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2007年VOA慢速英语special200708150045

时间:2007-08-20 03:04:38

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(单词翻译)

VOICE ONE:

I'm Barbara Klein.

VOICE TWO:

And I'm Bob Doughty1 with EXPLORATIONS in VOA Special English. This week, we tell about a project to identify images of one million galaxies2 that have been captured by the Sloan Digital Sky Survey. We also tell about the Perseid Meteor Shower.

We begin with NASA's new spacecraft that will visit two of the biggest asteroids4.

(MUSIC)

VOICE ONE:

For many years, the United States space agency has studied the major planets in
An artist's picture of the Dawn spacecraft

detail. For example, NASA is observing Mars from orbit and also on its surface with the Mars Rovers. Jupiter has also been visited several times by Pioneer, Voyager and Galileo spacecraft. The Deep Impact mission even visited a comet.

But there are objects in our solar system that remain mysterious. These are the asteroids and dwarf5 planets.

Now NASA has designed a mission that will visit two of the important members of this group of objects. A new spacecraft called Dawn will visit Ceres and Vesta, two large bodies in what is known as the asteroid3 belt.

The asteroid belt took shape early in the formation of the solar system, about four and one-half billion years ago. Astronomers6 believe that the force of gravity from Jupiter prevented the rocky material between it and Mars from forming a planet. The result is that there are thousands of rocky bodies circling the sun between the orbits of Mars and Jupiter.

VOICE TWO:

Ceres is the largest object in the asteroid belt. It is over nine hundred kilometers across. It was the first object of its kind ever discovered. In August of last year, however, astronomers changed the way they define Ceres. It is now a dwarf planet. Ceres shares this classification with two other objects: Pluto7 and Eris. But Ceres is a rocky world much closer to the sun.

Astronomers are interested in Ceres because it may hold water. Measurements of light reflected from the dwarf planet suggest this. Astronomers believe that the outer covering of Ceres may contain up to twenty-five percent water ice. This could mean that there is more water on Ceres than there is fresh water on Earth.

VOICE ONE:

Vesta was the fourth object of its kind discovered. Astronomers believe it is covered with rock that melted and then became solid again. There is also a giant hole, or crater8, four hundred sixty kilometers across on the asteroid's south pole. Astronomers believe a massive crash took place between Vesta and another object. The force was so great that Vesta lost one percent of its total mass.

What happened to all this material? It spread throughout parts of the solar system. Five percent of all meteorites9 we find on Earth might be from this one event on Vesta. Meteorites are small pieces of space rock that fall to Earth.

VOICE TWO:

Now Dawn will explore these bodies in greater detail than ever before. Dawn is a new kind of spacecraft. It improves on technology used in NASA's Deep Space One mission. That spacecraft visited the comet Temple One and an asteroid. However, Dawn's mission will be much longer.

Dawn's engines use what is called an ion propulsion system. Ion engines use electrical current and fuel made of the element xenon to power the spacecraft through space. Electricity comes from two large solar arrays over eight meters long. The wide flat surfaces of the solar arrays gather sunlight and turn it into electricity.

VOICE ONE:

Dawn's eyes are two cameras that are exactly alike. They can measure light in seven different colors. There are two other instruments on Dawn. One is a Gamma Ray and Neutron10 Detector11. This device measures a form of light, gamma rays, and neutrons12, which are particles in the centers of atoms. The detector measures the light and particles, showing scientists what kind of substances make up the surface of the objects. This device will also show if there is water ice on Ceres.

NASA had planned to launch Dawn in July. But now the spacecraft is set to launch in September.

(MUSIC)

VOICE TWO:

Researchers spend millions of dollars on equipment and tools they need to observe the universe. They are able to see and study objects that are millions of light-years away. However, people can observe some very interesting things with their own eyes. Any person who wants to know about the night sky can go outside, look up, and see some extraordinary sights.


A Perseid meteor

This month, people everywhere have the chance to see the Perseid meteor shower. The meteors seem to come out of the group of stars called Perseus.

The Perseids come every year, near the middle of August. The meteor shower comes from dust left behind by the comet Swift-Tuttle. The comet takes about one hundred thirty years to go around the sun, and leaves dust in its path. When the Earth passes through this trail of material, the dust hits the Earth's atmosphere.

This dust is moving very fast, about sixty kilometers a second. Because the meteors are moving so fast, they make bright streaks13 as they burn up in the atmosphere.

VOICE ONE:

The best way to see these meteors is to get away from cities with bright lights. People in big cities will be able to see the brightest meteors. But many, many more will be visible in the darkness of the countryside. The view this year will be especially good, because there will be very little moonlight.

There will be different kinds of meteors during different parts of the meteor shower. For example, there will be a few meteors called earthgrazers near the beginning of the shower. These appear early in the evening when the constellation14 of Perseus first rises into the sky. Earthgrazers are meteors that show up on the horizon and then trail overhead. A NASA official described them as long, slow and colorful.

