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 is
Black Holes Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is
admin
2012-12-03
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.
The attraction of two large stars leads to gravity.
选项
A、Right
B、Wrong
C、Not mentioned
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/XYQd777K
本试题收录于:
职称英语理工类B级题库职称英语分类
0
职称英语理工类B级
职称英语
相关试题推荐
FortyMayBetheNew30asScientistsRedefineAgeIs40reallythenew30?Inmanywayspeopletodayactyoungerthantheirp
EveryDogHasItsSayKimikoFukuda,aJapanesegirl,alwayswonderedwhatherdogwastryingtosay.Wheneversheputonma
MigrantWorkersInthepasttwentyyears,therehasbeenanincreasingtendencyforworkerstomovefromonecountrytoanot
ExercisingYourMemory1Agingdoesnotmeanadramaticdeclineinmemorypower,unlessyouhelpithappenbylettingyourmind
InterviewTheimportanceandfocusoftheinterviewintheworkoftheprintandbroadcastjournalistarereflectedinsever
OldMothers’ChildrenHaveHigherDiabetes(糖尿病)RiskChildrenofoldermothersrunahigherriskofdevelopinginsulin-depen
AImportanceofstayingintellectuallyactiveBEffectsofagingonaperson’srecallabilityCShort-termmemoryversuslong
CosmeticSurgerySurgerythatcanimprovethewayapersonlooksisbecomingmoreandmorepopularintheUnitedStates.This
SomesleepdrugsdomorethanmakeyousleepTheUnitedStatesFoodandDrugAdministration(美国食品及药品管理局)hasorderedcompani
ArtificialSpeechBecausespeechisthemostconvenientformofcommunication,inthefuturewewantessentiallynaturalcon
随机试题
绒毛膜癌最主要的转移途径是
茶艺人员发现有陌生客人进店,此时应该选择
按我国消费税制度规定,下列商品中,属于消费税课税对象的是
郁证的临床表现是
引起压疮的原因不包括
吸气时对心脏外形的主要影响是
男性,45岁,发热、咳嗽1周,曾少量咳痰伴痰中带血3次。胸片示右中叶3cm×3cm类圆形阴影,中间可见空洞,无液平。痰找结核菌一次,结果阴性,胸部CT示空洞为偏心空洞,部分洞壁有结节状隆起。进一步的检查应首先考虑
肛管直肠癌的早期症状除便血外,还可见()
汉宣帝时期,一村民甲的儿子将邻居的女儿强奸,事发后,甲将儿子隐匿于山中,后被官府发现,将两人一同拘捕监禁,则下列说法不正确的是哪些?()
ApprenticeshipshavelongbeenpopularinEurope,butworkforce-orientedhighschooltrainingisnearlyascommonin【M1】______U
最新回复
(
0
)