首页
登录
职称英语
What forms of radiation are feared by astronauts? [originaltext] Not long ag
What forms of radiation are feared by astronauts? [originaltext] Not long ag
游客
2023-11-13
9
管理
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 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、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
转载请注明原文地址:https://tihaiku.com/zcyy/3184556.html
相关试题推荐
FoodwasteinSeattleisfinallymadeintoakindof[br][originaltext](11
Themanstopstotakehisdogoutsidetodoexercisebecause[br][originaltext
Themanstopstotakehisdogoutsidetodoexercisebecause[br][originaltext
Themanstopstotakehisdogoutsidetodoexercisebecause[originaltext]M:Th
WhatdoestheMinisterwanttokeepaneyeon?[br][originaltext]RussianE
WhatdoestheMinisterwanttokeepaneyeon?[originaltext]RussianEmergen
Whatisthefocusofthenews?[br][originaltext]FINAsaidGreekgovernmen
Whatisthefocusofthenews?[originaltext]FINAsaidGreekgovernmentoffi
Whichfonmswasthebasisforphotography?[br][originaltext]Thecamerais
Whichfonmswasthebasisforphotography?[originaltext]Thecameraisoften
随机试题
NowomancanbetoorichortoothinThissayingoftenattributedtothelat
与左心功能不全的表现不符的是()。A.中心静脉压>1.8kPa B.肺毛细
施工现场有多台塔式起重机作业时,()应当应当组织制定并实施防止塔式起重机相互碰
临床常用的超声探头频率是A.2.5~3.0MHz B.3.5MH C.5.0
患儿,男,6月,反复发热入院,最高体温38.3℃,无咳嗽、咳痰,尿频,排尿哭闹,
多节串联使用的金属氧化物避雷器,如果其中一节进水受潮,热像图的特征是()(
桑代克提出的学习律有A.准备律 B.练习律 C.效果律 D.频因律
在人的身心发展中,有的方面在较早的年龄阶段就已达到较高的发展水平,有的则要到较晚
激素的第二信使( )。A.ATP B.NAD+ C.cAMP D.cGM
某化工建设项目设计年生产能力5万吨,预计年固定总成本为400万元,产品销售价格8
最新回复
(
0
)