2006年VOA标准英语-Ion-Smashing Yields New Knowledge, But Som

By Carolyn Weaver¹
Washington, DC
09 February 2006
 
watch Brookhaven report

Experimental results at Brookhaven National Laboratory’s supercollider that replicate² in miniature the “Big Bang,” when the universe exploded into being, were named the top physics story of 2005 by the American Institute of Physics. But some observers say that the possible risks of the experiments, which smash together gold ions traveling near the speed of light, remain an open question.

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Brookhaven National Laboratory's Relativistic Heavy Ion Collider (courtesy Brookhaven)  
  

Seen from above, the Relativistic Heavy Ion Collider, or RHIC, at New York’s Brookhaven National Laboratory, looks like a racetrack. And it is a kind of race track: two “beam pipes” in a tunnel nearly four kilometers around, in which gold nuclei³ are accelerated to close to the speed of light, and are crashed into each other at intersecting points along the way. Out of the kinetic⁴ energy of those collisions, new matter is created for a brief instant: a shower of quarks and gluons, the smallest particles known – and at seven trillion degrees, hotter than anything now in the universe. 

 
Brookhaven physicist⁵ Peter Steinberg
  
“It’s basically a living embodiment of E=mc squared,” says Brookhaven physicist Peter Steinberg. “Einstein’s theory told us a hundred years ago that you can trade off energy for mass, and vice⁶ versa. We’re essentially⁷ converting the kinetic energy, the energy from the motion of these nuclei, converting it into lots of particles.”

The four detectors⁹ that bestride the collision points are massive machines, with “time projection¹⁰ chambers¹¹” that record the collisions and their after-moments. The latest results made big news last year when Brookhaven physicists¹² reported that the quark-gluon plasma¹³ was not a gas as expected, but rather a very dense¹⁴ liquid.

 
Artitst's drawing of gold ions colliding (courtesy Jeffery Mitchell, Brookhaven National Laboratory) 
  
“Most people believe the universe itself, a couple of microseconds after the Big Bang, was essentially one big state of quark-gluon plasma,” Mr. Steinberg explains. “And so learning about the properties and the nature of this material at RHIC, we are probably gaining some insight into what the universe looked like right after the Big Bang.”

Scientists from more than a dozen nations collaborate¹⁵ at RHIC. The work is unclassified. But is it safe to recreate conditions that haven’t existed since the beginning of time? Before the supercollider opened in 2000, several reputable physicists raised the possibility that the experiments could create a chain reaction of “strangelets,” quarks missing an electron that would turn other nearby atoms into strange matter, too. 

Author Richard A. Posner, a critic of RHIC  
  
Federal appeals court judge and author Richard A. Posner outlines the scenario¹⁶ in his latest book, Catastrophe¹⁷: Risk and Response.  “Within a fraction of a second, this strange matter would expand, so the entire earth was a strangelet,” he said in an interview. “And because of its great density¹⁸, the earth in its strange form would be only 100 meters in diameter. And then it would blow up.” 

In response to these concerns, Brookhaven asked a panel of four leading physicists to assess the risks. Their report concluded that the chance of a strangelet accident was no more than one in fifty million – and might not even be physically¹⁹ possible. They also dismissed the risk of other cosmic accidents. But some observers still object that RHIC experiments amount to “betting the planet” -- however unlikely the chance of losing.  Richard A. Posner, who advocates the use of cost-benefit analyses in making policy decisions, says, “It’s a very abstract scientific interest that drives this research. It doesn’t sound like a particularly good investment, in which event why take even a very small risk?” 

A view of the STAR detector⁸, one of four such experiments at RHIC   
  
“If we really saw it in those terms, if we sat at a table and asked ourselves, are we going to bet the planet to learn something that could potentially be very useful to mankind in the fullness of time, we’d probably go, ‘no,’” Peter Steinberg replies. “But the reality is, nobody I know doing this has even any gut-level feeling, ‘oh gosh, maybe we’re doing something dangerous.’” A critical point, says Mr. Steinberg, is that RHIC’s experimental findings in five and a half years of operation have shown no sign of any dangers, and have reduced any grounds for concern over risk. 

“The more we learn, the experts are less worried,” he says, “and when that happens, you should worry less, too. If the experts get more worried, then you should start to get more worried, but the experts feel better about it year by year, because we’re learning more. And it’s only the people who aren’t the experts who are actively²⁰ keeping these discussions going.”

