2007年VOA标准英语-Astronomers Search for Origin of What Cannot be

By Jessica Berman
Washington
14 September 2007

Scientists have known for some time that most of the stuff in the Universe is so-called dark matter, material that cannot be seen directly because it does not interact with light.  That makes it very difficult to study.  But now, as we hear from VOA's Jessica Berman, researchers say the arrangement of the oldest stars in the universe may provide clues to help them learn more about dark matter.

Artist's rendition of dark matter

Immediately after the Big Bang, experts say the universe expanded rapidly, but stayed mostly smooth and dark for about 100 million years.

Then things began to change. Scientists say that within that blanket of darkness, dark matter began to exert forces that pulled hydrogen, helium and lithium gases together to form stars.  

"You may say, why care about the first stars in the Universe?  But the first stars produced the first light in the Universe," he said.

That is Astronomer² Tom Theuns (TOONZ) at Britain's Durham University. Writing in the American journal Science.  Theuns and his colleagues describe a way that those stars, which are billions of years old, may help today's scientists unravel³ part of the dark matter mystery.

It depends on whether those oldest stars are in long strings⁴ or clumped⁵ together.

The dark matter that existed soon after the Big Bang may have been either "warm" or "cold."  Those are the terms astronomers⁶ use to describe how much energy the matter contained, or more simply, how fast its particles moved. The researchers developed a sophisticated mathematical model to show that stars would have clustered together in clumps⁷ under the influence of cold dark matter. In contrast, warmer dark matter would have produced stars in long strings, or filaments⁹. Theuns says his theory may provide at least part of an explanation for the origin of the super-massive black holes at the center of some galaxies¹⁰.

"So what we think is possible that is that in these filaments that you form in warm dark matter, if you form many stars along this filament⁸, that you will get collisions between the stars," he added.  "So, soon collisions between the stars will make up a star that are so massive that it cannot remain a star, it becomes a black hole. And once it becomes a black hole, it can grow very rapidly by swallowing these stars that are around."

Astronomers do not yet have telescopes that can see the distant stars that were formed some 13 billion years ago, when the universe was young, so even if Theuns' theory is correct, it still does not provide any immediate¹ insight to the nature of dark matter, even though it suggests that dark matter may have had a crucial role in the arrangement of stars in the early universe.

1 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

2 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。

3 unravel   

v.弄清楚（秘密）；拆开，解开，松开

参考例句：

• He was good with his hands and could unravel a knot or untangle yarn that others wouldn't even attempt.他的手很灵巧，其他人甚至都不敢尝试的一些难解的绳结或缠在一起的纱线，他都能解开。
• This is the attitude that led him to unravel a mystery that long puzzled Chinese historians.正是这种态度使他解决了长期以来使中国历史学家们大惑不解的谜。

4 strings   

n.弦

参考例句：

• He sat on the bed,idly plucking the strings of his guitar.他坐在床上，随意地拨着吉他的弦。
• She swept her fingers over the strings of the harp.她用手指划过竖琴的琴弦。

5 clumped   

adj.[医]成群的v.（树、灌木、植物等的）丛、簇( clump的过去式和过去分词 )；（土、泥等）团；块；笨重的脚步声

参考例句：

• The bacteria clumped together. 细菌凝集一团。 来自《现代英汉综合大词典》
• He clumped after her, up the stairs, into his barren office. 他拖着沉重的步伐跟在她的后面上楼了，走进了他那个空荡荡的诊所。 来自辞典例句

6 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》

7 clumps   

n.（树、灌木、植物等的）丛、簇( clump的名词复数 )；（土、泥等）团；块；笨重的脚步声v.（树、灌木、植物等的）丛、簇( clump的第三人称单数 )；（土、泥等）团；块；笨重的脚步声

参考例句：

• These plants quickly form dense clumps. 这些植物很快形成了浓密的树丛。 来自《简明英汉词典》
• The bulbs were over. All that remained of them were clumps of brown leaves. 这些鳞茎死了，剩下的只是一丛丛的黃叶子。 来自《简明英汉词典》

8 filament   

n.细丝；长丝；灯丝

参考例句：

• The source of electrons in an electron microscope is a heated filament.电子显微镜中的电子源，是一加热的灯丝。
• The lack of air in the bulb prevents the filament from burning up.灯泡内缺乏空气就使灯丝不致烧掉。

9 filaments   

n.（电灯泡的）灯丝( filament的名词复数 )；丝极；细丝；丝状物

参考例句：

• Instead, sarcomere shortening occurs when the thin filaments'slide\" by the thick filaments. 此外，肌节的缩短发生于细肌丝沿粗肌丝“滑行”之际。 来自辞典例句
• Wetting-force data on filaments of any diameter and shape can easily obtained. 各种直径和形状的长丝的润湿力数据是易于测量的。 来自辞典例句

10 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。