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
33
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://jikaoti.com/ti/TYuGFFFM
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
Ifyouweretobeginanewjobtomorrow,youwouldbringwithyousomebasicstrengthsandweaknesses.Successor【61】inyourwor
Nosooner______thenewsthantheyrushedoutintothestreet.()
Throughouthistorymanhashadtoacceptthefactthatalllivingthingsmustdie,butpeoplenowlivelongerthanthey【36】.Yet
Throughouthistorymanhashadtoacceptthefactthatalllivingthingsmustdie,butpeoplenowlivelongerthanthey【36】.Yet
Forthispart,youareallowed20minutestowriteashortcompositionofabout100-120wordsontherifle:Hope.Baseyourco
Asheartdiseasecontinuestobethenumber-onekillerintheUnitedStates,researchershavebecomeincreasinglyinterestedin
Mostanimalshavelittleconnectionwithanimalsofadifferentkind,unlesstheyhuntthemforfood.Sometimes,however,twoki
Mostanimalshavelittleconnectionwithanimalsofadifferentkind,unlesstheyhuntthemforfood.Sometimes,however,twoki
WhatisthetypicalAmericanfamily【21】?MarriedAmericanadultswillnametheirhusbandorwifeandtheirchildren【22】their"im
Unlessyouworkhardyou______yourtest.
随机试题
下列哪种因素可能造成管线外壁腐蚀?()
下列食物中富含碘的是
男,23岁。发热5天,最高温度39.6℃。发热前有寒战,无咳嗽、咳痰。腹痛、腹泻,尿量减少。入院查体:T38.6℃,心率108次/分,BP80/60mmt{g。实验室检查:WBC23.6×109/L,N86%,可见中、晚幼粒细胞,Hb78g/L。以下做法不
进口的食品、食品添加剂、食品容器、包装材料和食品用工具及设备,进口单位在申报检验时,应当提供输出国(地区)所使用的农药、添加剂、熏蒸剂等有关资料和检验报告。( )
“备案号”栏:()。“征免性质”栏:()。
证券公司可以自有资金参与本公司设立的集合资产管理计划。( )
注册会计师无法对被审计单位会计报表的应收账款项目实施必要的审计程序,且无替代审计程序,则注册会计师可出具( )审计报告。
每秒钟通过信道传输的二进制位数是(5)。每秒钟能够过信道传输的有效数据位是(6)。从信息流的传送效率来看,(7)系统工作效率最低。从吞吐量来看(8)系统最强。
一般来说,占维护工作比例最高的是()。
Anintellectualbreakthrough,______,doesnotautomaticallyensurethatthetransitionismadefromtheorytopractice.
最新回复
(
0
)