英语听力：自然百科 穿越银河系的旅行 Through Milky Way—22

 All of the galaxies¹, all of the stars, and gas and dust and planets, and everything else that we can see with our greatest telescopes represent about half of one percent of what’s actually/out there. The rest is invisible. It is mostly some mysterious substance that we call “dark matter”. 

 

 

 

You can’t see dark matter. The reason why you can see normal matter is because light shines on it and reflects off it. That’s how you can see me. Dark matter doesn’t work that way. The light goes right through the dark matter. 

 

The way we detect/ dark matter is because it has / mass. Anything with mass affects other things via gravity, that’s the golden rule of mass. That’s what mass does. It tugs² on / other things because of / gravity.

 

Without dark matter, the Milky³ Way couldn’t exist. So the galaxy⁴ is spinning, / the galaxy is spinning fairly rapidly. The reason why it can spin so rapidly is because it has so much dark matter. The dark matter has a lot of mass, and therefore it has a lot of gravity, and that’s what keeps the stars within around. 

 

If we were to magically take all the dark matter away from our galaxy, it would fly apart. The stars would just keep going straight, and in/ very short amount of time the galaxy would just be gone. There will be just a mass of stuff flying in very its way. And that’s not just true of our galaxy, it’s true of every galaxy, and every cluster of galaxy in the universe. They are all held together by this invisible stuff that we call dark matter. So we need the dark matter. It is the glue that holds galaxies together. 

 

The discovery of/ dark matter has revolutionized / star picture of the Milky Way. The stars of the galaxy represent just a fraction of its mass. The rest is made up of an invisible halo of dark matter. It surrounds you, me, and every single star. The stars are just the central region. The halo is at least ten times bigger, and weighs much more than ten times more. Then all the stars, and gas and dust that we can see, it’s the whole structure that’s the real Milky Way galaxy.

1 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。

2 tugs   

n.猛拉( tug的名词复数 )；猛拖；拖船v.用力拉，使劲拉，猛扯( tug的第三人称单数 )

参考例句：

• The raucous sirens of the tugs came in from the river. 河上传来拖轮发出的沙哑的汽笛声。 来自辞典例句
• As I near the North Tower, the wind tugs at my role. 当我接近北塔的时候，风牵动着我的平衡杆。 来自辞典例句

3 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。

4 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。