How we explore unanswered questions in physics | James Beacham

Translator: Leslie Gauthier Reviewer: Camille Martínez

譯者: Helen Chang 審譯者: JiYuan Zhang

There is something about physics

物理學中有件事情

that has been really bothering me since I was a little kid.

自幼時就一直非常困擾我。

And it's related to a question

近百年來科學家思索著這個問題

that scientists have been asking for almost 100 years,

with no answer.

但沒有答案。

How do the smallest things in nature,

自然界中最小的東西， 即量子世界的微粒子，如何與

the particles of the quantum world,

match up with the largest things in nature --

自然界中最大的東西，即星系裡 以重力連結的行星和恆星相對應呢？

planets and stars and galaxies held together by gravity?

As a kid, I would puzzle over questions just like this.

童年的我，為這樣的問題搜索枯腸。

I would fiddle around with microscopes and electromagnets,

我操作顯微鏡和電磁鐵，

and I would read about the forces of the small

我研讀微物質的力學

and about quantum mechanics

和量子力學，

and I would marvel at how well that description matched up

讚嘆其描述和我們的觀察 是如此的相應。

to our observation.

Then I would look at the stars,

我也觀看星星，

and I would read about how well we understand gravity,

閱讀我們所知的重力，

and I would think surely, there must be some elegant way

想當然耳，大和小的兩個系統 必然有種精美而優雅的相應方式。

that these two systems match up.

But there's not.

但可惜卻沒有。

And the books would say,

根據書本，

yeah, we understand a lot about these two realms separately,

我們很懂這兩個各別的系統，

but when we try to link them mathematically,

但是一旦嘗試以數學模式來連結，

everything breaks.

就完全行不通了。

And for 100 years,

百年來，

none of our ideas as to how to solve this basically physics disaster,

我們對於如何解決 這基本的物理問題一籌莫展，

has ever been supported by evidence.

沒有可以支持的證據。

And to little old me --

對於小老弟在下──

little, curious, skeptical James --

小小、好奇、不信服的詹姆斯──

this was a supremely unsatisfying answer.

這是絕對不可接受的。

So, I'm still a skeptical little kid.

今天的我，仍是個不易信服的小孩。

Flash-forward now to December of 2015,

時間快轉到 2015 年十二月，

when I found myself smack in the middle

我重拍額頭，

of the physics world being flipped on its head.

突然有個物理世界裡的靈光一閃。

It all started when we at CERN saw something intriguing in our data:

始自我們在歐洲核子研究組織 CERN 看到有趣的數據：

a hint of a new particle,

它們隱射一種新的粒子，

an inkling of a possibly extraordinary answer to this question.

暗示一個可能不同凡響的解答。

So I'm still a skeptical little kid, I think,

我仍是個不信服的小子，

but I'm also now a particle hunter.

現在也是個找尋粒子的人。

I am a physicist at CERN's Large Hadron Collider,

我是 CERN 的物理學家， 用「大型強子對撞機（LHC）」，

the largest science experiment ever mounted.

一具到目前為止所安裝過的 最大型的科學實驗儀器。

It's a 27-kilometer tunnel on the border of France and Switzerland

這是條在法國和瑞士邊界間的 二十七公里長的隧道，

buried 100 meters underground.

埋在一百公尺深的地下。

And in this tunnel,

隧道裡，

we use superconducting magnets colder than outer space

我們用比外太空更低溫的超導磁體

to accelerate protons to almost the speed of light

把質子加速到接近光速，

and slam them into each other millions of times per second,

使它們每秒彼此互相撞擊數百萬次，

collecting the debris of these collisions

收集碰撞的碎片，

to search for new, undiscovered fundamental particles.

搜索新的、尚未被發現的基本粒子。

Its design and construction took decades of work

其設計和施工費時幾十年，

by thousands of physicists from around the globe,

全球各地數以千計的 物理學家通力合作，

and in the summer of 2015,

在 2015 年夏天，

we had been working tirelessly to switch on the LHC

我們不眠不休地讓 LHC 開始運轉，

at the highest energy that humans have ever used in a collider experiment.

