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