首页
登录
职称英语
According to the best evidence gathered by space probes and astronomers, Mars
According to the best evidence gathered by space probes and astronomers, Mars
游客
2023-12-18
12
管理
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. [br] With which of the following is the passage primarily concerned?
选项
A、The possibility of changing the Martian environment.
B、The challenge of interplanetary travel.
C、The advantages of establishing colonies on Mars.
D、The need to study the Martian ecology.
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3282900.html
相关试题推荐
SevenTypesofEvidenceItisimportanttolearntouseeviden
SevenTypesofEvidenceItisimportanttolearntouseeviden
SevenTypesofEvidenceItisimportanttolearntouseeviden
SevenTypesofEvidenceItisimportanttolearntouseeviden
SevenTypesofEvidenceItisimportanttolearntouseeviden
Accordingtothelaw,childreninBritainbetweentheagesofshouldreceiveeff
Ateamofinternationalresearchershasfoundnewevidencethatanendangered
Ateamofinternationalresearchershasfoundnewevidencethatanendangered
Ateamofinternationalresearchershasfoundnewevidencethatanendangered
Accordingtoreportsinmajornewsoutlets,astudypublishedlastweekinclu
随机试题
[originaltext]Thefamilyischanging.Inthepast,grandparents,parents,a
[originaltext]W:Hello,Bob.Youlookverysad.Whathappened?M:Don’tmention
Throughouthistoryhas【C1】______changedhisphysicalenvironmentinordert
钎焊的优点包括( )。 A、对母材的物理化学性能通常没有明显的不利影响
《10kV-500kV输变电设备交接试验规程》中规定,SF6断路器相间分闸不同期
某商场有若干销售员,按照四人一组分就会多出一人,按照五人一组分也多一个,按照六人
(2019年真题)根据《环境影响评价技术导则地下水环境》(HJ610-2016)
关于解决工程价款结算争议的说法,正确的是()。A.装饰装修工程的承包人请求工程
男性,21岁,近半年来反复心悸、胸痛、劳力性呼吸困难,时有头晕或短暂神志丧失。体
治疗不稳定型心绞痛不恰当的措施是( )。A.静脉滴注尿激酶 B.皮下注射低分
最新回复
(
0
)