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
The Discovery of Astronomers The discovery of planets around distant stars has become like space-shuttle launches—newsworthy
The Discovery of Astronomers The discovery of planets around distant stars has become like space-shuttle launches—newsworthy
admin
2013-01-10
112
问题
The Discovery of Astronomers
The discovery of planets around distant stars has become like space-shuttle launches—newsworthy but just barely. With some 50 extrasolar planets under their belt, astronomers have to announce something reafly strange to get anyone’s attention.
Last week they did just that. Standing in front of colleagues and reporters at the American Astronomical Society’s semiannual meeting in San Diego, the world’s premier planet-hunting team—astronomer Geoffrey Marcy of the University of California, Berkeley, and his colleagues—presented not one but two remarkable finds. The first is a pair of planets, each about the mass of Jupiter, that whirl around their home star 15 light-years from Earth in perfect lockstep. One takes 30 days to complete an orbit, the other exactly twice as long. Nobody has ever seen such a configuration. But the second discovery is far stranger—a solar system 123 light-years away, in the constellation Serpens, that harbors one " ordinary" planet and another so huge—17 times as massive as Jupiter—that nobody can quitefigure out what it can be. It is, says Marcy, "a bit frightening. "
What’s frightening is that these discoveries make it clear how little astronomers know about planets and they add to the dawning realization that our solar system— and by implication Planet Earth may be a cosmic oddball. For years theorists figured that other stars would have planets more or less like the ones going around the sun. But starting with the 1995 discovery of the first extrasolar planet—a gassy monster like Jupiter but orbiting seven times as close to its star as Mercury orbits around our sun— each new find has seemed stranger than the last. Searchers have found more "hot Jupi-ters" like that first discovery. These include huge planets that career around their stars not in circular orbits but in elongated ones; their gravity would send any Earthlike neighbors flying off into space. Says Princeton astronomer Scott Tremaine: "Not a single prediction for what we’d find in other systems has turned out to be correct."
Last week’s giant was the most unexpected discovery yet. Conventional theory suggests that it must have formed like a star, from a collapsing cloud of interstellar gas. Its smaller companion, only-seven times Jupiter’s mass, is almost certainly a planet, formed by the buildup of gas and dust left over from a star’s formation.
Yet the fact that these two orbs are so close together suggests to some theorists that they must have formed together—so maybe the bigger one is a planet after all.
Or maybe astronomers will have to rethink their definition of "planet." Just because we put heavenly objects into categories doesn’t mean the distinctions are necessarily valid. And as Tremaine puts it, "When your classification schemes start breaking down, you know you’re learning something exciting. This is wonderful stuff."
The case of the giant heavenly body demonstrates that______.
选项
A、conventional theory cannot explain such astronomical phenomenon satisfactorily
B、it is either a star or a planet
C、it was formed like a star and orbits like a planet
D、theorists give a wrong definition of "planet"
答案
A
解析
事实细节题。文中介绍了传统理论解释该天文发现时所面临的困境。此天体看似像恒星,但运行轨道又接近行星,因此难以确定它究竟是什么。显然,传统理论无法令人满意地解释这种天体。
转载请注明原文地址:https://kaotiyun.com/show/uDhK777K
0
专业英语四级
相关试题推荐
About______Americanhomeshavethehabitofkeepingpets.
Mostearthquakesoccurwithintheupper15milesoftheearth’ssurface.Butearthquakescananddooccuratalldepthstoabout
WriteonANSWERSHEETTWOanoteofabout50~60wordsbasedonthefollowingsituation:YouareBertha.Youhavejustheardt
Inordertomakemyself~inEnglish,Iamstudyinghard.
Onereasonhumanbeingscanthriveinallkindsofclimatesisthattheycancontrolthequalitiesoftheairintheenclosedsp
Crimeplaguesoursociety,almostallaroundusinourdailylives.Dailywehearmanyinstancesof【C1】______crimessuchasmurd
Itisappropriateonananniversaryofthefoundingofauniversitytoremindourselvesofitspurposes.Itisequallyappropria
Theaudiencewaitedin______silencewhiletheiragedspeakersearchedamonghisnoteforthefigureshecouldnotremember.
Ofallthesoldierstheyhadthe______ofbeingthefiercest,themostpatriotic,thetoughest.
Thesummitwillbeanopportunityforeverystateheadtogive_____totheirfeelings.
随机试题
采购管理系统子系统包括()。
汽轮机冷态启动时,在哪些转速应停留,并进行哪些工作?
某1型糖尿病患者,查餐后2小时血糖为30mmol/L(540mg/dl)。给胰岛素稀释后静滴,静滴时病人自觉多汗、手抖、饥饿,应考虑其原因是
下列关于绩效评价指标叙述错误的是:()。
某公司7月份发生下列经济业务(不考虑相关税费):(1)销售材料一批,货款2000元,当即存入银行。(2)销售产品一批,货款5000元,当即收到4000元存入银行,其他货款暂欠。(3)预付7~12月的固定资产租金3000元。(4)收到3月份的应收销货
二手资料仅包括二手数据。()
某企业适用的城市维护建设税税率为7%,2011年8月份该企业应缴纳增值税200000元、土地增值税30000元、消费税150000元、资源税20000元,8月份该企业应记入“应交税费——应交城市维护建设税”科目的金额为()元。
商业银行的最高风险管理/决策机构是()。
将数据3127.1845按照四舍五入要求精确到百分位后的结果是(65)。
Thisprojectwouldgivescientistsnew______intowhatishappeningtotheEarth’satmosphere.
最新回复
(
0
)