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La detección de 4He en partículas estratosféricas da evidencia de un origen extraterrestre
R S Rajan1, D E Brownlee, D Tomandl
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, D.C. 98195, USA.
Nature
|May 12, 1977
Resumen
Los científicos detectaron altas concentraciones de helio-4 (4He) en las partículas de la estratosfera, confirmando que eran verdaderos micrometeoritos. Este hallazgo indica un origen extraterrestre y un mínimo calentamiento atmosférico durante la entrada.
Área de la Ciencia:
- Estudios del polvo cósmico Estudios del polvo cósmico
- Ciencias planetarias Ciencias planetarias.
- Química de la atmósfera química de la atmósfera
Sus antecedentes:
- Los micrometeoritos son pequeñas partículas interplanetarias que se predice que sobrevivirán a la entrada atmosférica.
- Recientes colecciones de partículas estratosféricas sugieren orígenes extraterrestres debido a la composición elemental que coincide con los meteoritos primitivos.
Objetivo del estudio:
- Para investigar la composición de las partículas estratosféricas para confirmar su estado de micrometeorito.
- Para identificar evidencia de exposición al viento solar y al mínimo calentamiento atmosférico en las partículas recogidas.
Principales métodos:
- Recopilación de partículas estratosféricas de tamaño micrométrico durante dos años.
- Análisis de la composición elemental para comparar con los meteoritos primitivos.
- Detección de concentraciones de helio-4 (4He) dentro de las partículas.
Principales resultados:
- Se detectaron grandes concentraciones de helio-4 (4He) en varias partículas estratosféricas.
- La presencia de 4He sugiere exposición al viento solar.
- La retención de helio indica que las partículas no fueron sometidas a un calentamiento por fricción significativo durante la entrada atmosférica.
Conclusiones:
- El helio-4 detectado confirma que las partículas estratosféricas son verdaderos micrometeoritos.
- Estas partículas proporcionan evidencia de material extraterrestre que ha interactuado mínimamente con la atmósfera de la Tierra.
- Los hallazgos apoyan las predicciones de Whipple con respecto a la supervivencia de los micrometeoritos.
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