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
67
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.
It can be inferred from the passage that the Cepheid variable method of estimating galactic distances would be likely to yield experimentally flawed results in which of the following circumstances?
选项
A、If the luminosity of ordinary stars being compared with that of a Cepheid star were affected by parallax.
B、If the apparent brightness of the Cepheid star being studied required an unusually long period of time to vary.
C、If the gravitational interference surrounding the Cepheid star being observed were more negligible than in most cases.
D、If the Cepheid star being studied existed on the periphery of the universe, at an extremely large distance from the observer.
E、If the Cepheid star being studied were in the same galaxy as the observer.
答案
D
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
______theyhavethesamename,AmericanandEnglishfootballareverydifferent.
Host:Oh,notyet.I’mjustgoingtomakesomecoffee.Guest:______,thoughI’dreallylovetostay.I’vegottobeupbysi
She()beillbecauseIsawherplayingtennisjustnow.
Thebottlewaspartiallyfilledwithwetsand.
Howsharksnavigatethevastandseeminglyfeaturelessoceanhaslongbeenamystery.Nowthere’sevidencetheymayfollowtheir
GiventhepersistentandintransigentnatureoftheAmericanracesystem,whichprovedquiteimpervioustoblackattacks
InTheSimpleSoybean,theauthorismuchlessrestrainedinhisenthusiasmforthebean’smedicalefficacythanheisinhiste
SupernovasintheMilkyWayarethelikeliestsourceformostofthecosmicraysreachingEarth.However,calculationsshowthat
Annoyedbythenewemployee’sexcessively______manner,thesupervisoradvisedhimthatsuchfawningwasinappropriate.
随机试题
科目三道路驾驶技能和安全文明驾驶常识考试满分分别为100分,成绩分别达到80和90分的为合格。
女,51岁,诊断为“宫颈癌”,妇科检查发现癌组织浸润达阴道穹窿处,双侧宫旁柔软,无增厚,未及浸润结节。最早出现的症状为
药物的临床试验分为四期,Ⅱ期临床试验是对治疗作用的初步评价,多发病应该不少于
对运输过程中货物的毁损、灭失,下列哪些情况下承运人不能免责()。
大跨度吊桥的主缆索多采用( )。
下列关于个人独资企业设立条件的表述中,符合《个人独资企业法》规定的是()。
依据法律关系主体的权利人性质不同,由政府代表国家行使教育权利被称为()。
老师、家长都反映彬彬是个“不开窍”的孩子。一道应用题,老师课堂上讲过,家长又帮复习过,可他做起来还是出错;别的同学背课文,一下子背出了,可他读了好多遍,还是记不住;常用字也常会出错,到考试就更糟了,渐渐地彬彬失去了学习兴趣。但他的手工却做得十分精巧,还代表
某刑警队侦查员邢某着便装执行任务时,看到熊某正在商店购买东西。邢某上前要熊某跟他走一趟。熊某知其是侦查员,于是撒腿就跑。邢某抬起警棒,朝熊某喊“站住”。随即朝熊某砸去,正中脑部,将其打倒在地,熊某死亡。问题:谁为赔偿请求人?谁为赔偿义务机关?
不同的事物在开水中会出现不同的现象,胡萝卜会变软、鸡蛋会变硬、茶叶会使开水变成香气四溢的茶水。对此,请谈谈你的理解。
最新回复
(
0
)