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
Until recently most astronomers believed that the space between the galaxies in our universe was a near perfect vacuum. This ort
Until recently most astronomers believed that the space between the galaxies in our universe was a near perfect vacuum. This ort
admin
2019-02-01
66
问题
Until recently most astronomers believed that the space between the galaxies in our universe was a near perfect vacuum. This orthodox view of the universe is now being challenged by astronomers who believe that a heavy "rain" of gas is falling into many galaxies from the supposedly empty space around them. The gas apparently con- denses into a collection of small stars, each a little larger than the planet Jupiter. These stars vastly outnumber the other stars in a given galaxy. The amount of " intergalactic rainfall" into some of these galaxies has been enough to double their mass in the time since they formed. Scientists have begun to suspect that this intergalactic gas is probably a mixture of gases left over from the "big bang" when the galaxies were formed and gas was forced out of galaxies by supernova explosions.
It is well known that when gas is cooled at a constant pressure its volume decreases. Thus, the physicist Fabian reasoned that as intergalactic gas cools, the cooler gas shrinks inward toward the center of the galaxy. Meanwhile its place is taken by hotter intergalactic gas from farther out on the edge of the galaxy, which cools as it is compressed and flows into the galaxy. The net result is a continuous flow of gas, starting as hot gases in inter galactic space and ending as a drizzle of cool gas called a "cooling flow," falling into the central galaxy.
A fairly heretical idea in the 1970’s, the cooling-flow theory gained sup- port when Fabian observed a cluster of galaxies in the constellation Perseus and found the central galaxy, NGC 1275, to be a strange-looking object with irregular, thin strands of gas radiating from it. According to previous speculation, these strands were gases that had been blown out by an explosion in the galaxy. Fabian, however, disagreed. Because the strands of gas radiating from NGC 1275 are visible in optical photographs, Fabian suggested that such strands consisted not of gas blown out of the galaxy but of cooling flows of gas streaming inward. He noted that the wavelengths of the radiation emitted by a gas would changes as the gas cooled, so that as the gas flowed into the galaxy and became cooler, it would emit not x-rays, but visible light, like that which was captured in the photographs. Fabian’s hypothesis was supported by Canizares’ determination in 1982 that most of the gas in the Perseus cluster was at a temperature of 80 mil lion degrees Kelvin, whereas the gas immediately surrounding NGC 1275(the subject of the photographs)was at one-tenth this temperature.
The author uses the phrase "orthodox view of the universe"(lines 4 - 5)to refer to the belief that
选项
A、the space between the galaxies is devoid of matter.
B、the space between galaxies is occupied by stars that cannot be detected by optical photographs.
C、galaxies have decreased in mass by half since their formation.
D、galaxies contain stars, each the size of Jupiter, which form clusters.
E、galaxies are being penetrated by gas forced out of other galaxies by supernova explosions.
答案
A
解析
文中L4—5指出的“正统观念”是指哪种信念?看原文,这一正统观点即原文第一句话的内容。∴A正确。星系之间的空间是真空的。B、C、D、E都和原文叙述无关。
转载请注明原文地址:https://www.kaotiyun.com/show/i1kO777K
本试题收录于:
GMAT VERBAL题库GMAT分类
0
GMAT VERBAL
GMAT
相关试题推荐
Forthispart,youareallowedthirtyminutestowriteacompositiononthetopic"TheLifeonInternet".Youshouldwriteatle
Itwassuggestedthat________bigeventliketheYearofRussiainChinashouldcertainlybenefit________relationshipbetweenth
Doyouknowinsurance(保险)?Buyinginsuranceisameansbywhichpeoplecanprotectthemselves【C1】______largelosses.Protection
Itwassuggestedthat_______bigeventliketheYearofRussiainChinashouldcertainlybenefit________relationshipbetweenth
Herskirthadbeenso________inpackingthatshehadtoironitbeforegoingout.
Donald:Let’seatout,shallwe?Debra:【D5】______I’vegonethroughmypaycheckfortheweekalready.Donald:Don’tworryabout
Understandingthistransitionrequiresalookatthetwo-sidedconnectionbetweenenergyandhumanwell-being.Energycontribute
Bytheyear2020,China’spopulationprobably________1.4billion.
Lastyear______ofnewbookswerepublishedonenvironmentalprotection.
Modernanthropologistsholdthatreferentialsymbolism—i.e.oralspeech,writing,nationalflags,andflagsignaling-deve
随机试题
方程|x-1|+|y-1|=1所表示的图形是()。
Overtheyears,collegestudentshavestoodtogetherforwhattheybelievein,fromcivilrightstoanti-warpoliciestothemor
治疗链霉素急性毒性反应时,应立即注射
护理诊断指出护理方向,有利于()。
女性。45岁,病人高热大汗,未补充水分已有3日.现出现明显口渴、尿少、口干舌燥、皮肤弹性下降,尿比重1.040。目前的表现是Ⅱ度脱水,失水约是体重的
“进口口岸”栏应填()。“运输工具名称”栏应填()。
某省知识产权局对职务发明人姚某与其所在单位的职务发明报酬纠纷作出了调解,姚某对该调解不服。根据行政复议法及相关规定,姚某可以通过下列哪种途径解决该纠纷?
很多家长只重视孩子学习成绩的提高,一味重智轻德,父母对孩子百依百顺,把孩子惯成了“小皇帝”、“小公主”,导致越来越多的年轻人对父母对长辈不够尊重,对他人冷漠无情,甚至缺乏基本的社会公德,对民族和社会更缺乏一份感情和责任。上述文字所阐述的家庭教育问题在于(
食品药品监督管理局向一药店发放药品经营许可证。后接到举报称,该药店存在大量非法出售处方药的行为,该局在调查中发现药店的药品经营许可证系提供虚假材料欺骗所得。关于对许可证的处理,该局下列哪一做法是正确的?
属于从物权的是()。
最新回复
(
0
)