2006年VOA标准英语-Astronomers Discover Two Moons Orbiting Pl

By Jessica Berman
Washington
22 February 2006

U.S. astronomers¹ have discovered two moons orbiting Pluto², an icy planet smaller than our moon. Scientists found the moons while surveying the sky as part of the New Horizons mission, which was launched earlier this year to explore the solar system's most distant planet.

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New Horizons probe atop its launch vehicle at Kennedy Space Center  
  

The New Horizon's space probe was launched in January to explore the icy planet of Pluto, and its moon Charon, 6.5 billion kilometers from Earth.

It will take almost 10 years for the probe to reach Pluto, our solar system's most distant planet.

But scientists have found two more moons for the spacecraft to inspect during its brief nine-hour fly-by.

Using the Hubble Space Telescope, astronomers detected the two small, faint moons orbiting Pluto in the Kuiper Belt, a region of the galaxy³ beyond Neptune⁴ that is the cradle of asteroids⁵, comets, and icy bodies, including Pluto.

Artist's conception shows the Pluto system from the surface of one of its moons  
  
Hal Weaver⁶ of Johns Hopkins University Applied⁷ Physics Laboratory in Maryland is a scientist on the New Horizon's mission.

"It is going to give us two new Kuiper Belt objects to look at in addition to Pluto and Charon," he said. "With the New Horizons mission, it is basically four for the price of two."

The new moons are called P1 and P2. Weaver says they are 4,000-6,000 times fainter than Pluto, and two- to three-times as far away from Pluto as Charon.

For that reason, no one could see P1 and P2 with the world's best ground-based telescopes. But that did not stop Alan Stern of the Southwest Research Institute in Colorado, who began hunting for other moons around Pluto 15 years ago.

Pluto and Charon orbit around each other in what astronomers call a binary⁸ system. Experts say the twin orbits suggest that Pluto was created by a massive impact and Charon is a remnant of that explosion.

Stern reasoned, if that were the case "... Pluto would have small satellites accompanying its large one, Charon.  And when we got the right tool, we put the nail through the coffin⁹ in eight minutes flat with the Hubble Space Telescope."

Stern, the principal investigator¹⁰ for the New Horizons mission, says P1 and P2 track Charon's orbit perfectly¹¹, which supports the idea that Pluto was created by a massive impact.

Hal Weaver believes there could be many unique planets like Pluto at the edge of the universe.

"The exciting thing about all this is we have basically discovered a new solar system," he said. "This solar system that we are talking about now is very different from the one previous generations grew up with, our parents and even us, and what we were taught in school was that the solar system ended at Pluto."

Two papers by Weaver, Stern and their colleagues describing the discovery of Pluto's two moons appear in the February 23 issue of Nature.

1 astronomers   

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》

2 Pluto   

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。

3 galaxy   

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。

4 Neptune   

n.海王星

参考例句：

• Neptune is the furthest planet from the sun.海王星是离太阳最远的行星。
• 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。

5 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。

6 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。

7 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

8 binary   

adj.二，双；二进制的；n.双(体)；联星

参考例句：

• Computers operate using binary numbers.计算机运行运用二进位制。
• Let us try converting the number itself to binary.我们试一试，把这个数本身变成二进制数。

9 coffin   

n.棺材，灵柩

参考例句：

• When one's coffin is covered,all discussion about him can be settled.盖棺论定。
• The coffin was placed in the grave.那口棺材已安放到坟墓里去了。

10 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。

11 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。