第46篇 How the First Stars in the Universe Came into Existence
Researchers believe that our universe began with the Big Bang1 about 13 billion years ago, and that soon after that event, matter began to form as small dust grains and gases. How the first stars formed from this dust and gas has been a burning question2 for years, but a state-of-the-art3 computer simulation now offers the most detailed picture yet of how these first stars in the universe came into existence.
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 protostar4 the early stage of a massive primordial star of our universe -and the researchers' computer simulation sets the bar5 for further investigation into the star formation process. The question of how the first stars evolved is so important because their formations and eventually explosions 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 capable of synthesizing heavy elements, not just in later generations of stars, but soon after the Big Bang.
"This general 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 origins of life and planets," said Lars Hernquist, a Professor of Astronomy at Harvard University. "The abundance of elements in the universe has increased as stars have accumulated," he says,"and the formation and destruction of stars continues to spread these elements further across the universe. So when you think about it, all 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 the ambitious goal of piecing together the formation of an entire primordial star and of predicting the mass and properties of these first stars of the universe. More powerful computers, more physical data, and an 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 initiation when a stellar object becomes a true star. 词汇：
astronomical adj. 天文的；天文学的 pre-stellar adj. 前恒星的 synthesize v.合成，综合
protostar n.原恒星 stellar adj.恒星的；星球的 primordial adj. 原始的 注释：
1. the Big Bang：宇宙大爆炸，创始大爆炸。这是天体物理学关于宇宙起源的理论。根据 大爆炸理论，大约在 130 亿年前，宇宙所有的物质都高度密集在一点，有着极高的温度 ， 因而发生了巨大的爆炸。大爆炸以后，物质开始向外大膨胀，就形成了我们今天看到的 宇宙。但是，宇宙大爆炸仅仅是一种学说，是根据天文观测研究之后得到的一种设想。
2. burning question：最吸引人的问题，亟待解决的问题。
3. state-oe-the-art：形容词，意思是“最新的”、“达到最高技术水平的”、“代表当前科 技发展水平”。
4. protostar 原恒星，就是处于“原始状态”（处于慢收缩阶段的天体）的恒星。原恒星由 “大爆炸”后产生的星际云演变而来。
5. sets the bar：制定标准 练习：
1. What can the state-of-the-art computer simulation tell us about?
A How matter began to form the first stars after the Big Bang.
B How the Big Bang marked the beginning of our universe.
C How the Big Bang took place about 13 billion years ago.
D How dust grains and gases form after the Big Bang.
2. What does the "astronomical object" (paragraph 2) refer to?
A The early universe. B Cosmic dark ages.
C The first star formed in the universe. D Dust grains and gases.
3. What does the word "minute" mean in the expression "minute density variations"?
A A unit of time equal to one sixtieth of an hour. B A short interval of time.
C Exceptionally large. D Exceptionally small.
4. According to paragraph 4, what is NOT true about a protostar?
A It had a mass of one percent of the sun.
B It was developed into a massive star before the Big Bang.
C It began to combine heavy elements after it evolved into a massive star.
D It was evolved from pre-stellar gases.
5. All except one of the following indicate the goals of the simulation project. Which one is it?
A To know more about the mass and properties of the first stars of the universe.
B To apply the simulation to the study of nuclear reaction initiation.
C To know how a stellar object becomes a true star.
D To obtain a detailed picture of the early universe before the Big Bang. 答案与题解：
1. A 第一段最后一句告诉我们说，最先进的计算机模拟能详细描述 how these first stars in the universe came into existence。该段第一和第二句告诉我们，大爆炸 后，粉尘和气体开始聚集成物质，这些物质形成了宇宙中的星球。其他三选项都是错误 的理解。
2. C 根据上下文，astronomical object 指的是上段第二句中的“first stars”，即下面 一段第一句中的“protostar”。
3. D minute 在这里是形容词，意思是“极其细微的”，读作：/mai'nju:t/。
4. B A、C 和 D 的表述都可以在本段中找到。从上文和该段的最后一个句子可以得知，原 恒星进化的过程不是在宇宙大爆炸之前发生。所以，应该选择 B。
5. D A 是最后一段第一句句子的表述内容，B 和 C 是文章最后一句的表述内容。D 是对文 章的错误理解。