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
2025-02-22
24
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/3968340.html
相关试题推荐
Becauseofitsprecision,theCepheid-variablemethodofcorrelating
Whiletherehavebeencountlessattemptsatcorrelatingsunspotcycl
Whiletherehavebeencountlessattemptsatcorrelatingsunspotcycl
Whiletherehavebeencountlessattemptsatcorrelatingsunspotcycl
Whiletherehavebeencountlessattemptsatcorrelatingsunspotcycl
Whiletherehavebeencountlessattemptsatcorrelatingsunspotcycl
CURSORY:A、ungainlyB、methodicalC、instantlyusefulD、immutableE、glorifiedB
Itisthemarkofaneducatedmindtorest______withthedegreeofprecisionwhi
Adamswasso______thathisfriendsdidnotbotherto______him,becausetheypres
Becausemodernartisneithercompletelyacceptednorrejectedbycritics,their
随机试题
CollegeStudyingI.(1)_____ofpreparationforcollegestudying—Collegestudyin
CanthePCIndustryResurrectItself?A)Int
【B1】[br]【B13】A、leftB、workedC、pioneeredD、cultivatedC语义衔接题。前文提到了直到弗洛伊德提出他的理论
铝及铝合金管道保温时,应选用的保温材料为()。A:石棉绳 B:玻璃棉 C:
包括药物的生物转化与排泄的是A.药物的吸收B.药物的分布C.药物的生物转化D.药
某出版社出版了一本学术论文集,专门收集国内学者公开发表的关于如何认定和处理侵犯知
有关法的空间效力,下列说法不正确的有:A.法律是主权的反映,所以法律只适用于主权
A.朱砂安神丸 B.半夏厚朴汤 C.龙胆泻肝汤 D.归脾汤 E.六味地黄
对急性牙痛患者在未明确患牙前,切忌A.先问全身情况 B.先做局麻止痛 C.先
下列不符合登记账簿要求的有()。A、为防止篡改,文字书写要占满格 B、数字书写
最新回复
(
0
)