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
74
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.
We learn from the text that amateur astronomers______.
选项
A、began their discovery earlier than the professionals
B、tend to be the leaders in the area of astronomy
C、have some advantages in discovering new comets
D、established some theories on how comets come into being
答案
C
解析
对业余天文爱好者的阐述出现在文章的第三段,其中最后一句谈到“业余爱好者在发现新彗星的竞赛中也处于更领先的地位,他们的小望远镜因为焦距短,从而比蒙特维尔森天文台的大望远镜更占优势。”由此得出C是正确的。
转载请注明原文地址:https://kaotiyun.com/show/K9p4777K
0
考研英语一
相关试题推荐
Humanshavealteredtheworld’sclimateby(1)_____heat-trappinggasessincealmostthebeginningofcivilizationandevenprev
Bywhatmeansdothechildrenoftheauthor’sfamilygotoschool?Theauthor’sattitudetowardhousewives’workis______.
Ifanoccupationcensushadbeentakenintheeleventhcenturyitwouldprobablyhaverevealedthatquite90percentofthepeop
Thefirsttwostagesinthedevelopmentofcivilizedmanwereprobablytheinventionofprimitiveweaponsandthediscoveryoff
Thefirsttwostagesinthedevelopmentofcivilizedmanwereprobablytheinventionofprimitiveweaponsandthediscoveryoff
Accordingtothosewhosupportmergers,railwaymonopolyisunlikelybecause______.Accordingtothetext,thecostincreasein
Almostexactlyayearago,inasmallvillageinNorthernIndia,AndreaMillinerwasbittenonthelegbyadog."Itmusthave(
WriteacompositiononthetopicAREPETSGOODFORMANKINDontheoutlinebelow:1.Pet-keepingisbeneficialtopeopleins
Manyteachersbelievethattheresponsibilitiesforlearningliewiththestudent.(1)_____alongreadingassignmentisgiven,
WhenIcaughthim______Istoppedbuyingthingsthereandstarteddealingwithanothershop.
随机试题
A.120g/LB.110/LC.100g/LD.90~60g/LE.60~30g/L6~14岁小儿诊断贫血的标准是血红蛋白低于
滴虫性阴道炎的传染方式,下列哪项是错误的
背景资料:2015年某业主将一栋大型剧院建筑的拆除任务,发包给无拆除资质的防腐保温劳务公司,由于不了解拆除作业的危险性,操作人员决定先拆混凝土梁,后拆混凝土板。操作时,现场无安全人员在场,也无安全措施。在梁拆至一半时全部楼板塌下,造成多人死亡。事后检查该施
发行可转换公司债券的上市公司涉及()事项时,证券交易所可以根据实际情况或者中国证监会的要求,决定可转换公司债券的停牌与复牌、转股的暂停与恢复事宜。
以下关于公司的特征描述正确的是( )。
表1一2是某一机械制造企业2008年1月至3月企业人工成本支出的统计表。[2008年11月三级真题]请您:指出各项人工成本的列支科目并填写在(丙)栏内。
苏联教育家赞可夫提出的教学原则有()。
材料四:2018年全年粮食种植面积11704万公顷,比上年减少95万公顷。其中,小麦种植面积2427万公顷,减少24万公项;稻谷种植面积3019万公顷,减少56万公顷;玉米种植面积4213万公顷,减少27万公顷;棉花种植面
下列说法中,不正确的是:
Whatdowelearnabouttheman?
最新回复
(
0
)