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
77
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
SomecallittheSmartShooter,anewrifleforAmericaninfantrytroopsthatistwoweaponsinone,isaccurateupto1,000yar
NowadaysInternetisrevolutionizingourglobeandgreatlyfacilitatingourmodernlife.Asamatteroffact,wecandoalmoste
SinceWorldWarII,therehasbeenaclearlydiscernibletrend,especiallyamongthegrowinggroupofcollegestudents,towarde
Atthefall2001SocialScienceHistoryAssociationconventioninChicago,theCrimeandJusticenetworksponsoredaforumonth
WhendidMrs.Westongotoseeherdoctor?
StudentsarecalledinAmericanclasses
Becausethesupplyofnaturalgaswasplentiful______otherchoiceslikecoalandfueloil,manypeopleuseitforheatingandc
ThatwasnotthefirsttimetheCEO______us.Ithinkit’shightimetheboard______strongactionsagainsthim.
Perhapsthemythoftheperfectcommunicatorcomesfrombelievingtoostronglyinnovels,television,orfilms.Intheseplaces
Becauseofthesevereinternationalsituation,thegovernmenthasurgedpeopletobe_______withfoodandwater.
随机试题
T触发器的特点是:每输入一个时钟脉冲,就得到一个输出脉冲。()
女,36岁,近5年反复痰中带血或大咯血。轻咳,为少量黏液痰,无低热。胸片示:左下肺纹理增粗、紊乱呈卷发样,余未见异常。首先应考虑
A.α1受体B.α2受体C.β1受体D.β2受体E.β3受体
在进口倾销对国内产业造成实质损害的情况下,反倾销税可以追溯征收。该反倾销税可适用于下列哪些产品?
饭店、旅馆、教学楼,宜选用()探测器。
《商业银行授信工作尽职指引》对()提出了明确要求。
在系统科学发展领域,被称为“新三论”的是()。
杨丽萍的孔雀舞
[*]
Manyyoungpeoplebelievegoodgradesandexcellentinternshipswilllandthemtheiridealjob.However,contrarytowhattheyt
最新回复
(
0
)