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
2013-11-10
35
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 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、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
听遍全文我们知道“There are two sorts of radiation man must fear in space.”“The first is radiation from the sun”“The second,less harmful form comes from the so-called Van Allen Belts”,因此宇航员们所惧怕的就是这两种射线。
转载请注明原文地址:https://kaotiyun.com/show/k7GK777K
0
专业英语四级
相关试题推荐
Manystudentsfindtheexperienceofattendinguniversitylecturestobeaconfusingandfrustratingexperience.Thelecturersp
Virtuallyeverythingastronomersknownaboutobjectsoutsidethesolarsystemisbasedonthedetectionofphotons-quantaofele
Teachersneedtobeawareoftheemotional,intellectual,andphysicalchangesthatyoungadultsexperience.Andtheyalsoneed
WhichofthefollowingisNOTmentionedinthenews?
WriteonANSWERSHEETTWOacompositionof200wordsonthefollowingtopic:ProfitsofPraiseYou
Foryearspediatriciansdidn’tworrymuchabouttreatinghypertensionintheirpatients.Afterall,kidsgrowsofast,it’shard
Inwinterdrivershavetroublestoppingtheircarsfrom______onicyroads.(2000年考试真题)
Whyitisunrealistictosendastronautsbacktothemoonnow?
Accordingtotoday’sweatherforecast,whichpartofEuropehasdryweather?
Tomisimmenselycuriousabouteverythingandaseagertofindtheanswersasifhe______dealingwiththesubjectforthefirst
随机试题
损伤按部位不同可分为
Thiswasnoordinaryclass.ThestudentswhocametogetherwereallscienceorengineeringprofessorsatCornellUniversity.The
腹腔穿刺术可选择的穿刺点有()
甲施工企业违反行政法规规定,行政机关拟对其作出吊销资质证书的处罚,下列说法正确的是()。
下列可以归类为长期融资的是()。
某企业生产一种电子元器件,生产线上产品不合格品率约为20%,而顾客要求成品供货合格品率必须在99.9%以上。针对这种情况,企业分别对零件和半成品进行全数检验,挑选合格品投入下道工序,并在此基础上对成品采用GB/T2828.1进行出厂检验,并对拒收批次进行全
讲究礼仪礼节礼貌,是传统社会的繁文缛节,现代社会生活节奏加快,已经没有必要花费时间和精力甚至金钱去讲究了。()
随着年龄的增长,人体对热量的日需求量逐渐减少,而对维生素的需求却日趋增多。因此,为了摄取足够的维生素,老年人应当服用一些补充维生素的保健品,或者应当注意比年轻时食用更多的含有维生素的食物。为了对上述断定作出评价,回答以下哪个问题最为重要?(
课程标准
A、Foodisnolongerabasicneedforus.whileitwasforprimitivepeople.B、Weeatawidevarietyoffood.C、Wenolongereat
最新回复
(
0
)