时间:2019-01-30 作者:英语课 分类:2006年慢速英语(十)月


英语课

EXPLORATIONS - How the Distant World of Eris Caused Big Changes Here on EarthBy Mario Ritter

Broadcast: Wednesday, October 11, 2006

VOICE ONE:

I'm Shirley Griffith.

VOICE TWO:


An artist's picture of Eris

And I'm Steve Ember with the VOA Special English program EXPLORATIONS. The International Astronomical 1 Union has given a name to a solar system object discovered last year. How the distant, icy world called Eris shook up astronomy and struck Pluto 2 from the list of planets is a story worth telling.

(MUSIC)

VOICE ONE:

On August twenty-fourth, astronomers 4 made a big change to our model of the solar system. They voted to change the number of planets at a meeting of the International Astronomical Union in Prague, the capital of the Czech Republic. Astronomers debated several proposals, including expanding the definition of the word planet to include a total of twelve solar system objects.

But in the end, they decided 5 to limit the definition of planet only to very large bodies.
International Astronomical Union President Ronald Ekers speaks at the IAU General Assembly in August

They decided to call Pluto a dwarf 6 planet -- not a real planet at all. Our new model of the solar system now has eight planets.

A discovery made last year seems to have forced this change. The discovery was a very distant object beyond Pluto's orbit. The new object was considered bigger than Pluto. It did not have an official name for more than a year after its discovery.

Many astronomers believed the new object, now called Eris, was the last evidence needed to prove that Pluto was not a planet. They said since Pluto was not even the largest object beyond the orbit of Neptune 7, it could not possibly be considered a true planet.

(MUSIC)

VOICE TWO:

Astronomy has always used names from ancient stories, or myths. The names of all the planets, except Earth, come from Roman mythology 8. For example, Mercury was the flying messenger to a whole family of gods. True to its name, Mercury orbits the sun faster than any other planet 鈥?in about eighty-seven days.

Venus is the Roman goddess of love and is the brightest and most beautiful planet seen from Earth.

Mars, the red planet, is named for the Roman god of war. Jupiter, the second brightest planet, is the king of the Roman gods. Saturn 9 is named for Jupiter's father. It takes almost thirty years to circle the sun 鈥?slowest among the bright planets.

In seventeen eighty-one, a planet beyond the orbit of Saturn was discovered. It was given the name Uranus 10, the god of the sky and father to Saturn. And more than sixty-five years later, the last large planet to be discovered was named Neptune, god of the sea and brother to Jupiter.

VOICE ONE:

The word nomenclature describes a system of naming things in an area of science. Nomenclature in astronomy is especially careful to consider past traditions. This could be because study of the sky has taken place longer than written history. It could be that the apparent movement of bodies in the sky is linked to timekeeping. Whatever the reason, object names in astronomy have to stand the test of time.

(MUSIC)

VOICE TWO:

In nineteen thirty, a young American astronomer 3, Clyde Tombaugh, discovered an object beyond the orbit of Neptune. The object was soon named Pluto, the Roman god of the underworld and death.

The name seemed to fit. Pluto is so distant that one orbit around the sun takes two hundred and forty-eight years. At that distance, the sun is much less bright than it is on Earth. It seemed Pluto was a dark, distant world, like the god of the underworld himself.

VOICE ONE:

There was another reason why Pluto seemed to be a good name. The first letters of Pluto, P and L, are the first letters of the name of the man whose effort brought about Pluto's discovery. His name was Percival Lowell. He started Lowell observatory 11 in Arizona where Clyde Tombaugh discovered Pluto. Lowell also did mathematical work suggesting the presence of a large planet beyond Neptune 鈥?Planet X.

Lowell died in nineteen sixteen. He had expected his Planet X to be massive enough to affect the orbit of Neptune. Today, we know Pluto's gravitational field is far too small to influence Neptune at all.

VOICE TWO:

Planets have special signs, or symbols. Except for Uranus, these symbols all come from ancient tradition. The sign for the new planet also honored Percival Lowell. It was the letter P on top of the letter L.

But, Pluto's symbol is no longer that of a planet after the meeting of the International Astronomical Union. Instead, Pluto got a number. Planets do not have numbers in astronomical nomenclature. But other small objects orbiting the sun do.

The first such object was Ceres, which was discovered in eighteen hundred. At the time, astronomers did not know about small solar system objects. Ceres orbits the sun between Mars and Jupiter and is about nine hundred fifty kilometers across.

Ceres also has a number: one. Ceres was the first object of its kind to be discovered. But Pluto, which has only recently become a non-planet, is not so lucky. Pluto is about two thousand three hundred kilometers across 鈥?much bigger than Ceres. But it now has the hard-to-remember number of one-three-four-three-four-zero.

