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
2012-12-31
74
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/aAeC777K
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
Mostpeoplewanttowork,butithasbecomemoredifficultintoday’sworldtofindworkforeverybody.Theeconomies(经济)ofth
Man’sfirstroaninvention,andoneofthemostimportantinventionsinhistory,wasthewheel.Alltransportationandeverymac
Aroundtheworldmoreandmorepeoplearetakingpartindangeroussportsandactivities.Ofcourse,therehavealwaysbeenpeop
Aroundtheworldmoreandmorepeoplearetakingpartindangeroussportsandactivities.Ofcourse,therehavealwaysbeenpeop
OnedayIwasshoppingwithMarywhenagroupofwhitemenfoundus.Atallman【21】upandaskedmewhereIlived.Marywassoan
Socialcustomsandwaysofbehavingchange.Thingswhichwereconsideredimpolitemanyyearsagoarenowacceptable.Justafew
Socialcustomsandwaysofbehavingchange.Thingswhichwereconsideredimpolitemanyyearsagoarenowacceptable.Justafew
Americaisacountryonthemove.Inunheardofnumbers,peopleofallagesareexercisingtheirwaytobetterhealth.According
TheAmericanideaofcustomerserviceistomakeeachcustomerthecenterofattention.PeoplegoingshoppinginAmericacanexp
AyoungpairofpandasisexpectedtosettleintheirnewhomeintheAtlanta’sZooto-morrow,tileBeijingYouthDailyreporte
随机试题
从四肢静脉注入对比剂后,肝静脉期显示时间约为
婴儿腹泻治疗原则不包括
在国际贸易的货款结算中,托收通常采用()
年度终了,根据本年度财政直接支付预算指标数与当年财政直接支付实际支出数的差额,借记“财政应返还额度一财政直接支付”科目。贷记“财政补助收入”科目;下年初,作相反会计分录。()
国家实施东北地区等老工业基地振兴战略的目标是:经过十到十五年的努力,实现东北地区的全面振兴。将东北建设成为(),以及国家生态安全的重要保障区。
以下历史事件,发生在我国新民主主义革命时期的有()。
实现可持续发展的关键是()。
★「☆∵※「∵
2012年全国各城市第三产业增加值增速达到和超过10%的城市有()。
(1)证明:(2)求
最新回复
(
0
)