VOA慢速英语20060124b

SCIENCE IN THE NEWS - Spacecraft Comes Home With Stardust Memories of the Solar SystemBy Caty Weaver¹, Brianna Blake and George Grow

Broadcast: Tuesday, January 24, 2006

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VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English. I'm Bob Doughty².

VOICE TWO:

And I'm Pat Bodnar. This week on our show: Star dust memories of our solar system ...

VOICE ONE:

Measuring the effects of world trade on global warming ...

VOICE TWO:

And are frogs feeling the heat from higher world temperatures?

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VOICE ONE:

On January fifteenth, a long-awaited American spacecraft returned safely to Earth. The flight lasted seven years and more than four thousand million kilometers. It carried home a small amount of star dust and space dust from the tail of the comet called Wild-Two.


Lead scientist Donald Brownlee makes a victory sign as material from the Stardust capsule is examined

And yes, the engineers and scientists who waited all these years were wildly happy.

VOICE TWO:

Donald Brownlee of the University of Washington in Seattle is the lead investigator³ on the Stardust program for the NASA space agency. He described the contents of the capsule as a treasure from the edge of the solar system.

NASA launched the Stardust spacecraft toward the path of Wild-Two in nineteen ninety-nine. In January of two thousand four, the ship came within two hundred forty kilometers of the comet.

Stardust opened a collector to capture material from the comet's tail. Inside the collector was a substance called aerogel to trap particles floating in space. Aerogel weighs almost nothing. It looks a lot like smoke. Scientists call it glass smoke.

VOICE ONE:

Comets are often called dirty snowballs. Scientists say they contain materials left over from the huge cloud of gas and dust that formed into the sun and the planets.

Courtesy of NASA

Stardust photograph comet hspace=2 src=/specialenglish/images/NASA_stardust_photograph_co.jpg width=150 vspace=2 border=0>
Stardust meets the comet, an artist's version

Stardust spent about six months collecting particles. Then the robotic craft moved the collector into a sample return capsule, and headed for Earth.

On January fourteenth, Stardust released the forty-five-kilogram capsule. It happened about one hundred ten thousand kilometers above the Earth. That capsule is what landed at an Air Force testing ground in the desert of the western state of Utah. It shot through the atmosphere at about forty-five thousand kilometers an hour, a record speed for a spacecraft re-entry.

Now, scientists expect to learn more about the birth of the solar system more than four and one-half thousand million years ago. In fact, Donald Brownlee says some of the captured particles are sure to be older than the sun.

VOICE TWO:

The scientists and engineers were tense as they awaited the return of the Stardust capsule. Then they saw long-distance images of an open parachute.

In two thousand four, NASA watched the return of a similar spacecraft, Genesis. It returned with material expelled from the sun. Its parachute, however, failed. Genesis crashed into the Utah desert. It broke open, but scientists have said it could still have some research value.

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VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English from Washington.

A new study finds a direct link between the warming of the Earth's atmosphere and the loss of some kinds of creatures.


Frogs said to be extinct

The study involved brightly colored frogs that live in mountain forests of Central and South America. There were about one hundred ten kinds of these harlequin frogs twenty years ago. Now, scientists say, more than seventy have disappeared.

Experts believe that a fungus⁴ killed them. The bacterial⁵ disease has attacked frogs and other amphibians⁶ around the world. Amphibians live on land and in water. They are considered easy victims because of their thin skin.

VOICE TWO:

But the new study found that the losses of harlequin frogs happened in years with sharp increases in world temperatures. American biologist Alan Pounds led the study. He says the timing⁷ of the events shows a very clear relationship. Mister Pounds works at the Monteverde Cloud Forest Preserve and Tropical Science Center in Costa Rica.

Yet the fungus grows best in cooler temperatures. The scientists offer an explanation. They say warmer weather led to more water in the air, which led to more clouds. The cloud cover produced cooler days, though the nights got warmer. The scientists say the conditions helped spread the fungus. They say the recent losses are tied to global warming.

But other scientists are not so sure. Some criticized the new study. They say it did not consider other environmental changes that could have affected⁸ the frogs.

VOICE ONE:

Scientists say more than one hundred species of amphibians around the world have disappeared since nineteen eighty. Some say almost one-third of the world's six thousand different frogs, toads⁹ and salamanders are threatened.

Ecologist Karen Master took part in the study. She says many ecological¹⁰ systems are at risk from global warming. She says eighteen to thirty-five percent of plant and animal populations could disappear in the next forty-five years.

Researchers say climate change is also a danger to humans. The World Health Organization says higher temperatures are helping¹¹ to spread diseases tied to insects and water. As a result, it estimates that an additional one hundred fifty thousand people will die this year and five million others will get sick.

