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
42
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
Inlessthan30years’timetheStarTrekholodeckwillbeareality.Directlinksbetweenthebrain’snervoussystemandacomp
Nobodyyetknowshowlongandhowseriouslytheshakinessinthefinancialsystemwill______downtheeconomy.
Inthefollowingtext,somesentenceshavebeenremoved.ChoosethemostsuitableonefromthelistA—Grefitintoeachofthen
Inthefollowingtext,somesentenceshavebeenremoved.ChoosethemostsuitableonefromthelistA—Grefitintoeachofthen
Inthefollowingarticle,somesentenceshavebeenremoved.ChoosethemostsuitableonethelistA—Gtofitintoeachofthenu
Britishtrialsystemismorelikeagamethanaseriousattempttodojustice.Itimpliesthat______.Thepassage______.
KarlVonLinne(orLinnaeus,asheiswidelyknown)wasaSwedishbiologistwhodevisedthesystemofLatinisedscientificnames
随机试题
利舍平的禁忌证:肼屈嗪的禁忌证:
基本经济进货批量模式所依据的假设不包括()。
下列各项中,不符合借贷记账法记账规则的是()。
氮、磷等营养物质大量进入水体,引起的主要危害是()。
老李说:“虽然高等学校入学人数已经逐年下降,但是小学入学人数却增长了很多。所以,地区教育部门建议建一所新的小学。”老刘说:“另一个解决办法是把一些高校的教室用作小学教室。”下列哪项最好地支持了老刘的方案?
给定材料1.2017年5月12日,全世界互联网用户都因为“蠕虫”式勒索病毒软件传播而人心惶惶。在国内,不仅是个人用户,一些政府机构的计算机也遭到攻击,网络安全问题再次引发高度关注。恰逢此时,我国第一部网络安全法《中华人民
计算不定积分.
【F1】Duringthepastgeneration,theAmericanmiddle-classfamilythatoncecouldcountonhardworkandfairplaytokeepitself
HowmanyofficersdoestheHongKongPolicedepartmentroughlyhaveaccordingtothenews?
Whichofthefollowingsentencesexpressesafact?
最新回复
(
0
)