•Largest moon of
 Saturn
 •Has thick
 atmosphere
 –Pressure ~ 1 earth atmosphere
 –Mostly N2,
 some CH4
 –Gas held because of low
 T
 •UV acting on CH4 Þ smog
 –Ethane produced –
 Lakes?
 –Can “see”
 surface only in IR
 •Cassini dropped a probe
 in early 2005.
 •“Code of the Lifemaker” by James P. Hogan, good sf