ALH84001が火星から地球へ低温で移転した
B P Weiss1, J L Kirschvink, F J Baudenbacher
1Division of Geological and Planetary Sciences, 170-25, California Institute of Technology, Pasadena, CA 91125, USA. bweiss@gps.caltech.edu
まとめ
火星の隕石ALH84001は,40°Cを超えたことがないという磁気証拠を示しています. この温度は微生物を滅菌するには低すぎるため,隕石による惑星間生命移転の理論を裏付けている.
科学分野:
- 惑星科学は惑星科学である.
- 天体生物学 アストロバイオロジー
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 火星への大きな衝突は,物質を宇宙に放出すると理論化されています.
- このような噴出は,火星の物質を高温まで加熱すると予想されます.
- 隕石の熱史を理解することは,パンスペルミア仮説の評価に不可欠です.
研究 の 目的:
- 火星の隕石ALH84001.1の熱史を調査する.
- 惑星間移動中に微生物の生存の可能性を評価する.
- パンスペルミアにおける隕石の役割を評価する.
主な方法:
- 火星の隕石 ALH84001.1 の磁場の分析
- 空間的に異質な磁気化パターンのイメージング.
- 磁気特性の強度の変化を決定するための制御された加熱実験.
主要な成果:
- ALH84001の磁気化パターンは,骨折や岩石の断片と関連しています.
- 隕石を40°Cまで加熱すると,一部の磁気特性の強度が低下した.
- これは,隕石の内部が火星から放出されて以来,40°C以下にとどまっていたことを示しています.
結論:
- ALH84001の低温の歴史は,生命力のある微生物を収容する可能性を支持しています.
- 隕石が経験した気温は,不妊化には不十分です.
- これらの発見は,隕石による惑星間の生命の移転の仮説を裏付けている.
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