英语听力：自然百科 穿越银河系的旅行 Through Milky Way—25

 What happens is that, first the dark matter forms the structure, the ordinary matter then follows the dark matter. The ordinary matter is hydrogen and helium at this stage. And the hydrogen and helium fall/ to the center of the dark matter halos that are forming and that's when it becomes the galaxies¹.

 

 

 

If these ideas are right, then the link between these minute ripples² in the early universe and the vast cosmic web that now fills space is dark matter.

 

 

 

But of course, dark matter is invisible, so there is no way to see it creating the cosmic web. But it is possible to simulate the process using one of the world's most powerful supercomputers.

 

 

 

Here we are at NASA AMES, the research center where we have the Pleiades supercomputer. Each one of these cabinets contains 512 processors, let me show you. So that's half a terabyte in each one of these cabinets. There's a hundred ton of these cabinets to make up the entire Pleiades supercomputer. So this is a really big supercomputer, this is NASA's biggest.

 

 

 

The challenge is to develop a virtual universe from its early beginnings to the present day to see what role dark matter might have played in shaping the cosmos³. If you try to do this using a home computer, it would take almost 700 years.

 

 

 

If we're doing our job right, we can put the pictures into a video if you like that shows the whole structure of the universe.

 

 

 

And this is the end-result. It's called Bolshoi, an amazing visualization⁴ of what the structure of dark matter might look like in the universe today.

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 ripples   

逐渐扩散的感觉( ripple的名词复数 )

参考例句：

• The moon danced on the ripples. 月亮在涟漪上舞动。
• The sea leaves ripples on the sand. 海水在沙滩上留下了波痕。

3 cosmos   

n.宇宙；秩序，和谐

参考例句：

• Our world is but a small part of the cosmos.我们的世界仅仅是宇宙的一小部分而已。
• Is there any other intelligent life elsewhere in the cosmos?在宇宙的其他星球上还存在别的有智慧的生物吗？

4 visualization   

n.想像，设想

参考例句：

• In 2D visualization and drawing applications, vertical and horizontal scrolling are common. 在二维的可视化及绘图应用中，垂直和水平滚动非常普遍。 来自About Face 3交互设计精髓
• Ophthalmoscopy affords the only opportunity for direct visualization of blood vessels. 检眼镜检查法提供直接观察血管的唯一机会。