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Las brumas orgánicas fractales proporcionaron un escudo ultravioleta para la Tierra temprana
1Department of Atmospheric and Oceanic Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0311, USA.
Science (New York, N.Y.)
|June 5, 2010
Resumen
La Tierra Arquea probablemente tenía una neblina de hidrocarburos que la protegía de la radiación ultravioleta. Esta neblina fractal era gruesa en la luz UV pero transparente a la luz visible, evitando un enfriamiento significativo.
Área de la Ciencia:
- La geociencia es la ciencia de la tierra.
- Ciencias de la atmósfera Ciencias atmosféricas.
- Astrobiología Astrobiología.
Sus antecedentes:
- El Eón Arcaico (hace 3.8 a 2.5 mil millones de años) contó con una atmósfera única.
- Se plantea la hipótesis de que han existido neblinas fotoquímicas, compuestas de aerosoles de hidrocarburos.
- La estructura fractal de estos aerosoles podría impactar significativamente las propiedades radiativas atmosféricas.
Objetivo del estudio:
- Para investigar las propiedades radiativas de las neblinas de hidrocarburos de agregados fractales.
- Para determinar los posibles efectos de blindaje de tales brumas en la Tierra primitiva.
- Para evaluar el impacto de la neblina en el clima de la Tierra temprana.
Principales métodos:
- Modelado de transferencia radiativa de la neblina de los agregados fractales.
- Análisis del grosor óptico en las longitudes de onda ultravioleta y visible.
- Estimación del impacto de la neblina en la temperatura planetaria.
Principales resultados:
- La neblina del agregado fractal era ópticamente gruesa en longitudes de onda ultravioleta (UV).
- La neblina se mantuvo relativamente transparente en las longitudes de onda visibles medias.
- Una tasa de producción de bruma de 10-14 g/año con un radio de monómero de 50 nm ofrecía una fuerte protección UV.
Conclusiones:
- La neblina fotoquímica arcaica proporcionó una protección significativa contra la radiación UV dañina.
- La neblina causó un enfriamiento anti-invernadero mínimo, lo que sugiere un impacto limitado en la temperatura global.
- Estos hallazgos tienen implicaciones para la habitabilidad de la Tierra primitiva y la búsqueda de vida en exoplanetas.
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