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
WATER AND LIFE ON MARS 1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In
WATER AND LIFE ON MARS 1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In
admin
2012-01-14
26
问题
WATER AND LIFE ON MARS
1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In the nineteenth century, it was commonly accepted that life, perhaps even intelligent life, was widespread in the solar system, and Mars was an obvious target in the search for life. New photographic technology offered a way for astronomers to learn more about the red planet. In 1888, Italian astronomer Giovanni Schiaparelli produced images that showed a network of long, thin, dark lines crossing the surface of Mars. He called these features canali in Italian, which became "canals" or "channels" in English. The strange appearance of the canals suggested to some scientists that they had been formed artificially rather than naturally. The mystery deepened when Schiaparelli observed that many of the canals in the photographs were actually double.
2 Other photographic images of Mars revealed its seasonally changing polar ice caps and features that appeared to be ancient islands located in what was now a dry streambed. When the islands were first discovered, some scientists speculated that a thick water-laden atmosphere capable of generating heavy rains had once existed on Mars. However, others remained unconvinced of the presence of water. Then, in 1963, a team of astronomers obtained a good photographic plate of the near-infrared spectrum of Mars. The photograph showed that, faintly but definitely, water vapor lines could be seen. This photograph established that there really was water on Mars, though the amount was very small.
Today, the presence of water vapor in the Martian atmosphere is generally accepted, as is the belief that the atmosphere was once much denser than it is now, with a much greater abundance of water vapor.
3 The surface of Mars is dry today, but it does contain significant amounts of ice and signs that liquid water once flowed over the planet. All of the locations where evidence of water has been found are ancient, probably formed very early in Martian history. Data transmitted from spacecraft on Mars in 2004 have revealed that water was once common across a vast region of the planet, possibly as shallow lakes or seas that dried out and then filled up again. There are signs that the wind blew debris around during dry stages. These seas and lakes extended across hundreds of thousands of square miles, creating
habitable
conditions during long stretches of time billions of years ago.
4 Evidence of water includes the presence of various minerals known as evaporates, deposits left behind when liquid water turns to vapor. Small areas of mineral deposits have been found in Valles Marineris, a huge hole on Mars that is larger than the Grand Canyon on Earth. The minerals there contain water, so they had to be formed in the presence of water. Geologic research has also turned up clay and gypsum deposits that were formed by water in the soil. Rocks that clearly formed in water extend throughout 300 meters of layered materials in several locations across the Martian plains. The layers were built up over time, which means water was present, at least temporarily, for extended periods on ancient Mars.
5 Besides the ice packs at Mars’s poles, astronomers have discovered a frozen sea near its equator. This frozen sea is the size of the North Sea on Earth and appears similar to the ice packs on Antarctica. Scientists have also detected evidence of lava flows 20 million years ago as well as signs that some volcanoes may still be active. Several recently formed volcanic cones near Mars’s North Pole indicate that the planet’s core may interact with the surface, meaning there was both warmth and moisture in the recent pas-circumstances that might have supported life.
6 Liquid water is the key ingredient for life as we know it. Of all the other planets in the solar system, Mars is most like Earth. The fact that water existed on ancient Mars does not necessarily mean life ever emerged there; however, all of the available evidence does suggest that Mars meets all the requirements that are needed for life to exist.
What discovery led some scientists to think that the Martian atmosphere had produced heavy rains in the past?
选项
A、A network of canals on the surface
B、Ancient islands in a dry streambed
C、Water vapor lines on a photographic plate
D、Volcanic cones near the planet’s North Pole
答案
B
解析
The discovery of ancient islands in a dry streambed led some scientists to think that the Martian. atmosphere had produced heavy rains in the past. Clues: ...features that appeared to be ancient islands located in what was now a dry streambed. When the islands were first discovered, some scientists speculated that a thick water-laden atmosphere capable of generating heavy rains had once existed on Mars. (1.1)
转载请注明原文地址:https://kaotiyun.com/show/owyO777K
0
托福(TOEFL)
相关试题推荐
Usingdataisacomplexbusiness.Wellbeforeachampionship,sportsscientistsandcoachesstarttopreparetheathletebydeve
TheHistoryoftheGuitarTheword’guitar’wasbroughtintoEnglishasanadaptationoftheSpanishword’guitarra,’whichwas,
Lookatthefollowingdescriptionsandthelistofcompaniesbelow.Matcheachdescriptionwiththecorrectcompany,A-F.
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?AccordingtoMrSingh,whatareyoungIndia
Howdidthestudentgettheuniversityprospectus?Whodecidesthecountryinwhichthestudentwillworkinyearthree?
Theprofessorsaysthatsuperhighways______.【28】
Whichpiechartshowsthereasonswhycustomersfailedtoreporttheproblemdirectlytosupermarketstaff?
Listentothedirectionsandmatchtheplacesinquestions11-15totheappropriateplaceamongA-Eonthemap.TheComplaint
Listentothedirectionsandmatchtheplacesinquestions11-15totheappropriateplaceamongA-Eonthemap.InternetUnit
随机试题
A.犬细小病毒B.犬瘟热病毒C.狂犬病病毒D.伪狂犬病病毒E.犬传染性肝炎病毒能致犬肠炎,属腺病毒科的病毒是()
所谓实,是指
下列关于人民法院的表述中,正确的有()。
F公司是一家专营进口高档家具的企业。媒体曝光该公司有部分家具是在国内生产后,以“先出口,再进口”的方式取得进口报关凭证,在销售时标注为外国原产,以高于出厂价数倍的价格销售。此时,已经在F公司购买家具的顾客,可以行使下列哪些权利?(2011年试卷一第65题)
以下属于现状变更的是()。
背景:某房建工程地上20层,地下两层,建筑面积43210m2。筏板基础,剪力墙结构。某省建筑安装工程总公司中标施工总承包。工期:2007年1月1日~2009年1月1日。省建筑安装工程总公司授权全资子公司——第一分公司组织实施。施工单位成立了直营项目部,并
设银行利率为6%,按复利计算,若五年后想购买一台价格为16万元的设备,现在应存入银行( )万元。
某自行车厂(增值税一般纳税人)生产销售自行车,出厂不含税售价为280元/辆。2019年5月末留抵税额3000元,6月该厂购销情况如下:(1)向当地百货大楼销售800辆,百货大楼当月付清货款后,厂家给予了8%的现金折扣。(2)向外地特约经销点销售500辆
下列选项中属于系统软件的有()。
优先股的“优先”是指()。
最新回复
(
0
)