首页
登录
职称英语
How many things can you see in the night sky? A lot! On a clear night you mi
How many things can you see in the night sky? A lot! On a clear night you mi
游客
2025-04-21
20
管理
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. [br] 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
题目问:当你看到一个黑洞时,为什么你不能见到光?倒数第二段“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 noting but blackness.”通过这段话可知,黑洞是如此的紧凑,以至于它的重力吸收一切东西。甚至是光。黑洞里的光永远也到不了你的眼睛里。这就是你为什么看到一片漆黑的原因。所以,答案是A。
转载请注明原文地址:http://tihaiku.com/zcyy/4046824.html
相关试题推荐
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Howmanythingscanyouseeinthenightsky?Alot!Onaclearnightyoumi
Howmanythingscanyouseeinthenightsky?Alot!Onaclearnightyoumi
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
Fearanditscompanionpainaretwoofthemostusefulthingsthatmenanda
随机试题
【试题要求】 1.任务描述 图1为一山区希望小学的平面图,砖墙承重,
豆腐蛋白质的消化率高于整粒大豆,主要原因是去除了()。A.脂肪 B.蛋
检验检测机构应当建立与活动范围相适应的管理体系,作业指导书不在此范围。()
下列各项,不属受精卵着床条件的是()A.子宫内膜发生蜕膜变 B.必须有足
患者江某,新产后一周小腹隐隐作痛,数日不止,喜按喜揉,恶露量少,色淡红,质稀无块
国家药典、局颁标准中所收载的处方称为A.医师处方 B.协定处方 C.法定
月圆:团聚 A.农民:勤劳 B.绿色:环保 C.太阳:炎热 D.朝
国务院和地方各级人民政府用于实施义务教育财政拨款的增长比例应当()财政经常性收入
某地一软弱地基采用换填法处理: I.某一内墙基础传至室内地面处的荷载值Fk=2
以下关于经营企业麻醉药品、一类精神药品、存放的说法中,正确的是A.专库或专柜存放
最新回复
(
0
)