英语听力：自然百科 穿越银河系的旅行 Through Milky Way—13

 In about four or five billion years, it will grow into a much bigger star, a star called a red giant. And that outer atmosphere of gases will be held so loosely by the sun at that time that the gases will be blown away gently in what I call a cosmic burp. 

The remains¹ of these cosmic burps also litter our galaxy² spiral arms, stars that die by shedding layers of elements. 

 

Some layers are oxygen, and some layers are silicon³, and some layers are sulfur⁴, and those are the different colors we see in the Hubble Space Telescope images. 

Not far from our sun is a place where a star is dying, the Helix Nebula⁵, it gives a spectacular insight into how most stars end their lives. Our sun is destined⁶ to create a similar vista⁷ when it too dies 5 billion years from now. 

 

But this doesn’t happen in every neighborhood. At the center of the galaxy is a place of mystery where stars disappear altogether. It’s here we’ll venture next. 

 

On the next stage of our journey through the Milky⁸ Way, we are heading to the center of our galaxy. 

 

If we were to take a trip from the spiral arms out where we are by the sun, down to the center of the galaxy, it will be an interesting trip. It will be very much like moving from the suburbs into the heart of a very busy metropolitan⁹ area. 

 

As we get towards the heart of the Milky Way, the number of stars increases. 

 

Though the density¹⁰ of stars is tremendous in the center of the galaxy, it’s about a billion times higher than out here by the sun.

 

1 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

2 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。

3 silicon   

n.硅(旧名矽)

参考例句：

• This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
• A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。

4 sulfur   

n.硫，硫磺（=sulphur）

参考例句：

• Sulfur emissions from steel mills become acid rain.炼钢厂排放出的硫形成了酸雨。
• Burning may produce sulfur oxides.燃烧可能会产生硫氧化物。

5 nebula   

n.星云，喷雾剂

参考例句：

• A powerful telescope can resolve a nebula into stars.一架高性能的望远镜能从星云中分辨出星球来。
• A nebula is really a discrete mass of innumerous stars.一团星云实际上是无数星体不连续的集合体。

6 destined   

adj.命中注定的；(for)以…为目的地的

参考例句：

• It was destined that they would marry.他们结婚是缘分。
• The shipment is destined for America.这批货物将运往美国。

7 vista   

n.远景，深景，展望，回想

参考例句：

• From my bedroom window I looked out on a crowded vista of hills and rooftops.我从卧室窗口望去，远处尽是连绵的山峦和屋顶。
• These uprisings come from desperation and a vista of a future without hope.发生这些暴动是因为人们被逼上了绝路，未来看不到一点儿希望。

8 milky   

adj.牛奶的，多奶的；乳白色的

参考例句：

• Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
• I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。

9 metropolitan   

adj.大城市的，大都会的

参考例句：

• Metropolitan buildings become taller than ever.大城市的建筑变得比以前更高。
• Metropolitan residents are used to fast rhythm.大都市的居民习惯于快节奏。

10 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。