手机APP下载

您现在的位置: 首页 > 英语听力 > 双语有声读物 > 万物简史 > 正文

万物简史(MP3+中英字幕) 第222期:把铅撵出去(11)

来源:可可英语 编辑:villa   可可英语APP下载 |  可可官方微信:ikekenet
  


扫描二维码进行跟读打分训练

For seven years, first at the University of Chicago and then at the California Institute of Technology (where he moved in 1952), he worked in a sterile lab, making very precise measurements of the lead/uranium ratios in carefully selected samples of old rock.

有7年时间,先是在芝加哥大学,后在加州理工学院(他于1952年迁往那里),他在无菌实验室里埋头苦干,仔细选择古老岩石的样品,精密测定里面铅/铀的比例。
The problem with measuring the age of the Earth was that you needed rocks that were extremely ancient, containing lead- and uranium-bearing crystals that were about as old as the planet itself—anything much younger would obviously give you misleadingly youthful dates—but really ancient rocks are only rarely found on Earth. In the late 1940s no one altogether understood why this should be. Indeed, and rather extraordinarily, we would be well into the space age before anyone could plausibly account for where all the Earth's old rocks went. (The answer was plate tectonics, which we shall of course get to.) Patterson, meantime, was left to try to make sense of things with very limited materials. Eventually, and ingeniously, it occurred to him that he could circumvent the rock shortage by using rocks from beyond Earth. He turned to meteorites.
测定地球年龄的问题在于,你需要有极其古老的岩石,内有含铅和铀的晶体,其古老程度几乎与这颗行星一样──要是岩石年轻得多,测出的年代显然会比较年轻,从而得出错误的结论,而真正古老的岩石在地球上是很难找得着的。到20世纪40年代末,谁也不知道这是什么原因。实际上,要等到太空时代,才可能有人貌似有理地说明地球上古老岩石的去向,这真是不可思议的。(答案在于板块构造,我们当然将谈到这个问题。)与此同时,彼得森只能在材料非常有限的情况下把这一切搞清楚。最后,他突然聪明地想到,他可以利用地球之外的岩石,从而绕开缺少岩石的问题。他把注意力转向陨石。
地球爷爷

The assumption he made—rather a large one, but correct as it turned out—was that many meteorites are essentially leftover building materials from the early days of the solar system, and thus have managed to preserve a more or less pristine interior chemistry. Measure the age of these wandering rocks and you would have the age also (near enough) of the Earth.

他提出了一个假设──一个很有远见的假设,结果证明非常正确,即,许多陨石实际上是太阳系早期留下来的建筑材料,因此多少保留着原始的内部化学结构。测定了这些四处游荡的岩石的年代,你也就(接近于)测定了地球的年龄。

重点单词   查看全部解释    
measure ['meʒə]

想一想再看

n. 措施,办法,量度,尺寸
v. 测量,量

联想记忆
limited ['limitid]

想一想再看

adj. 有限的,被限制的
动词limit的过

 
planet ['plænit]

想一想再看

n. 行星

 
essentially [i'senʃəli]

想一想再看

adv. 本质上,本来

 
assumption [ə'sʌmpʃən]

想一想再看

n. 假定,设想,担任(职责等), 假装

联想记忆
pristine ['pristi:n]

想一想再看

adj. 远古的,原始状态的,未受损的,新鲜而纯净的

联想记忆
eventually [i'ventjuəli]

想一想再看

adv. 终于,最后

 
precise [pri'sais]

想一想再看

adj. 精确的,准确的,严格的,恰好的

联想记忆
extremely [iks'tri:mli]

想一想再看

adv. 极其,非常

联想记忆
institute ['institju:t]

想一想再看

n. 学会,学院,协会
vt. 创立,开始,制

联想记忆

发布评论我来说2句

    最新文章

    可可英语官方微信(微信号:ikekenet)

    每天向大家推送短小精悍的英语学习资料.

    添加方式1.扫描上方可可官方微信二维码。
    添加方式2.搜索微信号ikekenet添加即可。