Here is an image.
这是一张照片。
Since galaxy clusters are representative slices of the universe, scaled-down versions.
因为星团可以看做是宇宙的缩小版。
They are mostly made up of dark matter,
它们也是大部分由暗物质构成，
and that's what you see in this bluish purple.
这就是你看到的偏蓝的紫色。
The red represents the hot gas,
红色代表高温气体，
and, of course, you can see many galaxies.
当然，你可以看到很多星系。
What's happened is a particle accelerator at a huge, huge scale.
发生的事情就是一个非常巨大版本的粒子加速器。
And this is very important,
这很重要，
because what it means is that very, very small effects that might be difficult to detect in the lab,
因为这意味着，在实验室里某些因为太小而很难检测到的效果，
might be compounded and compounded into something that we could possibly observe in nature.
可能因为不断的叠加，而让我们在自然界观测到。
So, it's very funny.
这很好玩。
The reason why galaxy clusters can teach us about dark matter,
为什么星团可以教我们暗物质的知识，
the reason why galaxy clusters can teach us about the physics of the very small,
为什么它们可以教我们关于“极小”的物理，
is precisely because they are so very big.
其原因就是因为它们太大了。
Fourth thing: the physics of the very strange.
第四个问题：关于“非常奇怪”的物理学。
Certainly what I've said so far is crazy.
我刚才所说的已经很疯狂了。
Okay, if there's anything stranger I think it has to be dark energy.
但是，如果有比那些更疯狂的，我认为就是暗能量了。
If I throw a ball into the air,
如果我把一个球扔向空中，
I expect it to go up.
我预计它将上升。
What I don't expect is that it go up at an ever-increasing rate.
而我不会预计它以越来越快的速度上升。
Similarly, cosmologists understand why the universe is expanding.
同样的，宇宙学家理解为什么宇宙在膨胀。
They don't understand why it's expanding at an ever-increasing rate.
他们不理解的是，为什么宇宙膨胀的速度越来越快。
They give the cause of this accelerated expansion a name,
他们为加速膨胀的原因取了个名字，
and they call it dark energy.
叫做暗能量。
And, again, we want to learn more about it.
同样，我们希望对它了解更多。
So, one particular question that we have is,
其中一个问题是，
how does dark energy affect the universe at the largest scales?
暗能量是如何在极大的尺度上影响宇宙的？
Depending on how strong it is,
取决于能量的强弱，
maybe structure forms faster or slower.
或许结构的形成会有快有慢。
Well, the problem with the large-scale structure of the universe is that it's horribly complicated.
但是对于宇宙的大尺度结构，问题是它复杂得可怕。
