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
59
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.
It can be inferred from the passage that, if Fabian is correct, gas in the peripheral regions of a galaxy cluster
选项
A、streams outward into intergalactic space.
B、is hotter than gas in the central regions of the galaxy.
C、is composed primarily of gas left over from the big bang.
D、results in the creation of unusually large stars.
E、expands to increase the size of the galaxy.
答案
B
解析
如果F的观点正确,一个星系周围区域的气体有何特点?A.向星际间释放。和F的观点相反。从文章第二段F的推理过程可得:他认为星系间的热气体向星系中心流动,在这个过程中气体也逐渐变冷(L25—37)。B.正确。比星系中心的气体要热。推理见A。C.“big bang”和F的推理过程毫无关系。D.“unusually large stars”原文未提。E.“increase the size”原文无。
转载请注明原文地址:https://kaotiyun.com/show/Y1kO777K
本试题收录于:
GMAT VERBAL题库GMAT分类
0
GMAT VERBAL
GMAT
相关试题推荐
Ican’tspeakJapanese,butIdowishI______
Doyouknowinsurance(保险)?Buyinginsuranceisameansbywhichpeoplecanprotectthemselves【C1】______largelosses.Protection
WashingtonIrvingwasAmerica’sfirstmanofletterstobeknowninternationally.Hisworkswerereceivedenthusiasticallyboth
Thegovernmentplaced_________onthenumbersofforeigncarsthatcouldbeimported.
Extensivenewstudiessuggestthattheworldhasmadeextraordinaryprogressinreducingpovertyinrecentdecades.Theresearch
——Youseemtoshowinterestincooking.——What?________,I’mgettingtiredofit.
Itseemsthatoil______fromthispipeforsometime.Wewillhavetotakethemachineaparttoputitright.
Weshouldalwaysbearinmindthat______decisionsoftenresultinseriousconsequences.
Dina:Youlookrun-down,Brian.Brian:Yeah.I’vebeenfeelingundertheweatherrecently.【D8】______andIstillhaven’tgotten
Allthefollowingcasesareon-the-jobsmokingexceptthat______.Passivesmokingmeans______.
随机试题
在下列物质中,不属于常用化工生产基础原料的是()。
对全身性强直一阵挛发作的处理,强调()
代理记账机构在经营期间达不到《代理记账管理办法》规定的设立条件,整改期限为()。
当一个经济社会的实际产出不能实现充分就业时,要实现较高的经济增长速度,可采取的措施之一是()。[2006年真题]
资产负债表中的应付账款项目,应()。
开放式基金合同生效后每6个月结束之日起45日内,将更新的()登载在管理人网站上,更新的该文件摘要登载在指定报刊上;在公告的15日前,应向中国证监会报送更新的文件,并就更新内容提供书面说明。
在党的八大上,确定“我国国内的主要矛盾已经是人民对于建立先进的工业国的要求同落后的农业国的现实之间的矛盾,是人民对于经济文化迅速发展的需要同当前经济文化不能满足人民需要的状况之间的矛盾”。()
【2014黑龙江大庆】盲人可以借助自己的触摸觉来代替自己的视觉,这是感觉的()。
人民警察遇到下列情形,可以使用警棍、催泪弹、高压水枪、特种防暴枪的是()。
"Abortionisapersonalissue.Nooneactuallyknowswhattheywoulddountiltheyareactuallyinapositiontohavetodecide
最新回复
(
0
)