首页
登录
职称英语
What forms of radiation are feared by astronauts? [br] [originaltext] Not l
What forms of radiation are feared by astronauts? [br] [originaltext] Not l
游客
2023-11-13
11
管理
问题
What forms of radiation are feared by astronauts? [br]
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 perhaps 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 ac five 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、Between 12 and 21 miles.
B、1,000 miles.
C、150 miles.
D、1,500 miles.
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3184557.html
相关试题推荐
WhatdestroyedSaint-Pierre?[originaltext]PeoplesaidthatSaint-Pierrewa
Whatisthemainsubjectofthistalk?[br][originaltext]Goodafternoon,
Whatistheconversationfocusedon?[br][originaltext]W:Ipersonally,um,do
Accordingtothepolls,whichpartytakestheleadatpresent?[originaltext]
Whothespeakerspeakingto?[br][originaltext]MayIhavetheattentionof
Whothespeakerspeakingto?[originaltext]MayIhavetheattentionofalls
whyistheweightlossplancalledtheScarsdalediet?[br][originaltext]
whyistheweightlossplancalledtheScarsdalediet?[br][originaltext]
Whatisthetalkmainlyabout?[br][originaltext]The23rdOlympicgameswe
Whatisthetalkmainlyabout?[br][originaltext]The23rdOlympicgameswe
随机试题
据相关资料显示,到去年年底,中国智能手机市场已成为全球智能手机出货量(shipment)第一的市场。Accordingtorelateddata,by
[originaltext]MystorybeganintheyearsfollowingWorldWarⅡ,whenmenl
TheWebsometimesisseemedastheSirenspecterthatluresusintositting
化学发光免疫分析主要用于检测A.体液中大分子蛋白质 B.体液中小分子蛋白质或多
绝大多数鼻咽癌属于A.低分化腺癌 B.高分化腺癌 C.高分化鳞癌 D.低分
上颌神经的终末支为() A.眶下神经 B.上牙槽前神经 C.鼻
诊断孕期胎儿宫内窘迫,下列检查方法错误的是A.测定尿E值 B.羊水肌酐值 C
基金管理人未经登记不得开展股权投资基金()业务。 Ⅰ.管理 Ⅱ.募集A
能行气消食化痰的药物是A.枳实 B.厚朴 C.鸡矢藤 D.莱菔子
(2020年真题)赵某收到一张支票,发现记载金额的中文大写和数码不一致。下列关于
最新回复
(
0
)