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I recently received this question via email:
我最近通过电子邮件收到这样一个问题：
Hello there, Imagine we build a giant ring around the whole globe, perfectly round, no ups and downs.
您好，想象我们在地球外建一个大环，完美的圆，没有凹凸起伏。
What you didn't know is that I installed explosives all around on each pole holding it up, and then boom.
你不知道的是，我在每根用于支撑大环的柱子上安装了炸药，然后爆炸了。
All the poles break at the same time.
所有的柱子都同时折断。
What will happen to the ring? Will it just sit there in the air?
这个环会发生什么？它会在空中吗？
Or will it fall down? Will it start spinning like crazy? Best regards, Martin from Sweden.
还是会掉下来？它会像疯子一样绕地球旋转吗？诚挚的问候，来自瑞典的马丁。
First off, Martin, I cannot condone secretly installing explosives on poles holding up infrastructure projects.
首先，马丁，我不能宽恕在电线杆上秘密安装炸药阻碍基础设施项目。
Second, I have a feeling you might really like the planet Saturn.
第二，我觉得你可能真的很喜欢土星。
And Third, fun question! The answer depends a lot on how strong the ring is,
第三，问题很有趣！那个环会怎样很大程度上取决于环的强度，
but in general you've touched upon an idea called symmetry breaking.
但总的来说，你提到了一个叫做对称性破缺的概念。
As you've realized, a perfectly symmetric ring
正如你已经意识到的，一个完美对称的环
doesn't have any particular reason to fall or break in any one point!
没有任何特别的理由在任何一点上掉落或断裂！
Like a perfectly balanced pencil, which way will it fall?
就像一支完美平衡的铅笔，它会朝哪个方向掉下去？
Anyway, if the ring is really really strong, then it should just stay exactly where it is,
不管怎么说，如果环真的很结实，那它应该保持在原来的位置，
"hovering", though that actually means being held up by its own strength,
那就是在地球外徘徊，虽然这实际上意味着由它自己的力量来支撑，
because each part will be gravitationally pulled toward the center of the earth,
因为每个部分会同时被地球的万有引力吸向地球，
and since those forces are spread equally around the ring in a symmetric way they'll cancel out.
而这些力是以对称的方式均匀地分布在环的周围，它们就会互相抵消。
Like how in tug of war if both sides pull the same amount the rope won't move.
就像在拔河比赛中，如果双方力量一样大的话，绳子就不会动。
Now, if the ring's not sufficiently strong, it might buckle in places and become scrunched up,
现在，如果环的强度不够强，它可能会在某些地方弯折并被挤压成一团，
like the coins that my friend Dianna shrunk by putting them in a very strong,
就像我朋友Dianna的一枚硬币，在非常强
very quickly changing magnetic field. It's interesting to note that the properties of circumferences
又快速变化的磁场里缩小。有趣的是注意到，圆周的特性
mean you'd only have to take out a few meters for the ring to be small enough to just lie on the ground.
意味着你只需要抽出环的几米，那个环就会小到躺在地球上。
As for "will it start spinning like crazy"?
至于“它会不会像疯子一样旋转”？
I think you might be referring to the idea that the earth is spinning to the east "underneath" the ring or underneath all of us right now.
我想你可能指的是地球在环的里面向东自转，或者是现在在我们脚下自转。
I actually have a whole other video about that, that you should definitely check out.
我有一个关于地球自转的完整视频，你一定要看看。
Thanks for your question, and stay away from the high explosives.
谢谢你的问题，还有记得远离爆炸物。
