阅读理解(第3l~45题,每题3分,共15分)
请根据短文内容,为每题确定1个最佳选项。
How the First Stars in the Universe Came into Existence
How the first stars formed from this dust and gas has been a burning question for years,but a state-of-the-art computer simulation now offers the most detailed picture yet of how these first stars in the universe came into existence,researchers say.
The composition of the early universe was quite different from that of today,and the physics that governed the early universe were also somewhat simpler.Dr.Naoki Yoshida and colleagues in Japan and the U.S.incorporated these conditions of the early universe,sometimes referred to as the "cosmic dark ages,"to simulate the formation of an astronomical object that would eventually shine its light into this darkness.
The result is a detailed description of the formation of a protostar-the early stage of a massive primordial star of our universe,and the researchers'computer simulation,which has been called a "cosmic Rosetta Stone."sets the bar for further investigation into the star formation process.The question of how the first stars evolved is so important because their formations and eventual explo-sions provided the seeds for subsequent stars to come into being.
According to their simulation,gravity acted on minute density variations in matter,gases,and the mysterious"dark matter''of the universe after the Big Bang in order to form this early stage of a star-a protostar with a mass of just one percent of our sun.The simulation reveals how pre-stellar gases would have actually evolved under the simpler physics of the early universe to form this protostar.
Dr.Yoshida's simulation also shows that the protostar would likely evolve into a massive star capableof synthesizing heavy elements,not just in later generations of stars,but soon after the Big Bang.
"This geneal picture of star formation,and the ability to compare how stellar objects form in different time periods and regions of the universe,will eventually allow investigation into the originsof life and planets,"said Lars Hernquist,a Professor of Astronomy at Harvard University and a coauthor of this latest report."The abundance of elements in the universe has increased as stars haveaccumulated,"he says,"and the formation and destruction of stars continues to spread these ele. ments further across the universe.So when you think about it.a11 of the elements in our bodies originally formed from nuclear reactions in the centers of stars,long ago."
Their simulation of the birth of a protostar in the early universe signifies a key step toward theambitious goal of piecing together the formation of an entire primordial star and of predicting the massand properties of these first stars of the universe.More powerful computers,more physical data,andan even larger range will be needed for further calculations and simulations,but these researchers hope to eventually extend this simulation to the point of nuclear reaction in.itiation-when a stellar ob. ject becomes a true star.
"Dr.Yoshida has taken the study of primordial star formation to a new level with this simulation,but it still gets us only to the halfway point towards our final goal.It is like laying the foundation of a skyscraper,"said Volker Bromm,Assistant Professor of Astronomy at the University of Tex. as,Austin and the author of a companion article."We must continue our studies in this area to un-derstand how the initially tiny protostar grows,layer by layer,to eventually form a massive star.Buthere,the physics become much more complicated and even more computational resources are needed."
31.According to the first two paragraphs,the early universe_______.
A.was governed by simpler physics
B.got fewer stars shinning in it
C.started over 13 billion years ago
D.was composed in a way similar to that of today
32.What can the state-of-the.art computer simulation tell us about?
A.How the Big Bang occurred about 13 billion years ago.
B.How"cosmic dark ages"came into existence.
C.How dust grains and gases were formed after the Big Bang.
D.How the first stars canle into being after the Big Bang.
33.What does the"astronomical object"in paragraph 2 refer to?
A.cosmic dark ages.
B.dust grains and gases.
C.a protostar.
D.the early universe.
34.According to paragraph 4,what is NOT true about a protostar?
A.It developed into a massive star during the Big Bang.
B.It evolved from pre-stellar gases.
C.It was able to integrate heavy elements when evolving into a massive star.
D.It had a mass of one percent of the sun.
35.According to the last paragraph,all of the following are goals of the simulation project EXCEPT
A.to know more about the mass and properties of the first stars of the universe
B.to simulate the process of how the early universe began
C.to apply the simulation to the study of nuclear reaction initiation
D.to discover the truth about the formation of a protostar
参考答案及解析
31.A [解析]本题是细节考查题。题目是:根据前两段,宇宙的早期_________。原文是 "宇宙最初的构成同今天的有所不同,而宇宙早期的主要物理现象也比较简单。"选项A"主要物理现象也比较简单";选项B"在其中闪烁的星星更少";选项C"开始于130亿年前";选项D"和今天(宇宙)的构成方式相似"。因此只能选A。
32.D[解析]本题是细节考查题。题目问:这台最先进的电脑模拟系统告诉我们什么? 原文是"现在一种最先进的电脑模拟系统可以提供宇宙中最初的星辰产生的最详细的图片。" 选项A"130亿年前宇宙大爆炸是如何发生的";选项B"宇宙黑暗时代是如何形成的";选项C "在大爆炸后宇宙微尘和气体是如何形成的";选项D"在大爆炸后宇宙最初的星辰是如何形成的"。因此只能选D。
33.C[解析]本题是细节考查题。原文是"这一时期有时也被称为'宇宙的黑暗时代',模拟了最终在夜空中闪耀的天体的形成过程。"选项A"宇宙的黑暗时代";选项B"微尘和气体";选项C"原恒星";选项D"宇宙早期"。因此只能选C。
34.A [解析]本题是细节考查题。题目问:根据第四段,如下关于原星辰的说法哪个不正确?原文第四段中提到了B、C、D的内容,而提到A的相关内容时原文是说"after the Big Bang",在大爆炸之后。因此只能选A。选项A"在宇宙大爆炸中成为大恒星";选项B"组成早期星辰的气体";选项C"在形成巨大星体时能够合成重元素";选项D"只有太阳百分之一大"。
35.B[解析]本题是细节考查题。题目问:根据最后一段,如下哪个不是此模拟工程的目的?原文最后一段作为此项工程的目的提及了A、C、D选项所述内容,而B只是手段,而非目的。所以只能选B。选项A"更多的了解宇宙最初的星辰的体积和属性";选项B"模拟宇宙早期的形成过程";选项C"将模拟结果应用于核反应的初期阶段";选项D"发现原星辰形成的真相"。