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
41
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
"探测者号"飞船在环绕火星飞行的近三年时间里传回了大约65000张图片,这些图片上满都是人们预想的那种水痕迹。
解析
转载请注明原文地址:https://kaotiyun.com/show/0Y44777K
0
考研英语一
相关试题推荐
InanarticlesomeChinesescholarsaredescribedasbeing"tantalizedbythemysteriousdragonbonehieroglyphics."Tantalized
Inthisfactorythemachinesarenotregulated______butarejointlycontrolledbyacentralcomputersystem.
Nobodyyetknowshowlongandhowseriouslytheshakinessinthefinancialsystemwill______downtheeconomy.
(Continued)exposuretostresshasbeenlinkedto(worsened)functioningoftheimmunesystem,(leaving)apersonmoreliable(f
Inthefollowingtext,somesentenceshavebeenremoved.ChoosethemostsuitableonefromthelistA—Grefitintoeachofthen
Inthefollowingtext,somesentenceshavebeenremoved.ChoosethemostsuitableonefromthelistA—Grefitintoeachofthen
Apolicemanhastobetrainedincriminallawbecause______.Whatisthemostsuitablewordthatdescribestheworkofapolice
Inthefollowingarticle,somesentenceshavebeenremoved.ChoosethemostsuitableonethelistA—Gtofitintoeachofthenu
Inthefollowingarticle,somesentenceshavebeenremoved.ChoosethemostsuitableonethelistA—Gtofitintoeachofthenu
随机试题
A.免疫耐受B.免疫自稳C.免疫防御D.免疫识别E.免疫监视机体抵抗微生物感染的基本免疫功能
患者男性,50岁,咳嗽、咳痰20余年,气喘10余年,3天前受凉后咯黄黏痰,查体双肺少许湿啰音及哮鸣音,外周血白细胞12×109/L,中性粒细胞80%,胸片显示肺纹理增重,散在小点片状阴影,最重要的治疗措施为
A.阴中求阳B.阳中求阴C.培土生金D.滋水涵木E.金水相生肾气丸所体现的配伍意义是
在工程网络计划中,工作K的最早开始时间为第18天,持续时间为5天。该工作有3项紧后工作,它们的最早开始时间分别为第25天、第27天和第30天,则工作K的自由时差为( )。
法定代理是基于( )的代理。
_________是世界上最早普及义务教育的国家。
如果你是公务员,你怎样让老百姓说出他们内心真实的想法呢?
在市场上,一台彩色电视的标价是7000元,此时执行价值尺度职能的货币是
请在【答题】菜单下选择【进入考生文件夹】命令,并按照题目要求完成下面的操作。注意:以下的文件必须都保存在考生文件夹下。文档“北京政府统计工作年报.docx”是一篇从互联网上获取的文字资料,请打开该文档并按下列要求进行排版及保存操作:在封面页与正文之
Tounderstandthecultureofdifferentplaces,especially______containingasmanydifferentsubculturesastheUnitedStates,
最新回复
(
0
)