call the Second Law of Thermodynamics.

被物理學家稱為熱力學第二定律。

This movement toward disorganization might lead you to think that organized structures

這種秩序崩壞的傾向可能讓你認為有組織的結構─

– like, say, living beings – would never spontaneously come into existence.

如生命，應該無法自行生成。

Of course entropy can go down in part of the universe -- you can trade a decrease in entropy

當然在宇宙的某部分，熵可能減少─你可以用該處

in one place (like cooling water so it crystallizes into ice) for an equal or larger increase

熵的下降(例如把一杯水凍成冰)換來其他地方相等或更多

in entropy somewhere else (like heating the back of your fridge).

的熵增加(例如從冰箱後面放出熱能)。

Order increases here, but only at the cost of decreasing order there.

這裡的秩序增加，只會換來那裡的混亂。

But we can still ask: why do intricate, complex structures come into being in the universe,

但我們還是要問：複雜的結構怎能在宇宙中出現，

if the overall tendency is toward increasing disorder?

若一切都將趨於無序？

The secret is that order and complexity are very different ideas.

秘訣在於熵(秩序)與複雜度是不同的概念。

Entropy measures how many different ways you can make an arrangement of small-scale particles

熵度量的是，微觀粒子在宏觀特性相同的前提下

that have the same large-scale properties: like, 37 degrees celsius, brown hair, good

能有幾種排列方式。例如：攝氏37度、棕色頭髮、

at soccer, and so on.

足球很強，等等。

[There are lots of different ways!].

在這些條件下有很多組合方式。

Complexity, on the other hand, is a measure of how hard it is to describe a set of large-scale

然而複雜度， 是說明要描述一件宏觀事物的特性有多難。

properties.

然而複雜度， 是說明要描述一件宏觀事物的特性有多難。

Simple systems are easy to describe; complex systems require a lot more information.

簡單的系統很容易描述，複雜的系統則需更多資訊。

For example, take a cup filled with half coffee and half milk.

好比說，杯子裡有一半咖啡和一半牛奶。

It starts off in a state with relatively low entropy – you could swap coffee molecules

初始狀態的熵相對較低：你可以隨意互換咖啡分子、

with each other, or milk molecules with each other, without changing things substantially.

或互換牛奶分子，而不會改變其根本性質。

But if you swapped coffee molecules with milk molecules that would be a noticeable change.

但你若把咖啡分子和牛奶分子對調就有差了。

It’s also a simple setup -- milk on top, coffee on the bottom.

該狀態也很簡單，牛奶在上、咖啡在下。

Now, as the milk and coffee begin to mix, entropy goes up – where they are mixed together,

此時牛奶和咖啡開始混合，熵便上升了：當兩者交融，

swapping some coffee molecules for milk molecules no longer makes much of a difference.

把一些咖啡分子和牛奶分子交換， 不會產生那麼大的差別。

But the system also becomes more complex - to describe what you see, you would have to specify

這個系統也變得複雜：要描述這種景象，你得精確

exactly how all of those tendrils of milk and coffee intricately swirl into each other.

描繪那些漩渦中的牛奶和咖啡分子是如何盤旋。

Continuing on, entropy keeps going up, until the milk and coffee are completely mixed together

接著熵繼續增加，直到咖啡和牛奶徹底混合

and swapping any molecules of coffee and milk with any others doesn’t really make any

無論如何調換分子都不會產生差異。

difference at all.

無論如何調換分子都不會產生差異。

That’s equilibrium, where there are a huge number of arrangements of the molecules that

這就叫均衡，分子有太多種排列方式

look essentially the same.

但看起來都沒兩樣。

But this highly-mixed equilibrium is once again simple: it’s just a homogenous mixture

但這種完全混合的均衡再次變得簡單：純粹是一杯

of coffee and milk; no more complicated fractal swirly stuff.

咖啡和牛奶的混合體，沒有任何碎形漩渦。

This general principle is borne out time and time again: while entropy increases, complexity

這種規律不斷重演：當熵增加，

initially grows, then decays.

複雜度先增加後下降。

Complexity can be a natural step along the path to increasing entropy.

複雜度可以是熵上升過程中的自然現象，

The best example is the universe itself.

最好的例子就是宇宙本身。

The early universe was very smooth and very dense: that’s low-entropy, and also extremely simple.

早期的宇宙非常均勻而稠密：熵很低，複雜度也很低。

The far future will be smooth again, but very dilute: that’s high-entropy, and again extremely simple.

早期的宇宙非常均勻而稠密：熵很低，複雜度也很低。

It’s now, in the medium-entropy middle, that things look complex.

遙遠的未來也很均勻但非常空洞：熵很高，

Stars and galaxies and veins of minerals in rock and swirling clouds and amino acids and

複雜度卻又很低。

proteins and human beings and cats – we’re at the exciting, beautiful stage of the coffee

而如今，熵介於中間，而事物顯得複雜。

mixing!

恆星、星系、岩石中的礦脈、翻騰的雲、胺基酸、

But just as with the coffee and milk, in the far distant future complexity will decrease

蛋白質、人、喵星人─我們正處於刺激而美麗的

again, and complicated stuff like us will at last be simplified out of existence.

咖啡混合時代！

Hey, Henry here, thanks for watching.

但一如咖啡與牛奶，在久遠的未來複雜度會再次下降，

This is the third video in a series about time and entropy made in collaboration with

複雜的事物，如我們，終將分解消逝。

physicist Sean Carroll.

安安我是Henry，感謝您的收看。

The series is supported with funding from Google’s Making and Science initiative,

本集是第三部關於時間和熵的影片， 與物理學家Sean Carroll合作。

which seeks to encourage more young people (and people of all ages) to learn about and

本集是第三部關於時間和熵的影片， 與物理學家Sean Carroll合作。

fall in love with science and the world around them, and the videos are based off of Sean’s

本系列由Google的Making & Science計畫支持贊助，

book “The Big Picture: On the Origins of Life, Meaning, and the Universe Itself,”

該計畫為鼓勵更多年輕人(也包含其他年齡)學習

which you can find online or in bookstores around the world.

並喜愛科學及周遭世界，本片是以Sean所著