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
What forms of radiation are feared by astronauts?
What forms of radiation are feared by astronauts?
admin
2010-01-15
43
问题
What forms of radiation are feared by astronauts?
Not long ago it was assumed that the dangers man would meet in space would be terrible, the main ones being radiation and the danger of being hit by meteors. It is per- haps worth remembering that less than two centuries ago the dangers of train travel seemed similarly terrible. A man would certainly die, it was thought, if carried along at a speed of thirty kilometers per hour.
There are two sorts of radiation man must fear in space. The first is radiation from the sun, and this is particularly dangerous when the sun is very active and explosions are occurring on its surface. The second, less harmful form comes from the so-called Van Allen Belts. These are two areas of radiation about 1,500 miles away from the earth. Neither of these forms of radiation area is dangerous to us on the earth, since we are protected by our atmosphere. Specifically, it is that part of our atmosphere known as the ozonosphere which protects us. This is a belt of the chemical ozone between 12 and 21 miles from the ground, which absorbs all the radiation.
Once outside the atmosphere, however, man is no longer protected, and radiation can be harmful in a number of ways. A distinction must be drawn between the short-and long-term effects of radiation. The former are merely unpleasant, but just because an astronaut returning from a journey in space does not seem to have been greatly harmed, we cannot assume that he is safe. The long-term effects can be extremely serious, even leading to death.
选项
A、Radiation from the sun.
B、Radiation from the Van Allen Belts.
C、Radiation from the meteors.
D、Both A and B.
答案
D
解析
听遍全文我们知道“There are two sorts of radiation man must fear in space.”“The first is radiation from the sun”“The second,less harmful form comes from the so-called Van Allen Belts”,因此宇航员们所惧怕的就是这两种射线。
转载请注明原文地址:https://kaotiyun.com/show/pLnK777K
0
专业英语四级
相关试题推荐
(1)Thishasbeenquiteaweekforliterarycoups.Inanalmostentirelyunexpectedmove,theSwedishAcademyhavethislunchtim
PASSAGETWOFromthelastparagraphwhatwastheauthor’sattitudetowardsthecapabilityoftheWorldBanktosolveitsproble
FourreasonsthatrosyNovemberjobsreportwasevenbetterthanitseemed.It’simportantnottomaketoomuchoutofasingl
ThroughouttheU.S.studentsaregettingouttheirNo.2pencils,readyendureastress-packedfourhoursofbubblinginanswers
(1)Procrastinationcomesinmanydisguises.Wemightresolvetotackleatask,butfindendlessreasonstodeferit.Wemig
Anarrowingofyourinterestsisimpliedinalmostanytransitionfromastudyenvironmenttomanagerialorprofessionalwork
Readcarefullythefollowingtwoexcerptsonprivatetutoring,andthenwriteyourresponseinNOLESSTHAN300WORDS,inwhic
Inrecentyears,itisnotuncommonthatacollegedegreecannotearnacollegegraduateadecentjobwhileskilledworkersf
WhatwasthemostimportantjobfortheastronautsofDiscovery?
Howisit______yourroommate’srequestandyoursareidentical?
随机试题
WhatwastheconsequenceoftheSevenYears’WarbetweentheBritishandtheFrench?
A.美托洛尔B.氨氯地平C.卡托普利D.特拉唑嗪E.安体舒通高血压伴前列腺肥大首选
社区卫生服务的目的是
关于假设检验,以下正确的一项是
学龄期儿童造血的红骨髓位于
下列何种药物可以制成胶囊剂
2011年末我国大陆总人口为134735万人,比上年末增加644万人,其中城镇人口为69079万人,占总人口比重首次超过50%,达到51.3%。全年出生人口1604万人,出生率为11.93‰,自然增长率为4.79‰。2011年末我国大陆共有医疗卫
经营净收益除以净利润所反映的财务指标是()。
美育的最终目的是()。
如何认识教学过程中教师的主导作用与学生的主动性的关系?【2010年-江西师大】【2019年-内蒙古师大/山西师大】
最新回复
(
0
)