接近地球的不名星体

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33 接近地球的不名星体

DATE=6-6-01
TITLE=EXPLORATIONS#1955 - Near Earth Objects
BYLINE=Paul Thompson

VOICE ONE: 
This is Steve Ember.
VOICE TWO:
And this is Shirley Griffith with the VOA Special English program EXPLORATIONS.  Today, we will tell about Near Earth Objects.  These are objects made of rock or ice that travel in space.  Their (1)orbits around the sun often bring them near Earth. 
((THEME))
VOICE ONE:
In the southwestern American state of (2) Arizona there is a huge, round hole in the ground.  This kind of hole is called a (3) crater².  The crater is named for Daniel Barringer, the first scientist to study it.  
The Barringer Crater is more than forty-five meters across.  It is two-hundred-thirteen meters deep.  It is in the shape of an almost perfect circle.
Scientists say the event that caused this hole took place about fifty-thousand years ago.  In studying the crater, they found (4)evidence that an object from space traveling at more than sixty-four thousand kilometers an hour (5)crashed into the ground. 
Scientists say the object was made of the metals (6) iron and (7) nickel³.  It was about forty-five meters across and weighed several thousand tons.
VOICE TWO:
The rock from space that created the Barringer Crater hit the Earth with the force of about twenty-million tons of (8) explosives⁴.  It caused tons of rock and dirt to be thrown into the air.  
Huge rocks fell back to earth for many kilometers around the huge hole.  Some of these rocks are as large as houses.  The force of the object hitting the Earth killed all living things within one-hundred kilometers.  
VOICE ONE:
The Barringer Crater is only one of about one-hundred-twenty known examples of damage (9)caused to the Earth by objects from space.  The crater was the first one to be recognized as caused by something from space. 
Workers who (10)discovered pieces of the space rock that created the huge hole (11)identified it in the Nineteen-Twenties.  Since the Nineteen-Sixties, scientists have discovered more evidence to (12)confirm that a space object did cause the Barringer Crater.  They found evidence of (13)massive⁵ (14)pressure and (15)extreme heat caused by an explosion⁶. 
Scientists say it is hard to find evidence of damage caused by space objects because as the years pass, wind, rain, ice, snow and other weather conditions change the land.  Huge holes like the Barringer Crater are filled with rocks, dirt, plants or perhaps water.  Many years later any evidence of damage is well hidden.
The Barringer Crater has not changed much from the time it was created.  This is because the space rock hit the Earth in an area of very dry desert.
VOICE TWO:
The (16)huge object that created the Barringer Crater caused a great deal of damage.  Yet the damage was only in a local area.  If an object that size hit a modern city, it would cause massive damage and loss of life. 
In July of Nineteen-Oh-Eight, a huge space rock exploded near the area of Siberia called Tunguska.  Russian scientists believe this was the largest object from space to hit the Earth in the past two-thousand years.
A huge forest was destroyed, but no one was (17)injured or killed in Tunguska.  Scientists never found a crater or pieces of the space rock that caused the explosion.  They believe it exploded as it got very near the ground.  The explosion was so huge that (18) devices⁸ in Germany which measure earthquakes recorded the event.  
VOICE ONE:
Scientists now know that much larger space rocks have hit Earth than those involved in Tunguska or Barringer.  Tests show that a huge space object may have hit the area near the (19)Gulf of (20)Mexico about sixty-five million years ago.  Scientists say the object was so large that it caused millions of tons of dirt and dust to rise in the atmosphere.  
The scientists believe the dirt and dust blocked sunlight from reaching the ground for a very long time.  Plants died from the lack of sunlight.  Animals who ate these plants had no food and they died also.  The lack of sunlight caused the planet⁹ to cool.  Many areas became extremely cold.  Millions of animals died because of the cold. 
Many scientists say there is strong evidence to suggest that this event may have killed almost seventy percent of everything living on Earth.  It probably killed all of the huge (21)reptiles called (22) dinosaurs¹⁰ that then ruled the Earth.
((MUSIC BRIDGE))
VOICE TWO:
Scientists say the Earth has been hit by objects from space many times in the past, and that it will be hit again in the future.  They have a saying about these kinds of events.  They say the question is not "will a space object ever hit the Earth again."  They say the question is "when will the Earth be hit." 
Scientists call objects in space that come near our planet, "Near Earth Objects."  They are mainly of two kinds-(23) asteroids¹² or (24) comets.  (25)Asteroids are usually made of (26)carbon or minerals.  Comets are usually made of ice and rock.
VOICE ONE:
Scientists have identified about two-thousand Near Earth Objects in orbit¹ now.  Of these, three-hundred-nine travel near Earth and are considered possible threats to our planet.  They are called (27) Potentially (28) Hazardous¹⁴ Asteroids-or P-H-As. 
This does not mean all three-hundred-nine P-H-As will hit the Earth.  It means only that it is possible they could.  Space experts in many countries closely¹⁵ observe these P-H-As.
VOICE TWO:
Earthquakes are measured by an international system known as the (29) Richter Scale.  The Richter scale measures how strong an Earthquake is when it happens.  The higher the number on the Richter scale, the stronger the earthquake and the more damage it can cause.
Scientists who study Near Earth Objects and P-H-As have a (30)similar (31)method to measure the threat of asteroids and comets.  It is called the (32)Torino Scale.  Richard Benzel of the (33)Massachusetts Institute of Technology created the Torino Scale.  He first explained the scale at a United Nations (34)conference in Nineteen-Ninety-Five in Turin, Italy.
VOICE ONE:
The Torino Scale is a system of numbers from zero to ten.  An asteroid¹¹ is given a Torino number after scientists learn its size, speed and how close to Earth it will pass in its orbit around the Sun.
An asteroid that is rated zero on the Torino Scale is considered to have almost no chance of ever hitting Earth. 
An asteroid that is a number ten on the Torino Scale is a huge object which is going to hit Earth.  It will cause massive damage and loss of life for most of our planet.
VOICE TWO:
Scientists say at the present time no space object they have seen has a Torino Scale number greater than one.  However they say this could easily change in the future.  
There is one asteroid that could threaten Earth.  It is called Asteroid Two-Thousand-S-G-Two-hundred-Forty-Four.
This asteroid will not come near the Earth until September twenty-first, Two-Thousand-Thirty.  NASA experts say it has a Torino number of one now and should miss the Earth.  They say they will know more about this asteroid in the future as they continue to study its orbit.  Scientists say the object is large enough to cause severe local damage if it does hit the Earth.
NASA experts say their major concern is the asteroids and comets they do not know about.  Learning¹⁶ to find and study the orbit of each new asteroid and comet¹³ is a difficult (35)task.  They say they must improve their ability to find space objects to provide the Earth with a warning in time to take protective¹⁷ measures.
VOICE ONE:
Scientists have known about the threat from Near Earth Objects for many years.  Teams of (36)astronomers around the world are searching the sky for Near Earth Objects.  These teams are involved in (37)joint projects with the United States (38) Air Force, the (39) Defense¹⁸ Department, (40) NASA and several major universities.  Recently they have begun studying several methods that would protect Earth if it were threatened by an object from space.
Scientists at the Los (41)Alamos Laboratory¹⁹ in (42)New Mexico and the Lawrence Livermore Laboratory in California are studying ways to destroy Near Earth Objects that may threaten Earth.  Methods might include firing a (43)nuclear device⁷ into space to destroy the object.  
Some scientists say if they have the time and equipment, they could use non-nuclear explosives to move an object out of its path.  They might be able to place a small (44)rocket motor on an asteroid to change its path.  They say this could be done before the space rock becomes a dangerous threat.  
Scientists are quick to say there is no need for fear or (45) alarm at the present time.  However they all agree that they must prepare for what could happen in the future.
((THEME))
VOICE TWO:
This Special English program was written and produced by Paul Thompson.  Our studio engineer was Keith Holmes. This is Shirley Griffith.
VOICE ONE:
And this is Steve Ember.  Join us again next week for another EXPLORATIONS program on the Voice of America.

