首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
As NASA prepares to set twin robots loose on the Martian surface and makes plans to send another in 2007, the agency’s long term
As NASA prepares to set twin robots loose on the Martian surface and makes plans to send another in 2007, the agency’s long term
admin
2014-02-20
61
问题
As NASA prepares to set twin robots loose on the Martian surface and makes plans to send another in 2007, the agency’s long term goal is clear: determine whether the red planet does or ever did harbor life.
But the current search for life is necessarily limited to life as we know it, organisms dependent on liquid water. A SPACE, com reader recently suggested that "We as humans are arrogant, simply believing that any other form of life will be just like us. " Researchers devoted to the search for extraterrestrial(ET)have a similar view. "Scientists’ approach to finding life is very Earth-centric," says Kenneth Nealson, a geobiologist at the University of Southern California. "Based on what we know about life on Earth, we set the limits for where we might look on other planets," Nealson said. Within that framework, however, there are extreme cases of life on Earth that suggest the range of places to look on frigid Mars.
Nealson and his colleagues recently found the most extreme sort of organism in a salty liquid lake under the permafrost of Siberia. The organism, named cryopegella, can exist at colder temperatures than any previously discovered. Nealson’s team figures that if the ice at the polar caps of Mars warmed to liquid water, organisms like cryopegella could have awakened and repaired any damage that might have occurred to their various cellular components. That does not mean there are necessarily dormant microbes within the ice caps of Mars. But it does suggest a broader range of potential cradles for life.
Other researchers agree, and a host of so-called "extremophile" discoveries on Earth in recent years indicate the polar regions of Mars might be prime hunting grounds. As on Earth, organisms there might be slathered in natural antifreeze or be able to go dormant for tens of thousands of years, waiting for a brief thaw, their moment in the Sun.
Meanwhile, scientists recognize that there could indeed be life elsewhere in the universe that does not require water. And some astrobiologists are trying to explore the possibilities. But it is a tough problem to approach. In looking for "life as we don’t know it," it’s hard to even imagine what to expect.
Life might or might not exist on Mars. If there are critters there, they might or might not be like bacteria on Earth. In laboratory conditions, scientists in 2001 were able to get one-celled organisms to incorporate an amino acid—a fundamental building block of life—that no other known life uses. The discovery borders on the creation of artificial life, experts said. It also suggests that ET might operate by entirely different rules than those we’re used to.
If life on Mars is fundamentally different from what scientists understand life to be, then current spacecraft and others in the works may well not recognize what’s right under their mechanical noses.
According to Kenneth Nealson, scientists’ current approach to finding life is______.
选项
A、limited
B、costly
C、centralized
D、earthly
答案
A
解析
细节题。文章第三段讲到了纳尔森的观点。他认为科学家目前探索宇宙生命的方式非常“地球中心化”,也就是说目前的探索方式都是基于我们所知道的地球上的生命形式,我们对可能探索的宇宙中其他星球上的地方设定界限。因此我们可知,他认为目前的方式都是有局限的,即A。而B(花费巨大的)在文章没有提到;C(集中化的)和D(现世的,世俗的)都是对原文中“Earth—centric”一词不准确的理解。
转载请注明原文地址:https://kaotiyun.com/show/ErXO777K
0
在职攻硕英语联考
相关试题推荐
WorldWarIIiscommonlyacknowledged______someofthe20thcentury’smostnotablepoetry.
Thedevelopmentofwritingwasoneofthegreathumaninventions.Itisdifficult【C1】______manypeopletoimaginelanguagewitho
Iamwritingthisathomebecauselastweekmyergonomic(符合人体工程学的)chairattheofficefellapart,unableanylongertobearmyw
Iamwritingthisathomebecauselastweekmyergonomic(符合人体工程学的)chairattheofficefellapart,unableanylongertobearmyw
Innocountry______Britain,ithasbeensaid,canoneexperiencefourseasonsinthecourseofasingleday.
Colorisveryimportanttomostanimalsforithelpsthemtogetalongintheworld.Color【C1】______tomakeananimaldifficult
Accommodationsmustbemadeforstudentswithlearningdisabilities.
Standardusageincludesthosewordsandexpressionsunderstood,used,andacceptedbyamajorityofthespeakersofalanguagei
Electroniccommunication,duetoitsspeedandbroadcastingability,isfundamentallydifferentfromPaper-basedcommunications
Weknowtheatmosphereas______.Quantityofenergycontainedintheatmosphereis______.
随机试题
原房屋纳税人把房卖给甲,由甲纳税,这种情况属于()。
Thepurposeofanapplicationletteristohelpyouto"sell"yourself.Youshould【C1】______thejobyouwantclearly,andshould
男,68岁。体检胸片发现右肺下叶周围性结节,大小约2.5cm×2cm。最佳的确诊方法是
献血后的生理恢复不包括
在一次关于国家预算研讨会上,参会代表分别作出如下发言:甲:国家预算是指经法定程序批准的、国家在一定期间内预定的财政收支计划,是国家进行财政分配的依据和宏观调控的重要手段。国家预算在经济生活中主要起到财力保证、调节制约、统计和反映监督的作用。
某企业2008年亏损20万元,2009年亏损10万元,2010年盈利5万元,2011年亏损15万元,2012年盈利8万元,2013年盈利6万元,2014年度盈利74万元,则2014年度的应纳税所得额是()。
从所给的四个选项中,选择最合适的一个填人问号处,使之呈现一定的规律性:
设随机变量X,Y相互独立,且X~N(0,),Y~N(0,),z=|x-y|,求E(Z),D(Z).
已知矩阵有两个线性无关的特征向量,则a=__________.
A、Helpthemanplanastudentrally.B、Usethestudentparkinglot.C、Makeadonationtosupportthegroup.D、Signapetition.D
最新回复
(
0
)