好奇号：火星上的水域奇境（图）

The Curiosity rover has entered a martian terrain offering clear signs of ancient water and tantalizing hints of a scientific bonanza. In a press teleconference today, NASA rover team members reported the discovery of mineral-filled veins (white arrows) and small mineral spheres (black arrows) that require that water once saturated the muddy floor of Gale crater. But geologists are particularly enticed by the sedimentary rock that Curiosity has roved across on its way from its landing site. As it descended deeper into the exposed strata and farther back in geologic time, it first encountered pebbles and cobbles laid down in deep torrents of water, then sandy sediments deposited by less turbulent currents, and finally fine, silty sediments. The silty sediments speak of a far quieter time in Gale, perhaps when a placid lake filled the crater. Lake sediments are the ideal place to look for organic matter lingering from ancient martian life, which is what Curiosity will do when it begins rock drilling in a few weeks. 

 “好奇号”探测器进入了火星一个区域，该区域拥有明显的迹象表明古代曾经存在水，这可能意味着科学上的一项重大发现。今天，NASA的火星探测器研究小组成员报道了这项发现：充满矿物质的岩脉（白箭头所指区域）以及小矿区（黑箭头所指区域）需要有水一度来浸泡盖尔火山口泥泞的底部才能够形成。然而，地质学家们对“好奇号”探测器从着陆地点开始一路上经过的沉积岩特别感兴趣。随着“好奇号”对暴露岩层的一步步深探，它所接触的地质时间也越来越早。“好奇号”首先遇到的是位于深水急流中的卵石，然后是在不太汹涌的水流中沉积下来的沙层，最后遇到的是颗粒细小的淤泥层。淤泥层表明了盖尔火山口中存在一个相对平静许多的时代，当时也许是平静的湖水填满了火山口。湖泊沉积层是一个理想的探测地，可以在那里寻找古代火星生命遗留下来的有机物质，这也正是“好奇号”几周以后开始钻取岩层时将要做的事情。