January 21, 2005 | David F. Coppedge

More Titan Results Announced

A week after the successful landing on Titan, ESA held its second main press conference on the findings.  The scientists were clearly upbeat about the results.  The probe transmitted data for 72 minutes from the surface after its 2.5 hour descent through the atmosphere.  The mesas, observed in stereo, are made of water ice about 100m high, and the channels are most likely formed by erosion from methane rain.  The dark material appears concentrated in the canyons that cut through the ridges.  The processed images show fluid flow in the form of rivers has been active, and also extruded water ice with possible methane springs.  Even the dark regions show evidence of fluid flow.
    The dark “lakes” or playas do not appear to have surface liquid now, although it seems evident they did in the recent past.  From the surface, the “stones” of ice appear to have been rounded by erosion.  Most of the elevated features are composed of dirty water ice with crushed ice scattered around.  The eroding agent, which rains down and flows over the surface, is almost certainly liquid methane.  Except for the chemistry and temperatures involved, the processes appear familiar to us on earth: condensation, evaporation, erosion, rain, rivers, wind and weather.  Huygens did not sense rain on the day of landing, but the scientists suspect it rained recently, and will probably rain more, in this strange place.  The rains could be seasonal.  In short, dark material precipitates from the atmosphere, and is washed off the icy mesas by methane rain, where it flows down the channels to the flat areas.  It’s like Arizona except for the chemistry and the cold.
    The Surface Science Package (SSP) worked well after landing.  The probe may have settled about 10-15cm into the soil.  Because the probe gives off heat from the mass spectrometer, and a 20W light bulb, scientists detected volatiles evaporating from the landing site.
    From the mass spectrometer data, the team found that methane density increased during the descent and was strongest at the surface where it appears to be emitted from the soil.  This was a big and important surprise.  A reservoir of liquid methane must be evaporating from the subsurface.  The dark “seas” are not from liquid ethane, but liquid methane.  The scientists were pleased that many aspects of pre-Huygens models, including atmospheric composition, pressure and temperature, turned out to be quite correct.
    The chemists found radiogenic argon, but not primordial argon, in the atmosphere.  The methane must be primordial, it was said, because the water ice is too cold to provide a source of oxygen which would have created carbon dioxide (as on Mars).  Good thing there was no free oxygen, or this world of highly flammable gases would have exploded.  The haze layer exists lower than previously thought.  The methane must condense, they believe; but why is it still present at all?  It has to be continually renewed or else it would be long gone.  Is there a reservoir inside Titan?  This is a puzzle they are working on.
    Where are the pools of methane?  It appears the landing site is a bit of a “desert.”  If it rains methane, the fluid appears to sink into the surface rather than remain in pools.  Like dried up ponds, the flat areas appear to have liquid under the surface.  How often does it rain?  They could not say.  The fact that liquid was evident just a few centimeters below the surface leads them to infer it must rain often.

Wow – truth is stranger than fiction.  What a strange and imaginative world!  And think, all this is just from one small location on a sphere bigger than Mercury.  It looks like our prediction won: no thick deposits of hydrocarbon precipitates were described, only water-ice geology with thin coatings of dirty snows that are easily washed off.  Before gloating, we would need to know how deep the flat lakebeds are.  Our opponents also need to come up with a plausible source for the methane.
    Truth is also better than speculation.  Results will continue to be announced as time goes on.  It will be interesting to see what complex chemicals were detected from the surface.  The analysis will take some time.  Don’t expect the chemical evolutionists to be vindicated, even if they try to draw a happy Charlie face in the mud of this dynamic scene of frigid sterility.

Categories: Solar System

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