【英语时差8，16】太阳为什么发光

 What makes the sun shine? For a lot of folks, this is the kind of thing that doesn't even require explanation: it just does. But just being a commonplace phenomenon in no way explains it. Something must cause the sun to shine.   And, in fact, there is an answer. The sun, like every star, was created by the effect of gravity. Originally, all the matter that makes up the sun was in the form of dust and gas floating in space. This dust was composed of different elements, but was mainly hydrogen. Over time, the force of gravity caused that dust to start lumping together: the more it created lumps, the more dust those lumps pulled in. Lumps attached themselves to lumps, until after only a few billion years a titanic¹ mass was formed. This is called a proto-star.

Next, its own gravitational attraction crushes the proto-star tighter and tighter: the larger it is, the more powerfully will it compress its own insides. So tightly is it crushed, in fact, that the hydrogen atoms begin to fuse with each other. Whenever this happens, a blast of energy is released and a new element -- helium -- is produced.

Now the proto-star has become an actual star, crushing hydrogen into helium in an ongoing² controlled explosion. The outward force of the explosion keeps the star from contracting too small, while the inward crush of gravity keeps it from blowing apart. Once this equilibrium³ is reached, a star such as our own sun can stay balanced -- and shining -- for literally⁴ billions of years.   

1 titanic   

adj.巨人的，庞大的，强大的

参考例句：

• We have been making titanic effort to achieve our purpose.我们一直在作极大的努力，以达到我们的目的。
• The island was created by titanic powers and they are still at work today.台湾岛是由一个至今仍然在运作的巨大力量塑造出来的。

2 ongoing   

adj.进行中的，前进的

参考例句：

• The problem is ongoing.这个问题尚未解决。
• The issues raised in the report relate directly to Age Concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。

3 equilibrium   

n.平衡，均衡，相称，均势，平静

参考例句：

• Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
• This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。

4 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。