There will be more and more meteors overhead as the night goes on. This year, the most meteors were visible extremely early on August thirteenth. At that time, scientists say as many as one meteor per minute crossed the sky. However, the Perseids can be seen for about one week after this time as well. This is a great time to get outside and see astronomy in action.

(MUSIC)

VOICE TWO:

Professional astronomers have collected pictures of one million galaxies in our
A picture of the galaxy15 NGC 6070 from the Sloan Digital Sky Survey

universe. These pictures came from a project called the Sloan Digital Sky Survey. Now, the astronomers want to sort the galaxies they have found by shape.

However, there are too many galaxies for professional astronomers to look at and sort on their own. This would take a very long time. So they have asked the public for help. Astronomers want people around the world to help look at the pictures of the galaxies on a Web site and classify them into different kinds. All you need is a computer with connection to the Internet. This project is called Galaxy Zoo.

Astronomers want people instead of computers to help because some of the pictures are very hard to recognize. They say that people are much better at identifying these patterns and shapes. Some of the images of galaxies are unclear and the human eye is the best tool to help decide what shape a galaxy really is.

Scientists say that knowing how many of each kind of galaxy there are will help them understand more about our universe. The information will help answer questions about how galaxies are made and how they change over time. It will also help answer questions about how the universe works and moves.

VOICE ONE:

Project Galaxy Zoo was first announced on July eleventh. In the first sixty hours after the announcement, the Web site had been visited almost seven million times. So far, more than eighty-five thousand people are exploring the universe on the Internet. People have sent more than twelve million galaxy classifications. However, astronomers say that they need even more people to help.

Scientists want between ten and twenty different people to sort each of the one million galaxies. This will take a long time, even with so many people working on it. However, more and more people are signing up to look at these galaxies every day. When the results help scientists answer important questions about the universe thousands of people will be able to say, I helped. If you would like to join in, you can visit the Web site at www.galaxyzoo.org.

(MUSIC)

VOICE TWO:

This program was written by Erin Braswell and Mario Ritter who was also the producer. I'm Bob Doughty.

VOICE ONE:

And I'm Barbara Klein. Join us again next week for Explorations in VOA Special English.

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点击收听单词发音收听单词发音  

1 doughty Jk5zg     
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。
2 galaxies fa8833b92b82bcb88ee3b3d7644caf77     
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。
3 asteroid uo1yD     
n.小行星;海盘车(动物)
参考例句:
  • Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
  • It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小,但这样的危险还是存在的。
4 asteroids d02ebba086eb60b6155b94e12649ff84     
n.小行星( asteroid的名词复数 );海盘车,海星
参考例句:
  • Asteroids,also known as "minor planets",are numerous in the outer space. 小行星,亦称为“小型行星”,在外太空中不计其数。
  • Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。
5 dwarf EkjzH     
n.矮子,侏儒,矮小的动植物;vt.使…矮小
参考例句:
  • The dwarf's long arms were not proportional to his height.那侏儒的长臂与他的身高不成比例。
  • The dwarf shrugged his shoulders and shook his head. 矮子耸耸肩膀,摇摇头。
6 astronomers 569155f16962e086bd7de77deceefcbd     
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 Pluto wu0yF     
n.冥王星
参考例句:
  • Pluto is the furthest planet from the sun.冥王星是离太阳最远的行星。
  • Pluto has an elliptic orbit.冥王星的轨道是椭圆形的。
8 crater WofzH     
n.火山口,弹坑
参考例句:
  • With a telescope you can see the huge crater of Ve-suvius.用望远镜你能看到巨大的维苏威火山口。
  • They came to the lip of a dead crater.他们来到了一个死火山口。
9 meteorites 12efd1ed528a28fe1f7cb667a7fbc1e0     
n.陨星( meteorite的名词复数 )
参考例句:
  • Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
  • One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》
10 neutron 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。
11 detector svnxk     
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。
12 neutrons 8247a394cf7f4566ae93232e91c291b9     
n.中子( neutron的名词复数 )
参考例句:
  • The neutrons and protons form the core of the atom. 中子和质子构成了原子核。 来自《简明英汉词典》
  • When an atom of U235 is split,several neutrons are set free. 一个铀235原子分裂时,释放出几个中子。 来自《简明英汉词典》
13 streaks a961fa635c402b4952940a0218464c02     
n.(与周围有所不同的)条纹( streak的名词复数 );(通常指不好的)特征(倾向);(不断经历成功或失败的)一段时期v.快速移动( streak的第三人称单数 );使布满条纹
参考例句:
  • streaks of grey in her hair 她头上的绺绺白发
  • Bacon has streaks of fat and streaks of lean. 咸肉中有几层肥的和几层瘦的。 来自《现代英汉综合大词典》
14 constellation CptzI     
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。
15 galaxy OhoxB     
n.星系;银河系;一群(杰出或著名的人物)
参考例句:
  • The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
  • The company has a galaxy of talent.该公司拥有一批优秀的人才。

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