Titan's changing lakes Options

[ngunn]

Today's big news?
http://ciclops.org/view/5471/CASSINI_FINDS...ILL_TITAN_LAKES

Changes in the south polar region were announced late last year. Is there more to this story now??

[volcanopele]

Where are the south polar dry lakes? What do you think those low, flat areas are in the RADAR sar data that match up with ISS dark areas? That being said, the north polar region seems to have more dedicated lake basins while the south pole has mostly opportunistic playas (though there are a few of those up north too).

As for Kraken Mare, again, I think it is still plausible that Mezzoramia is the south polar version of that sea.

[Jason W Barnes]

Where are the south polar dry lakes? What do you think those low, flat areas are in the RADAR sar data that match up with ISS dark areas?

I think they're dark areas. They could be anything.

If the ethane content of Kraken Mare is substantial, then there's just no way to move it around on seasonal timescales. Oded's Milankovic timescales, maybe.

- Jason

PS -- I can't even get a copy of this paper -- I guess we're not subscribed to Nature Geoscience here for some reason?

[ngunn]

If the ethane content of Kraken Mare is substantial, then there's just no way to move it around

If the lakebeds are porous maybe the ethane doesn't have to move between hemispheres on either timescale. When evaporation concentrates ethane in a lake it may be able to diffuse into the less concentrated subsurface alkanofer. Methane diffusing the other way would return to the lake, ensuring that evaporation could continue until the lake appears dry. Of course on this model you have to move even greater volumes of methane around - to lower not just the lakes but the surrounding alkanofer too.

[Juramike]

Of course on this model you have to move even greater volumes of methane around - to lower not just the lakes but the surrounding alkanofer too.

True. But if the subsurface is extremely porous, you may only need to move a small percentage of the overall amount to effect a large change in the base level. Picture a 1 km deep porous bed: 10% change would give you 100 m change in solvent level (ignoring volume of porous material).

So while the absolute amount of methane to move from pole to pole is large, the relative amount compared to the (still unknown) subsurface reservoir could be fractional.