60秒科学:Why Dwarf Galaxies Lack Star Power

Why Dwarf¹ Galaxies² Lack Star Power
In a study in the journal Nature, researchers show that the relative lack of star density³ in dwarf galaxies need not conflict with standard cosmological models if you include the blast effects of supernovae. Karen Hopkin reports

For astronomers⁴ who study the large-scale structure of the universe, dwarf galaxies have proven quite vexing⁵. Because the leading model of cosmology has been unable to account for their relative lack of substance. Now scientists writing in the journal Nature show that the current model can actually generate dwarf galaxies just fine. You just need to look at the stars.

There are two types of matter in the universe: ordinary matter, including the material that makes up stars. And dark matter: that mysterious stuff we can’t see but that clearly affects ordinary matter. It’s the presence of cold dark matter that explains how the young universe went from being smooth to being lumpy, as ordinary matter coalesced⁶ first into stars and then into galaxies. The problem is that dwarf galaxies are not as dense⁷ as the cold dark matter model says they should be.

Now an international team of astronomers says you can blame gusts⁸ of stellar wind. Because in the roiling⁹ cauldron of activity that governs galaxy¹⁰ formation, some stars go supernova. Those spectacular explosions literally¹¹ blow matter away, and you’re left with a dwarf galaxy that’s a lot like most independent films: a bit light on stars.
 

1 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。

2 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。

3 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

4 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》

5 vexing   

adj.使人烦恼的，使人恼火的v.使烦恼( vex的现在分词 )；使苦恼；使生气；详细讨论

参考例句：

• It is vexing to have to wait a long time for him. 长时间地等他真使人厌烦。 来自《现代英汉综合大词典》
• Lately a vexing problem had grown infuriatingly worse. 最近发生了一个讨厌的问题，而且严重到令人发指的地步。 来自辞典例句

6 coalesced   

v.联合，合并( coalesce的过去式和过去分词 )

参考例句：

• The puddles had coalesced into a small stream. 地面上水洼子里的水汇流成了一条小溪。
• The views of party leaders coalesced to form a coherent policy. 党的领导人的各种观点已统一为一致的政策。 来自辞典例句

7 dense   

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。

8 gusts   

一阵强风( gust的名词复数 )； （怒、笑等的）爆发； （感情的）迸发； 发作

参考例句：

• Her profuse skirt bosomed out with the gusts. 她的宽大的裙子被风吹得鼓鼓的。
• Turbulence is defined as a series of irregular gusts. 紊流定义为一组无规则的突风。

9 roiling   

v.搅混（液体）( roil的现在分词 )；使烦恼；使不安；使生气

参考例句：

• Now, all that could be seen was the roiling, lead--coloured sea, with its thunderously heaving waves. 狂风挟着暴雨如同弥漫大雾，排挞呼号，在海上恣意奔驶。 来自汉英文学 - 现代散文
• Rather, it is a roiling, seething cauldron of evanescent particles. 相反，它是一个不断翻滚、剧烈沸腾的大锅，内有逐渐消失的粒子。 来自互联网

10 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。

11 literally   

adv.照字面意义，逐字地；确实

参考例句：

• He translated the passage literally.他逐字逐句地翻译这段文字。
• Sometimes she would not sit down till she was literally faint.有时候，她不走到真正要昏厥了，决不肯坐下来。