多数著名彗星在其它星系中形成-凯发k8官网

多数著名彗星在其它星系中形成
文章来源:未知 文章作者:meng 发布时间:2010-06-14 05:52 字体: [ ] 
(单词翻译:双击或拖选)

many of the most well known comets, including halley, hale-bopp and, most recently, mcnaught, may have been born in orbit around other stars, according to a new theory by an international team of 1(天文学家) led by a scientist from the southwest research institute (swri) in 2, colo. dr. hal levison (swri), dr. martin duncan (queen's university, kingston, canada), dr. ramon brasser (observatoire de la côte d'azur, france) and dr. david kaufmann (swri) used computer simulations to show that the sun may have captured small icy bodies from its 3(兄弟姊妹) stars while it was in its birth star cluster(丛,蔟) , 4 creating a reservoir(水库,蓄水池) for observed comets.

while the sun currently has no companion stars, it is believed to have formed in a cluster containing hundreds of closely packed stars that were 5 in a 6 cloud of gas. during this time, each star formed a large number of small icy bodies (comets) in a disk from which planets formed. most of these comets were gravitationally 7 out of these prenatal(产前的) planetary systems by the newly forming giant planets, becoming tiny, free-floating members of the cluster.

the sun's cluster came to a violent end, however, when its gas was blown out by the hottest young stars. these new models show that the sun then gravitationally captured a large cloud of comets as the cluster 8(分散,传播) .

"when it was young, the sun shared a lot of spit with its 9, and we can see that stuff today," says lead author levison.

"the process of capture is surprisingly efficient and leads to the exciting possibility that the cloud contains a 10(百花香,混合物) that samples material from a large number of stellar siblings of the sun," says co-author duncan.

evidence for the team's 11 comes from the roughly 12(球形的,天体的) cloud of comets, known as the oort cloud, that surrounds the sun, extending 13 to the nearest star. it has been commonly assumed this cloud formed from the sun's proto-planetary disk. however, because 14 models show that comets from the solar system produce a much more anemic(贫血的) cloud than observed, another source is required.

levison says, "if we assume that the sun's observed proto-planetary disk can be used to estimate the 15 population(土著居民) of the oort cloud, we can conclude that more than 90 percent of the observed oort cloud comets have an extra-solar origin."

"the formation of the oort cloud has been a mystery for over 60 years and our work likely solves this long-standing problem," says brasser.



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1 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》
2 bnbzs     
n.巨砾;卵石,圆石
参考例句:
  • we all heaved together and removed the boulder.大家一齐用劲,把大石头搬开了。
  • he stepped clear of the boulder.他从大石头后面走了出来。
3 teszc     
n.同胞手足(指兄、弟、姐或妹)
参考例句:
  • many of us hate living in the shadows of a more successful sibling.我们很多人都讨厌活在更为成功的手足的阴影下。
  • sibling ravalry has been common in this family.这个家里,兄弟姊妹之间的矛盾很平常。
4 sokwv     
adv.因此,从而
参考例句:
  • i have never been to that city,,ereby i don't know much about it.我从未去过那座城市,因此对它不怎么熟悉。
  • he became a british citizen,thereby gaining the right to vote.他成了英国公民,因而得到了投票权。
5 lt9zts     
a.扎牢的
参考例句:
  • an operation to remove glass that was embedded in his leg 取出扎入他腿部玻璃的手术
  • he has embedded his name in the minds of millions of people. 他的名字铭刻在数百万人民心中。
6 aonzx     
a.密集的,稠密的,浓密的;密度大的
参考例句:
  • the general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
  • the path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。
7 slung     
抛( sling的过去式和过去分词 ); 吊挂; 遣送; 押往
参考例句:
  • he slung the bag over his shoulder. 他把包一甩,挎在肩上。
  • he stood up and slung his gun over his shoulder. 他站起来把枪往肩上一背。
8 b24c637ca8e58669bce3496236c839fa     
adj. 被驱散的, 被分散的, 散布的
参考例句:
  • the clouds dispersed themselves. 云散了。
  • after school the children dispersed to their homes. 放学后,孩子们四散回家了。
9 709961e45d6808c7c9131573b3a8874b     
n.兄弟,姐妹( sibling的名词复数 )
参考例句:
  • a triplet sleeps amongst its two siblings. 一个三胞胎睡在其两个同胞之间。 来自《简明英汉词典》
  • she has no way of tracking the donor or her half-siblings down. 她没办法找到那个捐精者或她的兄弟姐妹。 来自时文部分
10 ppkxj     
n.混合之事物;百花香
参考例句:
  • as tobacco cigarette burns,a potpourri of 4000 chemicals is released,including carbon monoxide and hydrocyanic acid.当烟被点燃时,融合了四千种化学品的气体被释放出来,其中包括一氧化碳和氢氰酸。
  • even so,there is a slight odour of potpourri emanating from longfellow.纵然如此,也还是可以闻到来自朗费罗的一种轻微的杂烩的味道。
11 lzoxm     
n.剧本,脚本;概要
参考例句:
  • but the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • this is a totally different scenario.这是完全不同的剧本。
12 7fqzq     
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。
13 xrvzdq     
adj.中途的,不彻底的,部分的;adv.半路地,在中途,在半途
参考例句:
  • we had got only halfway when it began to get dark.走到半路,天就黑了。
  • in study the worst danger is give up halfway.在学习上,最忌讳的是有始无终。
14 xunzms     
adj.详细的,详尽的,极注意细节的,完全的
参考例句:
  • he had made a detailed study of the terrain.他对地形作了缜密的研究。
  • a detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。
15 ybbzt     
adj.土产的,土生土长的,本地的
参考例句:
  • each country has its own indigenous cultural tradition.每个国家都有自己本土的文化传统。
  • indians were the indigenous inhabitants of america.印第安人是美洲的土著居民。
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