银河系正在逐渐增大-凯发k8官网

银河系正在逐渐增大
文章来源:未知 文章作者:meng 发布时间:2010-10-14 01:43 字体: [ ] 
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the first 1 formed before the universe was less than one billion years old and were much smaller than the giant systems — including the 2 way — that we see today. so somehow the average 3 size has increased as the universe has evolved. galaxies often collide and then 4(合并,融合) to form larger systems and this process is certainly an important growth 5. however, an additional, gentler way has been proposed. a european team of 6 has used eso's very large telescope to test this very different idea — that young galaxies can also grow by sucking in cool streams of the hydrogen and helium gas that filled the early universe and forming new stars from this 7 material. just as a commercial company can expand either by 8 with other companies, or by hiring more staff, young galaxies could perhaps also grow in two different ways — by merging with other galaxies or by 9 material.

the team leader, giovanni cresci (osservatorio astrofisico di arcetri) says: "the new results from the vlt are the first direct evidence that the 10 of 11(原来的,古时的) gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young universe." the discovery will have a major impact on our understanding of the evolution of the universe from the big bang to the present day. theories of galaxy formation and evolution may have to be re-written.

the group began by selecting three very distant galaxies to see if they could find evidence of the flow of pristine gas from the surrounding space and the associated formation of new stars. they were very careful to make sure that their 12 galaxies had not been disturbed by interactions with other galaxies. the selected galaxies were very regular, 13 rotating discs, similar to the milky way, and they were seen about two billion years after the big bang (at a redshift of around three).

in galaxies in the modern universe the heavy elements are more abundant close to the centre. but when cresci's team mapped their selected distant galaxies with the sinfoni spectrograph(光谱仪) on the vlt they were excited to see that in all three cases there was a patch of the galaxy, close to the centre, with fewer heavy elements, but hosting vigorously forming stars, suggesting that the material to fuel the star formation was coming from the surrounding pristine gas that is low in heavy elements. this was the smoking gun that provided the best evidence yet of young galaxies accreting primitive gas and using it to form new generations of stars.

as cresci concludes: "this study has only been possible because of the outstanding performance of the sinfoni instrument on the vlt. it has opened a new window for studying the chemical properties of very distant galaxies. sinfoni provides information not only in two 14(空间的) dimensions, but also in a third, 15 dimension, which allows us to see the internal motions inside galaxies and study the chemical composition of the interstellar(星际的) gas."



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1 fa8833b92b82bcb88ee3b3d7644caf77     
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。
2 jd0xg     
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。
3 ohoxb     
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 qcpxf     
v.(使)结合,(使)合并,(使)合为一体
参考例句:
  • i can merge my two small businesses into a large one.我可以将我的两家小商店合并为一家大商行。
  • the directors have decided to merge the two small firms together.董事们已决定把这两家小商号归并起来。
5 zcwxr     
n.机械装置;机构,结构
参考例句:
  • the bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
  • the mechanism of the machine is very complicated.这台机器的结构是非常复杂的。
6 569155f16962e086bd7de77deceefcbd     
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》
7 vswz0     
adj.原始的;简单的;n.原(始)人,原始事物
参考例句:
  • it is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
  • his book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。
8 65cc30ed55db36c739ab349d7c58dfe8     
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。
9 f86865665bd26596fdf1bff752bfc00a     
v.共生( accrete的现在分词 );合生;使依附;使连接
参考例句:
  • accreting to statistic, 75 percent of students'school time is spent in the class. " 据统计,学生在学校的活动总量有75%的时间是在课堂上度过的。 来自互联网
10 5jnyi     
n.自然的增长,增加物
参考例句:
  • every culture is an accretion.每一种文化都是长期积淀的结果。
  • an accretion of sediment at the mouth of the river caused serious flooding.河口堆积物的增加导致河水严重泛滥。
11 5bqyc     
adj.原来的,古时的,原始的,纯净的,无垢的
参考例句:
  • he wiped his fingers on his pristine handkerchief.他用他那块洁净的手帕擦手指。
  • he wasn't about to blemish that pristine record.他本不想去玷污那清白的过去。
12 xvtwm     
n.样本,标本
参考例句:
  • you'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
  • this specimen is richly variegated in colour.这件标本上有很多颜色。
13 iiuzlg     
adv.平滑地,顺利地,流利地,流畅地
参考例句:
  • the workmen are very cooperative,so the work goes on smoothly.工人们十分合作,所以工作进展顺利。
  • just change one or two words and the sentence will read smoothly.这句话只要动一两个字就顺了。
14 gvcww     
adj.空间的,占据空间的
参考例句:
  • this part of brain judges the spatial relationship between objects.大脑的这部分判断物体间的空间关系。
  • they said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。
15 fvbwg     
adj.幽灵的,鬼魂的
参考例句:
  • at times he seems rather ordinary.at other times ethereal,perhaps even spectral.有时他好像很正常,有时又难以捉摸,甚至像个幽灵。
  • she is compelling,spectral fascinating,an unforgettably unique performer.她极具吸引力,清幽如鬼魅,令人着迷,令人难忘,是个独具特色的演员。
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