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[00:00.00]Lesson Eight
[00:02.80]Text
[00:05.43]How I Designed an A Bomb
[00:09.59]in My Junior Year at Princeton John A . Phillips and David Michaelis
[00:19.15]The first semester of my junior year at Princeton University is a disaster,
[00:27.30]and my grades show it.
[00:30.54]D's and F's predominate,and a note from the dean puts me on academic probation1.
[00:40.39]Flunk one more course,and I'm out.
[00:44.83]Fortunately, as the new semester gets under way,
[00:50.47]my courses begin to interest me.
[00:55.01]Three hours a week,
[00:58.17]I attend one called Nuclear Weapons Strategy and Arms Control.
[01:04.63]One morning,Freeman Dyson,
[01:09.20]an eminent2 physicist3 assisting Hal Feiveson in the course,
[01:16.04]opens a discussion on the atomic bomb:
[01:20.72]"Let me describe what occurs when a 20-kiloton bomb is exploded,
[01:28.27]similar to the two dropped on Hiroshima and Nagasaki
[01:34.64]First, the sky becomes illuminated4 by a brilliant white light.
[01:41.59]Temperatures are so high around the point of explosion
[01:47.26]that the atmosphere is actually made incandescent5.
[01:52.72]To an observer standing6 six miles away
[01:57.68]the ball of fire appears brighter than a hundred suns.
[02:03.53]"As the fireball begins to spread up and out into a mushroom shaped cloud,
[02:10.66]temperatures spontaneously ignite all flammable materials for miles around.
[02:19.02]Wood frame houses catch fire.
[02:23.28]Clothing bursts into flame,
[02:27.44]and people suffer intense third degree lash7 burns over their exposed flesh.
[02:35.01]The very high temperatures also produce a shock wave
[02:40.94]and a variety of nuclear radiation capable of penetrating8 20 inches of concrete.
[02:49.59]Silence falls over the roomas the titanic9 proportions of the destruction begin to sink in
[02:57.53]"It takes only 15 pounds of plutonium to fabricate a crude atomic bomb,
[03:05.68]"adds Hal Feiveson. "
[03:09.20]If breeder reactors11 come into widespread use,
[03:14.48]there will be sufficient plutonium shipped around the country each year
[03:19.60]to fashion thousands of bombs.
[03:24.15]Much of it could be vulnerable to theft or hijacking12.
[03:30.81]"The class discusses the possibility of terrorists
[03:36.08] using a homemade atomic bomb to push their extravagant13 political demands.
[03:43.22]"That's impossible," a student objects.
[03:48.26]"Terrorists don't have the know how to build a bomb.
[03:53.61]Besides, they don't have access to the knowledge.
[03:58.58]"Impossible? Or is it?The question begins to haunt me.
[04:06.52]I turn to reference books and find,according to a famous nuclear physicist,
[04:13.78]that a terrorist group could easily steal plutonium
[04:19.42]or uranium from a nuclear reactor10
[04:24.41]and then design a workable atomic bomb
[04:29.27]with information available to the general public
[04:34.23]are legally available at hardware stores and chemical supply houses.
[04:41.68]Suddenly,an idea comes to mind.
[04:45.94]Suppose an average or below average in my case physics student
[04:53.20]could design a workable atomic bomb on paper?
[04:58.76]If I could design a bomb, almost any intelligent person could.
[05:05.53]But I would have to do it in less than three months
[05:10.36]to turn it inas my junior independent project.
[05:15.19]I decide to ask Freeman Dyson to be my adviser14.
[05:20.84]"You understand," said Dyson, "
[05:25.20]my government security clearance15 will prevent me from giving you any more information
[05:31.76]than that which can be found in physics libraries.
[05:37.03]And that the law of'no comment' governing scientists
[05:42.78] who have clearance to atomic research requires that,
[05:48.13]if asked a question about the design of a bomb,
[05:52.89]I can answer neither yes nor no?"
[05:58.64]"Yes, sir," I reply."I understand.""Okay, then.
[06:05.40]I'll give you a list of textbooks outlining the general principles
[06:11.57]and I wish you luck."
[06:14.80]A few days later,Dyson hands me a short list of books on nuclear reactor technology
[06:23.45]general nuclear physics and current atomic theory.
[06:29.51]"That's all?" I ask incredulously, having expected a bit more direction.