實驗用到人類前所未有的 最高撞擊能量。

Now, higher energy is important

高能量至關重要，對粒子而言，

because for particles, there is an equivalence

能量和質量轉換守恆，

between energy and particle mass,

and mass is just a number put there by nature.

質量只是個自然界擺在那兒的數字。

To discover new particles,

為要發現新的粒子，

we need to reach these bigger numbers.

我們必須耗費更多的能量。

And to do that, we have to build a bigger, higher energy collider,

因此，我們必須建造更大、 更耗能的對撞機；

and the biggest, highest energy collider in the world

而世界上最大的對撞機

is the Large Hadron Collider.

是 LHC。

And then, we collide protons quadrillions of times,

然後，我們碰撞質子 千萬億（10 的 24 次方）次

and we collect this data very slowly, over months and months.

我們經年累月慢慢地收集資料。

And then new particles might show up in our data as bumps --

或許新的粒子會以突起的形狀 呈現在資料的平滑線外──

slight deviations from what you expect,

稍微偏離預期值，

little clusters of data points that make a smooth line not so smooth.

小小群集的數據點， 使得平滑的線不再那麼地平滑。

For example, this bump,

例如，這個凸起，

after months of data-taking in 2012,

2012 年累月的數據採集後，

led to the discovery of the Higgs particle --

導致發現了「希格斯粒子」，

the Higgs boson --

或稱「希格斯玻色子」，

and to a Nobel Prize for the confirmation of its existence.

和因證明它存在而獲得的諾貝爾奬。

This jump up in energy in 2015

2015 年看到的能量凸起

represented the best chance that we as a species had ever had

代表人類發現新粒子的絕佳機會，

of discovering new particles --

new answers to these long-standing questions,

這些長期謎題的新解答，

because it was almost twice as much energy as we used

因它所耗的能量幾乎是 發現希格斯玻色子時耗能的兩倍。

when we discovered the Higgs boson.

Many of my colleagues had been working their entire careers for this moment,

我的許多同事 整個職涯都在追尋此刻，

and frankly, to little curious me,

坦率地說，對好奇的我而言，

this was the moment I'd been waiting for my entire life.

這是我一輩子等待的時刻。

So 2015 was go time.

2015 年是跳下去做， 不回頭的時刻。

So June 2015,

因此於 2015 年六月，

the LHC is switched back on.

LHC 又運轉了。

My colleagues and I held our breath and bit our fingernails,

同事和我屏息、緊張又興奮，

and then finally we saw the first proton collisions

終於看到質子以有史以來 最高的能量互撞。

at this highest energy ever.

Applause, champagne, celebration.

鼓掌，開香檳，慶祝。

This was a milestone for science,

這是科學的里程碑，

and we had no idea what we would find in this brand-new data.

我們不知道會在 這全新的數據裡找到什麼。

And then a few weeks later, we found a bump.

數週後，我們發現了凸起的數據。

It wasn't a very big bump,

凸起雖不算大，

but it was big enough to make you raise your eyebrow.

但已足以讓人訝異。

But on a scale of one to 10 for eyebrow raises,

從 1 到 10 的訝異程度，

if 10 indicates that you've discovered a new particle,

10 代表你已發現了新的粒子，

this eyebrow raise is about a four.

這是個程度大約 4 的訝異。

(Laughter)

（笑聲）

I spent hours, days, weeks in secret meetings,

我花了無數的時間秘密開會，

arguing with my colleagues over this little bump,

和同事辯論這個小凸起，

poking and prodding it with our most ruthless experimental sticks

努力在雞蛋裡挑骨頭，

to see if it would withstand scrutiny.

看它是否經得起最嚴厲的檢視。

But even after months of working feverishly --

即使在數月不眠不休地工作後──

sleeping in our offices and not going home,

不回家，而是睡在辦公室，

candy bars for dinner,

以糖果零嘴當晚餐，

coffee by the bucketful --

大桶大桶地喝咖啡──

physicists are machines for turning coffee into diagrams --

物理學家就是 把咖啡變成圖表的機器──

(Laughter)

（笑聲）

This little bump would not go away.

