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
Galaxies are the major’ building blocks Of the universe: A galaxy is giant family of many millions of stars, and it is held
Galaxies are the major’ building blocks Of the universe: A galaxy is giant family of many millions of stars, and it is held
admin
2010-07-06
34
问题
Galaxies are the major’ building blocks Of the universe: A galaxy is giant family of many millions of stars, and it is held together by its own gravitational field. Most of the material universe is organized into galaxies of stars together with gas and dust.
There are three main types of galaxy: spiral, elliptical, and irregular. The Milky Way is a spiral galaxy, a flattish disc of stars with two spiral arms emerging from its central nucleus. About one-quarter of all galaxies have this shape. Spiral galaxies are well supplied with the interstellar gas in which new stars form: as the rotating spiral pattern sweeps around the galaxy it compresses gas and dust, triggering the formation of bright young stars. The elliptical galaxies have a symmetrical elliptical or spheroidal shape with no obvious structure. Most of their member stars are very old and since ellipticals are devoid of interstellar gas, no new stars are forming in them. The biggest and brightest galaxies in the universe are ellipticals with masses of about 1013 times that of the sun, these giants may frequently be sources of strong radio emission, in which case they are called radio galaxies. About two-thirds of all galaxies are elliptical. Irregular galaxies comprise about one-tenth of all galaxies and they come in many subclasses.
Measurement in space is quite different from measurement on Earth. Some terrestrial distances can be expressed as intervals of time, the time to fly from one continent to another or the time it takes to drive to work, for example. By comparison with these familiar yardsticks, the distances to the galaxies are incomprehensibly large, but they too are made more manageable by using a time calibration, in this case the distance that light travels in one year. On such a scale the nearest giant spiral galaxy, the Andromeda galaxy, is two million light years away. The most distant luminous objects seen by telescopes are probably ten thousand million light years away. Their light was already halfway here before the Earth even formed. The light from the nearby Virgo galaxy set out when reptiles still dominated the animal world.
According to the passage, which of the following is NOT true of elliptical galaxies?
选项
A、They are the largest galaxies.
B、They mostly contain old stars.
C、They contain a high amount of interstellar gas.
D、They have a spherical shape.
答案
C
解析
转载请注明原文地址:https://jikaoti.com/ti/mXisFFFM
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
YouwillhearaninterviewwithProf.JesseAusubelabouthisoptimisticattitudestowardsenvironmentalissuestoday.Asyouli
YouwillhearaninterviewwithProf.JesseAusubelabouthisoptimisticattitudestowardsenvironmentalissuestoday.Asyouli
HowdoesReevefeelinacrisis?
Agingbabyboomersaredeterminedtofighttheagingprocess.Theyspendmillionsofdollarsayearon【C1】______theyperceiveas
Agingbabyboomersaredeterminedtofighttheagingprocess.Theyspendmillionsofdollarsayearon【C1】______theyperceiveas
ThefollowingisaninterviewwithEmmaRichards,oneofBritain’smostsuccessfulsailorsandtheyoungestpersontocompletet
ThefollowingisaninterviewwithEmmaRichards,oneofBritain’smostsuccessfulsailorsandtheyoungestpersontocompletet
ThefollowingisaninterviewwithEmmaRichards,oneofBritain’smostsuccessfulsailorsandtheyoungestpersontocompletet
随机试题
女性,25岁,2周前腹泻已愈。3天前双下肢麻木无力,今天出现胸闷、胸部束带感,排尿困难。查体:双上肢肌力5级,双下肢2级,T2以下各种感觉减退,腱反射消失,病理征(一)。该患者可采取哪些治疗措施,除了
A、花蕾B、开放的花C、未开放的花序D、已开放的花序E、花中的一部分菊花、旋覆花入药部分是()
(2011年)V形带传动中,最大有效拉力与下列哪个因素无关?()
记账以后,如发现记账错误是由于记账凭证所列会计科目有误引起的,应采用()进行错账更正。
下列各项中,属于企业筹集资金的要求的有()。
A注册会计师负责对常年审计客户甲公司20×8年度财务报表进行审计,撰写了总体审计策略和具体审计计划,部分内容摘录如下:(1)初步了解20×8年度甲公司及其环境未发生重大变化,拟信赖以往审计中对管理层、治理层诚信形成的判断。(2)因对甲公司内部审计人员的客观
A股是以人民币标明面值、以人民币认购和进行交易、供()买卖的股票。
毛泽东首次明确提出要“使中国稳步地由农业国转变为工业国,把中国建设成一个伟大的社会主义国家”的任务是在()。
Ourcharityeventhadsuchhighat-tendance______wehavereachedourdonationgoals.
A、Allthe55,000attendantsoftheresearchwereregularrunners.B、Onaverage,runnerslived3yearslongerthannon-runners.C
最新回复
(
0
)