Chemistry ModelsChemistry Models
Yuk YungYuk Yung
GPS CaltechGPS Caltech
Sagan Exoplanet Summer Sagan Exoplanet Summer WorkshopWorkshopJul 20 2009Jul 20 2009
ModelsA
Common photochemistry: hundreds of molecules, thousands of reactions
Transport: 1-D diffusion vertical
2-D advection
3-D general circulation model
Yung and DeMore, 1999
Jupiter: The cosmic reference pointJupiter: The cosmic reference point
Titan: Nature’s Laboratory of Organic Synthesis Titan: Nature’s Laboratory of Organic Synthesis
Mars: Is Methane biologically produced?Mars: Is Methane biologically produced?
Earth: The cosmic end memberEarth: The cosmic end member
Conclusions Conclusions
Today’s OutlineToday’s Outline
Gravity and EscapeGravity and Escape
Yung and DeMore, 1999
Determines EvolutionDetermines Evolution
77
Amino acids
Proteins(Catalysts)
Fatty acids Nucleotides
Lipids(Membranes)
Nucleic acids(Information)
PurinesPyrimidines
Sugars
The chiral Molecules of LifeThe chiral Molecules of Life
Jupiter: The cosmic reference pointJupiter: The cosmic reference point
Titan: Nature’s Laboratory of Organic Synthesis Titan: Nature’s Laboratory of Organic Synthesis
Mars: Is Methane biologically produced?Mars: Is Methane biologically produced?
Earth: The cosmic end memberEarth: The cosmic end member
Conclusions Conclusions
Today’s OutlineToday’s Outline
Hydrocarbons
Winter Circulation
Hydrocarbon Gradients
21
C2H2 Abundance
Photochemical results
Liang et al. 2007
CH4; hydrostatic
CH4; non-hydrostaticHC3N
HCN
C6N2
C6H6 C6N2; condensation line
Mars: Gone with the (Solar) WindMars: Gone with the (Solar) Wind
Isotopic FractionationIsotopic Fractionation
Kass and Yung Science 1995Kass and Yung Science 1995Kass and Yung Science 1995Kass and Yung Science 1995
Jupiter: The cosmic reference pointJupiter: The cosmic reference point
Titan: Nature’s Laboratory of Organic Synthesis Titan: Nature’s Laboratory of Organic Synthesis
Mars: Is Methane biologically produced?Mars: Is Methane biologically produced?
Earth: The cosmic end memberEarth: The cosmic end member
Conclusions Conclusions
Today’s OutlineToday’s Outline
Escape and Rayleigh DistillationEscape and Rayleigh Distillation
Methane on Mars
* Spectroscopic detection* Biological Production ? * Geochemical Sources ?
Mumma et al. 2009
(Nair, Summers, Miller, and Yung, ICARUS, 2005)
INMS
SOIR
This shows the residual circulation of the stream function. The solid lines represent a clockwise flow and the dotted a counterclockwise flow. The top left graph is for January, the top right for April, the bottom left for July, and the bottom right for October.
This is a 3D representation of the methane concentration on Mars for the BASE model simulation for months 36 to 54. It is evident that the most change occurs in the southern polar regions.
This shows the Methane concentration for 6 boxes in the troposphere. Of particular interest is the top left graph, which represents the Southern pole where the concentration changes dramatically as a result of condensation and evaporation of Carbon Dioxide.
The Earth produced hydrogenfrom some of this water
H2
volcano
Cf. Anatahan, N Marianas (Credit: A. Sauter).
Carbon dioxide exhaled from volcanoes in single-passmagma-transfer to produce the early atmosphere
CO2 >> S8, NO
So the atmosphere was carbon dioxide (CO2)
The atmosphere was carbon dioxide (CO2)
and the ocean was carbonated water,
i.e. acidic (pH 5.5)
4H2 + 2CO2 CH3COOH + 2H2O
& 4H2 + CO2 CH4 + 2H2O
Hydrogen plus carbon dioxidereact slowly to producemethane or acetate
Reactions that are quickened to LIFE
Exothermic and
From W. Bach
OceanAcidic on-axis400C springsFe,Zn,Ni,Co
Dudley Foster (WHOI)National GeographicNovember 1979,
Too hot,too acidic,too oxidized & too spasmodic(melting point oflead is 327.5ºC)
Exothermic and
From W. Bach
Main energy dischargeat alkaline off-axis site
Ocean
ALKALINE SUBMARINE SPRINGCaCO3
Mg(OH)2
pH 11 T 91C
H2 15mmol
~100,000 years
Kelley et al. 2001, Nature 412, 145Science 2005, 307Früh-Green + 2003, Science 301, 495Ludwig et al. 2005EOS, 86,V51B-1487
compartments
Martin et al. Nature Microbiol Rev 6, 805
credit: Deb Kelley
Lost City Abiotic H2 >
CH4 > HCOO- > CH3COO-
Serpentinization Reactions
+ CHOO-
+formate
120ºC
90ºC
40ºC
Boetius, 2005 Science, 307, 1420
+ CHOO-
Früh-Green et al., 2003 Science 301, 495
3MgFeSiO4 + 4H2O 3SiO2 + Fe3O4 + 3Mg2+ +6OH- + H2
Serpentinite
State rock of California
overall reaction:
olivine + water magnetite + serpentine + alkali + H2
Mg2.85Fe0.15Si2O5(OH)4
3MgFeSiO4 + 4H2O 3SiO2 + Fe3O4 + 3Mg2+ + 6OH- + H2
Bach et al. 2006 Geophys. Res. Lett, 33, L1330
and CH4 > HCOO- > CH3COO-
Geochemicalpath
Can the geochemical pathbe quickened through anFeS membrane?
Recast from Maden 2000Biochem. J. 350, 609
40 mm
Na2S
FeCl2
FeCl2
Na2S
FeS
FeS compartments
‘HadeanOcean’
Forced injection
“seep”
Simulation of an alkaline seepage into acidulous ocean
FeS
‘crust’
Jupiter: The cosmic reference pointJupiter: The cosmic reference point
Titan: Nature’s Laboratory of Organic Synthesis Titan: Nature’s Laboratory of Organic Synthesis
Mars: Is Methane biologically produced?Mars: Is Methane biologically produced?
Earth: The cosmic end memberEarth: The cosmic end member
Conclusions Conclusions
Today’s OutlineToday’s Outline
Li et al. PNAS 2008
Habitable Zone
Earth (Snowball, Gaia Lifeboat)Earth (Snowball, Gaia Lifeboat)
Liang et al. PNAS 2007
Li et al. PNAS 2009 (in press)
O3
H2O
H2O
CO2
Absorption in Earth’s Atmosphere
Li et al. PNAS 2009 (in press)
Extending the Lifespan by Regulating Pressure
Li et al. PNAS 2009 (in press)
Testable Hypothesis
Planets have evolved
Isotopic composition provides clues
Look of life supporting chemistry
Conclusions:ChemistryConclusions:Chemistry
ThanksThanks
Yung’s Group at Caltech,Yung’s Group at Caltech,Liang (Taiwan), Jiang (U Houston)Liang (Taiwan), Jiang (U Houston)Lunine’s book 2004Lunine’s book 2004Prof Michael RussellProf Michael RussellNASA/JPLNASA/JPLNSFNSFESAESA
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