[06:38.29]At subsequent meetings Dyson explains only the basic principles of nuclear physics
[06:46.15]If I ask about a particular design or figure,
[06:51.19]he will glance over what I've done and change the subject.
[06:56.37]At first, I think this is his way of telling me I am correct.
[07:02.11]To make sure, I hand him an incorrect figure.
[07:07.39]He reads it and changes the subject.
[07:11.83]Over spring vacation,I go to Washington,D.C
[07:17.71]to search for records of the Los Alamos Project
[07:23.35]that were declassified16 between 1954 and 1964.
[07:30.22]I discover a copy of the literature given to scientists
[07:36.07]who joined the project in the spring of 1943.
[07:41.95]This text carefully outlines all the details of atomic fissioning
[07:49.11]known to the world's most advanced scientists in the early '40s.
[07:55.77]A whole batch17 of copies costs me about $ 25.
[08:01.83]I gather them together and go over to the bureaucrat18 at the front desk.
[08:08.49]She looks at the titles and then looks up at me.
[08:13.17]"Oh, you want to build a bomb, too?" she asks matter-of-factly.
[08:20.90]I can't believe it.
[08:24.06]Do people go in there for bomb-building information every day?
[08:30.41]When I show the documents to Dyson, he is visibly shaken.
[08:36.05]His reaction indicates to me that I actually stand a chance of coming up with a workable design
[08:44.88]The material necessary to explode my bomb is plutonium-239.
[08:52.35]Visualize an atomic bomb as a marble inside a grape fruit
[08:58.88]inside a basketball inside a beach ball.
[09:04.52]At the center of the bomb is the initiator,
[09:09.38]a marble-size piece of metal.
[09:13.43]Around the initiator is a grapefruit-size ball of plutonium-239.
[09:21.08]Wrapped around the plutonium
[09:24.64]is a threeinch reflector shield made of beryllium.
[09:30.70]High explosives are placed symmetrically around the beryllium shield.
[09:36.94]When these detonate,an imploding19 shock wave is set off,
[09:44.41]compressing the grapefruit-size ball of plutonium to the size of a plum.
[09:51.67]At this moment, the process of atoms fissioning or splitting apart begins.
[09:59.72]There are many subtleties20 involved in the explosion of an atomic bomb
[10:06.09]Most of them center on the actual detonation21
[10:10.95]of the explosives surrounding the beryllium shield.
[10:15.92]The grouping of these explosives
[10:19.76]is one of the most highly classified aspects of the atomic bomb,
[10:25.21]As the next three weeks go by,
[10:29.29]I stop going to classes altogether and work day and night.
[10:35.74]I develop a terrible case of bloodshot eyes.
[10:40.89]Sleep comes rarely.
[10:44.44]I approach every problem from a terrorist's point of view.
[10:50.50]The bomb must be inexpensive to construct,
[10:55.26]simple in design and small enough to sit unnoticed in the trunk of a car.
[11:03.01]As the days and nights flow by,
[11:07.06]I scan government documents for gaps
[11:11.63] indicating an area of knowledge that is still classified.
[11:17.20]Essentially, I am putting together a huge jigsaw22 puzzle.
[11:23.08]The edge pieces are in place and various areas are getting filled in,
[11:29.42]but pieces are missing.
[11:32.79]Whenever the outline of one shows up,
[11:36.92]I sit down to devise the solution that will fill the gap.
[11:42.67]With only two weeks left, the puzzle is nearly complete,
[11:48.73]but two pieces are still missing:
[11:52.80]which explosives to use,and how to arrange them around the plutonium.
[11:59.65]Seven days before the design is due,
[12:04.09]I'm still deadlocked23 I realize something drastic must be done,
[12:11.45]and I start all over at the beginning.
[12:15.82]Occasionally I find errors in my old calculations,and I correct them.
[12:23.47]I lose sense of time.
[12:26.81]With less than 24 hours to go,
[12:30.97]I run through a series of new calculations,
[12:36.22]mathematically figuring the arrangement of the explosives around the plutonium
[12:42.75]If my equations are correct,
[12:46.82]my bomb might be just as effective as the Hiroshima and Nagasaki bombs.
[12:54.27]But I can't be sure until I know the exact nature of the explosives I will use
[13:01.64]Next morning, with my paper due at 5 p.m.,
[13:07.20]I call the Du Pont Company from a pay phone
[13:12.55]and ask for the head of the chemical explosives division,
[13:18.30]a man I'll call Mr.Graves."Hello, Mr. Graves.
