Exploring Planets and Earth

Yuk Ling Yung

Caltech

Venus (Stability of CO2 atmosphere)

McElroy, Sze and Yung 1973Yung and DeMore Icarus 1982

CO2 is unstable against UV

A tiny amount of Cl (< 1ppm)Catalytically oxidizes CO back to CO2 via the peroxychloroformyl radical (ClCO3)

Titan = Prebiotic Earth?

Titan: Moon of Saturn

1.5 bar N2, 95K

Yung et al 1984

Organic synthesis

CH4 + UV = CxHy

C2H6 Lakes predicted by Lunine, Stevenson and Yung 1983; observed by Cassini 2010

Global Climate Change

Three leading anthropogenic greenhouse gases

CO2

CH4

N2O

Habitability

Wang, Yung et al. 1976

Yung et al. 1976

First global map of CO2 from AURA satellite

Chahine, .. Yung, 2008

V2x

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Li, …Yung 2009Time 15 June 2009

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