這個小凸起並未消失。

So after a few months,

幾個月後，

we presented our little bump to the world with a very clear message:

我們向世界展示了這個小凸起 和一個非常明確的信息：

this little bump is interesting but it's not definitive,

這個小凸起有趣，但是不明確，

so let's keep an eye on it as we take more data.

讓我們收集更多的數據 並持續關注它。

So we were trying to be extremely cool about it.

我們試圖非常冷靜地看待它。

And the world ran with it anyway.

儘管如此，世界隨它起舞。

The news loved it.

新聞界喜愛它。

People said it reminded them of the little bump

人們說它讓他們想起發現 希格斯玻色子路上的那個小凸起。

that was shown on the way toward the Higgs boson discovery.

Better than that, my theorist colleagues --

更棒的是，我的理論派同事們──

I love my theorist colleagues --

我喜歡我的理論派同事們──

my theorist colleagues wrote 500 papers about this little bump.

我的理論派同事們寫了五百篇 關於這個小凸起的文章。

(Laughter)

（笑聲）

The world of particle physics had been flipped on its head.

粒子物理學的世界已然翻轉。

But what was it about this particular bump

這個小凸起的什麼特點

that caused thousands of physicists to collectively lose their cool?

使得成千上萬的物理學家 熱血沸騰呢？

This little bump was unique.

這個小凸起獨一無二。

This little bump indicated

這個小凸起顯示

that we were seeing an unexpectedly large number of collisions

我們看到了意料之外的大量碰撞，

whose debris consisted of only two photons,

碰撞後只殘留兩個光子，

two particles of light.

兩個光粒子。

And that's rare.

這相當罕見。

Particle collisions are not like automobile collisions.

粒子碰撞不像汽車碰撞。

They have different rules.

碰撞的規則不同。

When two particles collide at almost the speed of light,

當兩個粒子以接近光速的速度互撞，

the quantum world takes over.

行為就由量子世界的規則所掌控。

And in the quantum world,

在量子世界中，

these two particles can briefly create a new particle

這兩個粒子能短暫地 創造一個新粒子，

that lives for a tiny fraction of a second

只瞬間存在，

before splitting into other particles that hit our detector.

頃刻後分裂成其他粒子， 並擊中我們的偵測器。

Imagine a car collision where the two cars vanish upon impact,

想像一下兩輛汽車互撞， 汽車在相撞的當下消失，

a bicycle appears in their place --

原地出現了一輛自行車──

(Laughter)

（笑聲）

And then that bicycle explodes into two skateboards,

那輛自行車緊接著爆炸， 變成兩個滑板，

which hit our detector.

撞到我們的偵測器。

(Laughter)

（笑聲）

Hopefully, not literally.

當然不是字面上的撞上，

They're very expensive.

偵測器可是很貴的啊。

Events where only two photons hit out detector are very rare.

僅僅兩個光子撞擊偵測器的 事件非常地罕見。

And because of the special quantum properties of photons,

由於光子具有量子的特性，

there's a very small number of possible new particles --

新粒子，也就是這些虛搆的自行車， 出現的機率相當罕見，

these mythical bicycles --

that can give birth to only two photons.

只產生兩個光子的新粒子非常罕見。

But one of these options is huge,

但是有一選項極可能發生，

and it has to do with that long-standing question

和一個長期存在的未解題有關，

that bothered me as a tiny little kid,

就是那個自幼就困擾我的重力問題。

about gravity.

Gravity may seem super strong to you,

或許你認為重力強而有力，

but it's actually crazily weak compared to the other forces of nature.

但是相較於自然界的其他力量， 它其實超弱的。

I can briefly beat gravity when I jump,

當我跳起時，能夠短暫地擺脫重力，

but I can't pick a proton out of my hand.

但我卻無法用手撿起一粒質子。

The strength of gravity compared to the other forces of nature?

