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[职称英语考试真题] 2012年职称英语考试理工B阅读理解

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  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.

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