stood up in front of the Prussian Academy of Sciences in Berlin

百年前的此月，

to present a radical new theory of space, time and gravity:

36 歲的愛因斯坦

the general theory of relativity.

在柏林普魯士科學院前

General relativity is unquestionably Einstein's masterpiece,

發表有關時空與重力的 開創性理論：

a theory which reveals the workings of the universe at the grandest scales,

廣義相對論。

capturing in one beautiful line of algebra

這無疑是愛因斯坦的傑作，

everything from why apples fall from trees to the beginning of time and space.

揭露大尺度世界的運行法則，

1915 must have been an exciting year to be a physicist.

以一則優美的公式囊括一切，

Two new ideas were turning the subject on its head.

從為何蘋果會從樹上掉落

One was Einstein's theory of relativity,

到時空的起源。

the other was arguably even more revolutionary:

1915 年是令物理學家 興奮的一年，

quantum mechanics,

兩個嶄新的觀念 在物理界掀起革命。

a mind-meltingly strange yet stunningly successful new way

一是愛因斯坦的相對論，

of understanding the microworld, the world of atoms and particles.

另一個可說是 更革命性的量子力學。

Over the last century, these two ideas have utterly transformed

這是一個十分艱深 但有效的新方法，

our understanding of the universe.

讓我們理解 原子與粒子的小尺度世界。

It's thanks to relativity and quantum mechanics

上個世紀這兩個理論

that we've learned what the universe is made from,

完全顛覆我們對宇宙的認知。

how it began and how it continues to evolve.

多虧這兩個理論，

A hundred years on, we now find ourselves at another turning point in physics,

我們得以了解宇宙的 構成、形成與演進。

but what's at stake now is rather different.

百年後的今日，

The next few years may tell us whether we'll be able

我們站在物理學新的轉捩點，

to continue to increase our understanding of nature,

但情況與當時卻相當不同，

or whether maybe for the first time in the history of science,

未來幾年或許會告訴我們

we could be facing questions that we cannot answer,

是否可以進一步 加深對自然的認知，

not because we don't have the brains or technology,

抑或將是科學史上首次

but because the laws of physics themselves forbid it.

人類面臨無法解釋的問題，

This is the essential problem: the universe is far, far too interesting.

不是因為 缺乏足夠才智或科技，

Relativity and quantum mechanics appear to suggest

而是物理定律阻止了我們。

that the universe should be a boring place.

以下是主要問題：

It should be dark, lethal and lifeless.

宇宙實在太多采多姿，

But when we look around us, we see we live in a universe full of interesting stuff,

相對論與量子力學卻暗示：

full of stars, planets, trees, squirrels.

宇宙應該是很空寂的，

The question is, ultimately,

應該是黑暗、致命、無生氣的。

why does all this interesting stuff exist?

但當我們環顧四周，

Why is there something rather than nothing?

會發現我們處於一個充滿

This contradiction is the most pressing problem in fundamental physics,

恆星、行星、樹木與動物的新奇世界 。

and in the next few years, we may find out whether we'll ever be able to solve it.

最終，問題是：

At the heart of this problem are two numbers,

為什麼有這些有趣的萬物存在？

two extremely dangerous numbers.

為什麼是「有」， 而不是「虛無」？

These are properties of the universe that we can measure,

這個矛盾在基礎物理中 最迫切的問題。

and they're extremely dangerous

而在未來幾年，

because if they were different, even by a tiny bit,

我們也許會知道 是否有能力解決它。

then the universe as we know it would not exist.

在這問題的核心是兩個數字，

The first of these numbers is associated with the discovery that was made

兩個極端危險的數字，

a few kilometers from this hall, at CERN, home of this machine,

關乎兩項可以量測的宇宙特質。

the largest scientific device ever built by the human race,

它們非常危險，

the Large Hadron Collider.

因為假若它們之值 與現今有絲毫差異，

The LHC whizzes subatomic particles around a 27-kilometer ring,

那我們所熟知的宇宙 便不復存在。

getting them closer and closer to the speed of light

第一個數字與在 距此數公里之外的

before smashing them into each other inside gigantic particle detectors.

歐洲核子研究組織(CERN）裡，

On July 4, 2012, physicists at CERN announced to the world

人類所建造最大的科學儀器--

that they'd spotted a new fundamental particle

大強子對撞機（LHC） 所做的發現有關。

being created at the violent collisions at the LHC: the Higgs boson.

