2006年VOA标准英语-Scientists Find Milky Way Eats an Intrudin

By David McAlary
Washington
10 January 2006

Before you continue thinking about our Milky¹ Way galaxy² as a peaceful, spiral disk of stars slowly rotating through the heavens, consider this: It is hungrily digesting the remains³ of another galaxy trapped in its grip, all the while flapping its outer edge.

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It is hardly neighborly to eat a visitor, but that is exactly what the Milky Way appears to be doing.

Astronomers⁵ have concluded this after mapping the stars in half of the northern sky with the Sloan Telescope in New Mexico. The project is measuring distances to nearly 50-million stars, building a three-dimensional map of the Milky Way.

In the process, scientists have noticed a huge, very faint group of hundreds of thousands of seemingly alien stars spread out over an area about 5,000 times the size of a full moon. This star group is within our galaxy's confines, about 30,000 light years away, the distance light travels in that length of time.

The collection does not seem to be part of the galaxy's central bulge⁶, nor of the flattened⁷ disk of stars around the bulge where our solar system resides, nor of the extended, spherical⁸ halo of stars surrounding the galaxy.

Princeton University astronomer⁴ Robert Lupton says the most likely interpretation⁹ of the new structure is of another, smaller galaxy being consumed by the Milky Way.

"We're seeing a cloud of stars somewhere stuck above the plane of our galaxy. We believe it is almost certainly a dwarf¹⁰ galaxy merging¹¹ with the Milky Way. It is almost certainly a galaxy being ripped up, eaten, and otherwise digested by our galaxy," said Lupton. "So the Milky Way is still growing. It's not a static system. It's growing by cannibalizing smaller neighbors."

Lupton says astronomers have come to understand that such mergers¹³ are the way galaxies¹⁴ expand.

"People would imagine that there was, long ago, a period when many galaxies grew by mergers," he said. "If you look out at the well known galaxies that we see around us, many of those are still interacting, although interacting was very much commoner for big galaxies in the past."

The merger¹² of the Milky Way with the dwarf galaxy creates an overdensity of stars in that region of the Milky Way, which covers an area 45,000 light years across. Lupton told the American Astronomical¹⁵ Society meeting in Washington that our galaxy is taking a long time to swallow its dwarf neighbor.

"It's being eaten and it's going to be part of the Milky Way in another billion years," added Lupton. "So welcome to our newest member."

Meanwhile, another pair of satellite galaxies is causing the Milky Way to warp¹⁶ at its edge, much like the upturn¹⁷ in the brim of a hat.

Scientists have long known about the warpage¹⁸, but by studying patterns of hydrogen gas, only now do they understand that the cause is the motion of two small nearby galaxies orbiting the Milky Way called the Magellanic Clouds. As these galaxies circle us, they plow¹⁹ through unseen dark matter thought to exist around the galaxy, amounting to an estimated 90 percent of the matter in it. The motion of the Magellanic Clouds through the dark matter creates a wake like a boat sailing through water. This wake increases the dark matter's gravitational pull on the Milky Way's disk, according to astronomer Leo Blitz of the University of California at Berkeley.

"As the Magellanic Clouds orbit the Milky Way, the warp looks like it's flapping in the breeze," he said. "We talk about it flapping like a tablecloth²⁰ in the breeze. The center doesn't move very much, but the outer parts flap around."

Some astronomers do not believe dark matter is causing the galactic warp or the flapping, but Blitz says the Magellanic Clouds alone are not massive enough to have such a strong effect. Because many other galaxies have warped²¹ disks, he says similar dynamics²² might explain them as well.

"We need dark matter to see the strong bending modes that we see and this is probably a common feature of spiral galaxies in general," added Blitz.

