PLANETARY PROBE - ORIGIN OF ATMOSPHERE OF VENUS

The high temperatures and chemical composition, as determined by space probe and terrestrial observation, suggest that the present atmosphere of Venus has formed by chemical interaction with the lithosphere. Although the precise reactions have not been identified, good theoretical approximations to the molecular abundance may be obtained from reactions applicable to terrestial rocks. The high temperatures and chemical reactivity create conditions on Venus which are fundamentally different from those on the cooler terrestrial planets where the attainment of equilibrium is prevented by kinetic barriers.