VOICE ONE:

The huge size of Pluto's number is the result of new technology that has changed the way astronomers search the skies. Before computer technology, astronomers looking for new objects used a painfully slow process. They compared large photographs of exactly the same area of sky taken hours or days apart. Every star in these pictures is in exactly the same place on the photograph.

But a solar system object like a planet, asteroid 12 or comet would move and appear in a different place on the second photograph. In this search method, an astronomer is looking for one small point that is misplaced among many thousands. That is how Clyde Tombaugh found Pluto.

Today there is a faster way. Computers search photographs taken by robotic telescopes for stars that have moved. Now discoveries happen almost too fast.

Fewer than eight thousand small solar system bodies had been found by the end of nineteen ninety-six. But in September, Pluto got its number after more than one hundred thirty thousand earlier discoveries.

(MUSIC)

VOICE TWO:

Eris was discovered in the modern way. The team of Mike Brown, Chad Trujillo and David Rabinowitz used pictures taken by the Samuel Oschin telescope at Palomar Observatory in California. This telescope operates like a huge camera pointing at the sky. In fact, the picture that identified Eris was taken on October twenty-first, two thousand three. The team did not recognize Eris until early last year.

But the astronomers did not think it was time to announce the discovery because more research was needed. News started to leak out however.

On July twenty-ninth of last year they were forced to announce a new object. Their early measurements showed that it was more than three thousand kilometers across and took five hundred and sixty years to orbit the sun.

VOICE ONE:

The news was like fuel on a fire. Astronomers heatedly argued whether Pluto was a planet or not on television shows. Reports from the meeting of the International Astronomical Union in Prague described some of the arguments as almost violent. In the end, astronomers voted to define Pluto as something other than a planet.

The new object was known as Xena until September thirteenth when it was officially given the name Eris. Astronomers Brown, Trujillo and Rabinowitz had suggested the name one week before.

In mythology, Eris is the Greek name for the goddess of discord 13 鈥?or bad relations and trouble. Greek mythology tells us that she was not invited to the marriage of a king named Peleus and a sea goddess called Thetis. Eris was angry that she was not invited. She put in motion a series of events that caused the Trojan War. The Greek poet Homer tells the story of that war in the long poem, The Iliad.

VOICE TWO:

But Eris has not finished causing trouble. In September of last year, a team using a telescope at the Keck Observatory in Hawaii discovered that Eris has a moon. It has been given the name Dysnomia, the daughter of Eris in Greek mythology.

And better measurements of Eris show that it is about two thousand four hundred kilometers across -- only a little larger than Pluto. In fact, Eris could even be smaller than Pluto.

The team that discovered Eris says many more discoveries in the distant area beyond Neptune are likely in the near future. Who knows what changes we will have to make to our model of the solar system next time?

(MUSIC)

VOICE ONE:

This program was written and produced by Mario Ritter. I'm Shirley Griffith.

VOICE TWO:

And I'm Steve Ember. You can read and listen to this program on our Web site, www.unsv.com. Join us again next week for Explorations in VOA Special English.



adj.天文学的,(数字)极大的
  • He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
  • Houses in the village are selling for astronomical prices.乡村的房价正在飙升。
n.冥王星
  • 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。
n.天文学家
  • A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
  • He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。
n.天文学者,天文学家( astronomer的名词复数 )
  • 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》
adj.决定了的,坚决的;明显的,明确的
  • This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
  • There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。
n.矮子,侏儒,矮小的动植物;vt.使…矮小
  • 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。
n.海王星
  • Neptune is the furthest planet from the sun.海王星是离太阳最远的行星。
  • Neptune turned out to be a dynamic,stormy world.海王星原来是个有生气、多风暴的世界。
n.神话,神话学,神话集
  • In Greek mythology,Zeus was the ruler of Gods and men.在希腊神话中,宙斯是众神和人类的统治者。
  • He is the hero of Greek mythology.他是希腊民间传说中的英雄。
n.农神,土星
  • 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。
n.天王星
  • Uranus is unusual because it is tilted.天王星非常特殊,因为它是倾斜的。
  • Uranus represents sudden change and rebellion.天王星代表突然性的改变和反叛。
n.天文台,气象台,瞭望台,观测台
  • Guy's house was close to the observatory.盖伊的房子离天文台很近。
  • Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
n.小行星;海盘车(动物)
  • 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。
n.不和,意见不合,争论,(音乐)不和谐
  • These two answers are in discord.这两个答案不一样。
  • The discord of his music was hard on the ear.他演奏的不和谐音很刺耳。
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