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
68
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 center of a black hole is empty.
选项
A、Right
B、Wrong
C、Not mentioned
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/WYQd777K
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
ABiologicalClockEverylivingthinghaswhatscientistscallabiologicalclockthatcontrolsbehavior.Thebiologicalcloc
ABiologicalClockEverylivingthinghaswhatscientistscallabiologicalclockthatcontrolsbehavior.Thebiologicalcloc
Someabnormalhumanbehaviormaybecausedbyeatingsubstancesthatupsetdelicatechemicalbalancesinthebrain,
CellPhones:HangUporKeepTalking?Millionsofpeopleareusingcellphonestoday.Inmanyplacesitisactuallyconsider
Weallageatdifferentrates.Heredityclearlyplaysanimportantpart.Butrecentresearchstudiesbygerontologistsindicate
TeachingandLearningMedicineAwardTwoscientistswhohavewonpraiseforresearchintothegrowthofcancercellscouldb
EatingPotatoesGivesYourImmuneSystemaBoostEatingpotatoesisnotonlygoodforbowelhealth,butalsoforthewholei
EveryDogHasItsSayKimikoFukuda,aJapanesegirl,alwayswonderedwhatherdogwastryingtosay.Wheneversheputonmake
Ithinkthenewstrategyourmanagercameupwithwon’tworkinthemarket.
Beijingisapleasantplacewithconvenienttransportationandcommunicationsystem.
随机试题
在考生文件夹下的“samp1.accdb”数据库文件中已建立3个关联表对象(名为“职工表”、“物品表”和“销售业绩表”)、一个窗体对象(名为“iTest”)和一个宏对象(名为“mTest”)。请按以下要求,完成表和窗体的各种操作:(1)分析表对象
外表皮灰棕色或灰褐色,切面射线呈放射状排列,髓小或有时中空,气微,味微苦而涩的饮片是
管弦乐幻想曲《荒山之夜》的作者是【】
产妇出血的主要原因为此患者给缩宫素后,宫体变硬,但仍然有少量鲜红色血液流出,检查宫颈缝合处无明显渗出,此时考虑出血可能来源于
A.羽扇豆烷B.齐墩果烷型C.达玛烷型D.乌苏烷型E.羊毛甾烷型熊果酸属于()。
80年代以后,随着_____和维果斯基的理论被大景介绍到美国,加之认知心理学研究的深刻影响,人们对学习概念的理解发生了很大变化。
A.急性B淋巴细胞性白血病B.急性T淋巴细胞性白血病C.急性粒细胞性白血病D.急性红白血病E.急性巨核细胞性白血病CDl3阳性见于
当今时代的主题是()
Insettingenvironmentalstandardsforindustryandotherstomeet,itisinadvisabletorequirethebestresultsthatstate-of-
______isoftenthecase,onethirdoftheworkershaveover-fulfilledtheproductionplan.
最新回复
(
0
)