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
专升本
How many things can you see in the night sky? A lot! On a clear night you might see the Moon, some planets, and thousands of spa
How many things can you see in the night sky? A lot! On a clear night you might see the Moon, some planets, and thousands of spa
admin
2013-12-10
39
问题
How many things can you see in the night sky? A lot! On a clear night you might see the Moon, some planets, and thousands of sparkling stars. You can see even more with a telescope.
But scientists believe there are some things in the sky that we will never see. We won’t see them with the biggest telescope in the world, on the clearest night of the year. That’s because they’re invisible. They’re the
mysterious
dead stars called black holes.
As a star’s gases burn, they give off light and heat. But when the gas runs out, the star stops burning and begins to die.
As the star cools, the outer layers of the star pull in toward the center. The star squashes(挤压)into a smaller and smaller ball. If the star was very small, the star ends up as a cold, dark ball called a black dwarf. If the star was very big, it keeps squashing inward until it’s packed together tighter than anything in the universe.
Imagine if the Earth were crushed until it was the size of a tiny marble. That’s how tightly this dead star, a black hole, is packed. What pulls the star in toward its center with such power? It’s the same force that pulls you down when you jump—the force called gravity. A black hole is so tightly packed that its gravity sucks in everything—even light. The light from a black hole can never come back to your eyes. That’s why you see nothing but blackness.
So remember; Scattered in the silent darkness are black holes—the great mystery of space.
Why can’t you see light when you look at a black hole?
选项
A、Because most black holes are so far away.
B、Because the gravity of a black hole is so strong that it sucks the light inward.
C、Because as the star’s gases burn, it stops giving off heat and light.
D、Because as a star cools, its outer layers pull in toward its center.
答案
B
解析
倒数第二段。在星星燃料烧尽冷却的过程中,自身的引力把所有的东西往里吸,包括光,而不是释放。所以你看不见光。选项B是正确的。选项C与事实相反。选项D不完整,除了外层被吸入,最关键的是光也被吸入。
转载请注明原文地址:https://kaotiyun.com/show/oOeC777K
本试题收录于:
英语题库成考专升本分类
0
英语
成考专升本
相关试题推荐
Television—thatmostattractivemoderntechnology,markedbyrapidchangeandgrowth—ismovingintoanewerawhichpromisesto
ThehomecomputersindustryhasbeengrowingrapidlyintheUnitedStatesforthelasttenyears.Computersusedtobelarge,ex
Ifyouweretobeginanewjobtomorrow,youwouldbringwithyousomebasicstrengthsandweaknesses.Successor【61】inyourwor
Themodernageisanageofelectricity.Peoplearesousedtoelectriclights,radios,televisions,andtelephonesthatitish
Increasingly,overthepasttenyears,people--especiallyyoungpeoplehavebecomeawareoftheneedtochangetheireatingha
Throughouthistorymanhashadtoacceptthefactthatalllivingthingsmustdie,butpeoplenowlivelongerthanthey【36】.Yet
Asheartdiseasecontinuestobethenumber-onekillerintheUnitedStates,researchershavebecomeincreasinglyinterestedin
AcrosstheUnitedStates,scientistsaremountingwhatmaybecomethemostinnovativeagriculturalresearchdrivesincethe1920
TheotherdayIheardanAmericansaytoaChinesestudentofEnglish"YouspeakverygoodEnglish."Butthestudentanswered,"
UnlessyouhavevisitedthesouthernUnitedStates,youprobablyhaveneverheardofkudzu.Kudzu,asanysouthernfarmerwills
随机试题
水平防潮层应设置在室内地坪(±0.000)以下()处。
某工厂生产的产品在甲、乙两个市场的销售量分别为Q1与Q2,其售价分别为P1与P2,需求函数分别为Q1=24-0.2P1,Q2=10-0.05P2,总成本为C=35+40(Q1+Q2),问这两个市场的定价分别定为多少时,可使总利润最大?最大利润是多少?
Thebus______hasgoneupanothernickel.
引起吸气性呼吸困难的疾病是
下列关于建筑防烟系统联动控制要求的做法中,错误的是()。
组织结构的主要特征因素包括()个方面。
数据库管理系统为用户和应用程序提供了_______语言,用此语言可以定义数据库的模式结构,但此语言执行后的结果不能回滚。
一个标准的1000Mbps交换式以太网结构中
定义无符号整数类为UInt,下面可以作为类UInt实例化值的是
A、Writinghelpsrelievestress.B、Cancercanbecured.C、Writingimprovestreatment.D、Writershardlyhavecancer.A
最新回复
(
0
)