Instability of a highly reducing atmosphere on the primitive Earth |
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Authors: | Mikio Shimizu |
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Affiliation: | Institute of Space and Aeronautical Science, University of Tokyo, Tokyo, Japan |
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Abstract: | The eddy diffusion coefficient in the primitive upper atmosphere of highly reducing type (CH4H2) is estimated to be of the order of 108 cm2sec?1 or a little less, by solving the dissipation equation of internal gravity waves. Such a strong atmospheric mixing is clearly inconsistent with the previous assumption by McGovern that photochemical equilibrium was established in the upper atmosphere. By taking into account the mixing effect, the exospheric temperature of the highly reducing atmosphere has been computed to be higher than 1300°K. The result indicates that the hypothetical reducing atmosphere might have disappeared, if it existed, in a short time due to the gravitational escape of hydrogen and, consequently, that an anoxygenous but non-reducing atmosphere might be a more plausible environment for the origin of life. |
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