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El metano biogénico, el escape de hidrógeno y la oxidación irreversible de la Tierra primitiva
D C Catling1, K J Zahnle, C McKay
1Mail Stop 245-3, Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA. catling@humbabe.arc.nasa.gov
Science (New York, N.Y.)
|August 4, 2001
Resumen
Tierra temprana de la Tierra temprana.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Astrobiología Astrobiología.
- Ciencias de la atmósfera Ciencias atmosféricas.
Sus antecedentes:
- La atmósfera arcaica tenía bajos niveles de oxígeno (O2).
- El metano (CH4) probablemente está presente en altas concentraciones (10^210^3 ppmv) como un gas de efecto invernadero.
- La luminosidad más baja del Sol primitivo requería gases de efecto invernadero para el calor planetario.
Objetivo del estudio:
- Investigar el papel del metano en el clima de la Tierra temprana.
- Explique la oxidación irreversible del medio ambiente de la superficie de la Tierra.
- Conectar la composición atmosférica, los gases de efecto invernadero y la oxidación planetaria.
Principales métodos:
- Se analizó la composición atmosférica y las reacciones químicas.
- Escape modelado de hidrógeno y su impacto en la oxidación.
- Evaluó el equilibrio entre la fotosíntesis y la metanogénesis.
Principales resultados:
- Los altos niveles de metano implican una fuga de hidrógeno al espacio significativamente más rápida.
- El escape de hidrógeno conduce a una ganancia neta de oxígeno atmosférico.
- Las tasas de oxidación irreversibles calculadas de 10^1210^13 moles de oxígeno por año.
Conclusiones:
- El papel del metano como gas de efecto invernadero está relacionado con la oxidación de la Tierra.
- El mecanismo de escape de hidrógeno proporciona una vía para la oxidación irreversible de la superficie.
- Este proceso puede explicar la transición a un ambiente terrestre oxigenado.
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