LHC 在長達 27 公里的環中，

Now, if you followed the news at the time,

加速次原子粒子 直至接近光速，

you'll have seen a lot of physicists getting very excited indeed,

再使它們在 巨型粒子探測器中對撞。

and you'd be forgiven for thinking

2012 年 7 月 4 日，

we get that way every time we discover a new particle.

CERN 的物理學家 向全世界宣告，

Well, that is kind of true,

探測到新的基本粒子。

but the Higgs boson is particularly special.

在 LHC 的一場 劇烈對撞中產生

We all got so excited because finding the Higgs

希格斯玻色子。

proves the existence of a cosmic energy field.

如果你當時 有關注這個消息，

Now, you may have trouble imagining an energy field,

你會發現許多 物理學家十分興奮。

but we've all experienced one.

而你也會覺得，

If you've ever held a magnet close to a piece of metal

每次物理學家 發現新粒子都是如此，

and felt a force pulling across that gap,

沒錯。

then you've felt the effect of a field.

但希格斯玻色子格外特別，

And the Higgs field is a little bit like a magnetic field,

我們如此興奮是因為 發現希格斯玻色子，

except it has a constant value everywhere.

意味著宇宙能量場的存在。

It's all around us right now.

你可能無法想像一個能量場，

We can't see it or touch it,

但我們都有這種經驗：

but if it wasn't there,

如果你拿一個磁鐵 靠近金屬片，

we would not exist.

會感覺到之間 有一股無形的拉力，

The Higgs field gives mass

那麼你就是感受到 場的效應。

to the fundamental particles that we're made from.

希格斯場有點類似磁場，

If it wasn't there, those particles would have no mass,

但它在任何地方都是常數，

and no atoms could form and there would be no us.

它就在我們四周，

But there is something deeply mysterious about the Higgs field.

我們無法看或感受它，

Relativity and quantum mechanics tell us that it has two natural settings,

但倘若它不存在，

a bit like a light switch.

我們便不存在。

It should either be off,

希格斯場給予構成 我們的基本粒子質量，

so that it has a zero value everywhere in space,

如果它不存在，

or it should be on so it has an absolutely enormous value.

這些粒子便沒有質量，

In both of these scenarios, atoms could not exist,

原子無法形成，

and therefore all the other interesting stuff

也就不會有你我。

that we see around us in the universe would not exist.

但關於希格斯場有個謎團，

In reality, the Higgs field is just slightly on,

相對論與量子力學說 它有兩種自然狀態。

not zero but 10,000 trillion times weaker than its fully on value,

有點像是電燈開關，

a bit like a light switch that's got stuck just before the off position.

不是關--

And this value is crucial.

也就是說它到處的值都是零，

If it were a tiny bit different,

就是開--

then there would be no physical structure in the universe.

也就是說它到處都是個巨大定值。

So this is the first of our dangerous numbers,

在這兩個情況下 原子都無法存在，

the strength of the Higgs field.

也因此這世上我們所見

Theorists have spent decades trying to understand

一切有趣事物將不存在。

why it has this very peculiarly fine-tuned number,

事實上

and they've come up with a number of possible explanations.

希格斯場是稍稍打開的，

They have sexy-sounding names like "supersymmetry"

不是零，而是 開的值的一萬兆分之一，

or "large extra dimensions."

有點像是卡在 「關」前面一點的電燈開關。

I'm not going to go into the details of these ideas now,

這個值十分重要，

but the key point is this:

若它與此值有絲毫不同，

if any of them explained this weirdly fine-tuned value of the Higgs field,

在宇宙中將 不會有任何物理結構，

then we should see new particles being created at the LHC

這就是第一個危險的數字，

along with the Higgs boson.

希格斯場的強度。

So far, though, we've not seen any sign of them.

理論學家花了 幾十年的時間嘗試理解，

But there's actually an even worse example

為何是如此詭異精微的數值？

of this kind of fine-tuning of a dangerous number,

他們提出許多可行的解釋，

and this time it comes from the other end of the scale,

它們有酷炫的名字如

from studying the universe at vast distances.