相較於自然界的其他力量， 重力的強度如何呢？

It's 10 to the minus 39.

是 10 的負 39 次方。

That's a decimal with 39 zeros after it.

小數點之後跟著 39 個零。

Worse than that,

更糟的是，

all of the other known forces of nature are perfectly described

所有其他已知的自然界力量都可被 所謂的「標準模型」完美地描述。

by this thing we call the Standard Model,

which is our current best description of nature at its smallest scales,

那是我們目前描述自然界 最小尺度的最佳模型。

and quite frankly,

坦白說，

one of the most successful achievements of humankind --

那是人類最大的成就之一，

except for gravity, which is absent from the Standard Model.

重力標準模型不存在是唯一的例外。

It's crazy.

難以置信。

It's almost as though most of gravity has gone missing.

彷彿大部分的重力消失不見了。

We feel a little bit of it,

我們察覺到少許重力，

but where's the rest of it?

但其他的部分呢？

No one knows.

沒有人知道。

But one theoretical explanation proposes a wild solution.

但有個理論提供了瘋狂的解釋。

You and I --

你們和我──

even you in the back --

包括坐在後面的諸位──

we live in three dimensions of space.

我們生活在三度空間裡。

I hope that's a non-controversial statement.

希望這並無爭議。

(Laughter)

（笑聲）

All of the known particles also live in three dimensions of space.

所有已知的粒子也存在三度空間裡。

In fact, a particle is just another name

事實上，粒子只是別名，

for an excitation in a three-dimensional field;

是三度空間裡的激發；

a localized wobbling in space.

空間中的局部擺動。

More importantly, all the math that we use to describe all this stuff

更重要的是，我們用來描述 所有這些玩意的數學

assumes that there are only three dimensions of space.

全都假設只有三度空間。

But math is math, and we can play around with our math however we want.

但數學就是數學， 我們可以隨意擺弄數學。

And people have been playing around with extra dimensions of space

長久以來，人們一直悠遊於 更多維度的數學中，

for a very long time,

but it's always been an abstract mathematical concept.

但僅僅是個抽象的數學概念而已。

I mean, just look around you -- you at the back, look around --

我的意思是，看看你們的周圍── 坐在後面的諸位，請環顧四周──

there's clearly only three dimensions of space.

顯然只有三度空間。

But what if that's not true?

但，倘若事實並非如此呢？

What if the missing gravity is leaking into an extra-spatial dimension

如果消失的重力

流入了我們看不見的第四度空間呢？

that's invisible to you and I?

What if gravity is just as strong as the other forces

如果重力和其他的力量同樣有力，

if you were to view it in this extra-spatial dimension,

前提是增加維度來看待它;

and what you and I experience is a tiny slice of gravity

如果你我目前體驗到的重力 只是一小部分，

make it seem very weak?

所以才會看起來這麼弱呢？

If this were true,

假如這是真的，

we would have to expand our Standard Model of particles

我們就必須擴大粒子的標準模型， 包括其他的粒子，

to include an extra particle, a hyperdimensional particle of gravity,

「超維度的重力子」，

a special graviton that lives in extra-spatial dimensions.

存在另一度空間的重力子。

I see the looks on your faces.

我注意到你們的臉上的表情。

You should be asking me the question,

你們該問我：

「要怎樣去測試 這瘋狂而科幻的想法呢？

"How in the world are we going to test this crazy, science fiction idea,

stuck as we are in three dimensions?"

我們到底身處在三度空間裡啊！」

The way we always do,

老法子，

by slamming together two protons --

使兩個光子互撞──

(Laughter)

（笑聲）

Hard enough that the collision reverberates

碰撞反射到或許存在的 多度空間已經夠難了，

into any extra-spatial dimensions that might be there,

momentarily creating this hyperdimensional graviton

遑論頃刻間造出超維度的重力子，

that then snaps back into the three dimensions of the LHC

並且撞擊到三度空間的 LHC，

and spits off two photons,

又再分裂為兩個光子，

two particles of light.

