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
2013-04-22
27
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、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://jikaoti.com/ti/w86MFFFM
0
专业英语四级
相关试题推荐
Intherealworldmostpeoplehaveadefinitedislike【C1】______certainsortsofworkathome.Twoofthesetasksareironingclo
Incontrasttologic,thereiscommonsense,orstillbetter,theSpiritofReasonableness.IthinkoftheSpiritofReasonablen
WhowontheWorldCup1998footballgame?WhathappenedattheUnitedNations?Howdidthecriticslikemenewplay?【C1】______an
TheInternet,E-commerceandglobalizationaremakinganeweconomicerapossible.Inthefuture,capitalistmarketswilllargel
Truepatriotism______puttingtheinterestsofonecountryaboveeverything,______one’slife.
Wheredoestheconversationtakeplace?
Mostofthemembersmadesucha_____protestagainsttheproposalthatthecommitteehadtoyield.
Thissumofmoneyplayedavitalroleinthecompletionoftheproject,______it,theprojectwouldnothavebeencompletedso
HowmanyrefugeesCamefromVietnamsincetheearly1970s?
Howmanypassengerswillbeaffectedbythestrike?
随机试题
横向垄断协议是指两个或两个以上的因经营同类产品或服务而在生产或销售过程中处于同一经营阶段的同业竞争者,为限制竞争而达成的固定或者变更商品价格,限制商品的生产数量或者销售数量,分割销售市场或者原材料采购市场,限制购买新技术、新设备或者限制开发新技术、新产品的
根据克利夫·鲍曼的“战略钟”理论,下列各项中属于失败战略的是()。
患者,男,40岁,因反复发作性腹泻、腹胀半年余就诊,同时伴有消化不良、肠鸣增多、大便带黏液等症状。偶尔有腹痛,或伴有皮肤荨麻疹症状。患者自觉症状发作似与进食某些奶制品相关,患者进行双盲安慰剂对照食物激发试验后,牛奶为阴性,则以下项表述正确的是
细菌感染的治疗主要采用抗菌药物,主要作用机制为
A.甲氧氯普胺B.多潘立酮C.阿托品D.莫沙必利E.山莨菪碱苯并咪唑衍生物,选择性阻断外周多巴胺受体的是()。
在我国社会主义市场经济条件下,价格的功能是()。
银行或者其他金融机构的工作人员违反规定,为他人出具信用证或者其他保函、票据、存单、资信证明,情节严重的,处5年以下有期徒刑或者拘役;情节特别严重的,()。
我国开放式基金注册登记体系的模式不包括()。
以下叙述中正确的是
A、classicdisasterB、greatachievementC、commonpeople’slivesD、politicalnewsA
最新回复
(
0
)