(1)   orbit [ 5C:bit ]n.轨道
(2)   Arizona [9Ari`z[Un[] n.亚利桑那州(美国西南部的州)
(3) crater [ `kreit[] n.弹坑
(4) evidence [ 5evidEns ]n.证据
(5) crash [ krAF ]v.坠落, 坠毁
(6) iron [ `aiEn] n.铁
(7) nickel [ `nikl] n.[化]镍
(8) explosive [iks`plEUsiv] n.爆炸物, 炸药
(9) cause [ kC:z ] vt.引起
(10) discover [ dis5kQvE ]vt.发现
(11) identify vt.识别, 鉴别
(12) confirm [ kEn5fE:m ]vt.确定
(13) massive [ 5mAsiv ]adj.巨大的
(14) pressure [`preFE(r)]n.压力
(15) extreme [ iks5tri:m ]adj.极度的
(16) huge [ hju:dV ]adj.巨大的
(17) injure [ 5indVE ]vt. 伤害
(18) device [di`vais] n.装置, 设计, 图案, 策略, 发明物, 设备
(19) gulf [ ^Qlf ]n.海湾
(20) Mexico [5meksIkEJ]n.墨西哥(拉丁美洲国家)
(21) reptile [ 5reptail ]n.爬虫动物
(22) dinosaur [ `dain[sR:] n.恐龙
(23) asteroid [ `Ast[rRid] n.[天文]小游星, 小行星, 海盘车 adj.星状的
(24) comet [ `kRmit] n.彗星
(25) asteroid [ 5AstErCid ]n.[天文]小行星
(26) carbon [ 5kB:bEn ]n.[化]碳(元素符号C)
(27) potentially [p[tenF[lli] adv.潜在地
(28) hazardous [ `hAz[d[s] adj.危险的, 冒险的, 碰运气的
(29) Richter scale n.里克特震级, 里氏震级（共分10级）
(30) similar [ 5similE ]adj.相似的
(31) method [5meWEd]n.方法
(32) Torino [ tC5ri:nC ]托里诺[意大利西北部城市](即都灵)
(33) Massachusetts Institute of Technology n.马萨诸赛技术学会
(34) conference [ 5kCnfErEns ]n.会议, 讨论会, 协商会
(35) task [ tB:sk ]n.任务
(36) astronomer [E5strRnEmE(r)]n.天文学家
(37) joint [ dVCint ] adj.联合的
(38) Air Force 美国空军
(39) Defense Department n. (美国) 国防部
(40) NASA [ `nAsE] abbr .National Aeronautics²⁰ and Space Administration²¹ (美国)国家航空和宇宙航行局
(41) alamo  [ 5B:lEmEu, 5AlE- ]n.[植]白杨
(42) New Mexico [ nju: 5meksikEu ]n.美国新墨西哥州
(43) nuclear [ 5nju:kliE ]adj.[核]核子的, 原子能的, 核的
(44) rocket [ 5rCkit ]n.火箭
(45) alarm [E`lB:m] n.警报, 惊慌, 警告器 vt.恐吓, 警告

