北京时间8月11日消息，据美国《连线》杂志报道，科学家通过对火星勘探卫星获得的数据进行了分析表明，原始火星上的环境与原始地球类似，或许火星当时的环境也适合生命的形成。相关成果发表在《自然》（Nature）杂志上，这或许是一系列火星发现中最令人兴奋的一项。
地质专家吉姆·贝尔(Jim Bell)并没有参与此项研究，但他表示：“火星的环境很有可能适合生命存在。如果有某种生命形式，它们会生活在一个有益于它们存在的环境中，甚至会是一番生机勃勃的景象。”6月，火星不断蒸发的冰层时间推移图验证了长期被怀疑是否存在的火星水。很快，科学家发表报告称，火星曾经遍布着水，在该行星的发展史上扮演过重要角色。这周早些时候，美国航空航天局宣布发现了高氯酸盐，一种一些地球上的细菌新陈代谢产物。
这份研究报告描绘的火星上马沃斯山谷(Mawrth Vallis)，该山谷是由火星上的水流流经火星南半球的诺亚高地(Noachian highlands)形成的。地质学家发现了广泛存在的一种铁元素沉积层，至少在地球上，这种沉积层是由火山岩风化形成的，该沉积层可以支持细菌生命存在。生物谷
研究报告联合撰稿人美国布朗大学地质学家约翰·马斯特德(John Mustard)说：“在地球上，如果周围存在这种铁元素，就会被细菌所利用。”更让人感到惊奇的是，马斯特德的小组发现了粘土矿物层，有可能是由长期水渗透过铁元素沉积层形成的。马斯特德说：“几何关系表明火星曾存在大量水。贝尔说：“火星上有可能存在降雨现象，这种现象表明当时的环境提供了较高温度。与今天相比，过去火星上的环境与地球要相似的多。我们不知道它是否曾有生命存在，但上面曾有湖泊，池塘，河流，降雪和冰川。”
两位研究人员均谨慎地指出，这种沉积层有可能是一种地质巧合，但也认为火星上曾存在水是解释这种现象的一个答案。除了水，温暖的气候以及基本矿物，生命存在最后的一个条件就是含有碳元素的有机分子。马斯特德说，那些碳分子很容易通过火星早期落到上面的陨石沉积获得。科学家认为陨石也将开启生命的分子送到了地球，马斯特德指出，马沃斯山谷的粘土有可能很容易与有机物结合，创造出肥沃的生命成分。贝尔说，主要的问题是，这些条件是否足够长期存在，直到生命的出现。
他说：“如果只是昙花一现，火星不可能为复杂的化学成分提供足够时间产生生命并进行进化。但如果持续十亿年，或仅仅数亿年，火星或许会形成地球曾经的环境，一旦形成了与地球相似的环境，生命会迅速萌发。”（生物谷Bioon.com）
生物谷推荐原始出处：
Nature，doi:10.1038/nature07097，John F. Mustard, T. Titus & M. Wolff
Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument
John F. Mustard1, S. L. Murchie2, S. M. Pelkey1, B. L. Ehlmann1, R. E. Milliken3, J. A. Grant4, J.-P. Bibring5, F. Poulet5, J. Bishop6, E. Noe Dobrea3, L. Roach1, F. Seelos2, R. E. Arvidson7, S. Wiseman7, R. Green3, C. Hash8, D. Humm2, E. Malaret8, J. A. McGovern2, K. Seelos2, T. Clancy9, R. Clark10, D. D. Marais6, N. Izenberg2, A. Knudson7, Y. Langevin5, T. Martin3, P. McGuire7, R. Morris11, M. Robinson12, T. Roush6, M. Smith13, G. Swayze9, H. Taylor2, T. Titus14 & M. Wolff9Bioon
Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA
Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA
Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-301, 4800 Oak Grove Drive, Pasadena, California 91109, USA
Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Independence Avenue at 6th Street SW, Washington, DC 20560, USA
Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
National Aeronautics and Space Administration, Ames Research Center, 515 N. Whisman Road, Mountain View, California 94043, USA
Department of Earth and Planetary Sciences, Washington University, St Louis, Missouri 63130, USA
Applied Coherent Technology, 112 Elden Street Suite K, Herndon, Virginia 22070, USA
Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, Colorado 80301, USA
US Geological Survey, MS 964 Box 25046, Denver Federal Center, Denver, Colorado 80225, USA
ARES Code KR, National Aeronautics and Space Administration, Johnson Space Center, 2101 NASA Parkway, Houston, Texas 77058, USA
School of Earth and Space Exploration. Box 871404, Arizona State University, Tempe, Arizona 85287-1404, USA
National Aeronautics and Space Administration, Goddard Space Flight Center, Code 693.0, Greenbelt, Maryland 20771, USA
US Geological Survey, 2255 N. Gemini Drive, Flagstaff, Arizona, 86001, USA
Correspondence to: John F. Mustard1 Correspondence and requests for materials should be addressed to J.F.M. (Email: john_mustard@brown.edu).
Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L'Eau, les Glaces et l'Activitié) instrument1, 2, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains and a relatively narrow range of mineralogy (Fe/Mg and Al smectite clays). This was interpreted to indicate that phyllosilicate formation occurred during the Noachian (the earliest geological era of Mars), and that the conditions necessary for phyllosilicate formation (moderate to high pH and high water activity3) were specific to surface environments during the earliest era of Mars's history4. Here we report results from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM)4 of phyllosilicate-rich regions. We expand the diversity of phyllosilicate mineralogy with the identification of kaolinite, chlorite and illite or muscovite, and a new class of hydrated silicate (hydrated silica). We observe diverse Fe/Mg-OH phyllosilicates and find that smectites such as nontronite and saponite are the most common, but chlorites are also present in some locations. Stratigraphic relationships in the Nili Fossae region show olivine-rich materials overlying phyllosilicate-bearing units, indicating the cessation of aqueous alteration before emplacement of the olivine-bearing unit. Hundreds of detections of Fe/Mg phyllosilicate in rims, ejecta and central peaks of craters in the southern highland Noachian cratered terrain indicate excavation of altered crust from depth. We also find phyllosilicate in sedimentary deposits clearly laid by water. These results point to a rich diversity of Noachian environments conducive to habitability.
