Titan. On the nights of 18 and 19 December 2004, we conducted adaptive optics observations with VLT/NACO to search for and map the distribution of CO2 ice deposits on the spatially resolved surface of Titan (65 mas resolution). This experiment became possible because (1) solid CO2 possesses two narrow and strong absorption lines at 2012 nm and 2070 nm that fall into the 2.05 μm window of Titan's atmosphere and (2) the width of these bands matches the band pass of the Fabry-Perot instrument installed in NACO. We do not detect this chemical compound, but we can derive firm limits on the abundance of CO2 ice on the surface of Titan at sub-Earth longitudes 284°W and 307°W. With a spatial sampling of 65 mas, we conclude that a partial surface coverage of segregated CO2 ice does not exceed 7% or 14% for bright or dark surface regions, respectively.

Thanks remcook!!!!

It just seems to me that the theorectical modeling being done on Titan's surface can be simplistic. What happens to all that water/ammonia/methane/ethane/nitrogen ice as it gets buried in hydrocarbon gook? What is nature cooking up over geologic time here........... under pressure ...... what kinds of strange ice-hydrocarbon metamorphic minerology happens? And when this mixed and blended material gets brought back up to the surface by tectonic or erosional exposure, there must be inclusions of stuff with different solubilities and erosional characteristics....... ripe recipe, again, for karsts and caverns.

Craig