弦理论解析——现实的真正本质是什么？：英语精读讲义

What is the true nature of the universe?

宇宙的真正本质是什么？

To answer this question,

为了回答这个问题，

humans come up with stories to describe the world. 短語動詞

人类构思出各种故事来描述世界。

We test our stories and learn what to keep and what to throw away. 語法

我们测试这些故事，搞清楚该保留哪些、舍弃哪些。

But the more we learn, 語法

但是，我们了解得越多，

the more complicated and weird our stories become.

我们的故事就变得越复杂、越离奇。

Some of them so much so that it's really hard to know what they're actually about. 短語搭配

其中一些甚至复杂到让人很难搞懂它们到底在说什么。

Like string theory,

比如弦理论，

a famous, controversial,

这是一个著名的、备受争议的，

and often misunderstood story about the nature of everything.

并且经常被误解的，关于万物本质的故事。

Why did we come up with it,

我们为什么要提出它？

and is it correct or just an idea we should chuck out? 短語動詞

它是正确的，还是一个我们应该抛弃的想法？

To understand the true nature of reality,

为了理解现实的真正本质，

we looked at things up close and were amazed.

我们凑近观察事物，并感到惊叹。

Wondrous landscapes in the dust,

灰尘中奇妙的微观景象，

zoos of bizarre creatures,

千奇百怪的生物乐园，

complex protein robots.

复杂的蛋白质机器人。

All of them made from structures of molecules made up of countless even smaller things, 短語搭配

它们都是由分子结构组成的，而分子又由无数更小的东西组成，

atoms.

即原子。

We thought they were the final layer of reality

我们曾以为原子是现实的最后一层，

until we smashed them together really hard

直到我们用力将它们撞击在一起，

and discovered things that can't be divided anymore,

并发现了不能再分割的东西，

elementary particles.

基本粒子。

But now we had a problem.

但现在我们遇到了一个问题。

They're so small that we could no longer look at them. 語法

它们太小了，以至于我们无法再观察它们。

Think about it.

想想看。

What is seeing?

什么是“看”？

To see something,

要看到某个东西，

we need light,

我们需要光，

an electromagnetic wave.

一种电磁波。

This wave hits the surface of the thing and gets reflected back from it into your eye.

这种波击中物体的表面，然后反射到你的眼睛里。

The wave carries information from the object that your brain uses to create an image.

波携带着物体的信息，你的大脑利用这些信息生成图像。

So you can't see something without somehow interacting with it.

所以，如果不和物体发生某种相互作用，你就无法看到它。

Seeing is touching, 表達脈絡

看到就是接触，

an active process,

这是一个主动的过程，

not a passive one.

而非被动的。

This is not a problem with most things.

对于大多数事物来说，这不是问题。

But particles are very, very, very small.

但粒子非常、非常、非常小。

So small that the electromagnetic waves we use to see are too big to touch them. 語法

小到我们用来观察的电磁波都太大了，无法触碰到它们。

Visible light just passes over them.

可见光直接从它们上方穿过。

We can try to solve this by creating electromagnetic waves with more and much smaller wavelengths, 語法

我们可以尝试通过制造波长更短、更小的电磁波来解决这个问题，

but in quantum physics,

但在量子物理学中，

shorter wavelengths means more energy.

更短的波长意味着更多的能量。

So when we touch a particle with a wave that has a lot of energy,

所以，当我们用具有高能量的波去触碰一个粒子时，

it gets a kick. 用詞

它就会受到冲击。

By looking at a particle,

只要观察粒子，

we change it.

我们就会改变它。

In quantum physics,

在量子物理学中，

we cannot know where a particle is and where it's going with absolute precision.

我们无法绝对精确地知道一个粒子在哪里以及它要去哪里。

This fact is so important that it has a name,

这个事实非常重要，甚至有它专门的名字，

the Heisenberg uncertainty principle, 文化背景

海森堡不确定性原理，

the basis of all quantum physics.

它是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,

如果我们非常仔细地观察，

we can see a blurry sphere of influence,

我们可以看到一个模糊的势场，

but not the particles themselves.

