国家地理:送给外星人的地图(4)

Our galactic neighborhood has no obvious street signs, and crafting a map pointing to one planet among the billions (and billions) of worlds populating the Milky¹ Way is no simple feat².

我们的银河系中并没有明显的标识，要想绘制一张地图，指向银河系中数十亿颗星球中的一颗，这绝非易事。

Finding Earth means finding the solar system, and the sun is rather unremarkable. There's really no way to distinguish it from the other several hundred billion stars in the galaxy³, each of which is tracing its own path around the galactic center and slowly shifting in location relative to its neighbors. That stellar jostling means the constellations⁴ spangling Earth's skies won't be the same in our near future. In fact, in about 2,000 years, Polaris will no longer be the North Star, just as it was not the polestar for ancient Egyptian, Babylonian, and Chinese sky-watchers.

找到地球就意味着找到了太阳系，而太阳是相当不起眼的。我们根本没有办法将它与银河系其他数千亿颗恒星中分辨出来，每一颗都沿着自己的轨道环绕银河系的中心运行，与其邻近星球的相对位置在缓慢地变化着。恒星的这种相对位移意味着，在不久的将来，遍布在地球天空中的星座将不再是原来的样子。事实上，在大约2000年后，北极星将不再是指北星，就像它当初不再是古埃及、古巴比伦和古中国天文观测者的指北星一样。

So, what to do? Though normal stars with churning nuclear engines in their cores might not have distinctive⁵ fingerprints⁶, Dad realized that pulsars -- the corpses⁷ of stars that once were much larger than the sun -- are potentially uniquely identifiable. Discovered in 1967, pulsars spin very rapidly, often hundreds of times per second. Using powerful radio telescopes, astronomers⁸ can measure with extreme precision how quickly pulsars rotate, meaning that each of these spinning stellar relics⁹ writes its own signature in space. Dad selected 14 pulsars that could triangulate Earth's position, and he coded information about their rotation¹⁰ rates into the map.

那么，该怎么办呢？虽然正常恒星的中心有核物质在运转，但它们可能没有明显的特征，爸爸意识到脉冲星--曾经比太阳大得多的恒星的“尸体”--有可能是唯一可识别的。脉冲星于1967年被发现，它们的转速极快，往往每秒钟能旋转数百周。利用强大的射电望远镜，天文学家可以极其精确地测量脉冲星旋转的速度，这意味着每一颗旋转的恒星残骸都在太空中留下了自己的印迹。爸爸挑选出14颗能够对地球的位置进行三角测量的脉冲星，并将它们的旋转速度转换成编码，记录在地图上。

1 milky   

adj.牛奶的，多奶的；乳白色的

参考例句：

• Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
• I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。

2 feat   

n.功绩；武艺，技艺；adj.灵巧的，漂亮的，合适的

参考例句：

• Man's first landing on the moon was a feat of great daring.人类首次登月是一个勇敢的壮举。
• He received a medal for his heroic feat.他因其英雄业绩而获得一枚勋章。

3 galaxy   

n.星系；银河系；一群(杰出或著名的人物)

参考例句：

• The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
• The company has a galaxy of talent.该公司拥有一批优秀的人才。

4 constellations   

n.星座( constellation的名词复数 )；一群杰出人物；一系列（相关的想法、事物）；一群（相关的人）

参考例句：

• The map of the heavens showed all the northern constellations. 这份天体图标明了北半部所有的星座。 来自《简明英汉词典》
• His time was coming, he would move in the constellations of power. 他时来运转，要进入权力中心了。 来自教父部分

5 distinctive   

adj.特别的，有特色的，与众不同的

参考例句：

• She has a very distinctive way of walking.她走路的样子与别人很不相同。
• This bird has several distinctive features.这个鸟具有几种突出的特征。

6 fingerprints   

n.指纹( fingerprint的名词复数 )v.指纹( fingerprint的第三人称单数 )

参考例句：

• Everyone's fingerprints are unique. 每个人的指纹都是独一无二的。
• They wore gloves so as not to leave any fingerprints behind (them). 他们戴着手套，以免留下指纹。 来自《简明英汉词典》

7 corpses   

n.死尸，尸体( corpse的名词复数 )

参考例句：

• The living soldiers put corpses together and burned them. 活着的战士把尸体放在一起烧了。 来自《简明英汉词典》
• Overhead, grayish-white clouds covered the sky, piling up heavily like decaying corpses. 天上罩满了灰白的薄云，同腐烂的尸体似的沉沉的盖在那里。 来自汉英文学 - 中国现代小说

8 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》

9 relics   

[pl.］n.遗物，遗迹，遗产；遗体，尸骸

参考例句：

• The area is a treasure house of archaeological relics. 这个地区是古文物遗迹的宝库。
• Xi'an is an ancient city full of treasures and saintly relics. 西安是一个有很多宝藏和神圣的遗物的古老城市。

10 rotation   

n.旋转；循环，轮流

参考例句：

• Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
• The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。