首页
登录
职称英语
Upwards of a billion stars in our galaxy have burnt up their internal energy
Upwards of a billion stars in our galaxy have burnt up their internal energy
游客
2023-12-18
34
管理
问题
Upwards of a billion stars in our galaxy have burnt up their internal energy sources, and so can no longer produce the heat a star needs to oppose the inward force of gravity. These stars, Of more than a few solar masses, evolve, in general, much more rapidly than does a star like the Sun. Moreover, it is just these more massive stars whose collapse does not halt at intermediate stages (that is, as white dwarfs of neutron stars), Instead, the collapse continues until a singularity (an infinitely dense concentration of matter) is reached.
It would be wonderful to observe a singularity and obtain direct evidence of the undoubtedly bizarre phenomena that occur near one. Unfortunately in most cases a distant observer cannot see the singularity: outgoing light rays are dragged back by gravity so forcefully that even if they could start out within a few kilometers of the singularity, they would end up in the singularity itself. [br] The author’s primary purpose in the passage is to ______.
选项
A、describe the formation and nature of singularities
B、explain why large numbers of stars become singularities
C、compare the characteristics of singularities with those of stars
D、imply that singularities could be more easily studied if observers could get closer to them
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3284344.html
相关试题推荐
[originaltext]An$18.5billionbidforUnocalmadeThursdaybyoneofthela
[originaltext]An$18.5billionbidforUnocalmadeThursdaybyoneofthela
[originaltext]UnitesNationsChiefKofiAnnansaysaboutabilliondollarsi
[originaltext]An$18.5billionbidforUnocalmadeThursdaybyoneofthel
[originaltext]CHINA’Spopulationwillofficiallyreach1.3billionbyThursd
[originaltext]An$18.5billionbidforUnocalmadeThursdaybyoneofthela
Theworld’spopulationcontinuestogrow.Therenowareabout4billionofu
Theworld’spopulationcontinuestogrow.Therenowareabout4billionofu
Theworld’spopulationcontinuestogrow.Therenowareabout4billionofu
Theworld’spopulationcontinuestogrow.Therenowareabout4billionofu
随机试题
Formany,thepursuitofhappinessisalsothepursuitofprosperity.Parto
TheNBAlockout(停工)didnotfinishonThursdaynight,butitwasnearlyanen
ThePeakTimeforEverythingA)Couldyoupackmoreintoeach
高血压的血压控制目标是()A.将血压快速降至<140/90mmHg B.预
甲公司2019年3月5日向乙公司购买了一处位于郊区的厂房,随后出租给丙公司
关于2012年中秋、国庆黄金周期间的旅游情况,下列说法正确的是:() A.
世界上最高的高原是()。A.黄土高原 B.帕米尔高原 C.巴西高原
.以邪实为主、正虚为次的是 A.实证 B.虚证 C.实证夹虚
从2008年2月15日,《机关事业单位人员带薪休年假实施办法》正式开始实施,办法
与结核杆菌耐干燥有关的是A.胞壁致密 B.胞壁中脂质多 C.有芽胞 D.含
最新回复
(
0
)