英语听力：自然百科 穿越银河系的旅行 Through Milky Way—15

 Each tag is whipping around the center of the galaxy¹, the particular, the most striking thing you will notice is the motion of SO2.So SO2 goes on an incredible roller-coaster ride. It comes whipping around and then back out.

 

 

 

Something with tremendous gravitational pull sends SO2 on a rapid orbit / around the center of the galaxy, something with a huge mass.

 

 

 

SO2 goes around once every 15 years. And what it tells us is that there is 4 million times the mass of the sun confined within its orbit.

 

 

 

 

 

And astronomers² know of only one contender for something that has such a giant mass and it's so small.

 

 

 

So that's incredible amount of mass inside a very small volume and that's the key to prevent a black hole.

 

 

 

So at the center of our galaxy lies a massive black hole, an object whose gravity is so strong that not even light can escape it.

 

 

 

This is an image of the center of our galaxy. We can't see the black hole, but we can see bright clouds of gas and dust spiraling towards it. 

 

 

 

We are nearing the black hole, it's at the center of a stream of dust and gas, the entrails of stars shredded³ after straying too close.

 

 

 

Black holes grow with time and that happens by material falling onto it, accreting⁴ onto it. And that material can come in the form of either gas or stars that get torn apart by the black hole itself.

 

 

 

At the center, is the invisible black hole. What we were seeing is material it’s feeding on.

1 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。

2 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》

3 shredded   

shred的过去式和过去分词

参考例句：

• Serve the fish on a bed of shredded lettuce. 先铺一层碎生菜叶，再把鱼放上，就可以上桌了。
• I think Mapo beancurd and shredded meat in chilli sauce are quite special. 我觉得麻婆豆腐和鱼香肉丝味道不错。 来自《简明英汉词典》

4 accreting   

v.共生( accrete的现在分词 )；合生；使依附；使连接

参考例句：

• Accreting to statistic, 75 percent of students'school time is spent in the class. " 据统计，学生在学校的活动总量有75%的时间是在课堂上度过的。 来自互联网