超對稱或巨大額外維度。

One of the most important consequences of Einstein's general theory of relativity

我不會討論這些想法的細節，

was the discovery that the universe began as a rapid expansion of space and time

但重點是：

13.8 billion years ago, the Big Bang.

若它們真的解釋 怪異的希格斯場強度。

Now, according to early versions of the Big Bang theory,

那麼在 LHC 中我們應會觀察到

the universe has been expanding ever since

新粒子伴隨 希格斯玻色子產生，

with gravity gradually putting the brakes on that expansion.

但至今為止我們一無所獲。

But in 1998, astronomers made the stunning discovery

然而還有關於這種

that the expansion of the universe is actually speeding up.

精細危險數字的更慘例子。

The universe is getting bigger and bigger faster and faster

這次它來自另一個極端尺度：

driven by a mysterious repulsive force called dark energy.

大尺度下的宇宙學。

Now, whenever you hear the word "dark" in physics,

愛因斯坦廣義相對論，

you should get very suspicious

最重要的結論之一是

because it probably means we don't know what we're talking about.

發現在 138 億年以前，

(Laughter)

時空急速膨脹而生成宇宙，

We don't know what dark energy is,

這就是大霹靂。

but the best idea is that it's the energy of empty space itself,

根據大霹靂學說的早期版本，

the energy of the vacuum.

宇宙一直在膨脹，

Now, if you use good old quantum mechanics to work out

而重力使其膨脹速逐漸減緩。

how strong dark energy should be,

但在 1998 年，

you get an absolutely astonishing result.

天文學家發現 一件驚人的事實：

You find that dark energy

宇宙正在加速膨脹！

should be 10 to the power of 120 times stronger

宇宙之所以加速擴張，

than the value we observe from astronomy.

乃是受一種稱為暗能量 的神祕斥力所驅使。

That's one with 120 zeroes after it.

在物理學 當你聽到「暗」時，

This is a number so mind-bogglingly huge

你要有警覺心，

that it's impossible to get your head around.

因為這很可能意味著

We often use the word "astronomical" when we're talking about big numbers.

我們不知道自己在說什麼。

Well, even that one won't do here.

（笑聲）

This number is bigger than any number in astronomy.

我們不知道什麼是暗能量，

It's a thousand trillion trillion trillion times bigger

但最好的解釋是： 它是空無空間的能量、

than the number of atoms in the entire universe.

真空的能量。

So that's a pretty bad prediction.

如果你用舊的量子力學

In fact, it's been called the worst prediction in physics,

計算暗能量的強度。

and this is more than just a theoretical curiosity.

你會得到驚人的結果，

If dark energy were anywhere near this strong,

你會發現它的值應該是

then the universe would have been torn apart,

我們在天文學觀察到的值，

stars and galaxies could not form, and we would not be here.

再乘以10 的 120 次方。

So this is the second of those dangerous numbers,

就是 1 後面加 120 個 0。

the strength of dark energy,

這個數字如此龐大，

and explaining it requires an even more fantastic level of fine-tuning

以至於你的腦袋會當機。

than we saw for the Higgs field.

我們常用「天文數字」 來描述巨大數字，

But unlike the Higgs field, this number has no known explanation.

但在這兒卻不管用，

The hope was that a complete combination

因為它比天文學裡 的任何數字還大。

of Einstein's general theory of relativity,

它是整個宇宙原子數量 的一千兆兆兆倍，

which is the theory of the universe at grand scales,

所以這是個很差勁的預估。

with quantum mechanics, the theory of the universe at small scales,

事實上它被稱為 物理史上最糟的預估。

might provide a solution.

而這不單是理論上的事，

Einstein himself spent most of his later years

若暗能量到處都是如此強，

on a futile search for a unified theory of physics,

宇宙早就被撕碎了，

and physicists have kept at it ever since.

星星與星系也不會形成，

One of the most promising candidates for a unified theory is string theory,

我們也不會存在。

and the essential idea is,

這就是第二個危險的數字：

if you could zoom in on the fundamental particles that make up our world,

暗能量強度。

you'd see actually that they're not particles at all,

解釋它需要比我們在 希格斯場見到的

but tiny vibrating strings of energy,

更加精細的微調。

with each frequency of vibration corresponding to a different particle,

但與希格斯場不同的是，

a bit like musical notes on a guitar string.

