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
45
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
Sociologistsuse"power"torefertothecapacityofpeopletocontrolorinfluencetheactionsofothers.Sociologistsstudypo
Sociologistsuse"power"torefertothecapacityofpeopletocontrolorinfluencetheactionsofothers.Sociologistsstudypo
Hollywoodrackedupanother"record"yearattheboxoffice.ButthehigherticketsalesmaskfundamentalissuesintheU.S.mo
WhichofthefollowingisNOTcorrect?
Physicsisthepresentdayequivalentof______usedtobecallednaturalphilosophy,frommostofpresentdaysciencearose.
Whywerethetoptwodirectorsofsecretpoliceforcedout?
Surprisinglyenough,modernhistorianshaverarelyinterestedthemselvesinthehistoryoftheAmericanSouthintheperiodbefo
Itisappropriateonananniversaryofthefoundingofauniversitytoremindourselvesofitspurposes.Itisequallyappropria
Itisappropriateonananniversaryofthefoundingofauniversitytoremindourselvesofitspurposes.Itisequallyappropria
Certainlynocreatureintheseais【C1】______thanthecommonseacucumber.Alllivingcreatures,especiallyhumanbeings,havet
随机试题
晏殊,字同叔,著有_______。其词风流闲雅,温润秀洁,代表作有《浣溪沙》(一曲新词酒一杯)、《玉楼春》(绿杨芳草长亭路)。
下列句中“之”是实词,当“到”讲的是()
移植后不会发生排斥反应的是
建筑施工从业人员超过200人的才需要设置安全生产管理机构或者配备专职安全生产管理人员。()
关于基金份额的转托管,以下说法正确的是( )。
下列关于中小非金融企业集合票据的表述,错误的是()。
智力的性别差异研究成果表明,男女智力的总体水平()。
下列选项中属于直系拟制血亲的是()
TheStoryteller1StevenSpielberghasalwayshadonegoal:totellasmanyinterestingstoriestoasmanypeopleaspossibl
Cardiffisthecapitalof______
最新回复
(
0
)