首页
登录
职称英语
Because of its precision, the Cepheid-variable method of correlating
Because of its precision, the Cepheid-variable method of correlating
游客
2024-01-11
63
管理
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. [br] 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:http://tihaiku.com/zcyy/3353778.html
相关试题推荐
Claim:CountryX’sgovernmentloweredtariffbarriersbecausedoingsoservedth
Theinterviewisanessentialpartofasuccessfulhiringprogrambecause,with
Becausedinosaurswerereptiles,scientistsonceassumedthat,likeallreptiles
Nineteenth-centuryartcriticsjudgedartbytherealismofitsmethodofrepres
Becauseyoungchildrendonotorganizetheirattentionorperceptionssystematic
Becausenaturalgasiscomposedmostlyofmethane,asimplehydrocarbon,vehicle
Someanalystspointoutthatbecausepeoplearebecomingaccustomedtoasteady
TheRorschzchtestisgainingnewrespectasadiagnostictoolbecauseittakes
Teratomasareunusualformsofcancerbecausetheyarecomposedoftissuessuch
Theattorneyturneddownthelawfirm’sofferofapositionbecauseshesuspecte
随机试题
CARDINALMEZZOFANTIofBolognawasasaintwhowassaidtospeak72language
[originaltext]M:Howdifferentwouldyouimaginethelearningofasecondlangu
只有在他获得一定的说话能力,他才开始学读书写字。Onlyafterhehasacquiredconsiderablefacilityinspe
Toitsfans,itisaddictive.Tothemedia,itisapromisingmoney-maker.S
HowAdvertisementIsDoneThelanguageoftheadvertiser
一定范围内的土地被几个单位重复征用的,先前的使用者征而未用使土地造成闲置的,土地
对病人不一定有助益,可能违背医学伦理学有利原则的做法是A.根据病情作相应治疗B.
专供内服的液体制剂是A.洗剂 B.合剂 C.乳剂 D.滴鼻剂 E.滴牙剂
2012年1-4季度该市人均消费支出八大类中,同比增长的大类占人均消费总支出的比
在调查分析一决策基础之上的偏离一纠偏一再偏离再纠偏的工程造价控制属于()。
最新回复
(
0
)