万物简史 第183期:爱因斯坦的宇宙(26)

 　　We now know that Cepheids throb¹ as they do because they are elderly stars that have moved past their “main sequence phase,” in the parlance² of astronomers⁴, and become red giants. The chemistry of red giants is a little weighty for our purposes here (it requires an appreciation⁵ for the properties of singly ionized helium atoms, among quite a lot else), but put simply it means that they burn their remaining fuel in a way that produces a very rhythmic⁶, very reliable brightening and dimming. Leavitt's genius was to realize that by comparing the relative magnitudes of Cepheids at different points in the sky you could work out where they were in relation to each other. They could be used as “standard candles”—a term she coined and still in universal use. The method provided only relative distances, not absolute distances, but even so it was the first time that anyone had come up with a usable way to measure the large-scale universe.

　　我们现在知道，造父变星之所以搏动，是因为——用天文学家的行话来说——它们已经走过“主序阶段”，变成了红巨星。红巨星的化学过程有点儿难懂，已经超出了本书的宗旨（它要求了解很多东西，其中之一就是单离子化的氦原子的性质）。但是，简而言之，在燃烧剩余的燃料的过程中，它们产生了一种很有节奏、不停地一亮一暗的现象。莱维特的天才在于，她发现，通过比较造父变星在天空中不同角度的大小，就可以计算出它们之间的相对位置。它们可以被作为标准烛光——这个名称也是她创造的，现在依然广泛使用。用这种方法得到的只是相对距离，不是绝对距离。但是，即使这样，这也是第一次有人想出了一个计算浩瀚宇宙的实用方法。

　　爱因斯坦邮票

　　(Just to put these insights into perspective, it is perhaps worth noting that at the time Leavitt and Cannon⁷ were inferring fundamental properties of the cosmos⁸ from dim smudges on photographic plates, the Harvard astronomer³ William H. Pickering, who could of course peer into a first-class telescope as often as he wanted, was developing his seminal⁹ theory that dark patches on the Moon were caused by swarms¹⁰ of seasonally¹¹ migrating insects.)

　　（为了合理评价这些深邃的见解，也许值得注意的是，当莱维特和坎农在根据照片上远方星星的模糊影子推定宇宙的基本特性的时候，哈佛大学的天文学家威廉·H.皮克林——他当然能从一流的天文望远镜里想观察多少次就观察多少次——却在建立自己的理论，认为月球上的黑影是由大群大群的、随着季节迁徙的昆虫形成的。）

1 throb   

v.震颤，颤动；(急速强烈地)跳动，搏动

参考例句：

• She felt her heart give a great throb.她感到自己的心怦地跳了一下。
• The drums seemed to throb in his ears.阵阵鼓声彷佛在他耳边震响。

2 parlance   

n.说法；语调

参考例句：

• The term "meta directory" came into industry parlance two years ago.两年前，商业界开始用“元目录”这个术语。
• The phrase is common diplomatic parlance for spying.这种说法是指代间谍行为的常用外交辞令。

3 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。

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 appreciation   

n.评价；欣赏；感谢；领会，理解；价格上涨

参考例句：

• I would like to express my appreciation and thanks to you all.我想对你们所有人表达我的感激和谢意。
• I'll be sending them a donation in appreciation of their help.我将送给他们一笔捐款以感谢他们的帮助。

6 rhythmic   

adj.有节奏的，有韵律的

参考例句：

• Her breathing became more rhythmic.她的呼吸变得更有规律了。
• Good breathing is slow,rhythmic and deep.健康的呼吸方式缓慢深沉而有节奏。

7 cannon   

n.大炮，火炮；飞机上的机关炮

参考例句：

• The soldiers fired the cannon.士兵们开炮。
• The cannon thundered in the hills.大炮在山间轰鸣。

8 cosmos   

n.宇宙；秩序，和谐

参考例句：

• Our world is but a small part of the cosmos.我们的世界仅仅是宇宙的一小部分而已。
• Is there any other intelligent life elsewhere in the cosmos?在宇宙的其他星球上还存在别的有智慧的生物吗？

9 seminal   

adj.影响深远的；种子的

参考例句：

• The reforms have been a seminal event in the history of the NHS.这些改革已成为英国国民保健制度史上影响深远的一件大事。
• The emperor's importance as a seminal figure of history won't be diminished.做为一个开创性历史人物的重要性是不会减弱的。

10 swarms   

蜂群，一大群( swarm的名词复数 )

参考例句：

• They came to town in swarms. 他们蜂拥来到城里。
• On June the first there were swarms of children playing in the park. 6月1日那一天，这个公园里有一群群的孩子玩耍。

11 seasonally   

参考例句：

• The price of vegetables fluctuates seasonally. 蔬菜的价格随季节变动。 来自《简明英汉词典》
• They moved seasonally among various vegetation types to feed on plants that were flourishing. 它们还随着季节的变化而在各种类型植物之间迁移，以便吃那些茂盛的植物。 来自辞典例句