Yet Mr. Posner and a few other critics, including University of Cambridge physicist and mathematician²¹ Adrian Kent, say that a process for deciding on such experiments should be established that includes risk-analysis scholars and the public – particularly since next year the European Organization for Nuclear Research, or CERN, in Geneva, will open a collider 30 times more powerful than RHIC, that’s expected to offer the deepest views into the nature of matter yet.  

Some images and animations²² courtesy of Brookhaven National Laboratory and CERN.
 
 

1 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。

2 replicate   

v.折叠，复制，模写；n.同样的样品；adj.转折的

参考例句：

• The DNA of chromatin must replicate before cell division.染色质DNA在细胞分裂之前必须复制。
• It is also easy to replicate,as the next subsection explains.就像下一个小节详细说明的那样，它还可以被轻易的复制。

3 nuclei   

n.核

参考例句：

• To free electrons, something has to make them whirl fast enough to break away from their nuclei. 为了释放电子，必须使电子高速旋转而足以摆脱原子核的束缚。
• Energy is released by the fission of atomic nuclei. 能量是由原子核分裂释放出来的。

4 kinetic   

adj.运动的；动力学的

参考例句：

• There exist many sources of energy both potential and kinetic.存在着许多势能和动能的能源。
• The kinetic theory of gases is the best known example.气体动力学理论就是最有名的例子。

5 physicist   

n.物理学家，研究物理学的人

参考例句：

• He is a physicist of the first rank.他是一流的物理学家。
• The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。

6 vice   

n.坏事；恶习；[pl.]台钳，老虎钳；adj.副的

参考例句：

• He guarded himself against vice.他避免染上坏习惯。
• They are sunk in the depth of vice.他们堕入了罪恶的深渊。

7 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

8 detector   

n.发觉者，探测器

参考例句：

• The detector is housed in a streamlined cylindrical container.探测器安装在流线型圆柱形容器内。
• Please walk through the metal detector.请走过金属检测器。

9 detectors   

探测器( detector的名词复数 )

参考例句：

• The report advocated that all buildings be fitted with smoke detectors. 报告主张所有的建筑物都应安装烟火探测器。
• This is heady wine for experimenters using these neutrino detectors. 对于使用中微子探测器的实验工作者，这是令人兴奋的美酒。 来自英汉非文学 - 科技

10 projection   

n.发射，计划，突出部分

参考例句：

• Projection takes place with a minimum of awareness or conscious control.投射在最少的知觉或意识控制下发生。
• The projection of increases in number of house-holds is correct.对户数增加的推算是正确的。

11 chambers   

n.房间( chamber的名词复数 )；（议会的）议院；卧室；会议厅

参考例句：

• The body will be removed into one of the cold storage chambers. 尸体将被移到一个冷冻间里。 来自《简明英汉词典》
• Mr Chambers's readable book concentrates on the middle passage: the time Ransome spent in Russia. Chambers先生的这本值得一看的书重点在中间：Ransome在俄国的那几年。 来自互联网

12 physicists   

物理学家( physicist的名词复数 )

参考例句：

• For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说，这是受挫折的一年。 来自英汉非文学 - 科技
• Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。

13 plasma   

n.血浆，细胞质，乳清

参考例句：

• Keep some blood plasma back for the serious cases.留一些血浆给重病号。
• The plasma is the liquid portion of blood that is free of cells .血浆是血液的液体部分，不包含各种细胞。

14 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

15 collaborate   

vi.协作，合作；协调

参考例句：

• The work gets done more quickly when we collaborate.我们一旦合作，工作做起来就更快了。
• I would ask you to collaborate with us in this work.我们愿意请你们在这项工作中和我们合作。

16 scenario   

n.剧本，脚本；概要

参考例句：

• But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
• This is a totally different scenario.这是完全不同的剧本。

17 catastrophe   

n.大灾难，大祸

参考例句：

• I owe it to you that I survived the catastrophe.亏得你我才大难不死。
• This is a catastrophe beyond human control.这是一场人类无法控制的灾难。

18 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

19 physically   

adj.物质上，体格上，身体上，按自然规律

参考例句：

• He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
• Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。

20 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

21 mathematician   

n.数学家

参考例句：

• The man with his back to the camera is a mathematician.背对着照相机的人是位数学家。
• The mathematician analyzed his figures again.这位数学家再次分析研究了他的这些数字。

22 animations   

n.生气( animation的名词复数 )；兴奋；动画片；（指电影、录像、电脑游戏的）动画制作

参考例句：

• You'll see your team cheerleaders and mascot performing new animations as well. 你会看到啦啦队队长跟吉祥物也都会有全新的动作。 来自互联网
• Ability to create simple movie and animations using graphic & multimedia software. 能够用平面和多媒体软件制作简单的电影及动画。 来自互联网