Thank your lucky stars you live in a relatively peaceful corner of the galaxy. Astronomers have found six large planets whose off-kilter orbits suggest that they crashed through their solar systems, swallowing any smaller planets that got in their way. The findings indicate that solar system formation is often disorderly and unpredictable, and that some potential cousins of Earth may have been destroyed in the chaos.

 多虧我們的幸運(yùn)之星，我們生活在銀河系一個相對平靜的角落里,。天文學(xué)家們發(fā)現(xiàn)了六顆巨大的行星,，不規(guī)則的軌道表明它們在其恒星系統(tǒng)內(nèi)發(fā)生碰撞，吞沒了所有擋住去路的較小行星,。該發(fā)現(xiàn)說明,，恒星系統(tǒng)的形成通常是混亂而不可預(yù)測的，而且一些潛在的類地行星可能在這種混亂之中遭到毀滅,。

 Astronomers have long thought that the formation of a star and its solar system was straightforward. A large cloud of gas and dust begins to congeal gravitationally, starts rotating, and eventually flattens into an object called a protostellar disk. That rotation dictates the future spin of the sun and the orbit of its planets. This is essentially what happened in our own solar system. There can be irregularities, of course, such as the odd spin axis of Uranus, which for as-yet-unexplained reasons is nearly tilted on its side, and Pluto's odd orbit, which occasionally takes it inside the path of Neptune. But these oddballs are nothing compared with what astronomers are seeing with six newly discovered planets known as hot Jupiters.

 長期以來,，天文學(xué)家們認(rèn)為一顆恒星及其恒星系統(tǒng)是直接形成的。由氣體和塵埃構(gòu)成的巨大云團(tuán)在引力的作用下開始凝縮,，并且開始旋轉(zhuǎn),，最終變平成為平面狀物體，這種物體被稱為原恒星盤,。開始的旋轉(zhuǎn)決定著恒星未來的旋轉(zhuǎn)以及行星軌道的性質(zhì),。這基本上就是我們太陽系所發(fā)生的情況。當(dāng)然其中也會有不規(guī)則的現(xiàn)象,，如天王星奇特的自轉(zhuǎn)軸幾乎是向一側(cè)傾斜的,，其原因至今仍然無法解釋；再如冥王星的軌道很奇特,，有時它會在海王星的軌道之內(nèi)運(yùn)行,。但是這些奇怪的星球與天文學(xué)家們目前所觀察到的情況根本無法相提并論。據(jù)了解,，這六顆新發(fā)現(xiàn)的行星屬于熱木星,。

 Hot Jupiters resemble our largest planet in size and composition, yet they orbit much closer to their stars, sometimes well within what would be the orbit of Mercury. But the newly discovered worlds add an extra twist: all orbit in the opposite direction from all of the other objects in their solar system (a so-called retrograde orbit), and all orbit at severe angles.

 在大小和構(gòu)成成分上，熱木星跟我們太陽系最大的行星類似,，但是它們的軌道距其恒星要近得多,，有時比水星的軌道距太陽還要近。這些新發(fā)現(xiàn)的星球又增加了一種額外的旋轉(zhuǎn)：它們在軌道上運(yùn)行的方向跟其所在的恒星系統(tǒng)內(nèi)所有其他天體的運(yùn)行方向相反（即所謂的“逆行軌道”）,，而且所有的軌道都有著明顯的角度,。

 The implications are twofold, a team of astronomers led by Andrew Collier Cameron of the University of St. Andrews in the United Kingdom reports today at a meeting of the Royal Astronomical Society in Glasgow in the U.K. First, objects at least as large as these planets, and probably larger, must have shoved them severely out of their original orbits, probably well above or below the plane of their solar system. The encounters hurtled the gas giants in toward their parent suns. Then, each star's gravity caught the errant planet and whipped it around in a highly irregular, tight, and retrograde orbit. During this period of irregularity, which may have lasted millions of years, any rocky inner world sitting in the path of the hot Jupiter and its new orbit would have been obliterated.

 今天，英國圣安德魯斯大學(xué)的安德魯·科利爾·卡梅倫帶領(lǐng)著一組天文學(xué)家,，在英國格拉斯哥舉行的一次皇家天文學(xué)會會議上報道：該發(fā)現(xiàn)具有雙重意義,。首先，至少象這些行星這么大,、甚至很可能更大的天體一定撞擊過它們,，使它們嚴(yán)重地偏離了原有的軌道,，造成了其軌道明顯地高于或低于恒星系統(tǒng)的平面。猛烈沖撞使這些巨型氣態(tài)行星向內(nèi)靠近了其主恒星,。其次,，每一顆恒星的引力都吸引著那顆漂游的行星，使其在極不規(guī)則的近圍軌道上作逆向運(yùn)行,。這種不規(guī)則的時期可能已經(jīng)持續(xù)了幾百萬年,，在此期間，位于熱木星原有軌道以及新軌道上的任何系內(nèi)的巖石行星都有可能已遭毀滅,。

 The finding "adds to the accumulating evidence that the pathways that bring these giant planets close to their parent stars are messy and chaotic," says planetary scientist Jonathan Fortney of the University of California, Santa Cruz. It also suggests that there's "an incredible diversity in the structure of planetary systems,” he says.

 加州大學(xué)圣克魯茲分校的行星科學(xué)家喬納森·福特尼說,，該發(fā)現(xiàn)使不斷積累起來的證據(jù)更加充分了，說明巨型行星靠近其主恒星的途徑是混亂不堪的,。他說,，該發(fā)現(xiàn)還表明，行星系統(tǒng)在結(jié)構(gòu)上存在令人難以置信的多樣性,。

 These new worlds imply that there's a "dramatic and exciting process of gravitational billiards" at work, agrees astrophysicist Alan Boss of the Carnegie Institution of Washington in Washington, D.C. The finding lends credence to the idea that some gas giants in nascent solar systems “have to fight it out among themselves to see what orbit they will win and occupy," says Boss, a process he likens to "battles for office space on university campuses."

 華盛頓卡內(nèi)基研究院的天體物理學(xué)家艾倫·博斯同意上述觀點(diǎn),，他表示，這些新星球的發(fā)現(xiàn)意味著它們經(jīng)歷了一個引人矚目而且令人興奮的“引力撞球游戲”過程,。博斯說，該發(fā)現(xiàn)使人們相信：在新形成的恒星系統(tǒng)中,，一些巨型氣態(tài)行星不得不從同類行星中殺出一條路來,，以確定將要爭得和占有哪一條軌道。博斯將這個過程比喻成“在大學(xué)校園里爭搶辦公空間”,。