String Theory Explained – What is The True Nature of Reality? · Kurzgesagt – In a Nutshell
本视频用通俗方式讲解弦理论，探讨宇宙本质。适合练习科学类词汇和复杂句型理解。
What is the true nature of the universe?
宇宙的真正本质是什么？
To answer this question, humans come up with stories to describe the world.
为了回答这个问题，人类创造了各种故事来描述这个世界。
We test our stories and learn what to keep and what to throw away.
我们会测试自己创作的故事内容，从而判断哪些部分应该保留下来，哪些部分应该舍弃。
But the more we learn, the more complicated and weird our stories become.
然而，我们了解得越多，我们的故事就越显得复杂和离奇。
Some of them so much so, that it's really hard to know what they're actually about.
其中有些内容实在过于复杂，以至于我们很难真正理解它们的含义（或者说：这些内容的设计目的实在难以被理解）。
Like string theory.
就像弦理论一样。
A famous, controversial and often misunderstood story, about the nature of everything.
这是一个著名却充满争议、且常常被误解的故事，它探讨了万物本质的奥秘。
Why did we come up with it and is it correct?
我们为什么要提出这个想法？这个想法是否正确呢？
Or just an idea we should chuck out?
还是说，这只是一个我们应该抛弃的想法罢了？
To understand the true nature of reality, we looked at things up close and were amazed.
为了理解现实的真正本质，我们仔细观察了各种事物，结果感到非常惊讶。
Wonderous landscapes in the dust, zoos of bizarre creatures, complex protein robots.
尘土中的奇妙景观、由奇异生物构成的“动物园”，以及那些复杂的蛋白质机器人……
All of them made from structures of molecules made up of countless even smaller things: Atoms.
它们都是由分子结构构成的，而这些分子又是由无数更微小的物质——原子——组成的。
We thought they were the final layer of reality, until we smashed them together really hard and discovered things that can't be divided anymore:
我们原本以为它们就是现实的最终构成层次，直到我们用力将它们相互碰撞，从而发现了一些根本无法再被分割开来的东西……
Elementary particles.
基本粒子。
But now, we had a problem: They are so small that we could no longer look at them.
但现在我们遇到了一个问题：这些样本太小了，我们根本无法再观察它们了。
Think about it: what is seeing?
仔细想想：所谓的“看见”到底是什么呢？
To see something, we need light, an electromagnetic wave.
要想看到某样东西，我们需要光——也就是一种电磁波。
This wave hits the surface of the thing and gets reflected back from it into your eye.
这股光波照射到物体的表面后，被反射回来并进入你的眼睛。
The wave carries information from the object that your brain uses to create an image.
这股“波浪”携带着来自物体的信息，你的大脑会利用这些信息来形成相应的图像。
So you can't see something without somehow interacting with it.
因此，如果你想看到某样东西，就必须以某种方式与它进行互动。
Seeing is touching, an active process, not a passive one.
眼见为实”其实是一个主动的过程，而非被动的过程。
This is not a problem with most things.
对于大多数物品来说，这都不是一个问题。
But particles are But particles are very, But particles are very, very, But particles are very, very, very small.
但是这些粒子非常非常非常小。
So small that the electromagnetic waves we used to see are too big to touch them.
它们实在太小了，以至于我们用来观测它们的电磁波，其波长实在太大，根本无法直接“触碰到”这些微小的物体。
Visible light just passes over them.
可见光只是从它们表面穿过而已。
We can try to solve this by creating electromagnetic waves with more and much smaller wavelengths.
我们可以尝试通过生成波长更短（且数量更多）的电磁波来解决这个问题。
But more wavelengths, means more energy.
但是，波长越长，所蕴含的能量也就越大。
So, when we touch a particle with a wave that has a lot of energy it alters it.
当我们用一个具有大量能量的波去照射某个粒子时，这个粒子就会发生改变。
By looking at a particle, we change it.
当我们观察一个粒子时，实际上就已经改变了它。
So, we can't measure elementary particles precisely.
因此，我们无法精确地测量基本粒子。
This fact is so important that it has a name: The Heisenberg uncertainty principle.
这一事实非常重要，以至于它被专门赋予了一个名称：海森堡不确定性原理。
The basis of all quantum physics.
所有量子物理学的基础。
So, what does a particle look like then?
那么，粒子到底长什么样呢？
What is its nature?
它的本质是什么？
We don't know.
我们不知道。
If we look really hard, we can see a blurry sphere of influence, but not the particles themselves.
如果我们仔细观察，或许能够看到一个模糊的“影响范围”（即某种力量或影响的覆盖区域），但却无法看到那些构成这种影响的微观粒子本身。
We just know they exist.
我们只是知道它们的存在而已。
But if that's the case, how can we do any science with them?
但如果真是这样的话，我们又该如何利用它们来进行科学研究呢？
We did what humans do and invented a new story: A mathematical fiction.
我们做了人类常会做的事——编造了一个新的故事：一个基于数学原理的虚构故事。
The story of the point particle.
点粒子的故事。