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 planets around distant stars has become like space-shuttle launches newsworthy but just barely. With some 50 ex
The discovery of planets around distant stars has become like space-shuttle launches newsworthy but just barely. With some 50 ex
admin
2010-04-30
74
问题
The discovery of planets around distant stars has become like space-shuttle launches newsworthy but just barely. With some 50 extra-solar planets under their belt, astronomers have to announce something really 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 (木星), 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 (巨蛇座), that harbors one "ordinary" planet and another so huge 17 times as massive as Jupiter that nobody can quite figure 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 extra-solar planet a gassy monster like Jupiter but orbiting seven times as close to its star as Mercury (水星) orbits around our sun each new find has seemed stranger than the last. Searchers have found more "hot Jupiters" 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 mined 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, as Tremaine puts it, "When your classification schemes start breaking down, you know you’re learning something exciting. This is wonderful stuff."
The searchers used NOT to believe______.
选项
A、other stars may have the planets resembling those going around the sun
B、planet forms owing to the gas and dust in star formation
C、the formation of star is subsequent to that of planet
D、star is formed by the collapsing interstellar cloud
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/ikOK777K
0
大学英语六级
相关试题推荐
Peopleusetheword"unidentified"todescribethereportedflyingobjectsbecausewhattheseobjectsareisstillunknown.One
WecaninferfromthefirstparagraphthatLewisThomasbelievesthat______.WhichofthefollowingstatementsisTRUEaboutR
A、Itincreasedthestudents’whitebloodcellcount.B、Itincreasedsomestudents’energylevel.C、Itimprovedthestudents’abi
Inthepast,manydoctorsmanagedtofoolpatientsbytakingadvantageof______.Whydidn’tthequacksprescribeanymedicine
A、Theyhavecomplicatedexplanationswhicharequitebeyondyourunderstanding.B、Theyareprintedinverysmallcharacters.C、T
A、Britain.B、TheUnitedStates.C、France.D、Japan.BWhereweretheexpressionsofHightechandstateofartfirstused?
A、Itbillsthecustomeronceamonth.B、It’sakindofATMcards.C、It’sakindofcreditcards.D、Ittakesoutthemoneyfromt
Theintelligencetestisanattempt______(估量任何一个儿童的思维也和推理能力).
A、Thatshehasstoppedsmoking.B、Thatshedoesnotwanttogetmarried.C、Thatshehasaskedthemantoquitsmokingmanytimes
A、TogototheUnitedStates.B、Toapplyforascholarship.C、Toplaythepianoonceagain.D、Tohaveherperformancetaped.D细
随机试题
泌尿、男生殖系统结核最主要的是()
根据《反不正当竞争法》的规定,下列哪一行为属于不正当竞争行为中的混淆行为?(卷一/2007年第22题)
公路土工合成材料的宽条拉伸试验,规定试样宽度为50mm。()
市场经济在其数百年的发展过程中,在国际上逐步形成了三种基本的企业制度,分别是()。
王某向李某借款20万元,以自己所有的一块奇石设定质押,双方于2月15日签订了质押合同,3月1日王某方将该石转移给李某占有,交付奇石时,王某未将奇石配套的翡翠基座一并交付。根据物权法律制度的规定,下列说法正确的有()。
关于中国共产党历史上的重大战斗,下列说法不正确的是()。
两个两位数相加,其中一个加数是73,另一个加数不知道,只知道另一个加数的十位数字增加5,个位数字增加1,那么求得的和的后两位数字是72,问另一个加数原来是多少?
设x,y∈R,a>1,b>1,若ax=by=3,a+b=的最大值为().
Canyoucometoschool______earliertomorrow?
A、Internationalchildren’sprojects.B、Socialandenvironmentalprojects.C、Projectsforpeoplewithnomoney.D、Projectsinvolv
最新回复
(
0
)