VOICE TWO:

Periods of warming and cooling are normal for Earth. But scientists widely believe that human activity is responsible for most of the recent warming. They say carbon dioxide and others gases from factories and vehicles trap extra heat in the atmosphere.

The Earth's average temperature rose by about six-tenths of one degree Celsius¹² in the twentieth century. A United Nations group has estimated that temperatures could rise one-point-four to five-point-eight degrees by the end of this century.

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VOICE ONE:

Another recent study looks at the importance of world trade in the production of carbon dioxide linked to climate change. This one is by two scientists at the National Center for Atmospheric¹³ Research in Boulder¹⁴, Colorado.




Shui Bin¹⁵ and Robert Harriss wondered about the growth of the huge trade deficit¹⁶ the United States has with China. What if the United States had produced the goods itself instead of importing them? What effect would there have been on air pollution?

VOICE TWO:

The findings suggest that in two thousand three, the United States would have released six percent more carbon dioxide. But China would have released fourteen percent less had it not made goods for the United States.

The two countries are the biggest producers of heat-trapping gases. The United States is estimated to produce about twenty-five percent of the world total. The scientists say China is responsible for about fifteen percent.

But, in general, China releases more industrial gases on average to make a product than the United States would. The scientists say this is because Chinese manufacturers depend more on coal and technologies that pollute more.

VOICE ONE:

The scientists examined the growth of imports from China between nineteen ninety-seven and two thousand three. They estimate that the trade imbalance added seven hundred twenty million metric tons of carbon dioxide to the atmosphere. That was one percent of the combined amount released by the two nations during that period.

The study found that in two thousand two and two thousand three, releases of carbon dioxide grew eight to nine percent a year in China. In the United States, the rate was about one percent a year.

The scientists note that neither country has approved the Kyoto Protocol¹⁷. That treaty aims to cut heat-trapping gases.

The National Science Foundation supported the research. The publication Energy Policy published the study online.

Shui Bin urged the United States to increase exports to China of technology for cleaner production. Not only could it help China reduces its pollution, she says. It could also improve the balance of trade between the two countries.

VOICE ONE:

If you have a question about science, send it to [email protected]. Be sure to include your name and where you are from.

Or write to VOA Special English, Washington D.C., two-zero-two-three-seven, U.S.A. We might be able to answer your question on our show. But we cannot answer questions personally.

SCIENCE IN THE NEWS was written by Caty Weaver, Brianna Blake and George Grow. Cynthia Kirk was our producer. I'm Bob Doughty.

VOICE TWO:

And I'm Pat Bodnar. Internet users can read and listen to our programs at www.unsv.com. Join us again next week for more news about science in Special English on the Voice of America.

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 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

3 investigator   

n.研究者，调查者，审查者

参考例句：

• He was a special investigator for the FBI.他是联邦调查局的特别调查员。
• The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。

4 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

5 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

6 amphibians   

两栖动物( amphibian的名词复数 )； 水陆两用车； 水旱两生植物； 水陆两用飞行器

参考例句：

• The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
• Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。

7 timing   

n.时间安排，时间选择

参考例句：

• The timing of the meeting is not convenient.会议的时间安排不合适。
• The timing of our statement is very opportune.我们发表声明选择的时机很恰当。

8 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

9 toads   

n.蟾蜍，癞蛤蟆( toad的名词复数 )

参考例句：

• All toads blink when they swallow. 所有的癞蛤蟆吞食东西时都会眨眼皮。 来自《简明英汉词典》
• Toads have shorter legs and are generally more clumsy than frogs. 蟾蜍比青蛙脚短，一般说来没有青蛙灵活。 来自辞典例句

10 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

11 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

12 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

13 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

14 boulder   

n.巨砾；卵石，圆石

参考例句：

• We all heaved together and removed the boulder.大家一齐用劲，把大石头搬开了。
• He stepped clear of the boulder.他从大石头后面走了出来。

15 bin   

n.箱柜；vt.放入箱内；[计算机] DOS文件名:二进制目标文件

参考例句：

• He emptied several bags of rice into a bin.他把几袋米倒进大箱里。
• He threw the empty bottles in the bin.他把空瓶子扔进垃圾箱。

16 deficit   

n.亏空，亏损；赤字，逆差

参考例句：

• The directors have reported a deficit of 2.5 million dollars.董事们报告赤字为250万美元。
• We have a great deficit this year.我们今年有很大亏损。

17 protocol   

n.议定书，草约，会谈记录，外交礼节

参考例句：

• We must observe the correct protocol.我们必须遵守应有的礼仪。
• The statesmen signed a protocol.那些政治家签了议定书。