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
Because of its precision, the Cepheid-variable method of correlating the luminosity of Cepheid stars with those of known
Because of its precision, the Cepheid-variable method of correlating the luminosity of Cepheid stars with those of known
admin
2011-01-17
61
问题
Because of its precision, the Cepheid-variable method of correlating the
luminosity of Cepheid stars with those of known types of ordinary stars is one of
the most important tools that astronomers have for ascertaining distances to
Line proximate galaxies. Fortunately, Cepheids are luminous enough to be observed
(5) in other galaxies, not just in our own, such that scientists have established a
benchmark for their true brightness. One first observes a Cepheid, notes the
time span for its luminance to vary, and plots that information on an already
established graph to derive its intrinsic luminosity. Comparing intrinsic
luminosity with apparent brightness allows one to calculate the star’s distance
(10) as long as the period-luminosity relation for the star in question is first corrected
for gravitational interference, parallax, and experimental error. Data gathered
by this process would suggest that the universe is expanding, but the method is
less reliable in the nether reaches of the universe, where the crucial evidence
for cosmic expansion would likely be spotted.
The passage is primarily concerned with
选项
A、describing an important technique
B、discussing a new method
C、investigating a controversial procedure
D、announcing a significant discovery
E、promoting a novel application
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/B9jO777K
本试题收录于:
GRE VERBAL题库GRE分类
0
GRE VERBAL
GRE
相关试题推荐
Haveyoueverheardofapawpaw(木瓜)?Ifnot,donotfeelbad.ManyAmericansdonotknowofthefruit,althoughitisnativeto
Haveyoueverheardofapawpaw(木瓜)?Ifnot,donotfeelbad.ManyAmericansdonotknowofthefruit,althoughitisnativeto
Although______happenedinthatdevelopedcountrysoundslikesciencefiction,itcouldoccurelsewhereintheworld.
Becauseofthepoorharvest,wheatpriceshave______inthelastsixmonths.
Theyovercameallthedifficultiesandfulfilledtheplantendaysaheadofschedule,______wassomethingwehadnotexpected.
BRISTLE:ANGER::
ENTHUSIASM:MANIA::
IMPERVIOUS:FRIABLE::
SupernovasintheMilkyWayarethelikeliestsourceformostofthecosmicraysreachingEarth.However,calculationsshowthat
AlthoughJohnson(i)____greatenthusiasmforhisemployees’project,inrealityhisinterestintheprojectwasso(ii)____as
随机试题
组成中含有二陈汤药物的方剂是
在马莱茨克的大众传播过程模式中,传者受到哪三个层面的制约和影响
肝体积明显缩小,外观黄绿色,表面呈结节状,光镜下见肝细胞大片坏死,同时可见肝细胞再生结节,明显淤胆,大量炎性细胞浸润,结节间纤维组织及小胆管明显增生,根据上述病变应诊断为
甲状腺激素的生物学作用是
A.呋喃唑酮B.甲氧苄啶C.氧氟沙星D.磺胺嘧啶E.甲硝唑服药后应多喝开水,防止尿内结晶形成的药物是
心血虚证与心阴虚证的共同见症是
设计、采购和施工总承包(EPC)的主要类型包括( )。
对非经营性方案,经济效果评价应主要分析拟定技术方案的()。
王某担任某县高二英语教师期间通过了硕士研究生入学考试,学校以王某服务期未满、学校英语教师不足为由不予批准王某在职学习。王某欲以剥夺其参加进修权利为由提出申诉,受理申诉的机构应当是()。
Theaveragepersonseestensofthousandsofimagesaday—imagesontelevision,innewspapersandmagazines,andonthesidesof
最新回复
(
0
)