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
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 spar
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 spar
admin
2015-01-09
45
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. You might see stars where before you only saw dark space. You might see that many stars look larger than others. You might see that some stars that look white are really red or blue. With bigger and bigger telescopes you can see more and more objects in the sky. And you can see those objects in more and more details.
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.
You might find it hard to imagine that stars die. After all,our Sun is a star. Year after year we see it up in the sky burning brightly,giving us heat and light. The Sun certainly doesn’t seem to be getting old or weak. But stars do burn out and die after billions of years.
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 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 each 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 black hole can never come back to your eyes. That’s why you see nothing but blackness.
So the next time you stare up at the night sky,remember: there’s more in the sky than meets the eyes! Scattered in the silent darkness are black holes—the great mystery of space.
What is the main idea of the article?
选项
A、The future of our Sun billions of years from now.
B、The difference between our Sun and a dead star.
C、The mystery of black holes in the universe.
D、The sparkling and dying stars in the sky.
答案
C
解析
题目问:文章的主要观点是什么?通过文章内容可知,文章主要是向读者在介绍黑洞的相关知识。包括黑洞是如何形成的,黑洞的特点等等。所以。答案是C。
转载请注明原文地址:https://kaotiyun.com/show/YBLO777K
0
考博英语
相关试题推荐
AnAmericanuniversitypresidentoncecommentedthat"Einsteinhascreatedanewoutlook,anewviewoftheuniverse.AItmayb
DuringMcDonald’searlyyearsFrenchfriesweremadefromscratcheveryday.RussetBurbankpotatoeswere【1】,cutintoshoestrin
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisortofindthegiftedfewan
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisortofindthegiftedfewan
Itisimportantthatanundergraduate______agradepointaverageofBinhismajorfield.
HerearetwoelementsinlifethatAmericansdosavecarefully:timeandlabor.Americansare"slavestonothingbutthecl
Howtoevaluatetheperformanceofstudentsisstillaproblemthattroublesmanyprofessors.
Theprofitmotiveisinherently______withprinciplesoffairnessandequity.
Allthekeywordsinthearticleareprintedin______typesoastoattractreaders’attention.
Unfortunately,hisdamagingattacksontheramificationsoftheeconomicpolicyhavebeen______byhiswholeheartedacceptanceof
随机试题
以下关于企业筹资结构的说法中,正确的是()
X线管的外观检查不包括
华生集团面临环境三个领域的问题采取的措施是()。华生集团以往的经营过份强调市场份额,应该将重点放于()。
在十一五时期,适当调整消费税征收范围,合理调整部分应税品目税负水平和征缴办法,完善()。
有关人体三大营养物质代谢之间关系的描述,正确的是()
这次招考人民警察面向的是基层。工作任务比较繁杂,条件艰苦,你认为你能够忍受吗?
下列关于社会主义初级阶段按劳分配的特点的说法正确的是()。
(10年)设已知线性方程组Aχ=b存在2个不同的解.(Ⅰ)求λ,a;(Ⅱ)求方程组Aχ=b的通解.
Classes______,thestudentsleftforhomewithoutdelay.
WhyWeLaughWestartfindingthingslaughable--ornotlaughable--earlyinlife.Aninfantfirstsmilesatapproximatelyeig
最新回复
(
0
)