万物简史 第27期:走进太阳系(5)

 　　As for Pluto¹ itself, nobody is quite sure how big it is, or what it is made of, what kind of atmosphere it has, or even what it really is. A lot of astronomers³ believe it isn't a planet at all, but merely the largest object so far found in a zone of galactic debris⁴ known as the Kuiper belt.

　　至于冥王星本身，谁也不大清楚它有多大，是什么组成的，有什么样的大气，甚至它到底是个什么东西。许多天文学家认为，它其实算不上是颗行星，而只是我们在银河的废墟带（称之为凯珀带）发现的最大的物体。

　　The Kuiper belt was actually theorized by an astronomer² named F. C. Leonard in 1930, but the name honors Gerard Kuiper, a Dutch native working in America, who expanded the idea. The Kuiper belt is the source of what are known as short-period comets—those that come past pretty regularly—of which the most famous is Halley's comet. The more reclusive long-period comets (among them the recent visitors Hale-Bopp and Hyakutake) come from the much more distant Oort cloud, about which more presently.

　　凯珀带理论实际上是1930年由一位名叫F.G.伦纳德的天文学家提出来的，他用这个名字来纪念一位在美国工作的荷兰人杰勒德·凯珀。凯珀发展了这个理论。凯珀带是所谓短命彗星的源泉--那种经常一闪而过的星星--其中最著名的就是哈雷彗星。比较长命的彗星（其中有最近光顾的海尔－博普彗星和百武彗星）产生于遥远得多的奥尔特云，我们过一会儿就会谈到这个问题。

　　It is certainly true that Pluto doesn't act much like the other planets. Not only is it runty and obscure, but it is so variable in its motions that no one can tell you exactly where Pluto will be a century hence. Whereas the other planets orbit on more or less the same plane, Pluto's orbital path is tipped (as it were) out of alignment⁵ at an angle of seventeen degrees, like the brim of a hat tilted⁶ rakishly on someone's head.

　　冥王星的表现与别的行星很不一样，这种看法肯定没错儿。它不但又小又模糊，而且它的运行方式变化不定，一个世纪以后谁也说不准冥王星到底会在哪里。别的行星多少在同一平面上转动，而冥王星的运行轨道（似乎）是倾斜的，不和别的行星处于同一平面，而是形成一个17度的角，犹如有人头上潇洒地歪戴着帽子。

　　Its orbit is so irregular that for substantial periods on each of its lonely circuits around the Sun it is closer to us than Neptune⁷ is. For most of the 1980s and 1990s, Neptune was in fact the solar system's most far-flung planet. Only on February 11, 1999, did Pluto return to the outside lane, there to remain for the next 228 years.

　　它的轨道很不规则，在它寂寞地绕太阳转动的过程中，每一圈都在相当长的时间里比海王星距离我们更近。事实上，在20世纪80年代和90年代的大部分时间里，海王星是太阳系里离我们最远的行星。只是到了1999年2月11日，冥王星才回到外侧的轨道，此后它将在那里停留228年的时间。

 

1 Pluto   

n.冥王星

参考例句：

• Pluto is the furthest planet from the sun.冥王星是离太阳最远的行星。
• Pluto has an elliptic orbit.冥王星的轨道是椭圆形的。

2 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

3 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

4 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

5 alignment   

n.队列；结盟，联合

参考例句：

• The church should have no political alignment.教会不应与政治结盟。
• Britain formed a close alignment with Egypt in the last century.英国在上个世纪与埃及结成了紧密的联盟。

6 tilted   

v. 倾斜的

参考例句：

• Suddenly the boat tilted to one side. 小船突然倾向一侧。
• She tilted her chin at him defiantly. 她向他翘起下巴表示挑衅。

7 Neptune   

n.海王星

参考例句：

• Neptune is the furthest planet from the sun.海王星是离太阳最远的行星。
• Neptune turned out to be a dynamic,stormy world.海王星原来是个有生气、多风暴的世界。