但看不到粒子本身。

We just know they exist.

我们只知道它们存在。

But if that's the case, 短語搭配

但如果是这样的话，

how can we do any science with them?

我们怎么能对它们进行任何科学研究呢？

We did what humans do and invented a new story,

我们做了人类惯常做的事，编造了一个新故事，

a mathematical fiction. 習語

一个数学小说。

The story of the point particle.

点粒子的故事。

We decided that we would pretend that a particle is a point in space.

我们决定假装粒子是空间中的一个点。

Any electron is a point with a certain electric charge and a certain mass, 用詞

任何电子都是具有特定电荷和特定质量的一个点，

all indistinguishable from each other. 短語搭配

它们之间完全无法区分。

This way, 表達脈絡

这样一来，

physicists could define them and calculate all of their interactions.

物理学家就可以定义它们，并计算它们所有的相互作用。

This can be made precise in quantum field theory,

这在量子场论中可以被精确化，

and this solved a lot of problems.

并且解决了很多问题。

All of the standard model of particle physics is built on it, 短語動詞

粒子物理学的整个标准模型都是建立在它的基础上的，

and it predicts lots of things very well.

并且它非常准确地预测了许多事情。

Some quantum properties of the electron,

例如，电子的某些量子性质，

for example,

已经经过测试，

have been tested and are accurate up to 0.000000000002%. 短語搭配

其精确度达到了 0.000000000002%。

So while particles are not really points,

所以，虽然粒子并不是真正的点，

by treating them as if they were, 語法

但通过把它们当成点来对待，

we get a pretty good picture of the universe.

我们得到了关于宇宙的相当不错的图景。

Not only did this idea advance science, 語法

这个想法不仅推动了科学的发展，

it also led to a lot of real-world technology we use every day.

它还促成了我们每天使用的许多现实世界中的技术。

But there's a huge problem,

但这里有一个巨大的问题，

gravity.

引力。

In quantum mechanics,

在量子力学中，

all physical forces are carried by certain particles. 用詞

所有物理力都是由特定的粒子传递的。

But according to Einstein's general relativity, 短語搭配

但根据爱因斯坦的广义相对论，

gravity is not a force like the others in the universe.

引力与宇宙中的其他力不同。

If the universe is a play, 習語

如果宇宙是一出戏，

particles are the actors,

粒子是演员，

but gravity is the stage.

那么引力就是舞台。

To put it simply, 表達脈絡

简单来说，

gravity is a theory of geometry,

引力是一个关于几何的理论，

the geometry of space-time itself,

是时空本身的几何，

of distances which we need to describe with absolute precision.

那些我们需要用绝对精度来描述的距离的几何。

But since there is no way to precisely measure things in the quantum world,

但由于在量子世界中没有办法精确测量事物，

our story of gravity doesn't work with our story of quantum physics.

我们的引力故事与我们的量子物理学故事不相容。

When physicists tried to add gravity to the story by inventing a new particle,

当物理学家试图通过发明一种新粒子将引力加入这个故事时，

their mathematics broke down. 短語動詞

他们的数学崩溃了。

And this is a big problem.

这是一个大问题。

If we could marry gravity to quantum physics and the standard model, 習語

如果我们能把引力与量子物理学和标准模型结合起来，

we would have the theory of everything.

我们就能得到万物理论。

So very smart people came up with a new story.

于是非常聪明的人想出了一个新故事。

They asked,

他们问，

what is more complex than a point?

什么比点更复杂？

A line,

一条线，

or a string.

或者一根弦。

String theory was born.

弦理论由此诞生。

What makes string theory so elegant is that it describes many different elementary particles as different modes of vibration of the string. 語法

弦理论之所以如此优雅，是因为它将许多不同的基本粒子描述为弦的不同振动模式。

Just like a violin string vibrating differently can give you a lot of different notes, 表達脈絡

就像小提琴琴弦的不同振动可以产生许多不同的音符一样，

a string can give you different particles.

一根弦可以给你不同的粒子。

Most importantly,

最重要的是，

this includes gravity.

这包含了引力。

String theory promised to unify all fundamental forces of the universe.

