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You're hiking through the Rockies one day when you hear a low, ominous rumble. Landslide! Hundreds of tons of rock and soil are careening toward you at enormous speed.
一天，你徒步在岩石堆中穿行，这时你听到一阵低低的隆隆声，势头不妙。是山体滑坡！上百吨的岩石和泥土以极快的速度朝你倾泻下来.
Fortunately, there's a helicopter nearby and you lift off just in time to escape unharmed. But now you notice something odd. After the landslide has gone by, in its tracks little dainty flowers are still standing. Blades of grass are unbent. How is this possible?
幸运的是，附近有架直升飞机，你及时乘飞机起飞，逃过了这一劫。但你却注意到了一些奇怪的现象。滑坡结束后，美丽的花朵依旧挺立在石块冲刷过的地方，小草也没有被低下头来，是什么让这些植物还能生存下来呢？
Before we tell you the answer, here's another question. What happens when you drop a book flat onto a table?
在我告诉你答案之前，先问你另一个问题。如果你将一本书水平扔到桌面上，会发生什么呢？
If you try it, you'll see that the book doesn't hit the table unimpeded, but lands on a little cushion of compressed air. If you don't believe us, try putting some little pieces of paper on the table before dropping the book. The whoosh of compressed air escaping will blow them off.
试一下，你会发现书在撞击桌子的时候遇到了阻碍，落在了压缩空气形成的缓冲垫上。如果你不相信,你可以先在桌上放一些小纸片，再将书抛下去。受压的空气向外逃出，呼啸着将纸片吹走.
That's the same phenomenon that happens with landslides. When an enormous sheet of rocks and dirt gets moving, it acts like a solid object. It traps the air underneath it and actually rides downhill on a cushion of air. Strange as it may seem, much of the landslide never touches the ground at all.
这与山体滑坡时发生的现象相同。当巨大的泥石移动的时候，它们的行动就像一个固体。它将空气压在下面。实际上，其实它是在一个气垫上滚下去的。尽管看上去有点怪，但大多数山体滑坡从不会接触到地面。
Because the cushion of air stays underneath it, the rocks and dirt aren't slowed down by friction much and continue picking up speed as they fall. Large landslides have been clocked in excess of 100 miles an hour.
由于空气垫的作用，岩石和泥土并没有受到很大摩擦力而减速下滑，相反它们会不停地加速。规模大的山体滑坡时速超过100英里每小时.
So—could you just lie down and let the landslide whoosh over you? No, unless you are about the size of a blade of grass. People who are bigger than that should keep a helicopter handy.
因此，你会躺下来，让滑坡从你身上越过吗？绝对不行。除非你只有草叶般大小。比草叶体积大的人类应该保证身边有一架直升飞机。
