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
48
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
Inthefinalanalysis,itisour______ofdeathwhichdecidesouranswerstoall
Directions:Forthispart,youareallowed30minutestowriteashortessay
Asamediumofexchangemoneypermitstheseparationofexchangeintothetw
Sherefusedto______tomygoingabroad.A、convertB、contributeC、correspondD、c
个人献血登记记录包括( )。A.个人详细资料,献血者病史,同意书,身体基本检查
根据《著作权法》规定,表演者对其表演享有下列权利()A.表明表演者身份;保护表演
下列各项中,不符合内部牵制的要求的是()。A、出纳人员管票据 B、出纳人员
给临床资料赋予意义时可以使用()。单选A.投射法 B.统计分析法 C.
投资项目决策分析与评价的基本要求包括贯彻落实科学发展观、资料数据准确可靠和()
圆截面细长压杆的材料和杆端约束保持不变,若将其直径减小一半,则压杆的临界压力为原
最新回复
(
0
)