1 milky   

adj.牛奶的，多奶的；乳白色的

参考例句：

• Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
• I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。

2 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。

3 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

4 astronomer   

n.天文学家

参考例句：

• 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。

5 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》

6 bulge   

n.突出，膨胀，激增；vt.突出，膨胀

参考例句：

• The apple made a bulge in his pocket.苹果把他口袋塞得鼓了起来。
• What's that awkward bulge in your pocket?你口袋里那块鼓鼓囊囊的东西是什么？

7 flattened   

[医]（水）平扁的，弄平的

参考例句：

• She flattened her nose and lips against the window. 她把鼻子和嘴唇紧贴着窗户。
• I flattened myself against the wall to let them pass. 我身体紧靠着墙让他们通过。

8 spherical   

adj.球形的；球面的

参考例句：

• The Earth is a nearly spherical planet.地球是一个近似球体的行星。
• Many engineers shy away from spherical projection methods.许多工程师对球面投影法有畏难情绪。

9 interpretation   

n.解释，说明，描述；艺术处理

参考例句：

• His statement admits of one interpretation only.他的话只有一种解释。
• Analysis and interpretation is a very personal thing.分析与说明是个很主观的事情。

10 dwarf   

n.矮子，侏儒，矮小的动植物；vt.使…矮小

参考例句：

• 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。

11 merging   

合并（分类）

参考例句：

• Many companies continued to grow by merging with or buying competing firms. 许多公司通过合并或收买竞争对手的公司而不断扩大。 来自英汉非文学 - 政府文件
• To sequence by repeated splitting and merging. 用反复分开和合并的方法进行的排序。

12 merger   

n.企业合并，并吞

参考例句：

• Acceptance of the offer is the first step to a merger.对这项提议的赞同是合并的第一步。
• Shareholders will be voting on the merger of the companies.股东们将投票表决公司合并问题。

13 mergers   

n.（两个公司的）合并( merger的名词复数 )

参考例句：

• Mergers fall into three categories: horizontal, vertical, and conglomerate. 合并分为以下三种：横向合并，纵向合并和混合合并。 来自辞典例句
• Many recent mergers are concentrated within specific industries, particularly in retailing, airlines and communications. 现代许多合并企业集中进行某些特定业务，在零售业、民航和通讯业中更是如此。 来自英汉非文学 - 政府文件

14 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。

15 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。

16 warp   

vt.弄歪，使翘曲，使不正常，歪曲，使有偏见

参考例句：

• The damp wood began to warp.这块潮湿的木材有些翘曲了。
• A steel girder may warp in a fire.钢梁遇火会变弯。

17 upturn   

n.情况好转

参考例句：

• Experts have forecast an upturn in the stock market.专家已预测股票市场价格有上升趋势。
• The economy is experiencing an upturn.经济正在好转。

18 warpage   

n.翘曲，扭曲，热变形

参考例句：

• Uneven hardening, with the formation of soft spots, increases warpage. 淬火不均部件上将出现软点，增加翘曲可能性。 来自互联网
• It has improved surface aesthetics, excellent dimensional stability and low warpage characteristics. 它改进表面美观，良好的尺寸稳定性和低翘曲的特点。 来自互联网

19 plow   

n.犁，耕地，犁过的地；v.犁，费力地前进[英]plough

参考例句：

• At this time of the year farmers plow their fields.每年这个时候农民们都在耕地。
• We will plow the field soon after the last frost.最后一场霜过后，我们将马上耕田。

20 tablecloth   

n.桌布，台布

参考例句：

• He sat there ruminating and picking at the tablecloth.他坐在那儿沉思，轻轻地抚弄着桌布。
• She smoothed down a wrinkled tablecloth.她把起皱的桌布熨平了。

21 warped   

adj.反常的；乖戾的；（变）弯曲的；变形的v.弄弯，变歪( warp的过去式和过去分词 )；使（行为等）不合情理，使乖戾，

参考例句：

• a warped sense of humour 畸形的幽默感
• The board has warped. 木板翘了。 来自《现代汉英综合大词典》

22 dynamics   

n.力学，动力学，动力，原动力；动态

参考例句：

• In order to succeed,you must master complicated knowledge of dynamics.要取得胜利，你必须掌握很复杂的动力学知识。
• Dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。