时差N小时 离星星有多远?

Aristotle thought the stars were all exactly the same distance away, stuck to a dark shell that surrounded the Earth like the dome¹ of a planetarium². Now we know that the farthest galaxy³ is over a billion times more distant than the nearest star. How do astronomers⁴ tell how far away the stars are?

亚里士多德认为所有星星离我们的距离都是相等的，它们镶嵌在一个环绕在地球四周的，像天文馆的穹顶一样的黑色的硬壳上。现在我们知道最远星系的距离是最近星系的十亿倍。天文学家是如何知道星星离我们有多远呢？

One method works like the way your own eyes determine how far away earthbound objects are. Hold a finger upright at arm's length, then close an eye as if you were winking⁶. Open that eye and close the other. As you alternate eyes, your finger will seem to change position. Keep winking back and forth⁷, then move your finger closer to your face.

有一种方法跟你目测地面上物体的距离一样。竖起一根手指，并保持一段距离，然后闭上眼睛，仿佛你在思考一样。睁开一只眼睛并闭上另一只。当你变换眼睛的时候，手指的位置似乎改变了。继续来来回回地眨眼，然后移动手指，靠近你的脸。

The closer your finger is, the more it appears to jump compared to the background. This is the key to one method of measuring how distant the stars are. Closer stars seem to shift more than distant ones do when seen from different places. The farther apart your two observation points are, the more dramatic this shifting becomes.

你的手指靠脸越近，相对于背景物它似乎越是有大的跳跃。这是测量星星距离的方法的关键。从不同的地方看时，近一点的星星似乎比远一点的星星跳跃幅度要大。两个观测点相距越远，这种跳跃就更明显。

Your eyes are only inches apart, so no matter how much you wink⁵ at the stars, you won't be able to shift them with your eyes alone. Astronomers, however, can use telescopes in different parts of the world, thousands of miles apart. Even better, they can photograph a star once, then again six months later. During six months the Earth will have orbited to the other side of the sun, creating a pair of telescopic eyes that are almost two hundred million miles apart. With this distance, the shift becomes quite noticeable. This method has been used to math the location of thousands of nearby stars.

你的双眼只相距一英尺远，因此不论你的眼睛眨多少下，光靠眼睛来看星星你是不会产生这种视觉落差的。但是宇航员能在世界上相隔上千英里的不同角落使用望远镜。甚至更好的，他们能给一颗星星拍照，然后六个月后再拍一次。六个月之后，地球就在太阳另一侧的轨道上转动，这样就创造出一对相隔差不多一亿英里的望眼镜“双眼”。在这么远的距离下，跳跃就非常引人注目了。这种方式已被用来演算上千颗附近恒星的位置。

1 dome   

n.圆屋顶，拱顶

参考例句：

• The dome was supported by white marble columns.圆顶由白色大理石柱支撑着。
• They formed the dome with the tree's branches.他们用树枝搭成圆屋顶。

2 planetarium   

n.天文馆；天象仪

参考例句：

• The planetarium staff also prepared talks for radio broadcast.天文馆的工作人员还要准备讲稿给电台广播。
• It landed in a shallow basin fifty yards from the planetarium.它降落在离天文馆五十码处的一个浅盆地中。

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 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》

5 wink   

n.眨眼，使眼色，瞬间；v.眨眼，使眼色，闪烁

参考例句：

• He tipped me the wink not to buy at that price.他眨眼暗示我按那个价格就不要买。
• The satellite disappeared in a wink.瞬息之间，那颗卫星就消失了。

6 winking   

n.瞬眼，目语v.使眼色( wink的现在分词 )；递眼色（表示友好或高兴等）；（指光）闪烁；闪亮

参考例句：

• Anyone can do it; it's as easy as winking. 这谁都办得到，简直易如反掌。 来自《现代汉英综合大词典》
• The stars were winking in the clear sky. 星星在明亮的天空中闪烁。 来自《简明英汉词典》

7 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。