2006年VOA标准英语-Astronomers Find Signs Planets Might Form

By David McAlary
Washington
05 April 2006

New evidence from an orbiting U.S. telescope indicates that planets might rise up out of a dead star's ashes. This is the first time scientists have detected planet-building materials around a star that died in a fiery¹ blast.

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Legend tells of a mythical² bird that periodically burned itself to death and emerged from the ashes as a new phoenix³. Astronomers⁵ have found evidence that planets might do something similar.

 

Artist's concept of stellar rubble⁶  
  

The U.S. space agency's Spitzer Space Telescope surveyed the scene around a type of exploded star called a neutron⁷ star. It found a surrounding disk made up of debris⁸ shot out during the star's final death throes. Astrophysicist Deepto Chakrabarty of the Massachusetts Institute of Technology says the dusty rubble in this disk might ultimately stick together to form planets.

"Now, a remarkable⁹ thing about this disk is that it looks very much like a debris disk seen around young stars, and astronomers already know that planets can form from such disks. So it it possible by analogy that planets could also be forming in this very different, harsh environment around an old, dead star, a sort of birth after death, or renaissance," he said.

The neutron star that the Spitzer telescope observed is in the constellation¹⁰ Cassiopeia, 13,000 light years away, the distance it takes light to travel in that length of time. It was once a larger, bright star about 10 to 20 times more massive than our sun. The U.S. space agency says it probably collapsed¹² under its own weight in its death throes about 100,000 years ago and blasted apart in an explosion astronomers call a supernova.

Spitzer's heat seeking infrared¹³ eyes were able to detect the warm glow of the dusty disk surrounding the burnt-out star, which is so dense¹⁴ after its collapse¹¹ that a spoonful would weigh about two billion tons.

Until now, no one had ever seen such a disk around a dead star, but NASA astronomer⁴ Charles Beichman says scientists have been suggesting their possible presence since 1992, when the first planet discovered outside our solar system was detected around a neutron star.

"We think that the disk formed after the supernova explosion. Much of the material exploded into free space, but some of it just wouldn't have enough energy to escape the gravitational pull of the neutron star that was left. It would fall back down and probably was rotating so it formed into a disk-like structure, and that is what we are seeing in the Spitzer data," he said.

Beichman says the finding is another hint that planet formation is a very robust¹⁵ process that could happen in a wide variety of environments.

"We would like to understand the breadth of planet formation processes to understand better how our own planetary system was formed," he said.

This discovery is reported in the April 6 edition of the journal Nature.

1 fiery   

adj.燃烧着的，火红的；暴躁的；激烈的

参考例句：

• She has fiery red hair.她有一头火红的头发。
• His fiery speech agitated the crowd.他热情洋溢的讲话激动了群众。

2 mythical   

adj.神话的；虚构的；想像的

参考例句：

• Undeniably,he is a man of mythical status.不可否认，他是一个神话般的人物。
• Their wealth is merely mythical.他们的财富完全是虚构的。

3 phoenix   

n.凤凰，长生(不死)鸟；引申为重生

参考例句：

• The airline rose like a phoenix from the ashes.这家航空公司又起死回生了。
• The phoenix worship of China is fetish worship not totem adoration.中国凤崇拜是灵物崇拜而非图腾崇拜。

4 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。

5 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》

6 rubble   

n.（一堆）碎石，瓦砾

参考例句：

• After the earthquake,it took months to clean up the rubble.地震后，花了数月才清理完瓦砾。
• After the war many cities were full of rubble.战后许多城市到处可见颓垣残壁。

7 neutron   

n.中子

参考例句：

• Neutron is neutral and slightly heavier than the proton.中子是中性的，比质子略重。
• Based on the neutron energy,the value of weighting factor was given.根据中子能量给出了相应的辐射权重因子的数值。

8 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

9 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

10 constellation   

n.星座n.灿烂的一群

参考例句：

• A constellation is a pattern of stars as seen from the earth. 一个星座只是从地球上看到的某些恒星的一种样子。
• The Big Dipper is not by itself a constellation. 北斗七星本身不是一个星座。

11 collapse   

vi.累倒；昏倒；倒塌；塌陷

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。

12 collapsed   

adj.倒塌的

参考例句：

• Jack collapsed in agony on the floor. 杰克十分痛苦地瘫倒在地板上。
• The roof collapsed under the weight of snow. 房顶在雪的重压下突然坍塌下来。

13 infrared   

adj./n.红外线(的)

参考例句：

• Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
• Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。

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 robust   

adj.强壮的，强健的，粗野的，需要体力的，浓的

参考例句：

• She is too tall and robust.她个子太高，身体太壮。
• China wants to keep growth robust to reduce poverty and avoid job losses,AP commented.美联社评论道，中国希望保持经济强势增长，以减少贫困和失业状况。