1 orbit   

n.轨道；vt.使沿轨道运行；使进入轨道运行；vi.沿轨道运行，环行

参考例句：

• The space rocket was launched and went into orbit.宇宙火箭发射后进入轨道。
• We can draw the earth's orbit round the sun.我们可以画出地球绕太阳运行的轨迹。

2 crater   

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 nickel   

n.镍，（美国和加拿大的）五分钱

参考例句：

• Nickel can be used for making coins.镍可做成钱币。
• May I have a nickel?能给我五分钱吗？

4 explosives   

n.爆炸物，炸药( explosive的名词复数 )

参考例句：

• They caved in the roof of the underground passage with powerful explosives. 他们用强大的炸药把地下通道的顶部炸塌陷了。 来自《简明英汉词典》
• The slightest spark can set off the explosives stored here. 一点点火星就能够使储存这里的火药爆炸。 来自《用法词典》

5 massive   

adj.巨大的，大规模的，大量的，大范围的

参考例句：

• A massive sea search has failed to find any survivors.经过大规模的海上搜救仍未找到幸存者。
• He drank a massive amount of alcohol.他喝了大量的烈酒。

6 explosion   

n.爆发，发出，爆炸

参考例句：

• The police arrived right at the moment of the explosion.警察就在爆炸的那个时候赶到了。
• The shock of the explosion was felt far away.爆炸引起的震动很远都可感觉到。

7 device   

n.器械，装置；计划，策略，诡计

参考例句：

• The device will be in production by the end of the year.该装置将于年底投入生产。
• The device will save much time and effort for us.这种装置会使我们节省大量时间和气力。

8 devices   

n.设备；装置( device的名词复数 )；花招；（为实现某种目的的）计划；手段

参考例句：

• electrical labour-saving devices around the home 节省劳力的各种家用电器
• modern labour-saving devices such as washing machines and dishwashers 诸如洗衣机和洗碗机之类的现代化省力设备

9 planet   

n.行星

参考例句：

• Neptune is the furthest planet from the sun. 海王星是离太阳最远的行星。
• Rubbish, however, is only part of the problem of polluting our planet. 然而, 垃圾只是我们这个星球的污染问题的一个方面。

10 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

11 asteroid   

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。

12 asteroids   

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。

13 comet   

n.慧星

参考例句：

• Recently they have discovered a comet.最近他们发现了一颗彗星。
• Halley's Comet is going to come back in 2061.哈雷彗星将于2061年回归。

14 hazardous   

adj.(有)危险的，冒险的；碰运气的

参考例句：

• These conditions are very hazardous for shipping.这些情况对航海非常不利。
• Everybody said that it was a hazardous investment.大家都说那是一次危险的投资。

15 closely   

adv.紧密地；严密地，密切地

参考例句：

• We shall follow closely the development of the situation.我们将密切注意形势的发展。
• The two companies are closely tied up with each other.这两家公司之间有密切联系。

16 learning   

n.学问，学识，学习；动词learn的现在分词

参考例句：

• When you are learning to ride a bicycle,you often fall off.初学骑自行车时，常会从车上掉下来。
• Learning languages isn't just a matter of remembering words.学习语言不仅仅是记些单词的事。

17 protective   

adj.防护的，保护的

参考例句：

• A mother naturally feels protective towards her children.做母亲的天生要保护自己的孩子。
• We feel safe with a protective device in the house.我们因为家里有了防护装置而感到安全。

18 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

19 laboratory   

n.实验室，化验室

参考例句：

• She has donated money to establish a laboratory.她捐款成立了一个实验室。
• Our laboratory equipment isn't perfect,but we must make do.实验室设备是不够理想，但我们只好因陋就简。

20 aeronautics   

n.航空术，航空学

参考例句：

• National Aeronautics and Space undertakings have made great progress.国家的航空航天事业有了很大的发展。
• He devoted every spare moment to aeronautics.他把他所有多余的时间用在航空学上。

21 administration   

n.经营，管理；行政，行政机关，管理部门

参考例句：

• Who is in charge of the administration of your company?你们公司的行政工作由谁负责？
• The teachers are responsible to the school administration.教师向学校行政负责。