万物简史 第291期:砰!(26)

 　　Still less could we send up a shipload of space cowboys to do the job for us, as in the movie Armageddon; 我们更不可能发射一飞船警察去为我们干这个活儿，就像电影《善恶大决战》里的场面那样；

　　we no longer possess a rocket powerful enough to send humans even as far as the Moon. 我们不再拥有能把人送上月球的火箭。

　　The last rocket that could, Saturn¹ 5, was retired² years ago and has never been replaced. 最后一枚那种火箭——木星5型火箭——已于几年前退役，再也没有替身。

　　Nor could we quickly build a new one because, 我们也无法马上制造一枚，因为

　　amazingly, the plans for Saturn launchers were destroyed as part of a NASA housecleaning exercise. 木星火箭的图纸已经令人吃惊地在美国国家航空和航天局的一次春季大扫除中给销毁了。

　　Even if we did manage somehow to get a warhead to the asteroid³ and blasted it to pieces, 即使我们成功地设法将一枚弹头射中小行星并把它炸得粉碎，

　　the chances are that we would simply turn it into a string of rocks 我们很可能只能把它变成一连串岩石；

　　that would slam into us one after the other in the manner of Comet Shoemaker-Levy on Jupiter, 那些岩石会像苏梅克-列维彗星撞击木星那样一个接一个地朝我们砸过来，

　　but with the difference that now the rocks would be intensely radioactive. 不同之处在于那些岩石现在都具有强烈的辐射作用。

　　Tom Gehrels, an asteroid hunter at the University of Arizona, 亚利桑那大学负责寻找小行星的汤姆·格雷尔斯认为，

　　thinks that even a year's warning would probably be insufficient⁴ to take appropriate action. 即使有一年的预警时间也很可能不足以采取适当的行动。

　　The greater likelihood, however, is that we wouldn't see any object, even a comet, 然而，更大的可能性是，我们看不到任何物体，即使是彗星，

　　until it was about six months away, which would be much too late. 直到只剩下6个月左右时间，那时候就太晚了。

　　Shoemaker-Levy 9 had been orbiting Jupiter in a fairly conspicuous⁵ manner since 1929, but it took over half a century before anyone noticed. 自1929年以来，苏梅克-列维9号彗星一直在以比较明显的方式绕着木星运行，但直到半个多世纪以后才有人发现。

　　Interestingly, because these things are so difficult to compute⁶ and must incorporate such a significant margin⁷ of error, 由于这类事情很难测算，而且必须考虑这么大的误差，

　　even if we knew an object was heading our way we wouldn't know until nearly the end, 因此即使我们知道有个物体在朝我们飞来，也要等到差不多最后时刻，

　　the last couple of weeks anyway—whether collision was certain.  反正是最后几个星期——我们才会知道是不是肯定要发生撞击。

1 Saturn   

n.农神，土星

参考例句：

• 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。
• These comparisons suggested that Saturn is made of lighter materials.这些比较告诉我们，土星由较轻的物质构成。

2 retired   

adj.隐退的，退休的，退役的

参考例句：

• The old man retired to the country for rest.这位老人下乡休息去了。
• Many retired people take up gardening as a hobby.许多退休的人都以从事园艺为嗜好。

3 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。

4 insufficient   

adj.(for，of)不足的，不够的

参考例句：

• There was insufficient evidence to convict him.没有足够证据给他定罪。
• In their day scientific knowledge was insufficient to settle the matter.在他们的时代，科学知识还不能足以解决这些问题。

5 conspicuous   

adj.明眼的，惹人注目的；炫耀的，摆阔气的

参考例句：

• It is conspicuous that smoking is harmful to health.很明显，抽烟对健康有害。
• Its colouring makes it highly conspicuous.它的色彩使它非常惹人注目。

6 compute   

v./n.计算，估计

参考例句：

• I compute my losses at 500 dollars.我估计我的损失有五百元。
• The losses caused by the floods were beyond compute.洪水造成的损失难以估量。

7 margin   

n.页边空白；差额；余地，余裕；边，边缘

参考例句：

• We allowed a margin of 20 minutes in catching the train.我们有20分钟的余地赶火车。
• The village is situated at the margin of a forest.村子位于森林的边缘。