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VOA慢速英语2009年-EXPLORATIONS - 2009: A Year of Discove

时间:2010-01-11 05:19来源:互联网 提供网友:斗破苍穹   字体: [ ]
    (单词翻译:双击或拖选)

VOICE ONE:

I'm Mario Ritter.

VOICE TWO:

And I'm Steve Ember with EXPLORATIONS in VOA Special English. This week, we tell about some of the biggest space stories of two thousand nine. First, there was the American space agency's discovery of water on the moon. We also talk to a NASA expert about the discovery of methane1 gas on Mars. And we hear about the test flight of NASA's newest rocket.

(MUSIC)

VOICE ONE:

An artist's picture of LCROSS

Possibly the biggest space story this year was the discovery of water on the moon. The best evidence was provided by a dramatic experiment carried out on October ninth. NASA used its Lunar Crater2 Observing and Sensing Satellite, or LCROSS, to look for water deep beneath the lunar surface.

To get below the ancient lunar rocks, NASA crashed a rocket into the moon's south pole. The crash caused soil to be expelled many kilometers above the lunar surface. LCROSS studied the soil before it too crashed into the moon. The experiment pushed the search for water several meters below the lunar surface—much deeper than had been possible before.

VOICE TWO:

LCROSS scientists Anthony Colaprete and Kim Ennico study early results from the lunar impact experiment

In November, Anthony Colaprete, a leading scientist with the LCROSS project, spoke3 about information gathered by the spacecraft. He said about one hundred kilograms of water had been found in the material ejected by the moon crash. Water has now been confirmed in amounts much greater than had been thought.

In September, NASA scientists had announced the discovery of water molecules5 mainly in the moon's extreme northern and southern areas. They noted6, however, that they could also be seeing evidence of another molecule4, hydroxyl.

VOICE ONE:

Instruments on three separate spacecraft gathered that evidence of lunar water. NASA's Moon Mineralogy Mapper made the most recent observations. It was one of eleven scientific devices carried by the Chandrayaan-One spacecraft of the Indian Space Research Organization.

The Mapper is a spectrometer, which measures reflected light wavelengths7. The device shows scientists what an object is made of from great distances. Similar devices on NASA's Cassini and Epoxi spacecraft also reported water.

But those observations were made years ago. NASA scientists had not trusted the results without clear confirmation8.

The Moon Mineralogy Mapper could only examine lunar soil to a depth of a few millimeters. And the amount of water found in that layer was very small. Now, LCROSS has shown that large amounts of water could exist on the moon. And it raises even more questions.

Was water brought to the moon by space rocks and icy bodies called comets? Or could processes deep within the moon produce water? If that is the case, it may be possible that the moon could hold enough water for future explorations or even colonies.

(MUSIC)

VOICE TWO:

An image showing methane on Mars

The presence of water on the moon was not the only major solar system discovery NASA made this year. In January, a team of NASA and university scientists announced that they had found methane gas on Mars. The group used NASA's Infrared9 Telescope Facility and the W.M. Keck telescope. Both instruments are in Mauna Kea, Hawaii. Methane is better known as natural gas. On Earth, it is mainly produced by processes linked to biology.

This raises the exciting possibility that life may have existed in the past on Mars. Or it may still exist deep below the surface. Michael Meyer is lead scientist for NASA's Mars Exploration Program in Washington. He spoke to us about the finding.

MICHAEL MEYER: "It really means that the planet is more active than we thought, and more active--and that can be geologically or maybe even biologically."

VOICE ONE:

On Earth, biological activity is very effective in making methane. But Michael Meyer notes that methane also can come from a purely10 non-biological process called serpentinization. He says the methane discovery presents scientists with a mystery because it is still not clear how the gas is being produced.

Martian methane is also unusual because it is not evenly spread over the planet. It can become concentrated in small areas and then disappear. This suggests processes that both supply and remove methane from the atmosphere in certain places. Currently, the best explanation for the loss of methane is that it chemically reacts with dust in the atmosphere. The gas may then turn into something else such as carbon dioxide.

VOICE TWO:

An artist's picture of how methane could be formed under the Martian surface

NASA plans to send the Mars Science Laboratory to the red planet in the autumn of two thousand eleven. The exploration vehicle will be able to measure methane even at very low levels in many places on the surface.

Michael Meyer also says NASA is developing an orbiter with European scientists. It will be able to measure small amounts of many different gases. The orbiter could finally provide evidence about how methane on Mars is created and destroyed. Michael Meyer says planetary scientists often study processes that are very different from ones on Earth. But he says understanding these differences can help discover how some complex processes on our own planet really work.

(SOUND: NASA Rocket Launch)

VOICE ONE:

The Ares 1-X launch at the Kennedy Space Center in Florida

On October twenty-eighth, NASA took an important step into the future. The agency carried out a test flight of its next-generation launch vehicle for astronauts.

NASA is developing two separate rockets for the Ares program. Phil Sumrall is the Ares Project Office Advanced Planning Manager. He says this was done for safety reasons.

The loss of the space shuttle Columbia in February of two thousand three led to an investigation11 by the Columbia Accident Investigation Board. The group recommended that human life must not be risked simply to send equipment into space. The result was a design in which safety was the top concern.

PHIL SUMRALL: "We designed the Ares One to be the absolute safest possible vehicle that we could conceive."

VOICE TWO:

Space scientists designed Ares One with a system that would rescue astronauts whether there was a failure of the rocket in the launch area or during flight. Mister Sumrall says NASA estimates the new Ares One will be twenty to thirty times safer than the Space Shuttle.

