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
24
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
Imeant______youaboutit,butIforgottodoso.A、tellingB、havingtoldC、to
Whatcomestomindwhenyouheartheword--diversity?Issuesofraceorgend
急性氯气中毒的主要靶系统是A.血液系统 B.呼吸系统 C.心血管系统 D.
《中华人民共和国药品管理法实施条例》规定,在城乡集市贸易市场内设立药品销售点须同
以下有关钩藤的叙述正确的是A.钩藤无镇静作用 B.钩藤可温和持久降压 C
在(),因项目未正式发售,广告宣传力度较小,上门客户量相对较少,因此这个期间
下列关于散剂特点的叙述,错误的是A、比液体药剂稳定 B、分散度大,奏效较快
简述现代企业人力资源管理各个历史发展阶段的特点。
1998年,美国金融学教授()首次给出了金融工程的正式定义。 A.费舍B.
根据《民事诉讼法》,申请仲裁裁决强制执行的期间为()。A.6个月 B.1年
最新回复
(
0
)