万物简史 第220期:把铅撵出去(9)
时间:2017-03-16 00:36:05
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(单词翻译)
Holmes was heroic as much for the obstacles he overcame as for the results he achieved. By the 1920s, when Holmes was in the prime of his career, geology had slipped out of fashion—physics was the new excitement of the age—and had become severely1 underfunded, particularly in Britain, its spiritual birthplace. At Durham University, Holmes was for many years the entire geology department. Often he had to borrow or patch together equipment in order to pursue his radiometric dating of rocks. At one point, his calculations were effectively held up for a year while he waited for the university to provide him with a simple adding machine.
无论在克服困难方面,还是在取得的成就方面,霍姆斯都很有英雄气概。20世纪20年代,正当他的事业进入全盛期的时候,地质学已经不再吃香──物理学是那个时代的热门科学,资金严重缺乏,尤其在它的精神诞生地英国。多少年来,他是达勒姆大学地质系的惟一人员。为了进行测定岩石年代的工作,他常常不得不借用或拼凑设备。有一次,为了等校方为他提供一台简单的加法机,他的计算工作竟然耽搁了1年时间。
铅的危害
Occasionally, he had to drop out of academic life altogether to earn enough to support his family—for a time he ran a curio shop in Newcastle upon Tyne—and sometimes he could not even afford the ?5 annual membership fee for the Geological Society.
有时候,他不得不完全停止学术工作,以便挣钱来养家糊口──一度在纽卡斯尔开了个古董店,有时候他连地质学会每年5英镑的会费也缴不起。
The technique Holmes used in his work was theoretically
straightforward2 and arose directly from the process, first observed by Ernest Rutherford in 1904, in which some atoms decay from one element into another at a rate predictable enough that you can use them as clocks. If you know how long it takes for potassium-40 to become argon-40, and you measure the amounts of each in a sample, you can work out how old a material is. Holmes's contribution was to measure the decay rate of uranium into lead to calculate the age of rocks, and thus—he hoped—of the Earth.
霍姆斯在研究工作中使用的方法,在理论上其实并不复杂,直接产生于欧内斯特·卢瑟福于1904年最初发现的那个过程,即,有的原子以一种可以预测的比率从一种元素衰变成另一种元素,因此这个过程可以用来当时钟。要是你知道钾-40要经过多长时间才变成氩-40,并且测定样品里这两种元素的量,你就可以得出那种物质的年代。霍姆斯的贡献在于,以测定铀衰变成铅的比率来测定岩石的年代,从而──他希望──能测定地球的年龄。
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