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
According to the best evidence gathered by space probes and astronomers, Mars is an inhospitable planet, more similar to Earth’s
According to the best evidence gathered by space probes and astronomers, Mars is an inhospitable planet, more similar to Earth’s
admin
2010-07-19
105
问题
According to the best evidence gathered by space probes and astronomers, Mars is an inhospitable planet, more similar to Earth’s Moon than to Earth itself a dry, stark, seemingly lifeless world. Mars’ air pressure is equal to Earth’s at an altitude of 100,000 feet. The air there is 95% carbon dioxide. Mars has no ozone layer to screen out the Sun’s lethal radiation. Daytime temperatures may reach above freezing, but because the planet is blanketed by the mere wisp of an atmosphere, the heat radiated back into space. Even at the equator, the temperature drops to -50℃ (-6(YF) at night. Today there is no liquid water, although valleys and channels on the surface show evidence of having been carved by running water. The polar ice caps are made of frozen water and carbon dioxide, and water may be frozen in the ground as permafrost.
Despite these difficult conditions, certain scientists believe that there is a possibility of transforming Mars into a more Earth-like planet. Nuclear reactors might be used to melt frozen gases and eventually build up the atmosphere. This in turn could create a "greenhouse effect" that would stop heat from radiating back into space. Liquid water could be thawed to form a polar ocean. Once enough ice has melted, suitable plants could be introduced to build up the level of oxygen in the atmosphere so that, in time, the planet would support animal life from Earth and even permanent human colonies. "This was once thought to be so far in the future as to be irrelevant," said Christopher McKay, a research scientist at the National Aeronautics and Space Administration. "But now it’s starting to look practical. We could begin work in four or five decades."
The idea of "terra-forming" Mars, as enthusiasts call it, has its roots in science fiction. But as researchers develop a more profound understanding of bow Earth’s ecology supports life, they have begun to see how it may be possible to create similar conditions on Mars. Don’t plan on homesteading on Mars any time soon, though. The process could take hundreds or even thousands of years to complete, and the cost would be staggering.
Which of the following is NOT listed by the author as a characteristic of the planet Mars that would make colonization difficult?
选项
A、There is little liquid water.
B、Daytime temperatures are dangerously high.
C、The Sun’s rays are deadly.
D、Nighttime temperatures are extremely low.
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/T8lO777K
0
专业英语八级
相关试题推荐
ThethirdparagraphexaminesAmerica’sfuture-mindednessfromthe______perspective.Theauthorpredictsinthelastparagrap
ThethirdparagraphexaminesAmerica’sfuture-mindednessfromthe______perspective.Accordingtothepassage,peopleatpres
WilfredEmmanuel-Joneswasateenagerbeforehesawhisfirstcowinhisfirstfield.BorninJamaica,the47-year-oldgrewupi
Accordingtothepassage,thenewcollege-entrancesystemisdesignedto______.Accordingtothepassage,thereseemstobedi
Theexampleinthenewsitemiscitedmainlytoshow______.
Theword"astounding"inthesecondparagraphisclosestinmeaningtoAccordingtothepassage,domesticrobotswill
AccordingtoLandes,somecountriesaresopoormainlybecauseTheculturalelementsidentifiedbyLandes______thoseidentifi
Onecharacteristicoftherichclassesofadecliningsocietyistheirtendencyto______.Etiquetteasanartofgraciouslivi
Thefineneedlesareused______.Whyaresometattooistscalled"responsible"?
Cultureshockisapainfulexperiencewegothroughwhenweencountermanynewthingsinanothercountryandwe【1】______insom
随机试题
关于重组DNA技术的叙述,错误的是
A/第三代喹诺酮类抗菌药B/第二代喹诺酮类抗菌药C/第一代喹诺酮类抗菌药D/抗病毒药E/抗菌增效剂阿昔洛韦是
下列哪项不是宫内节育器的并发症
当承重模板的跨度大于4m时,其设计起拱值通常取跨度的()左右。
政府债务收入规模的衡量指标有()。
在我国,取得商标专用权的方式是()。
下列能源中不属于一次能源的是:
二进制数111111转换成十进制数是
AccordingtotheWorldHealthOrganization,airpollutionkillsabout________aroundtheworldeachyear.
Smallcommunities,withtheirdistinctivecharacter—wherelifeisstableandintenselyhuman—aredisappearing.Somehave【C1】____
最新回复
(
0
)