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
考研
Time was when the solar system had two watery worlds. (46)Directly next door to the warm. wet, loamy Earth was the warm, wet, lo
Time was when the solar system had two watery worlds. (46)Directly next door to the warm. wet, loamy Earth was the warm, wet, lo
admin
2010-06-17
45
问题
Time was when the solar system had two watery worlds. (46)
Directly next door to the warm. wet, loamy Earth was the warm, wet, loamy Mars, both planets covered with oceans and running with rivers-and both possibly teeming with life.
Billions of years ago, however, the low-gravity Mars had both its air and water leak away, causing the planet to become the dead, freeze-dried place it is today.
That is what the prevailing thinking has been. Now, it appears that thinking may be wrong. (47)
Recently, NASA released new images from the Mars Global Surveyor spacecraft that suggest water may be flowing up and streaming onto the Martian surface-dramatically increasing the likelihood that at least part of the planet is biologically alive.
"If these results prove true," says Ed Weiler, associate administrator of NASA’s Office of Space Science, "they have profound implications for the possibility of life."
Finding liquid water on Mars’ surface has never been easy-because it simply can’t exist there. The modern-day Martian atmosphere has barely 1 percent the density of Earth’s, and its average temperature hovers around-67 degrees Fahrenheit (-19 degrees Centigrade). In an environment as harsh as this, water would either vaporize into space or simply flash-freeze in place. (48)
Scientists studying Martian history have always looked for clues the planet’s ancient water left behind-tracks where vanished rivers once flowed, basins where vanished seas once stood.
(49)
The approximately 65,000 images the Surveyor orbiter has beamed home in the nearly three years it has been circling Mars are full of this kind of expected hydro-scarring.
But some of the pictures took scientists by surprise. The older a formation is, the more likely it is to have been distorted over the eons-smoothed by periodic windstorms or gouged by the occasional incoming meteor. However, a few of the newly discovered water channels look fresh. That discovery has lead astonished researchers to conclude that these channels may have been recently formed.
(50)
Planetologists have long assumed that if underground water was going to bubble up on Mars, it would have to be somewhere in the balmy equatorial zones: where temperatures at noon in midsummer may reach 68 degrees Fahrenheit (20 degrees Centigrade).
Almost all the new channels, however, were discovered at the planet’s relative extremes-north of 30 degrees north latitude and south of 30 degrees south latitude-and all were carved on the cold, shaded sides of slopes.
选项
答案
研究火星史的科学家们一直在寻找这个星球上古远的水曾经留下的线索—消失的河流曾经流淌过的印迹,或者是消逝的海洋曾经覆盖的盆地。
解析
转载请注明原文地址:https://kaotiyun.com/show/cY44777K
0
考研英语一
相关试题推荐
Googlerecentlyintroducedanewservicethataddssocial-networkingfeaturestoitspopularGmailsystem.Theserviceiscalled
InanarticlesomeChinesescholarsaredescribedasbeing"tantalizedbythemysteriousdragonbonehieroglyphics."Tantalized
Inthefollowingtext,somesentenceshavebeenremoved.ChoosethemostsuitableonefromthelistA—Grefitintoeachofthen
Youaregoingtoreadatextabouthowtokeepyourjob,followedbyalistofimportantexamples.Choosethebestexamplesfrom
Apolicemanhastobetrainedincriminallawbecause______.Whatisthemostsuitablewordthatdescribestheworkofapolice
Britishtrialsystemismorelikeagamethanaseriousattempttodojustice.Itimpliesthat______.Thepassage______.
Britishtrialsystemismorelikeagamethanaseriousattempttodojustice.Itimpliesthat______.Whichofthefollowingse
Howefficientisoursystemofcriminaltrial?Doesitreallydothebasicjobweaskofit—convictingtheguiltyandacquitting
KarlVonLinne(orLinnaeus,asheiswidelyknown)wasaSwedishbiologistwhodevisedthesystemofLatinisedscientificnames
随机试题
诊断咳嗽变异性哮喘的基本条件是
若计算机中连续2字节内容的十六进制形式为34和51,则它们不可能是()
调节红细胞生成的特异性体液因子是
急性胰腺炎患者的血清淀粉酶测定应在发病后
()是由一台服务器(通常是高档微机)将许多中低档微机连接在一起(由网络接口卡、通讯电缆连接),相互通讯、共享资源,组成的一个功能更强的计算机网络系统。
根据下面材料,回答下列题目:王先生有本金50万元,借款150万元,合计200万元投资股票,投资期限一年,股票期末净资产为240万元。假如借款利率10%,则他的净资产的投资报酬率为( )。
(2013年)2012年8月某商贸公司和张某、李某成立合伙企业。根据企业所得税和个人所得税相关规定,下列关于该合伙企业所得税征收管理的说法,错误的是()。
外包非核心业务有助于商业银行将重点放在核心业务上,从而提高效率、降低成本。()
【2016河南周口】“强、平衡、不灵活”的神经类型与下列()气质类型对应。
事业单位人事争议处理工作渠道主要有三种,即人事争议协商、人事争议调解、人事争议仲裁。()
最新回复
(
0
)