弦理论承诺统一宇宙的所有基本力。

This caused enormous excitement and hype.

这引起了巨大的兴奋和炒作。

String theory quickly graduated to a possible theory of everything. 習語

弦理论很快晋升为可能的万物理论。

Unfortunately,

不幸的是，

string theory comes with a lot of strings attached. 習語

弦理论附带了很多限制条件。

Much of the maths involving a consistent string theory does not work in our universe

涉及一致的弦理论的许多数学在我们的宇宙中行不通，

with its three spatial and one temporal dimensions. 用詞

因为我们的宇宙有三个空间维度和一个时间维度。

String theory requires 10 dimensions to work out.

弦理论需要 10 个维度才能成立。

So string theorists did calculations in model universes

所以弦理论家在模型宇宙中进行计算，

and then try to get rid of the six additional dimensions and describe our own universe. 短語動詞

然后试图去掉那六个多余的维度，并描述我们自己的宇宙。

But so far, 短語搭配

但到目前为止，

nobody has succeeded,

还没有人成功，

and no prediction of string theory has been proven in an experiment. 語法

而且弦理论的任何预测都没有在实验中被证明。

So string theory did not reveal the nature of our universe.

所以弦理论并没有揭示我们宇宙的本质。

One could argue that in this case, 表達脈絡

有人可能会争辩说，在这种情况下，

string theory really isn't useful at all.

弦理论真的毫无用处。

Science is all about experiments and predictions.

科学全在于实验和预测。

If we can't do those,

如果我们不能做这些，

why should we bother with strings? 語氣意圖

我们为什么还要在弦上费心思呢？

It really is all about how we use it.

实际上，一切都取决于我们如何使用它。

Physics is based on maths.

物理学基于数学。

2 + 2 makes 4.

2 + 2 等于 4。

This is true no matter how you feel about it. 語法

无论你对此有什么感觉，这都是真的。

And the maths in string theory does work out. 語法

而且弦理论中的数学确实是成立的。

That's why string theory is still useful.

这就是为什么弦理论仍然有用。

Imagine that you want to build a cruise ship,

想象一下，你想建造一艘游轮，

but you only have blueprints for a small rowing boat.

但你只有一艘小划艇的蓝图。

There are plenty of differences,

它们有很多不同之处，

the engine,

引擎、

the materials,

材料、

the scale.

规模。

But both things are fundamentally the same,

但这两者在根本上是一样的，

things that float.

都是漂浮在水上的东西。

So by studying the rowing boat blueprints, 語法

所以，通过研究划艇的蓝图，

you might still learn something about how to build a cruise ship eventually.

你可能仍然能学到一些最终如何建造游轮的知识。

With string theory,

借助弦理论，

we can try to answer some questions about quantum gravity

我们可以尝试回答一些关于量子引力的问题，

that have been puzzling physicists for decades, 語法

这些问题几十年来一直困扰着物理学家，

such as how black holes work or the information paradox.

比如黑洞是如何运作的，或者信息悖论。

String theory may point us in the right direction. 習語

弦理论可能会为我们指明正确的方向。

When used in this spirit, 語法

当本着这种精神使用时，

string theory becomes a precious tool for theoretical physicists

弦理论成为了理论物理学家的宝贵工具，

and help them discover new aspects of the quantum world

并帮助他们发现了量子世界的新面向

and some beautiful mathematics.

以及一些优美的数学。

So maybe the story of string theory is not the theory of everything, 語法

所以也许弦理论的故事并不是万物理论，

but just like the story of the point particle,

但就像点粒子的故事一样，

it may be an extremely useful story.

它可能是一个极其有用的故事。

We don't yet know what the true nature of reality is,

我们还不知道现实的真正本质是什么，

but we'll keep coming up with stories to try and find out

但我们会继续想出新的故事去尝试弄清楚，

until one day,

直到有一天，

hopefully,

希望

we do know.

我们真的能知道。

This video was supported by the Swiss National Science Foundation

本视频由瑞士国家科学基金会赞助支持，

and realized with the scientific advice of Alessandro Sfondrini.

并由 Alessandro Sfondrini 提供科学建议。