對於這個數字 沒有任何已知的解釋，

So it's a rather elegant, almost poetic way of looking at the world,

而希望繫於：

but it has one catastrophic problem.

愛因斯坦的相對論--

It turns out that string theory isn't one theory at all,

大尺度描述宇宙的理論

but a whole collection of theories.

與量子力學--

It's been estimated, in fact,

小尺度描述宇宙的理論，

that there are 10 to the 500 different versions of string theory.

兩者的大一統 可以提供解答，'

Each one would describe a different universe

愛因斯坦晚年大多時間致力於

with different laws of physics.

大一統論的尋找， 但並未成功。

Now, critics say this makes string theory unscientific.

而往後的物理學家也是如此。

You can't disprove the theory.

其中一個較有希望 的候選者是弦論，

But others actually turned this on its head

它的主要思想是：

and said, well, maybe this apparent failure

如果你能極近觀察 構成世界的基本粒子，

is string theory's greatest triumph.

你會發現它們根本不是粒子，

What if all of these 10 to the 500 different possible universes

而是細小振動的能量弦。

actually exist out there somewhere

不同的振動頻率 對應不同的粒子。

in some grand multiverse?

有點像是吉他弦的音階，

Suddenly we can understand

這是以極高雅 甚至如詩的方式

the weirdly fine-tuned values of these two dangerous numbers.

來看這個世界。

In most of the multiverse,

但它有個致命傷：

dark energy is so strong that the universe gets torn apart,

弦論根本不是一個理論，

or the Higgs field is so weak that no atoms can form.

而是許多理論的集合，

We live in one of the places in the multiverse

事實上估計約有

where the two numbers are just right.

十至五百個不同的弦論，

We live in a Goldilocks universe.

每一個都描述不同的宇宙

Now, this idea is extremely controversial, and it's easy to see why.

與不同的物理定律。

If we follow this line of thinking,

批評者表示這使弦論不科學，

then we will never be able to answer the question,

你無法證明它的對錯。

"Why is there something rather than nothing?"

但有人腦筋一轉說：

In most of the multiverse, there is nothing,

或許這顯見的失敗是

and we live in one of the few places

弦論最大的成功。

where the laws of physics allow there to be something.

若這十至五百個 理論描述的宇宙，

Even worse, we can't test the idea of the multiverse.

確實在多重宇宙的某處存在，

We can't access these other universes,

剎那間我們就可以解釋

so there's no way of knowing whether they're there or not.

那兩個怪異精細的危險數字。

So we're in an extremely frustrating position.

在多重宇宙大多地方，

That doesn't mean the multiverse doesn't exist.

暗能量太強以致宇宙會被撕裂，

There are other planets, other stars, other galaxies,

或希格斯場太弱以致原子無法形成。

so why not other universes?

我們在多重宇宙的一隅，

The problem is, it's unlikely we'll ever know for sure.

剛好這兩數字是恰當的。

Now, the idea of the multiverse has been around for a while,

我們住在 「金髮宇宙」（適當的宇宙）。

but in the last few years, we've started to get the first solid hints

這個想法十分具爭議性，

that this line of reasoning may get born out.

原因十分簡單，

Despite high hopes for the first run of the LHC,

如果我們順著這條思路，

what we were looking for there --

那我們遠永無法回答以下問題：

we were looking for new theories of physics:

為什麼是 「有」而不是「虛無」？

supersymmetry or large extra dimensions

在多重宇宙大多處什麼也沒有，

that could explain this weirdly fine-tuned value of the Higgs field.

我們住在其中一個少數地方，

But despite high hopes, the LHC revealed a barren subatomic wilderness

剛好物理定律允許存在物質。

populated only by a lonely Higgs boson.

更糟的是我們無法 檢驗多重宇宙的想法，

My experiment published paper after paper

我們無法去其他宇宙，

where we glumly had to conclude that we saw no signs of new physics.

所以無法得知它是否存在。

The stakes now could not be higher.

所以我們處於 一種令人氣餒的狀況。

This summer, the LHC began its second phase of operation

但那不代表 多重宇宙不存在，

with an energy almost double what we achieved in the first run.

既然有其他行星、恆星與星系，

What particle physicists are all desperately hoping for

為何其他宇宙不行？

are signs of new particles, micro black holes,