2012年职称英语考试试题理工类LifeFormFoundonSaturn39;sTitan.doc

2012年职称英语考试试题理工类：Life Form Found on Saturns Titan 引言：元宵以后，2012年职称英语考试时间马上要来到！在历年的职称英语考试中，专家进行分析，每年考试阅读中有很部分题目是来自职称英语考试教材。为此，小编为考生整理了一些理工类教材里面的重点职称英语考试试题供考生参考，希望对考生有帮助！祝学习愉快！ Life Form Found on Saturns Titan Scientists say they have discovered hints of alien life1 on the Saturns moon2. The discovery of a sort of life was announced after researchers at the US space agency,NASA3,analyzed data from spacecraft Cassini4,which pointed to,the existence of methane-based form of life on Saturns biggest moon. Scientists have reportedly discovered clues showing primitive alien beings arebreathing in Titans dense atmosphere filled with hydrogen. They argue that hydrogen gets absorbed before hitting Titans planet-like surface covered with methane lakes and rivers. This,they say,points to the existence of somebugs5 consuming the hydrogen at the surface of the moon less than half the size of the Earth. We suggested hydrogen consumption because its the obvious gas for life to consume on Titan,similar to the way we consume oxygen on Earth,says NASA scientist Chris McKay.If these signs do turn out to be a sign of life,it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth. To date,scientists have not yet detected this form of life anywhere,though there are liquid- water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin6(minus 290 degrees Farenheit),a methanebased organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titans surface and much too cold to support life as we know it. Scientists had expected the Suns interactions with chemicals in the atmosphere to produce a coating of acetylene on Titans surface. But Cassini detected no acetylene on the surface. The absence of detectable acetylene on the Titans surface can very well have a non-biolog