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
How many kinds of radiation are feared by astronauts?
How many kinds of radiation are feared by astronauts?
admin
2010-07-06
38
问题
How many kinds 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 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 danger 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 ns. 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、We are too far away from any harm.
B、We can protect ourselves.
C、There is part of the atmosphere protecting us.
D、There is special layers on our skin.
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/apDd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
5/five本题考查的是对数字的听音。在第一个话轮中,女士的回答直接指出:Igetupveryearly,aroundfiveo’clock,因此填入five或用阿拉伯数字。
Itwillbeareliefoverthedeathofafriendorarelativeifthefriendorrelativediesfrom______.Adoctorwillbeguilt
Thefirstparagraphismainlyabout______.Accordingtothispassage,optimumpopulation______.
Accordingtothepassage,thechiefpurposeofexplorersingoingtounknownplacesinthepastwas______.Atpresent,aproba
Theimportanceandfocusoftheinterviewintheworkoftheprintandbroadcastjournalistisreflectedinseveralbooksthath
Somepeoplewerejustborntorebel;CharlesDarwinwasoneofthem.【21】______NicholasCopernicus,BenjaminFranklinandBillGa
Somepeoplewerejustborntorebel;CharlesDarwinwasoneofthem.【21】______NicholasCopernicus,BenjaminFranklinandBillGa
Forthispart,youareallowed35minutestowriteacompositionbasedonthefollowingdirections: 1)Title:TheImportanceo
AstudybyscientistsinFinlandhasfoundthatmobilephoneradiationcancausechangesinhumanceilsthatmightaffectthebr
随机试题
砖是脆性材料,堆放时要求()坚实、平坦、干净,以保证堆垛稳固。
发动机可变配气相位技术只能用于汽油机上。()
在选拔录用程序中,每个应聘者必须接受所有的选拔测评,在做录用决策时,以他们各项得分的总和或加权处理后所得分数作为录用的参考依据。这指的是人员选拔模式中的【】
国务院关于2012年度国家科学技术奖励的决定通知国发
某工程业主与承包商签订了工程施工合同,合同中含有两个子项工程,估算工程量甲项为2300m3,乙项为3200m3,经协商合同价甲项为180元/m3,乙项为160元/m3。承包合同规定开工前业主应向承包商支付合同价款20%的预付款。则该项预付款的数额是(
下列做法属于有损于银行形象的是()。
根据《公安机关督察条例》的规定,督察机构对公安机关及其人民警察依法履行职责的哪些事项可以进行现场督察?()
经济利润
假设G={(x,y)|x2+y2≤r2}是以原点为圆心,半径为r的圆形区域,而随机变量X和y的联合分布是在圆G上的均匀分布.试确定随机变量X和Y的独立性和相关性.
AccountsAssistantEmployer:HANDLERECRUITMENTContact:SarahLeeLocation:WestEnd,LondonContract:Sixmonths
最新回复
(
0
)