2006年VOA标准英语-US Spacecraft Bringing Clues to Solar Syst

By David McAlary
Washington
10 January 2006

 
Courtesy of NASA
Artist's conception of Stardust spacecraft collecting dust from comet Wild-2 
  
A U.S. spacecraft is returning to Earth with a precious cargo¹ of stardust that was gathered during a 4.5 billion kilometer roundtrip journey to a distant comet.  The spacecraft is scheduled to deposit its treasure on Sunday in the Utah desert.  Scientists around the world will examine the material to better understand the origins of our solar system.

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The notion of stardust is romantic, the stuff of poetry and song.

But astronomers² like Donald Brownlee of the University of Washington have a more pragmatic outlook.  They see stardust as the source of key information about the makeup³ of the early solar system.  They want to study some of it under a microscope, so they designed a space mission launched seven years ago that captured particles streaking⁴ from comet Wild-2 during an encounter in 2003.

"Rays of material coming out are, in fact, the exact same small particles that went in to form the comet four-and-a-half billion years ago," he said.  "These are literally⁵ the building blocks of our planetary system.  The fact is all the atoms in our bodies were in stardust grains like are coming out of that comet now before the solar system formed."

Courtesy of NASA
Artist's impression of Stardust near comet Wild-2  
  
To get some of these grains, the Stardust spacecraft caught up with Wild-2 400 million kilometers from Earth, passing the icy body just 240 kilometers away.  As it moved through the gas and dust surrounding the comet, it caught more than 1,000 of its particles in a tray containing a wispy⁶ fiberglass filter.

"It looks like a large ice cube tray filled full of this magic material called aerogel," he explained.  "It is an ultra-low-density silica glass.  It is only a few times denser⁷ than air.  Our gift from the edge of the solar system will be contained in this grid⁸.  A couple of days after it lands, investigators⁹ from all over the world will be diligently¹⁰ digging into this, trying to reveal the secrets of our origin."

Scientists say they hope the stardust will confirm the long held suspicion that carbon grains from comets played a major role in the origin of life on Earth.  They point out that comets are the most carbon-rich bodies in the solar system, full of organic compounds that fall to Earth all the time.

But rather than collecting these grains from the ground and saving the mission cost of $168 million, Donald Brownlee says it was necessary to go to the comet to get them, because they are uncontaminated by earthly material.

"The particles coming out of the comet are exactly the particles that went in," he noted¹¹.  "That is the magic of this mission.  We are getting the very best primitive¹² samples that there are in the solar system."

The payoff comes Sunday when the Stardust spacecraft releases its sample return capsule 110,000 kilometers from Earth.  Project manager Tom Duxbury of the Jet Propulsion Laboratory in California says the capsule will enter the atmosphere at a record 45,000 kilometers per hour.

"We are coming in faster than any man-made spacecraft has ever come in before," he explained.  "We are going to come in under parachute control and this will take us down to a very soft landing onto the desert floor of Utah."

Helicopter crews are to retrieve¹³ the capsule for its trip to a special clean room at NASA's Johnson Space Center in Houston, Texas.

If the parachutes fail to open, Duxbury says that the container is durable¹⁴ enough to survive a crash landing.

"Our return capsule is quite small, but extremely rugged," he added.  "Also, we have our collector and aerogel inside a canister.  The aerogel is in this very, very strong, rigid¹⁵ aluminum¹⁶ grid.  So we think we have a very, very robust¹⁷ return capsule.  In the event that a parachute or so does not open or we might land hard, we know we can finish the rest of science opportunities."

NASA expects most of the collected stardust particles to be smaller than the width of a human hair.  As tiny as they are, Donald Brownlee says scientists will slice these particles into even smaller pieces for study, since even tiny pieces are thought to contain hundreds of thousands of microscopic¹⁸ grains.

"People all over the world will be analyzing¹⁹ these things down to the single atomic scale," said Mr. Brownlee.

1 cargo   

n.(一只船或一架飞机运载的)货物

参考例句：

• The ship has a cargo of about 200 ton.这条船大约有200吨的货物。
• A lot of people discharged the cargo from a ship.许多人从船上卸下货物。

2 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》

3 makeup   

n.组织；性格；化装品

参考例句：

• Those who failed the exam take a makeup exam.这次考试不及格的人必须参加补考。
• Do you think her beauty could makeup for her stupidity?你认为她的美丽能弥补她的愚蠢吗？

4 streaking   

n.裸奔（指在公共场所裸体飞跑）v.快速移动( streak的现在分词 )；使布满条纹

参考例句：

• Their only thought was of the fiery harbingers of death streaking through the sky above them. 那个不断地在空中飞翔的死的恐怖把一切别的感觉都赶走了。 来自汉英文学 - 家（1-26） - 家（1-26）
• Streaking is one of the oldest tricks in the book. 裸奔是有书面记载的最古老的玩笑之一。 来自互联网

5 literally   

adv.照字面意义，逐字地；确实

参考例句：

• He translated the passage literally.他逐字逐句地翻译这段文字。
• Sometimes she would not sit down till she was literally faint.有时候，她不走到真正要昏厥了，决不肯坐下来。

6 wispy   

adj.模糊的；纤细的

参考例句：

• Grey wispy hair straggled down to her shoulders.稀疏的灰白头发披散在她肩头。
• The half moon is hidden behind some wispy clouds.半轮月亮躲在淡淡的云彩之后。

7 denser   

adj. 不易看透的, 密集的, 浓厚的, 愚钝的

参考例句：

• The denser population necessitates closer consolidation both for internal and external action. 住得日益稠密的居民，对内和对外都不得不更紧密地团结起来。 来自英汉非文学 - 家庭、私有制和国家的起源
• As Tito entered the neighbourhood of San Martino, he found the throng rather denser. 蒂托走近圣马丁教堂附近一带时，发现人群相当密集。

8 grid   

n.高压输电线路网；地图坐标方格；格栅

参考例句：

• In this application,the carrier is used to encapsulate the grid.在这种情况下，要用载体把格栅密封起来。
• Modern gauges consist of metal foil in the form of a grid.现代应变仪则由网格形式的金属片组成。

9 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

10 diligently   

ad.industriously;carefully

参考例句：

• He applied himself diligently to learning French. 他孜孜不倦地学法语。
• He had studied diligently at college. 他在大学里勤奋学习。

11 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

12 primitive   

adj.原始的；简单的；n.原(始)人，原始事物

参考例句：

• It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
• His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。

13 retrieve   

vt.重新得到，收回；挽回，补救；检索

参考例句：

• He was determined to retrieve his honor.他决心恢复名誉。
• The men were trying to retrieve weapons left when the army abandoned the island.士兵们正试图找回军队从该岛撤退时留下的武器。

14 durable   

adj.持久的，耐久的

参考例句：

• This raincoat is made of very durable material.这件雨衣是用非常耐用的料子做的。
• They frequently require more major durable purchases.他们经常需要购买耐用消费品。

15 rigid   

adj.严格的，死板的；刚硬的，僵硬的

参考例句：

• She became as rigid as adamant.她变得如顽石般的固执。
• The examination was so rigid that nearly all aspirants were ruled out.考试很严，几乎所有的考生都被淘汰了。

16 aluminum   

n.(aluminium)铝

参考例句：

• The aluminum sheets cannot be too much thicker than 0.04 inches.铝板厚度不能超过0.04英寸。
• During the launch phase,it would ride in a protective aluminum shell.在发射阶段，它盛在一只保护的铝壳里。

17 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。

18 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。

19 analyzing   

v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析

参考例句：

• Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
• He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句