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Rock Layers in Gale Crater 盖尔陨坑的岩层
This oblique view of the lower mound inGale Crater shows layers of rock that preserve a record of environments onMars. Here, orbiting instruments have detected signatures of both clay mineralsand sulfate salts, with more clay minerals apparent in the foreground of thisimage and fewer in higher layers. This change in mineralogy may reflect achange in the ancient environment in Gale Crater. 这幅盖尔陨坑低处土丘的斜视图展示了保留了火星环境纪录的岩层。轨道器已经在这里探测到粘土矿物与硫酸盐的鲜明特征。图片的前景中还有更多明显的粘土矿物，在高一点的岩层上则少一些。这一矿物学上的改变反映了盖尔陨坑古环境的变迁。（此帖仅介绍图片大致内容，过长部分自动省略。。。） Mars scientists have several importanthypotheses about how these minerals may reflect changes in the amount of wateron the surface of Mars. The Mars Science Laboratory rover, Curiosity, will useits full suite of instruments to study these minerals to provide insights intothese ancient Martian environments. These rocks are also a prime target in thesearch for organic molecules since these past environments may have been habitable-- able to support microbial life. Scientists will study how organic molecules,if present, vary with mineralogical variations in the layers to understand howthey formed and what influences their preservation. The smaller hills in this view may provideclues to the modern water cycle on Mars. They contain sulfate salts that havewater in them, and as temperatures warm into summer, some of that water may bereleased to the atmosphere. As temperatures cool, they may absorb water fromthe atmosphere. The Mars Science Laboratory team will investigate how water isexchanged between these minerals and the atmosphere, helping us understandMars' modern climate. The hills are particularly useful for this investigationbecause different parts of the hills are exposed to different amounts ofsunlight and thus to different temperatures. Curiosity will be able to comparethe water in these contrasting areas as part of its investigations. This three-dimensional perspective view wascreated using visible-light imaging by the High Resolution Imaging ScienceExperiment camera on NASA's Mars Reconnaissance Orbiter and the High ResolutionStereo Camera on the European Space Agency's Mars Express orbiter.Three-dimensional information was derived by stereo analysis of image pairs.The vertical dimension is not exaggerated. Color information is derived fromcolor imaging of portions of the scene by the High Resolution Imaging ScienceExperiment camera. The Mars Science Laboratory spacecraft isbeing prepared for launch on Nov. 25, 2011. In a prime mission lasting oneMartian year -- nearly two Earth years -- after landing, researchers will usethe rover's tools to study whether the landing region has had environmentalconditions favorable for supporting microbial life and for preserving cluesabout whether life existed.
Image Credit: NASA/JPL-Caltech/Universityof Arizona
图片来源：NASA/加州理工学院喷气推进实验室/亚利桑那大学
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显身卡
。。。于是改为每周发一次啦。。。。。。
