火星の大規模な衝突による環境影響
Teresa L Segura1, Owen B Toon, Anthony Colaprete
1Program in Atmospheric and Oceanic Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado, Campus Box 392, Boulder, CO 80309-0392, USA.
Science (New York, N.Y.)
|December 10, 2002
まとめ
初期の火星に巨大な小惑星が衝突し,氷が溶け,世界的な降雨を引き起こし,川や水層を形成しました. 約35億年前に起こったこれらの出来事は,火星の表面と気候を大きく変えました.
科学分野:
- 惑星科学は惑星科学である.
- 地質学 地質学 地質学
- 気候科学 気候科学
背景:
- 火星の谷のネットワークは,約35億年前に,遅い重爆撃期の終わりに形成されました.
- 大規模な小惑星の衝突により,地球規模の噴出毛布が生み出され,火星の表面が大幅に暖められました.
研究 の 目的:
- 火星初期の大型小惑星の衝突による気候と水文学的影響を調査する.
- 衝突で発生した水蒸気と,その後の降雨が,火星の表面の特徴を形作る上で果たす役割を決定する.
主な方法:
- 小惑星の衝突による熱効果と大気効果をモデル化するために数値シミュレーションを使用した.
- 大気中に注入される水蒸気の量と,その結果生じる降水量を定量化した.
主要な成果:
- シミュレーションでは,衝突エジェクタが火星表面を長期にわたって凍結点以上に保ち,氷を溶かしたことを示しました.
- 小惑星の衝突により大気中に大量に降水し,大量の降雨を引き起こした.
- 大規模なインパクトから,年間約2メートルの降雨率が推定されました.
結論:
- 大規模な小惑星の衝突は,表面温暖化と降水による火星の渓谷ネットワークの形成に決定的な役割を果たしました.
- 川の形成や水層の充填など,衝突によって引き起こされた水理学的過程は,火星の初期に顕著であった.
- これらの発見は,古代火星の液体の水と居住可能性の可能性に関する新しい視点を提供します.
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