[13:25.56]My name is John Phillips,a student doing work on a physics project.
[13:32.83]I'd like to get some advice, if that's possible."
[13:37.79]"What can I do for you?"
[13:40.95]"Well," I stammer,"
[13:44.48]I'm doing research on the shaping of explosive products
[13:49.94]that create a very high density24 in a spherically25 shaped metal.
[13:57.20]Can you suggest a Du Pont product that would fit in this category?"
[14:03.68]"Of course." he says,in a helpful manner.
[14:08.85]"We sell the names of the product
[14:13.39]to do the job in similar density problem situations
[14:20.06]to the one you're talking about.
[14:23.82]"Mr. Graves has given me just the information I need.
[14:29.49]Now,if my calculations are correct with respect to the new information,
[14:36.85]all I have to do is complete my paper by five.
[14:42.31]Five minutes to five,I race over to the physics building and bound up the stairs
[14:50.36]Inside the office,everybody stops talking and stares at me.
[14:57.12]"I came to hand in my project," I explain.
[15:02.19]A week later, I return to the office to pick up my project.
[15:08.43]My paper is not there.
[15:12.27]"Aren't you the boy who designed the atomic bomb?"
[15:16.95]The secretary looks up, then freezes.
[15:21.21]"Yes," I reply.She takes a deep breath.
[15:27.16]"The question has been raised
[15:31.00]by the department whether your paper should be classified by the U. S. government
[15:37.98]"What! Classified?"She takes my limp hand shaking it vigorously.
[15:46.94]"Congratulations," she says, all smiles.
[15:52.19]"You've got one of the only A's in the department.
[15:57.15]"For a second I don't say anything.
[16:01.38]Here I have put on paper the plan for a device
[16:06.71]capable of killing26 thousands of people,
[16:11.57]and all I was worrying about was flunking27 out.
1 probation | |
n.缓刑(期),(以观后效的)察看;试用(期) | |
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2 eminent | |
adj.显赫的,杰出的,有名的,优良的 | |
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3 physicist | |
n.物理学家,研究物理学的人 | |
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4 illuminated | |
adj.被照明的;受启迪的 | |
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5 incandescent | |
adj.遇热发光的, 白炽的,感情强烈的 | |
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6 standing | |
n.持续,地位;adj.永久的,不动的,直立的,不流动的 | |
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7 lash | |
v.系牢;鞭打;猛烈抨击;n.鞭打;眼睫毛 | |
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8 penetrating | |
adj.(声音)响亮的,尖锐的adj.(气味)刺激的adj.(思想)敏锐的,有洞察力的 | |
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9 titanic | |
adj.巨人的,庞大的,强大的 | |
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10 reactor | |
n.反应器;反应堆 | |
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11 reactors | |
起反应的人( reactor的名词复数 ); 反应装置; 原子炉; 核反应堆 | |
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12 hijacking | |
n. 劫持, 抢劫 动词hijack的现在分词形式 | |
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13 extravagant | |
adj.奢侈的;过分的;(言行等)放肆的 | |
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14 adviser | |
n.劝告者,顾问 | |
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15 clearance | |
n.净空;许可(证);清算;清除,清理 | |
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16 declassified | |
adj.解密的v.对(机密文件等)销密( declassify的过去式和过去分词 ) | |
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17 batch | |
n.一批(组,群);一批生产量 | |
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18 bureaucrat | |
n. 官僚作风的人,官僚,官僚政治论者 | |
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19 imploding | |
v.(使)向心聚爆( implode的现在分词 ) | |
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20 subtleties | |
细微( subtlety的名词复数 ); 精细; 巧妙; 细微的差别等 | |
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21 detonation | |
n.爆炸;巨响 | |
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22 jigsaw | |
n.缕花锯,竖锯,拼图游戏;vt.用竖锯锯,使互相交错搭接 | |
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23 deadlocked | |
陷入僵局的;僵持不下的 | |
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24 density | |
n.密集,密度,浓度 | |
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25 spherically | |
球状地,球地 | |
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26 killing | |
n.巨额利润;突然赚大钱,发大财 | |
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27 flunking | |
v.( flunk的现在分词 );(使)(考试、某学科的成绩等)不及格;评定(某人)不及格;(因不及格而) 退学 | |
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