The other Ares launch vehicle is the huge Ares Five rocket. It will be the biggest rocket ever built. The Ares Five will be one hundred sixteen meters tall and weigh three point seven million kilograms. It will be able to lift nearly forty percent more than the Saturn12 Five rocket that sent Apollo astronauts to the moon.

VOICE ONE:

Much of the Ares technology has been developed from existing vehicles. Versions of the solid fuel rockets that are used on the Space Shuttle today will serve as the first stage of the Ares One and booster rockets on the Ares Five. An engine first developed for the Saturn Five moon rocket has been updated to be used on Ares.

Existing manufacturing technologies are also being used in new ways on Ares. The tanks of the Ares rockets will be made of aluminum13 lithium. This is a strong and light metal alloy14 that has been used on the Space Shuttle. But Ares will use new methods in metal-working science such as friction15 stir welding. This method uses heat and pressure to join pieces of metal together. Friction stir welding can be used to make complex curved and domed16 structures out of aluminum lithium and similar alloys17. And, friction stir welding uses fewer workers at less cost than other methods.

Scientists developed the new welding technology at the Marshall Space Flight Center in Montgomery, Alabama. It will be used when Ares is built at the Michoud Assembly Facility in New Orleans, Louisiana.

VOICE TWO:

Phil Sumrall says NASA's estimate to keep the Ares program going forward as planned calls for three billion dollars in additional spending a year.

He says if money is available, Ares Five could be ready for a test flight by two thousand seventeen. We asked Phil Sumrall how NASA expects to use Ares in its space exploration plans.


PHIL SUMRALL: "It's not just for going to the moon or near Earth objects. It's what we'd use to go to, eventually, to Mars or to the moons of Mars."

NASA named the new rocket system Ares, the Greek name for Mars. The name suggests the goal for a future generation of space explorers. They may be the first humans to set foot on another planet.

(MUSIC)

VOICE TWO:

I'm Steve Ember with Mario Ritter who also wrote and produced our program. You can find links to the NASA Web site at voaspecialenglish.com. You can also find transcripts18, MP3s and podcasts of our programs. Join us again next week for EXPLORATIONS in VOA Special English.

 


点击收听单词发音收听单词发音  

1 methane t1Eyx     
n.甲烷,沼气
参考例句:
  • The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
  • Methane may have extraterrestrial significance.甲烷具有星际意义。
2 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。
3 spoke XryyC     
n.(车轮的)辐条;轮辐;破坏某人的计划;阻挠某人的行动 v.讲,谈(speak的过去式);说;演说;从某种观点来说
参考例句:
  • They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
  • The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。
4 molecule Y6Tzn     
n.分子,克分子
参考例句:
  • A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
  • This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
5 molecules 187c25e49d45ad10b2f266c1fa7a8d49     
分子( molecule的名词复数 )
参考例句:
  • The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
  • Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
6 noted 5n4zXc     
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。
7 wavelengths 55c7c1db2849f4af018e7824d42c3ff2     
n.波长( wavelength的名词复数 );具有相同的/不同的思路;合拍;不合拍
参考例句:
  • I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话,因为我们俩完全不对路。 来自《简明英汉词典》
  • Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句
8 confirmation ZYMya     
n.证实,确认,批准
参考例句:
  • We are waiting for confirmation of the news.我们正在等待证实那个消息。
  • We need confirmation in writing before we can send your order out.给你们发送订购的货物之前,我们需要书面确认。
9 infrared dx0yp     
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。
10 purely 8Sqxf     
adv.纯粹地,完全地
参考例句:
  • I helped him purely and simply out of friendship.我帮他纯粹是出于友情。
  • This disproves the theory that children are purely imitative.这证明认为儿童只会单纯地模仿的理论是站不住脚的。
11 investigation MRKzq     
n.调查,调查研究
参考例句:
  • In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
  • He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。
12 Saturn tsZy1     
n.农神,土星
参考例句:
  • 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。
  • These comparisons suggested that Saturn is made of lighter materials.这些比较告诉我们,土星由较轻的物质构成。
13 aluminum 9xhzP     
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。
14 alloy fLryq     
n.合金,(金属的)成色
参考例句:
  • The company produces titanium alloy.该公司生产钛合金。
  • Bronze is an alloy of copper and tin.青铜是铜和锡的合金。
15 friction JQMzr     
n.摩擦,摩擦力
参考例句:
  • When Joan returned to work,the friction between them increased.琼回来工作后,他们之间的摩擦加剧了。
  • Friction acts on moving bodies and brings them to a stop.摩擦力作用于运动着的物体,并使其停止。
16 domed e73af46739c7805de3b32498e0e506c3     
adj. 圆屋顶的, 半球形的, 拱曲的 动词dome的过去式和过去分词形式
参考例句:
  • I gazed up at the domed ceiling arching overhead. 我抬头凝望着上方弧形的穹顶。
  • His forehead domed out in a curve. 他的前额呈弯曲的半球形。
17 alloys a0554febd06fadac0b9b8f0ad597e74d     
n.合金( alloy的名词复数 )
参考例句:
  • This is essentially a development of thoria dispersion strengthened nickel alloys. 这基本上是用二氧化钍弥散强度化的镍基合金。 来自辞典例句
  • The lack of deep hardening in these alloys negates their use. 这些合金缺乏深层硬化能力使它们无法利用。 来自辞典例句
18 transcripts 525c0b10bb61e5ddfdd47d7faa92db26     
n.抄本( transcript的名词复数 );转写本;文字本;副本
参考例句:
  • Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样,都是染色体DNA的转录产物。 来自辞典例句
  • You can't take the transfer students'exam without your transcripts. 没有成绩证明书,你就不能参加转学考试。 来自辞典例句
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