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
In 1995 the Galileo spacecraft captured data about Jupiter’s atmosphere--- namely, the absence of most of the predicted atmosphe
In 1995 the Galileo spacecraft captured data about Jupiter’s atmosphere--- namely, the absence of most of the predicted atmosphe
admin
2018-07-04
40
问题
In 1995 the Galileo spacecraft captured data about Jupiter’s atmosphere--- namely, the absence of most of the predicted atmospheric water--- that challenged prevailing theories about Jupiter’s structure. The unexpectedness of this finding fits a larger pattern in which theories about planetary composition and dynamics have failed to predict the realities discovered through space exploration. Instead of “normal planets” whose composition could be predicted by theory, the planets populating our solar system are unique individuals whose chemical and tectonic identities were created through numerous contingent events. One implication of this is that although the universe undoubtedly holds other planetary systems, the duplication of the sequence that produced our solar system and the development of life on Earth is highly unlikely.
Recently planetary scientists have suggested that the external preconditions for the development of Earth’s biosphere probably included four paramount contingencies. First, a climate conducive to life on earth depends upon the extraordinarily narrow orbital parameters that define a continuously habitable zone where water can exist in a liquid state. If Earth’s orbit were only 5 percent smaller than it is, temperatures during the early stages of Earth’s history would have been high enough to vaporize the oceans. If the Earth-Sun distance were as little as 1 percent larger, runaway glaciations on Earth about 2 billion years ago would have caused the oceans to freeze and remain frozen to this day.
Second, Jupiter’s enormous mass prevents most Sun-bound comets from penetrating the inner solar system. It has been estimated that without this shield, Earth would have experienced bombardment by comet-sized impactors a thousand times more frequently than has actually been recorded during geological time. Even if Earth’s surface were not actually sterilized by this bombardment, it is unlikely that any but the most primitive life-forms could have survived. This suggests that only planetary system containing both terrestrial planets like Earth and gas giants like Jupiter might be capable of sustaining complex life-forms.
Third, the gravitational shield of the giant outer planets, while highly efficient, must occasionally fail to protect Earth. Paradoxically, while the temperatures required for liquid water exist only in the inner solar system, the key building blocks of life, including water itself, occur primarily beyond the asteroid belt. Thus the evolution of life has depended on a frequency of cometary impacts sufficient to convey water, as well as carbon and nitrogen, from these distant regions of the solar system to Earth while stopping short of an impact magnitude that would destroy the atmosphere and oceans.
Finally, Earth’s unique and massive satellite, the Moon, plays a crucial role in stabilizing the obliquity of Earth’s rotational axis. This obliquity creates the terrestrial seasonality so important to the evolution and diversity of life. Mars, in contrast, has a wildly oscillating tilt and chaotic seasonality, while Venus, rotating slowly backward, has virtually no seasonality at all.
The passage suggests each of the following about water on Earth except:
选项
A、It was conveyed to Earth by comets.
B、It appeared on Earth earlier than did carbon and nitrogen.
C、Its existence in a liquid state is contingent on Earth’s orbital parameters.
D、Much of it came from a part of the solar system where water cannot exit in a liquid state.
E、It is unlikely that there would be much of it available to support life if the gravitational shield of the outer planets did not limit the frequency with which comets strike Earth.
答案
B
解析
A.It was conveyed to Earth by comets.水是被彗星带到地球的。
解析:定位到第四段第二句,不选。
B.It appeared on Earth earlier than did carbon and nitrogen.水的出现早于碳和氮。
解析:文章没提,选B。
C.Its existence in a hquid state is contingent on Earth’s orbital parameters.水之所以可以液态存在依赖于地球的轨道参数。
解析:定位到第二段第二句,不选。
D.Much of it came from a part of the solar system where water cannot exit in a liquid state.大部分水来自于水不会以液态存在的地方。
解析:定位到第四段第二句,不选。
E.It is unlikely that there would be much of it available to support life if the gravitational shield of the outer planets did not limit the frequency with which comets strike Earth.如果外部行星的引力屏障没有限制彗星撞击地球的频率的话,就不可能有水来维持生命。
解析:定位到第三段第二句,不选。
转载请注明原文地址:https://kaotiyun.com/show/a7jO777K
本试题收录于:
GRE VERBAL题库GRE分类
0
GRE VERBAL
GRE
相关试题推荐
Alanguageclasshas155students.80ofthemcanspeakEnglish,40ofthemcanspeakRussian,and60ofthemcanspeakFrench.
Itcanbeinferredfromthepassagethataccidental-deathdamageawardsinAmericaduringthenineteenthcenturytendedtobeba
Itcanbeinferredfromthepassagethataccidental-deathdamageawardsinAmericaduringthenineteenthcenturytendedtobeba
KazukoNakane’shistoryoftheearlyJapaneseimmigrantstocentralCalifornia’sPajaroValleyfocusesonthedevelopmentoffa
High-technologymedicineisdrivingupthenation’shealthcarecosts.Recentadvancesincataractsurgeryillustratewhythis
Anthropologistsassertthatculturesadvanceonlywhenindependencereplacesdependence—thatis,onlywhenimpositionbyoutside
Seniorexecutiveshadalargerpercentageincreaseinpayin1990thanthewagesofothersalariedworkers.
AlthoughjustinsidetheorbitofJupiter,amateurastronomerswithgoodtelescopesshouldbeabletoseethecometwithinthen
Slipsofthetonguedonotnecessarilyrevealconcealedbeliefsorintentionsbutratheraretheresultfromthecompetitionbet
Aspeoplerelymoreandmoreontechnologytosolveproblems,theabilityofhumanstothinkforthemselveswillsurelydeterior
随机试题
男性,30岁,右大腿远端肿痛伴有发热2周。检查:右大腿局部增粗,压痛。X线示股骨远侧干骺端骨质破坏,有骨膜增生现象。局部软组织间隙模糊。应诊断何种疾病:()
液体与气体的一个显著区别就是气体可压缩,液体不可压缩。()
某家庭食用自采蘑菇后出现大量流汗、流涎、流泪、瞳孔缩小、脉缓、呼吸急促等症状。引起此状最可能的蕈类毒素是
“接触区”是指A.牙与牙在邻面互相接触的部位B.轴面上的外形高点C.前牙唇面上的外形高点D.牙冠邻面最高的部分E.牙冠邻面的突出点
美国医学物理学家学会(AAPM)规定加速器X射线的稳定性每月监测的允许精度
对账的主要内容包括()。
结账的程序包括()。
《义务教育美术课程标准(2011年版)》中各学习领域分别由目标、()和评价要点三部分组成。
山东网友骂“兖州交警孬种”被拘5日,警方称其违法。根据材料回答以下两题:如果你是交通管理部门的领导。你怎么办?
Questions28-35Completethenotesbelowusingwordsfromthebox.Writeyouranswersinboxes28-35onyouranswersheet.
最新回复
(
0
)