兩個光粒子。

And this hypothetical, extra-dimensional graviton

這假設的超維度重力子，

is one of the only possible, hypothetical new particles

唯一可能假設的新粒子，

that has the special quantum properties

具有特別的量子空間特性，

that could give birth to our little, two-photon bump.

能產生我們這個小小的二光子凸起。

So, the possibility of explaining the mysteries of gravity

因此，解釋重力的奧秘，

and of discovering extra dimensions of space --

和發現另一度空間的可能性──

perhaps now you get a sense

現在或許你們稍稍明白了

as to why thousands of physics geeks collectively lost their cool

為何成千上萬的怪胎物理學家

會因小小的兩光子凸起而集體激動。

over our little, two-photon bump.

A discovery of this type would rewrite the textbooks.

這樣的發現將會改寫教科書。

But remember,

但請記住，

the message from us experimentalists

我們這些當時真正做實驗的人 傳達的訊息非常的清楚：

that actually were doing this work at the time,

was very clear:

我們需要更多的數據。

we need more data.

With more data,

有了更多的數據，

the little bump will either turn into a nice, crisp Nobel Prize --

這小小的凸起可能會成為 漂亮、清新的諾貝爾獎──

(Laughter)

（笑聲）

Or the extra data will fill in the space around the bump

或者增加的數據 會填滿凸起周邊的空間，

and turn it into a nice, smooth line.

使它成為平滑、順暢的線條。

So we took more data,

因此我們收取更多的數據，

and with five times the data, several months later,

又經過幾個月，增加了五倍的數據，

our little bump

我們的小凸起

turned into a smooth line.

成為平滑的線條。

The news reported on a "huge disappointment," on "faded hopes,"

新聞報導了「大失望」、 「消逝的希望」，

and on particle physicists "being sad."

以及粒子物理學家們很「悲傷」。

Given the tone of the coverage,

根據報導的語氣，

you'd think that we had decided to shut down the LHC and go home.

你們會認為我們已經決定 關掉 LHC，打道回府了。

(Laughter)

（笑聲）

But that's not what we did.

但我們沒那樣做。

But why not?

為什麼不呢？

I mean, if I didn't discover a particle -- and I didn't --

如果我沒發現新粒子── 而我的確沒發現──

if I didn't discover a particle, why am I here talking to you?

如果我沒發現新粒子， 怎麼還在這裡對你們演講？

Why didn't I just hang my head in shame

我怎麼沒羞恥地低著頭，

and go home?

躲回家裡去呢？

Particle physicists are explorers.

粒子物理學家是探索者。

And very much of what we do is cartography.

我們繪製很多的圖。

Let me put it this way: forget about the LHC for a second.

暫時先不管 LHC，讓我這樣來描述：

想像你是個太空探險家，

Imagine you are a space explorer arriving at a distant planet,

飛到一個遙遠的行星去搜索外星人。

searching for aliens.

What is your first task?

你的第一個任務是什麼？

To immediately orbit the planet, land, take a quick look around

是立刻環繞行星、掃視地面，

快速地巡視四周，

看有沒有大的、顯著的生命跡象，

for any big, obvious signs of life,

and report back to home base.

並回報基地。

That's the stage we're at now.

這正是我們眼前的階段。

We took a first look at the LHC

我們先快巡 LHC，

for any new, big, obvious-to-spot particles,

看有沒有大的、顯著的粒子，

and we can report that there are none.

我們回報沒有。

We saw a weird-looking alien bump on a distant mountain,

如同我們看到遠處 有個像是外星人的怪異凸起，

but once we got closer, we saw it was a rock.

一旦近看，發現只是個石頭。

But then what do we do? Do we just give up and fly away?

接下來呢？我們放棄、飛離嗎？

Absolutely not;

絕不；

we would be terrible scientists if we did.

