专四
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 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, 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 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 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 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 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 compamon, only seven times Jupiter's nass, 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 a aybe 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 to categories doesn't mean the distinctions are necessarily valid．And as Tremaine puts it, "When your lassification schemes start breaking down, you know you're learning something exciting．This is wonderful tuff．"
The author believes that
A．there is little for astronomers to discover now
B．the public has no interest in astronomical discoveries
C．astronomers have been making a lot of discoveries of planets
D．the discovery of planets is as important as the launch of space shuttles
第三段揭示这些发现说明天文学家对于行星的了解十分有限。
第四、五段指出这两项发现挑战了传统的天文学理论，有人提出也许应该重新对“行星”进行定义。
C。本题的出题点在数字处。根据题干信息The author believes将答案锁定在文章首段第二句。文章提到
With some 50 extrasolar planets under their belt，asa：onomers have to allnounce something really strange to get
anyone，S attention。即：已经发现了太阳系外50多颗行星，宇航员不得不发布一些真正非同寻常的发现才能吸引人们的注意力，可见，作者是说宇航员已经发现很多行星了，所以c正确。
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A．Because scientists cannot figure out what they can be．
B．Because astronomers have never seen similar orbiting pattern and size before．
C．Because the planets are very huge．
D．Because the planets are far from our solar system．
A．other stars have planets more or less like the one going around the sun
B．other stars have planets with bigger orbits
C．the way planets orbiting around the sun in our solar system is quite unique
D．planets in other systems have elongated orbits
A．it is either a star or a planet
B．it was formed like a star and orbits like a planet
C．it helps us change the definition of"planet"
D．it cannot be explained satisfactorily by conventional theory
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