Here are some images of clusters of galaxies. 这是一些星团的照片。 They're exactly what they sound like. 正如听上去一样。 They are these huge collections of galaxies, 它们是一堆星系， bound together by their mutual gravity
Here is a computer simulation. 这是计算机模拟。 And we need a way to simplify it. 我们需要简化它的方法。 Well, I like to think about this using an analogy. 我会用一个类比来理解。 If I want to understand the sinking of the Titanic,
And many of the questions that we might have about the universe at large scales, 我们关于宇宙在宏观上有很多问题， such as, how does gravity work? 比如，引力是怎么起作用的？ might be answered by studying these systems. 这些问题可能可以通过研
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
