現在の衝突クレーターの発生率と,火星の現在の溝の活動
Michael C Malin1, Kenneth S Edgett, Liliya V Posiolova
1Malin Space Science Systems, Post Office Box 910148, San Diego, CA 92191-0148, USA.
まとめ
最近の火星観測は,現在のクレーター形成率が月面モデルと一致していることを明らかにし,火星の表面が若いことを示唆しています. 新しい溝の堆積は,過去10年以内に火星に液体の水が流れていたことを示しています.
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
- 天体生物学 アストロバイオロジー
背景:
- 火星地球探査機 (MGS) 火星軌道探査機カメラ (MOC) は,火星表面の高解像度画像を提供している.
- 衝突クレーター形成や表面プロセスなど,火星の現在の地質活動の理解は,火星の居住可能性の評価に極めて重要です.
研究 の 目的:
- 火星の現在の衝突クレーター形成率を判断するためです.
- 火星の中緯度の峡谷における新しい堆積物を記録し,特徴づけること.
- 潜在的に液体の水を含む最近の表面プロセスの存在と性質を推論する.
主な方法:
- 火星軌道探査機 (MOC) が火星地球測量機 (MGS) に搭載した画像データ解析.
- 変化を検出するために,特定の地域を時間経過 (1999年5月~2006年3月) にわたってモニタリングする.
- 観測されたクレーター発生率と,スケール化された月球クレーター発生モデルの予測を比較する.
- 形成メカニズムを推論するために,新しい溝の堆積物の形態学的分析.
主要な成果:
- 2150万平方キロメートルの面積で,直径2メートルから150メートルまでの20の新しい衝突クレーターが特定されました.
- 観測されたクレーター形成率は,月面からスケールされたモデル予測と密接に一致し,クレーターのない表面は地質学的に若いという考えを支持しています.
- 1999年8月以降に観測された新しい溝の堆積物は,液体の水と同様の性質を持つ流体によって形成されたと一致する特徴を示しています.
- これらの堆積物は,拡張された,数字の枝,障害物の周りのダイバーション,および低い地形などの特徴を示しています.
結論:
- 火星の現在の衝突クレーター形成率は,測定可能であり,スケールアップされた月面モデルと一致しています.
- 火星の地質学的に若い表面の存在が確認され,活発なデヌデーションプロセスが示唆されています.
- 証拠は,最近 (過去10年以内に) 火星表面に液体の水が流れていたことを強く示唆しています.
- これらの発見は,火星上の既存の生命の探求に重大な意味を持つ.
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