2006年VOA标准英语-Astronomers Find That Many Milky Way Plane

By David McAlary
Washington
12 January 2006

As astronomers¹ detect more and more planets outside our solar system, they are finding that many of them have more than one sun, unlike Earth and its companions.

Imagine a world where it is always daytime. The notion of sunrise and sunset would not exist. According to a study led by Georgia State University graduate student Deepak Raghavan, this could be true of many planets discovered in the past decade in other solar systems because they have multiple suns.

"Over one fifth of the extrasolar planetary systems are in multiple star environments," Raghavan said. "So if you lived on any of these planets, you would have at least two suns in your sky."

Raghavan told the American Astronomical² Society meeting in Washington that he and colleagues painstakingly³ sifted⁴ through data already collected on 131 foreign planetary systems and backed up some of it with observations using a telescope in Chile. He found that 26 planetary groups orbit twin stars and three of them circle triplet stars.

In situations where it was unclear whether a planet had multiple suns, his team looked for evidence that stars close to each other traveled together.

"If we find two stars in the same piece of the sky moving in the same direction, we think that there is a good chance that they are related to each other and actually orbiting each other," he added. "If we find that the distances to the two stars are also of the same order, then we are ready to conclude that they are actually gravitationally bound to each other."

Astronomers were once unsure whether planets could form in so-called binary⁵ star systems. They thought the strong gravitational forces from one star might interfere⁶ with planet formation around the other.

But, as Raghavan's survey emphasizes, recent planet discoveries have shown otherwise, and work at the Carnegie Institution in Washington provides a theoretical explanation. It shows that gas giant planets like Jupiter can form from the disk of gas and dust surrounding two stars as they do around single stars if the gravitational interaction between them does not heat the matter up too much. The planet-forming disk would remain cool enough for ice grains to remain solid and permit the growth of solid cores that form the center of big gaseous⁷ planets.

Deepak Raghavan says his findings that planets can grow in multiple-sun systems reaffirm his belief that life is common in the universe. "For us folks that like extraterrestrial life and planets, these results show that planets are quite hardy," he said. "They do form and survive in a variety of environments."

Raghavan's study shows that some of the planets in the double and triple star systems are at a safe enough distance from the primary star to allow for liquid water. He says a planet in constant sunlight conjures⁸ up images of life very different from our own.

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 astronomical   

adj.天文学的，（数字）极大的

参考例句：

• 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。

3 painstakingly   

adv. 费力地 苦心地

参考例句：

• Every aspect of the original has been closely studied and painstakingly reconstructed. 原作的每一细节都经过了仔细研究，费尽苦心才得以重现。
• The cause they contrived so painstakingly also ended in failure. 他们惨淡经营的事业也以失败而告终。

4 sifted   

v.筛( sift的过去式和过去分词 )；筛滤；细查；详审

参考例句：

• She sifted through her papers to find the lost letter. 她仔细在文件中寻找那封丢失的信。 来自《简明英汉词典》
• She sifted thistles through her thistle-sifter. 她用蓟筛筛蓟。 来自《简明英汉词典》

5 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。

6 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

7 gaseous   

adj.气体的，气态的

参考例句：

• Air whether in the gaseous or liquid state is a fluid.空气，无论是气态的或是液态的，都是一种流体。
• Freon exists both in liquid and gaseous states.氟利昂有液态和气态两种形态。

8 conjures   

用魔术变出( conjure的第三人称单数 )； 祈求，恳求； 变戏法； （变魔术般地） 使…出现

参考例句：

• The word 'birthday' conjures up images of presents and parties. “生日”这个词使人想起礼物和聚会的情景。
• The name Sahara conjures up images of a desert of aridity. "撒哈拉"这个名字使人想起干旱的沙漠情景。