首页
登录
职称英语
The space between the stars is filled with matter that interstellar conditio
The space between the stars is filled with matter that interstellar conditio
游客
2024-01-10
50
管理
问题
The space between the stars is filled with matter that interstellar conditions should prevent from coalescing into solid particle. Yet surprisingly tiny frozen particles, referred to as interstellar grains, do develop in these spaces. These grains are formed out of chemical elements that are synthesized during thermonuclear fusion in stars and supernova explosions.
The study of interstellar grains has been hampered by the inaccessibility of naturally occurring specimens for use in laboratory experiments. To date, the only source of information about interstellar grains is the stellar electromagnetic radiation that reaches the Earth after passing through regions of space containing interstellar grains. By observing the wavelengths scattered and absorbed by the grains scientists have determined that a grain’s internal structure consists of a core composed of silicates (rocklike material) and a mantle composed entirely of organic compounds. It is hypothesized that each grain begins as a silicate “
seedling
” ejected from a mature star. Continuous physical and chemical evolution then occurs in the mantle formed around the seedling. [br] It can be inferred from the passage that the method currently used to analyze the structure of an interstellar grain could best be described is
选项
A、Unprecedented
B、Indirect
C、Comprehensive
D、Controversial
E、Unsound
答案
B
解析
根据第二段第一句可知,因为没法得到星际颗粒的标本,因此星际颗粒的研究方法都是间接的,选项B正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3349718.html
相关试题推荐
Solveforxifthemidpointbetweenthetwopoints(x,1)and(-2,-3)is(5,-1).
Whatisthedistancebetweenthepoints(3,-4)and(9,4)?UsetheDistanceForm
[img]2012q1/ct_egreqm_egreqtbz2_0223_20121[/img][br]Betweenwhichtwoconsecut
BoardAmeasuresbetween2.15feetand2.25feetinlength;boardBmeasuresbet
Solveforxifthemidpointbetweenthetwopoints(x,1)and(-2,-3)is(5,-1).12You
Whatisthemidpointbetweenthetwopoints(12,5)and(10,-7)?(11,-1)Usethemidpo
Solveforyifthedistancebetweenthetwopoints(2,8)and(-6,y)is17.23Usethe
Onthenumberline,2.3ishalfwaybetweenwhichofthefollowingnumbers?______
Inthefigurebelow,whatistherelationshipbetweenx,y,andz?[img]2014m9x/
Atthebeginningofatrip,thetankofDianascarwasfilledwithgasolinetoh
随机试题
Ifthedocumentsarriveontime,______inthedivisionshouldreceivetheircerti
[originaltext]FarmersandtheirsupportersprotestedWednesdayinhundredsof
[originaltext]W:Hi,Tony.WillyougotoTom’shometostudyinagroupthisa
Afteryearsofpromisesandfalsestarts,booksellersandtechnologycompanie
A:Whattimeisthismeetingsupposedtobegin?B:I’mnotsure.Ithoughtitwa
“科学知识和成功是公共财富,为人类共享。”以上描述属于下列哪一种科学规范A.普
Thechangeinthatvillagewasmiraculou
功能制护理的特点不包括A.以工作为中心的护理方式 B.分工不明确,不利于按护士
在燃气工程中,埋地铺设的聚乙烯管道长管段上通常设置补偿器的形式有()。A.
最新回复
(
0
)