In a paper by M.E. Brown, A.L. Smith, C.Chen at the Division of Geological and Planetary Sciences, California Institute of Technology they report discovering fog on Titan!
While Saturn’s moon Titan appears to support an active methane hydrological
cycle, no direct evidence for surface-atmosphere exchange has yet appeared.
It is possible that the identified lake-features could be filled with ethane, an involatile
long term residue of atmospheric photolysis; the apparent stream and
channel features could be ancient from a previous climate; and the tropospheric
methane clouds, while frequent, could cause no rain to reach the surface. We
report here the detection of fog at the south pole of Titan during late summer
using observations from the VIMS instrument on board the Cassini spacecraft.
While terrestrial fog can form from a variety of causes, most of these processes are
inoperable on Titan. Fog on Titan can only be caused by evaporation of liquid
methane; the detection of fog provides the first direct link between surface and
atmospheric methane. Based on the detections presented here, liquid methane
appears widespread at the south pole of Titan in late southern summer, and the
hydrolgical cycle on Titan is current active.
Read the full paper HERE
. (PDF warning!)