今天的撞击坑率和火星上的当代沟活动
Michael C Malin1, Kenneth S Edgett, Liliya V Posiolova
1Malin Space Science Systems, Post Office Box 910148, San Diego, CA 92191-0148, USA.
概括
最近的火星观测显示,当前的火山口形成率与月球模型一致,这表明火星表面很年轻. 新的峡谷沉积物表明,在过去的十年里,火星上流出了液态水.
科学领域:
- 行星科学 行星科学
- 地质地质地质地质地质地
- 天体生物学 天体生物学
背景情况:
- 火星全球测量器 (MGS) 火星轨道卫星摄像头 (MOC) 提供了火星表面的高分辨率图像.
- 了解目前火星上的地质活动,包括撞击坑和表面过程,对于评估火星的可居住性至关重要.
研究的目的:
- 为了确定火星上当前的撞击坑率.
- 为了记录和描述火星中度峡谷中的新沉积物.
- 推断最近表面过程的存在和性质,可能涉及液态水.
主要方法:
- 分析火星轨道卫星摄像机 (MOC) 在火星全球测量器 (MGS) 上获取的图像数据.
- 随着时间的推移 (1999年5月至2006年3月) 对特定地区的监测,以检测变化.
- 观测到的石坑率与月球石坑尺度模型的预测进行比较.
- 对新的沟沉积物进行形态分析,以推断形成机制.
主要成果:
- 在2150万平方公里的区域内,发现了20个新的撞击坑,直径从2米到150米,面积为2150万平方公里.
- 观察到的火山口形成率与从月球上缩放的模型预测密切匹配,这支持了没有火山口的表面在地质上很年轻的想法.
- 自1999年8月以来观察到的新峡谷沉积物表现出与液态水相似的性质的流体形成一致的特征.
- 这些沉积物表现出诸如延伸,数字分支,绕过障碍物的转移和低浮雕等特征.
结论:
- 火星上的当前撞击坑率是可以量化的,并且与缩小的月球模型相一致.
- 火星上地质上年轻的表面的存在得到证实,这意味着活跃的脱皮过程.
- 证据强烈表明,在不久的过去 (在过去的十年内) 液态水在火星表面流动.
- 这些发现对在火星上寻找现存生命有重大影响.
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