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
考研
Despite the fact that comets are probably the most numerous astronomical bodies in the solar system aside from small meteor frag
Despite the fact that comets are probably the most numerous astronomical bodies in the solar system aside from small meteor frag
admin
2011-03-11
30
问题
Despite the fact that comets are probably the most numerous astronomical bodies in the solar system aside from small meteor fragments and the asteroids, they are largely a mystery. Scientists do not know exactly what comets are or where they come from. Educated guesses are the best we have in hand.
Considering the role of comets in legend and the memory of man, it is remarkable that we still know so little, relatively, about them. The most famous comet of all, Halley’s Comet ( named for the man who predicted its return), was first sighted by the Chinese in 240 B.C., and it has returned to terrify the people of the world on a regular basis every since then. The ancient considered it an object of ill omen. By mysterious coincidence, the arrival of Halley’s Comet coincided with such events as the battle of Hastings in 1066, the Jewish revolt of 66 A.D., and the last battle of Attila the Hun against the Romans. Nor is it the only comet to fill man with awe, but merely the most famous in a rich aristocracy of blood-freezers.
Comets are even more fascinating to amateur astronomers than to professionals, because this is one area where amateurs can make major discoveries. Comet Ikeya Seki, one of the brightest comets to appear in this century was discovered in 1965 by a pair of Japanese amateurs, Ikeya and Seki. The person who discovers a new comet gets his (or her) name put on it. And amateurs have a head start in the race to discover new comets; the shorter focal lengths on their smaller telescopes give them a positive advantage over the huge telescopes such as Mount Wilson which is built to scan for galaxies, not comparatively short distances.
Most scientists tend to agree with astronomer Fred T. Whipple that a comet is really a large mushy snowball of frozen ices and gases ( ammonia, methane, possibly carbon dioxide) with a few bits of solid particles stuck inside. But no one is sure how comets are created in the first place.
Scientist believe that comets don’t exhibit their characteristic tail while they lurk fat out in space away from the warmth of the sun but, rather, wander in the form of frozen lumps, like icebergs. This is the core of the comets. Only when the comet approaches the heat of the sun, does the ice begin to melt and stream away in the form of visible gases. The tails of the comets stream out behind for, literally, astronomical distances. Halley Comet had a tail of 94 million miles long when it visited here in 1910.The Great Comet of 1843 had a tail of 186 million miles long.
The core of a comet______.
选项
A、has no solid form
B、wanders like a frozen lump when it’s far out in space
C、requires the warmth of the sun to survive
D、is always followed by a long tail
答案
B
解析
文章最后一段第一、二句说科学家们认为彗星在远离太阳的太空中是没有尾巴的,而是以冰块的形式飘荡;故B正确,D错误。既然以冰块的形式,那么就应该有固体形态,故A错误;文章提到,当彗核接近太阳,依靠太阳的热度形成尾巴,故C是错误的理解。
转载请注明原文地址:https://jikaoti.com/ti/YH0RFFFM
0
考研英语一
相关试题推荐
MorethantwocenturiesafterBenjaminFranklinusedonetostudylightning,ateamofatmosphericscientistshasfoundthatkit
Humanshavealteredtheworld’sclimateby(1)_____heat-trappinggasessincealmostthebeginningofcivilizationandevenprev
Humanshavealteredtheworld’sclimateby(1)_____heat-trappinggasessincealmostthebeginningofcivilizationandevenprev
Astothepunishmentthatchildrenundersevenareassignedtowrongdoing,PiagetsuggestsPiagetandKeaseywouldnothaveagr
AfterDollytheSheepcometheMickeyMice.(46)Scientistsareexpectedtorevealthattheyhavesucceededincreatingthefirst
ThesizeoftheEskimolanguagespokenbymostwhitesis______.Inthepassage,theauthormentioned:"Eskimowordsarehighly
Almostexactlyayearago,inasmallvillageinNorthernIndia,AndreaMillinerwasbittenonthelegbyadog."Itmusthave(
Almostexactlyayearago,inasmallvillageinNorthernIndia,AndreaMillinerwasbittenonthelegbyadog."Itmusthave(
Manyteachersbelievethattheresponsibilitiesforlearningliewiththestudent.(1)_____alongreadingassignmentisgiven,
Theauthorconsidersanewtheorythatcoherentlyrelatesdiversephenomenatooneanothertobethe______Whichofthefollowi
随机试题
患儿,男,1岁,T39℃,1小时前以上呼吸道感染急诊入院,治疗期间患儿出现双眼凝视,全身抽搐,意识丧失。该患儿最可能的诊断是
以下关于急性胆囊炎的护理措施,错误的是
男,50岁。患慢支肺气肿多年,某日上午因用力咳嗽,突感胸痛气促,立即被送到医院急诊科。体检发现:血压100/70mmHg,呼吸120次/分,烦躁,唇、指发绀,气管明显偏左,右侧胸廓饱满,叩诊鼓音,呼吸音明显减弱。拟诊右侧气胸,未作相应处理,立即送放射科作胸
在重整程序中,下列选项正确的是()。
监理大纲是建设工程监理系列文件之一,其主要作用有( )。
边铺衬玻璃布,边涂刷胶粘剂,直至要求层数,固化后即成玻璃钢制品的玻璃钢衬里施工方法是()。
对跨国劳务所得行使来源地管辖权的约束标准为( )。
用户每次打开Word程序编辑文档时,计算机都会把文档传送到另一台FTP服务器上,于是用户怀疑最大的可能性是Word程序中已被植入了______。
一个()允许用户为类定义一种模式,使得类中的某些数据成员、某些成员函数的参数和返回值能取任意数据类型。
Whatdidthewomandoontheweekend?
最新回复
(
0
)