首页
登录
职称英语
What forms of radiation are feared by astronauts? [br] [originaltext] Not lon
What forms of radiation are feared by astronauts? [br] [originaltext] Not lon
游客
2024-10-05
24
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 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、Between 12 and 21 miles
B、1,000 miles
C、150 miles
D、1,500 miles
答案
A
解析
“These are two areas of radiation about 1,500 miles away from the earth”,答案自然揭晓。
转载请注明原文地址:https://tihaiku.com/zcyy/3788282.html
相关试题推荐
What’stheUStroopcasualty?[br][originaltext]TheUSmilitarywrappedup
Theemergencyreliefwouldbeprovidedfor______.[originaltext]Legislation
AustraliareactedtowardstheFrenchtestby______.[originaltext]Francehas
Howshouldcheerleadingbeviewedaccordingtothepassage?[br][originaltext]
Howshouldcheerleadingbeviewedaccordingtothepassage?[br][originaltext]
Whatdoestheconversationsayaboutthepassenger’sticket?[br][originaltext
Whatdoestheconversationsayaboutthepassenger’sticket?[br][originaltext
Whatdoestheconversationsayaboutthepassenger’sticket?[originaltext]W:Ne
WhatistheStudentActionCoalitiontryingtodo?[br][originaltext]W:Hmm,h
WhatistheStudentActionCoalitiontryingtodo?[originaltext]W:Hmm,hi.M.
随机试题
Attitudesofrespect,modestyandfairplaycangrowonlyoutofslowlyacqu
Hefeelsthatheisnotyet______totravelabroad.A、toostrongB、enoughstrong
FilmisamediumthatmighthavebeenespeciallymadeforAmerica,avastco
下列关于氨的性质,说法正确的是()。A.氨是应用较广的中温制冷剂,标准沸点为
属于二级保护野生植物药材物种的是()。A.血竭B.诃子C.蔓荆子D.山茱萸E.
期货交易所涉及占其净资产()以上或者对其经营风险有较大影响的诉讼,期货交易所应
甲国民航客机在途径乙国时遭丙国人阿里的劫持,飞机被迫在乙国降落。阿里逃脱时伤两名
罂粟壳每张处方不得超过()用量,连续使用不得超过()A.3日、7天
下列与会计信息质量要求相关的业务,表述或处理正确的是()。A.甲公司将本年发生
背景资料 某水库枢纽工程由大坝、溢洪道、电站及灌溉引水洞等建筑物组成。其中大
最新回复
(
0
)