dioxide.”

天體生物學家麥可‧羅素曾說： 「生命的意義在於氫化二氧化碳。」

Or as Nobel prize-winning physiologist Albert Szent-Györgyi put it, “life is nothing

或如諾貝爾獎得主阿爾伯特·聖捷爾吉所言：

but an electron looking for a place to rest.”

「生命純粹是電子想找一處休息。」

While these aphorisms might not capture the “meaning of life” that most of us look

雖然這些格言可能和我們所認為 「生命的目的」有所落差，

for, their point is that living organisms ultimately depend on and facilitate the universe’s

他們都指出生命倚賴並增強宇宙的終極趨勢：

tendency to increase entropy.

熵增定律。

That may seem counter-intuitive, since living beings are themselves highly organized, while

這似乎違反直覺，畢竟生物井然有序，

entropy is a measure of disorder.

熵卻是混亂程度的指標。

But as we know, complexity is not the same thing as order.

但我們知道，複雜度與秩序是兩回事。

Every organism, just by living and breathing, acts to increase the entropy of the universe.

任何生命，單是生存呼吸，便會增加宇宙的熵。

Think of a photon arriving from the Sun, packed with useful energy.

設想一個光子從太陽發出來，充滿可用的能量。

It can be captured by a plant or microorganism that uses photosynthesis to store that energy

它可能被植物或微生物捕捉，以光合作用將其能量

in the form of sugar.

儲存到醣類中。

But the sugar doesn’t contain quite as much useful energy as the original photon – some

然而醣類含有的可用能量，不及原先的光子─

of the energy ends up heating the plant and its environment.

有些能量被浪費在加熱植物及周遭環境。

An animal like us eats the sugar, and uses its energy to create molecules of ATP, adenosine

有隻動物，比方說我們吃下醣類， 用其能量合成ATP分子(三磷酸腺苷)。

triphosphate.

有隻動物，比方說我們吃下醣類， 用其能量合成ATP分子(三磷酸腺苷)。

ATP is like a little power-pack of energy that can be sent to a part of the body where

ATP有如微小的能量包，可以運送到身體需要的地方，

it might be helpful, but ATP doesn’t have quite as much useful energy as the sugar that

但ATP中可用的的能量又不及用來製造它的醣類─

went into making it – some of that useful energy got lost pushing around all the cell

某些能量被用來推動那些製造ATP的細胞機器。

machinery that makes the ATP.

某些能量被用來推動那些製造ATP的細胞機器。

The proteins in your muscles utilize the energy in ATP to contract, so that you can lift a

你肌肉細胞的蛋白質利用ATP的能量收縮，讓你可以

barbell or a slice of pizza.

舉起啞鈴或一片披薩。

But not all of the useful energy of the ATP goes into lifting the pizza – as before,

但ATP中的所有可用能量也不是都用來舉起披薩─

some of it is degraded into noise and heat.

老樣子，某些能量耗散成聲音和熱能。

Not only that, ATP’s useful energy can also be used to repair broken-down cells or organs,

此外，ATO含有的能量也能用以修理損壞的細胞或器官，

again becoming less useful in the process.

在這過程中依然會浪費掉一些能量。

The pattern here is obvious: every step along the way, the energy in that original photon

規則已經很明顯了，每個步驟中，光子原本的能量

is gradually degraded, entropy increases, and at the end all that’s left is an organized

逐漸衰退，熵逐漸上升，最後剩下的是保持有序

but slightly warmer plant and cell and muscle, plus some high-entropy infrared light that

且稍微升溫的植物、細胞、肌肉，還有一些高熵的

gets radiated out into the universe.

紅外線散失到茫茫宇宙中。

Energy transforms from useful to useless in the cause of keeping organisms like us alive.

能量從有用到沒用，乃是我等生命賴以生存的過程。

In fact, life itself might have arisen because of entropy.

事實上，生命的誕生可能也和熵有關。

The early Earth had pockets of low-entropy conditions full of useful energy, like warm

早期地球有些低熵環境，充滿可用能量，如

alkaline vents on the ocean floor.

溫暖的深海鹼性熱泉。

But there may have been no simple chemical reaction that could take advantage of that

但當時沒有簡單化學反應能從中擷取能量，

energy, use up its usefulness, and allow the entropy to increase.

發揮其功用並讓熵增加。

There were, however, more complicated chains of reactions that could do the job.

然而更複雜的化學反應鍊也許辦得到。

In just the right circumstances, an appropriate network of chemical reactions might find a

在偶然的機遇下，適當的化學反應過程可能

way to sustain itself by tapping into the useful energy in its environment.

找到方法，取得環境中的可用能源以維繫自身。

Some networks might have become embedded in molecular membranes, the precursors of cell

某些反應網可能被分子膜包圍，即細胞膜的前身，

walls, and broken away from their point of origin, becoming the first “living” organisms.

離開它的誕生之處，成為史上第一個「活的」生命體。

Maybe that's how life began: a complex combination of chemical reactions that figured out how

也許這就是生命起源的過程，一串複雜的化學反應，

to tap into otherwise unavailable useful energy.

找到獨一無二的方法利用可用的能量。

We can tell a similar story about why stars shine.

用類似的模式也可以解釋恆星的生成。

Hydrogen nuclei have a ton of useful, low-entropy nuclear energy to release -- if you can get

氫原子核充滿著低熵的核能等待釋放─只要你能把它們

them to fuse together into helium.

融合成氦。

But there’s a big barrier to getting that to happen – fusion is hard!

但其中有莫大的障礙─核融合非常困難！

And yet, the cores of stars do the job marvelously, so stars, like life, also survive because

此時恆星中心發揮了功能，於是恆星如同生命，其存在

of the increase of entropy throughout the universe.

起因於整個宇宙的熵之增長。

Our sun takes a low-entropy fuel source and converts it into higher entropy energy.

太陽把低熵燃料(氫原子核)轉化成熵較高的能量(光子)，

Life takes that higher-entropy energy as a fuel source and converts it into even higher-entropy

生命用這股能量作為動力， 將其轉化為更高熵的能量(紅外線)。

energy.

生命用這股能量作為動力， 將其轉化為更高熵的能量(紅外線)。

In a very real sense, the purpose of life is to continue the mission of the stars.

沒有錯，生命的目的在於延續恆星之任務。

Hey, Henry here, thanks for watching.

安安我是Henry，感謝收看。

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

本片是和物理學家Sean Carroll合作關於時間與熵

physicist Sean Carroll.

系列影片的第五集。

This final video is supported by Audible.com, a leading provider of audiobooks including

這最終回由Audible.com贊助播出，有聲書的領導品牌

fiction, non-fiction and periodicals.

包含故事、非故事和期刊。

The videos in this series are based off of Sean’s book “The Big Picture: On the Origins

本片基於Sean所著《The Big Picture: On the Origins of Life, Meaning, and the Universe Itself》，

of Life, Meaning, and the Universe Itself,” which is available, read by him, on Audible.

在Audible上由他親自朗讀。

You can listen to “The Big Picture” or another book of your choice – but really,

你可以聆聽《The Big Picture》或其他自選書籍─

check out “The Big Picture” – for free, with a free 30-day trial at Audible.com/minutephysics.

但非常推薦《The Big Picture》─免費，包括Audible.com/minutephysics提供的30天免費試用。

Again, that’s audible.com/minutephysics.

再說一次，Audible.com/minutephysics。