Surface Chemistry of Titan Options

[Juramike]

The bulk of the liquid in the lakes on Titan is going to be a methane/ethane combination, but a lot of polymeric organic material is going to have been washed in from the terrain, as well as blown in from the dunes. (The lakes would be a dune trap). That means ice-silt and tholin-coated ice silt.

The higher-order organic polymers may act as a surfactant to coat the ice particles. I would hazard that the hydrophilic functionalities of the polymer subunits would side with the ice particle surface and the hydrophobic parts of the polymer would face the methane solvent. This would allow some really gnarly emulsions to set up.

A cross-section of a lake on Titan would look like a classic "nightmare extraction" sitting in a sep funnel in an organic chemistry laboratory. There would be a foamy goo or scum component floating on the surface, the methane/ethane layer as solvent possibly with low density organic shmeggums floating about, then a denser loose gelatinous organic polymer/solvent component full of organic yukkies (please excuse the med chem. technical jargon), then a more dense portion of organic polymer/organic solvent/water emulsion, and finally a water-ice silt bottom.

Water (ice) and organics are immiscible. But hexanes and acetonitrile (CH3CN) are also immiscible. By analogy, methane should also be immiscible with CH3CN (which would be a solid at Titan’s temperature, but a lower density component than ice). This should make for yet another fun emulsion possibility. [I’ve seen waaaaay too many ugly emulsions in sep funnels with “simple” organic components.]

With the complex organic chemistry at Titan, there is a very real possiblitiy of multiple layers of emulsions combined with an organic scum layer at the surface.

I’m not sure how any of this would affect specular reflections or even radar penetration. The surface would not look like the pretty foam of a bubble batch but more like the curd on overcooked pea soup.. Would certain layers reflect radar better than others? Can you get specular reflection when there are bubbles or “floaters” on the surface? What if the “floaters” are soft low density organics? How do organic emulsion blobs reflect radar?

The patterns we are seeing in the lower parts of the lakes may be channels in the goopy lower emulsion layers (think of the orange crud at the bottom of scummy ponds). I could imagine a scenario when higher density organic goo flows into the lakes and carves a path through the less dense emulsion. The real “bottoms” of the lakes may lie under meters of organic emulsion.

Lakes on Titan may resemble more of an open pit hazmat toxic waste dump (although I still like to think of it as “a pristine prebiotic environment”).


-Mike