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
As if to make up for the departure of the glamorous Hale-Bopp comet, astronomers have re- leased a flurry of reports on other ce
As if to make up for the departure of the glamorous Hale-Bopp comet, astronomers have re- leased a flurry of reports on other ce
admin
2010-07-06
27
问题
As if to make up for the departure of the glamorous Hale-Bopp comet, astronomers have re- leased a flurry of reports on other celestial matters. Refined measurements of the ages of stars appear to be resolving the seeming paradox in which some stars appeared to be older than the universe it- self. A new observation offers the first concrete clues regarding the nature of the mysterious flashes of energetic radiation known as gammaray bursts.
But by far tile most startling and tentative finding is that the universe has a preferred orientation. Such directionality would challenge one of the basic tenets of physics and astronomy, taken for granted by Einstein, Newton and even Kepler. These giants all assumed that space possesses a property called rotational symmetry: spin a chunk of cosmos sideways or flip it upside down, and measurements of events within it yield precisely tile same results.
In the April 21, 1997 issue of physical Review Letters, however, Borge Nodland of the University of Rochestre and John P. Ealston of the University of Kausas present evidence that the principle of rotational symmetry may be violated on a cosmic scale. Measurements of light from distant galaxies, they say, vary depending on the galaxies’ position in the sky.
Other theorists doubt whether the claim will stand up to close scrutiny; at least two critical analyses have already been posted on the Internet. For the moment, however, even the critics can savor the frisson of a tremor rocking their field’ s foundations. "Nobody would be happier than me if they were right," says Sean M. Curroll of the University of California at Santa Barbara.
The surprising work on cosmic asymmetry began three years ago, while Nodland was working for his doctorate under Ralston’s supervision. Ina search for signs of unconventional large - scale non - uniformity, the two researchers decided to investigate whether polarized light front remote galaxies changes with their direction or distance. (Polarized light typically swings within one plane rather than in all directions, ordinary sunlight does; it can be produced by a variety of phenomena. ) Polarized light often twists as it penetrates through space as a result of its encounters with electromagnetic fields; this well- understood phenomenon is called the Faraday effect. But Nodland and Raison wondered whether additional twisting effects might be at work.
To find out, they focused on studies of galaxies that emit large amounts of synchrotron radiation, a highly polarized form of electromagnetism generated by charged particles passing through a strong electromagnetic field. After combing through the published literature, Nodland and Ralston compiled polarization data for 160 galaxies.
Their investigation involved a crucial assumption, that the initial angle of polarization of the light relative to the plane of each galaxy was the same for all 160 galaxies. Given this assumption and the estimated distances to the galaxies (inferred from their red shifts), Nodland and Ralslon could calculate whether the light underwent any twisting other than that caused by the Faraday effect.
The departure of the splendid Hale-Bopp comet is mentioned______.
选项
A、to honor the contributions of Hale-Bopp.
B、to introduce to the topic of new report on cosmic matters.
C、to challenge the basic tenets of astronomy.
D、to recount the reactions of the public to the comet.
答案
B
解析
本题考查细节理解。在文章开头作者就提到彗星的消失引发了大量有关太空物质的报道。A 题目中没有提到。C 意为向天文学的基本原则发起挑战,这是定位理论的效应。D 意为重新说明公众对彗星的反应,文章中未涉及。
转载请注明原文地址:https://jikaoti.com/ti/d0nsFFFM
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
Accordingtothespeaker,whatareconveniencegoods?
Themostobviouspurposeofadvertisingistoinformtheconsumerofavailableproductsorservices.Thesecond【C1】______istos
WhenwastheAmericanFootballAssociationfounded?
Whatdidthespeakertalkaboutlasttime?
Withthewidespreadcomputers,thereisanincreaseinthenumberofpeoplemakinguseofInternet.SomepeoplebelievethatInt
EmployeesoftheTaffValeRailwayCompanyinSouthWalesgreasedthetracksandcuttelegraphwiresduringabitterstrikein1
Defendersofspecialprotectivelaborlegislationforwomenoftenmaintainthateliminatingsuchlawswoulddestroythefruitso
Whatisthemostfundamentaldifferencebetweenplantsandanimals?
Revolutionaryinnovationisnowoccurringinallscientificandtechnologicalfields.Thiswaveofunprecedentedchangeisdriven
随机试题
我国某公司向国外出口一批货物,税后货值117万人民币,增值税率为17%,出口退税率为5%,试计算该公司可以得到的退税额。
已知当x→0时,x2ln(1+x2)是sinnx的高阶无穷小,而sinnx又是1-cosx的高阶无穷小,则正整数n=().
下列不属于便秘的病因是
根据以下资料。回答以下问题。2008年底,我国网民数从1997年的62万增加到2.98亿,居世界第2位。其中宽带网民数达到2.7亿,手机网民数达到1.2亿。互联网普及率达到22.6%,超过全球平均水平。2008年底,我国互联网的国际出口
依据《生产经营单位安全培训规定》,下列关于非煤矿山企业主要负责人和生产管理人员的安全培训的说法,正确的是()。
《卓越绩效评价准则》国家标准的国标编号是()。
民生问题的发生源自人的正当需要难以被满足.而人的需要的满足必须有一定的资源、工具、手段和方式。在给定的社会历史条件下,人们用来解决民生问题的这些资源、工具、手段和方式都是特定的,是不以人的愿望为转移的。如果条件不具备,人们的民生需求就无法得到满足,由此产生
(2017国家25)各国在对外交往中常常会形成一套相对_______的话语体系,特别是拥有自己的核心话语。对外话语不仅体现一国的外交政策,更_______了一国对外沟通的基本态度和价值。依次填入画横线部分最恰当的一项是:
通常一台计算机系统的存储介质包括Cache、内存、磁带和硬盘,其中访问速度最+慢的是
Whodoesn’tknowthenameoftheobject?
最新回复
(
0
)