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
Black Holes Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe
Black Holes Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe
admin
2009-01-21
63
问题
Black Holes
Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家)think that at the center of a black hole there is a single point in space with infinite(无限的)density(稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point. Anything that crosses the black hole is pulled in by its great gravity.
Although black holes do exist, they are difficult to observe. These are the reasons.
-- No light or anything else comes out of black holes. As a result, they are invisible to a telescope.
-- In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon(视界)only 18 miles across.
-- The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion(万亿)miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.
选项
A、Right
B、Wrong
C、Not mentioned
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/kehd777K
本试题收录于:
职称英语理工类C级题库职称英语分类
0
职称英语理工类C级
职称英语
相关试题推荐
ThemainreadersofmedicaljournalsareAnarticledealingwithresultsfromdifferentstudiesonthesametopiciscalled
JewelThiefCapturedAt1:30thismorning,localpolicefinallycaughtthejewelthiefwhomtheyhadbeentryingtotrap(诱捕
BusinessMarketsAreBigBusinessInternationallyBusiness-to-businessmarketingisasignificanteconomicactivityinternat
GoingonaDietAtypicalpersonneedsabout1,800caloriesperdaytostayalive.Thesecalorieskeepyourheart【C1】______
EatHealthy"Cleanyourplate!"and"Beamemberoftheclean-plateclub!"JustabouteverykidintheUShasheardthisfro
Thereisagrowinggapbetweentherichandthepoor.
Whatdoactivistsworryabout?Theword"message"inthelastparagraphmeans______.
ContinuingMedicalEducationThereisincreasingrecognitionoftheneedforhealthworkerstocontinuetheireducationthro
AborntobemoreintelligentorlessintelligentBhaveabetterchancetodevelophisintelligenceCtaughttobemoreintelli
TheweatherisaconstantsubjectofconversationinBritain.
随机试题
()
下列关于化疗药物所引起的不良反应,描述错误的是
CR的中文全称是
患者,女性,42岁。近来偶有心慌不适,听诊心率90次/分,心律失常,第一心音强弱不等。该患者最有可能的诊断是
水工建筑物基础处理工程专业承包一级企业,资质标准要求企业注册资本金和净资产分别为()。
证券从业人员违反《证券业从业人员执业行为准则》的规定时,( )有权对机构和从业人员进行纪律惩戒。
下列各项中,属于波特价值链分析中基本活动的有()。
以房屋为客体的物权变动的公示方式是
[A]Developmentwelcomedbycityplanners[B]Reduceddemandsonspaceandenergy[C]Plansforfuturehomes[D]Worldwideexamp
A、Thewomandoesn’tneedtojointhechessclub.B、Thewomanneedslotsoftimetoplaychess.C、He’snotaverygoodchessplay
最新回复
(
0
)