atmospheric differences
Why large differences in H2O and CO2?
- Escape velocity Vg 68
- Venus retains H2O but not H2
- solar UV + H2O => H2 + O
- H2 escapes, O oxidizes rocks
- cf. Earth
- H2O frozen out it stratosphere TA 57
- clouds and moisture trapped in low atmosphere < 10 km
- O3 blocks UV -- protects H2O from destruction
- CO2
- Earth has a CO2 deficit
- Life on earth has sequestered CO2
- living plants and buried fossil fuels
- carbonate rocks (i.e. MgCO3, CaCO3)
- clamshells, coral, limestone, marble, chalk, Milk of Magnesia