若那樣做，我們就是差勁的科學家。

No, we spend the next couple of decades exploring,

不，我們用接下來的幾十年去探索，

mapping out the territory,

繪製地圖，

sifting through the sand with a fine instrument,

用精密儀器仔細地篩過沙土，

peeking under every stone,

翻遍每塊石頭，

drilling under the surface.

往地表下鑽。

New particles can either show up immediately

新粒子可能以 大而顯著的型態立即顯現，

as big, obvious-to-spot bumps,

or they can only reveal themselves after years of data taking.

或在收集許多數據後才會顯露出來。

Humanity has just begun its exploration at the LHC at this big high energy,

人類才剛開始以如此高的能量 在 LHC 上探索，

and we have much searching to do.

我們要找的可多著呢。

But what if, even after 10 or 20 years, we still find no new particles?

如果十或二十年後， 我們仍然沒發現新的粒子呢？

We build a bigger machine.

我們就建造更大的機器。

(Laughter)

（笑聲）

We search at higher energies.

我們用更高的能量去尋找。

We search at higher energies.

我們用更高的能量尋找。

Planning is already underway for a 100-kilometer tunnel

我們已在規畫一百公里長的隧道，

that will collide particles at 10 times the energy of the LHC.

它的撞擊力道是 LHC 的十倍。

We don't decide where nature places new particles.

大自然在何處擺放新粒子 不歸我們作主。

We only decide to keep exploring.

我們只能決定繼續探索。

But what if, even after a 100-kilometer tunnel

倘若用了一百公里的加速隧道，

or a 500-kilometer tunnel

五百公里的隧道，

or a 10,000-kilometer collider floating in space

或是一萬公里長，

漂浮在地球和月亮間 太空中的隧道，

between the Earth and the Moon,

we still find no new particles?

仍然找不到新粒子呢？

Then perhaps we're doing particle physics wrong.

也許我們粒子物理的理論是錯的。

(Laughter)

（笑聲）

Perhaps we need to rethink things.

也許我們需要重新思考。

Maybe we need more resources, technology, expertise

也許我們需要比現有 更多的資源、技術和專業知識。

than what we currently have.

We already use artificial intelligence and machine learning techniques

我們已經將人工智能和機器學習技術

in parts of the LHC,

用在部分的 LHC 中，

but imagine designing a particle physics experiment

想像把這種複雜的演算法 設計在粒子物理實驗裡，

using such sophisticated algorithms

that it could teach itself to discover a hyperdimensional graviton.

教會它自己去發現超維重力子。

But what if?

如果，

What if the ultimate question:

如果最終的問題：

What if even artificial intelligence can't help us answer our questions?

如果連人工智慧也不能 幫助我們回答問題呢？

如果這些數百年無解的問題，

What if these open questions, for centuries,

are destined to be unanswered for the foreseeable future?

注定在可預見的未來仍然無解呢？

What if the stuff that's bothered me since I was a little kid

如果那自幼就困擾我的問題

is destined to be unanswered in my lifetime?

注定在我的有生之年無解呢？

Then that ...

那……

will be even more fascinating.

就會更加地迷人了。

We will be forced to think in completely new ways.

我們將被迫以全新的方式思考。

We'll have to go back to our assumptions,

我們必須回到原先的假設，

and determine if there was a flaw somewhere.

確定是否某個環節有著缺陷。

And we'll need to encourage more people to join us in studying science

我們需要鼓勵更多人 加入我們學習科學，

since we need fresh eyes on these century-old problems.

因為我們需要清新的眼睛 研究這些百年的老問題。

I don't have the answers, and I'm still searching for them.

我仍在尋找，沒有答案。

But someone -- maybe she's in school right now,

但某人──也許正在就學，

maybe she's not even born yet --

也許尚未出生──

could eventually guide us to see physics in a completely new way,

最終能引導我們 以全新的方式去看待物理學，

and to point out that perhaps we're just asking the wrong questions.

指出來，我們可能只是問錯了問題。

Which would not be the end of physics,

這不會終結物理學，

but a novel beginning.

而會是個嶄新的開始。

Thank you.

謝謝。

(Applause)

（鼓掌）