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The rate of loss of water from mars
Author(s) -
Hodges R. Richard
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl013853
Subject(s) - mars exploration program , atmosphere (unit) , astrobiology , atmosphere of mars , oxygen , flux (metallurgy) , environmental science , atmospheric sciences , carbon dioxide , geology , chemistry , martian , physics , meteorology , organic chemistry
Photolysis of CO 2 in the upper atmosphere of Mars results in escaping oxygen and residual CO. Proceeding at a rate of .5–3 × 10 10 mole yr −1 , this process could reduce all of the atmospheric CO 2 to CO in 20–140 Myr. The persistence of CO 2 is maintained by re‐oxidation of CO through several processes that duplicate the classical water‐gas reaction, resulting in the destruction of water at a rate of a few mm per Myr. Owing to the continual decay of the solar EUV flux, oxygen escape and water loss have diminished with time roughly as t −2 . If, as seems likely, a predominantly CO 2 atmosphere appeared within 100 Myr of the formation of the planet, Mars should have lost several hundred meters of water over geologic time. Since very little carbon has escaped, the mass of the atmosphere has not been much greater than at present during the past 3.5 Gyr.