首页
登录
职称英语
What forms of radiation are feared by astronauts? [br] [originaltext] Not l
What forms of radiation are feared by astronauts? [br] [originaltext] Not l
游客
2023-11-21
37
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 per- haps 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/3207290.html
相关试题推荐
Afghanistan’sfirstmatchwillbeagainst[originaltext] KualaLumpur-Afghanist
What’stheUSmilitary’sinvestigationon?[br][originaltext]TheUSmilitar
Whatdoesthespeakertalkabout?[br][originaltext]Innormalcircumstances
Whatdoesthespeakertalkabout?[originaltext]Innormalcircumstanceswolve
Howlonghastheprotestlastedaccordingtothenews?[br][originaltext]Mo
Howlonghastheprotestlastedaccordingtothenews?[br][originaltext]Mo
Wecaninferfromthespeakerthat[br][originaltext]Today,Iwanttotalk
Wecaninferfromthespeakerthat[br][originaltext]Today,Iwanttotalk
WhichofthefollowingstatementsisTRUEaboutLisa?[br][originaltext]W:Now
WhichofthefollowingstatementsisTRUEaboutLisa?[originaltext]W:Now,spec
随机试题
______(瘫痪在床多年).helostallhopeofrecovery.Havingbeenlaidupwithparalysis
[originaltext]W:IsthereamancalledBeninyourdepartment?M:I’msorry.I’mn
Baby-NamingTrends[A]Overthelastfiftyyears,Americanparentshaver
典型慢性肾功能不全时的水电解质紊乱是A、代谢性酸中毒、低血钙、高血磷、高血钾
关于外币股权投资基金,表述错误的是()。A.外币股权投资基金既可以在中国境内以
A.香附B.醋香附C.四制香附D.酒香附E.香附炭具有疏肝止痛,并能消积化滞的是
中国临床检验标准委员会推荐尿比密测定的参考方法是( )。A.化学试带法 B.
呋喃唑酮是A.硝基呋喃类抗菌药 B.磺胺类抗菌药 C.异喹啉类抗菌药 D.
基金份额持有人是()。 A.基金投资者B.基金的出资人 C.基金资产
甘松除行气止痛外,又能A.温肾散寒 B.开郁醒脾 C.温肾纳气 D.燥湿化
最新回复
(
0
)