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
59
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.
The purpose of the author mentioning scientists’ laboratory creation in 2001 is to emphasize the idea that .
选项
A、it is hard to imagine what ET is really like
B、life might or might not exist on Mars
C、it is possible to create artificial life
D、Martians may live by entirely different rules
答案
D
解析
综合理解题。文章在倒数第二段提到了科学家2001年的实验室实验。在该实验中,科学家们能使一种单细胞生物体合成一种氨基酸,这种氨基酸是构建生命的基本单位,但任何已知的其他生命都不使用它。专家说,这一发现揭开了创造人工生命的序幕,但也暗示外星人存在的方式可能与我们所习惯了的完全不同,也就是说有一些生命形式与我们人类所知的是不同的。由于本文主要是讲外星人可能存在于我们人类假设的范围之外,因此作者用2001年这个实验的例子是为了进一步强调这一点,而不是为了强调人工创造生命的可能性,故D是正确答案。
转载请注明原文地址:https://kaotiyun.com/show/srXO777K
0
在职攻硕英语联考
相关试题推荐
Leadershipishardlyanewareaofresearch,ofcourse.Foryears,academicshavedebatedwhetherleadersarebornormade,whet
Thedevelopmentofwritingwasoneofthegreathumaninventions.Itisdifficult【C1】______manypeopletoimaginelanguagewitho
TheAustrianmanufacturingindustryconsistsofafewlargeorganizations,manyofwhichoperateundergovernmentauspices.
Concernwithmoney,andthenmoremoney,inordertobuytheconveniencesandluxuriesofmodernlife,hasbroughtgreatchanges
Everychemicalchangeeitherresultsfromenergybeingusedtoproducethechange,orcausesenergytobe______insomeform.
Weneedonehundredmoresignaturesbeforewetakethe______tothegovernor.
______theheattoasimmerandcontinuetocookforanother8~10minutesoruntilmostofthewaterhasevaporated.
Standardusageincludesthosewordsandexpressionsunderstood,used,andacceptedbyamajorityofthespeakersofalanguagei
A、Thewoman’shusbandmighthavebeenheldupbytraffic.B、Thewomanshouldgoandmeetherhusband.C、Thewoman’shusbandisw
随机试题
潮湿环境下,照明电源的电压不大于()V。
讨论函数在χ=0处连续性与可导性。
在生物个体中,几乎所有细胞都表达的基因是
肺炎克雷伯杆菌的特点是
若某项指标仅以过低为异常,且呈偏态分布,则99%参考值范围为
硬聚氯乙烯(PVC—U)管不适用于()。[2014年真题]
甲公司是一家建设投资公司,业务涵盖市政工程绿化、旅游景点开发等领域。近年来,夏日纳凉休闲项目受到青睐,甲公司计划在位于市郊的A公园开发w峡谷漂流项目(简称“W项目”),目前正在进行项目评价,有关资料如下:(1)甲公司与A公园进行洽谈并初步约定,甲公司一次
航空承运人依照《国内航空承运人赔偿责任限额规定》承担赔偿责任的,对每名旅客的最高赔偿责任限额为人民币15万元。()
2013年1月16日,陕西神木“房姐”龚爱爱被网民曝光拥有二十余处房产,价值高达10亿元,随后又被曝出同时有4个户口。2013年1月23日,网上又曝出山西运城市纪委干部张彦有两个户口,其公公身为前运城市财政局局长在各地拥有十余处房产,“房媳”出炉。随着众多
Theold______welllookedafterbythegovernment.
最新回复
(
0
)