字幕列表 影片播放
It's a little known secret
第二部 萬物之弦
But for more than half a century
優雅的宇宙
A dark cloud has been looming over modern science.
有個不為人所知的秘密
Here is the problem
半個多世紀以來
Our understanding of the universe
近代科學一直為烏雲籠罩
Is based on two separate theories.
問題就在於
One is Einstein's general theory of relativity—
我們對宇宙的認知
That's a way of understanding The biggest things in the universe,
是基於兩套不同的理論
Things like stars and galaxies.
一套是愛因斯坦的廣義相對論
But the littlest things in the universe,
描述的是宇宙間最龐大的物質
Atoms and subatomic particles,
像星球跟星系
Play by an entirely different set of rules called,
但宇宙中最微小的物質
"quantum mechanics."
原子跟亞原子粒子
These two sets of rules
則遵循另一種截然不同的定律
Are each incredibly accurate in their own domain
那就是"量子力學"
But whenever we try to combine them,
這兩種定律
To solve some of the deepest mysteries in the universe,
在各自的領域都準確無疑
Disaster strikes.
但一旦嘗試將其合二為一
Take the beginning of the universe, the "big bang."
去探索宇宙的終極奧秘時
At that instant a tiny nugget erupted violently.
災難降臨了
Over the next 14 billion years the universe expanded And cooled
以宇宙誕生之初 也就是"大爆炸"為例
into the stars, Galaxies and planets we see today.
在那一刻 極小的一點猛烈地爆發
But if we run the cosmic film in reverse,
經過140億年 宇宙不斷膨脹 冷卻
Everything that's now rushing apart comes back together
形成了現在所見的恆星 星系和行星
So the universe gets smaller, hotter and denser
但如果我們將宇宙誕生膠片倒轉
as we head back to the beginning of time.
讓所有分裂的物質再度聚合
As we reach the big bang,
宇宙將一直變小 變熱 密度變大
When the universe was both enormously heavy And incredibly tiny
我們將回到時間誕生之初
our projector jams.
抵達大爆炸那一刻時
Our two laws of physics, when combined, break down.
宇宙的質量無窮大而體積無窮小
But what if we could unite quantum mechanics
放映機將停滯於此
And general relativity
一旦這兩套物理定律在此相逢 便會決裂
And see the cosmic film in its entirety?
可要是我們能將量子力學
A new set of ideas called "string theory"
跟廣義相對論成功合併
May be able to do that.
再整體來看宇宙膠片會如何呢
And if it's right,
一種叫做"弦理論"的全新學說
It would be one of the biggest blockbusters In the history of science.
或許能達到目的
Someday, string theory may be able to explain all of nature
如果成功
From the tiniest bits of matter
將是科學史上最轟動事件之一
To the farthest reaches of the cosmos,
日後 弦理論或許能解釋自然界中的一切
Using just one ingredient, tiny vibrating strands of energy
從物質最微小的部分
called strings.
到茫茫宇宙最遙遠的地方
But why do we have to rewrite the laws of physics to accomplish this?
只用一種元素 微小振搗的能量
Why does it matter if the two laws That we have are incompatible?
叫作弦
Well, you can think of it like this.
為何我們要為此改寫物理學定律
Imagine you lived in a city ruled not
兩套定律互不相容有何要緊
By one set of traffic laws,
可以這樣試想
But by two separate sets of laws that conflicted with each other.
假設你住的城市
As you can see it would be pretty confusing.
不是被一種交通規則支配
To understand this place, You'd need to find a way
而是遵循兩套互相矛盾的規則
To put those two conflicting sets of laws together
你就會看到 情形會多混亂
Into one all-encompassing set that makes sense.
為瞭解宇宙 必須找到一種辦法
We work on the assumption that there is a theory out there,
將兩套矛盾的定律
And it's our job,
歸納為一套具有普適性的定律
If we're sufficiently smart and sufficiently industrious,
我們在努力證實存在這樣一套理論
To figure out what it is.
這就是我們的工作
We don't have a guarantee—
如果我們足夠聰明和勤奮
It isn't written in the stars that we're going to succeed
就能找到它
But in the end
我們不能保證
We hope we will have a single theory
成功是板上釘釘的事
That governs everything.
但說到底
But before we can find that theory,
我們希望能找到唯一的一套理論
We need to take a fantastic journey
適用於萬事萬物
To see why the two sets of laws We have
在找到那種理論之前
conflict with each other.
我們要先來一次奇幻旅程
And the first stop on this strange trip
看看為何現有的兩套定律
Is the realm of very large objects.
會互相衝突
To describe the universe on large scales
奇妙旅程的第一站
We use one set of laws,Einstein's general theory of relativity,
是龐然大物的國度
And that's a theory of how gravity works.
從宏觀角度描述宇宙時
General relativity pictures space as sort of like a trampoline
我們會用愛因斯坦的廣義相對論
A smooth fabric
它描述了引力是如何運作的
that heavy objects like stars and planets can warp and stretch.
廣義相對論描繪的宇宙像一張蹦床
Now, according to the theory,
一片光滑的結構
These warps and curves create what we feel as gravity.
重物如恆星和行星可以扭曲和擴張
That is,The gravitational pull that keeps the earth In orbit around the sun
根據這套理論
Is really nothing more than our planet Following the curves and contours
這些空間的扭曲讓我們感覺到了所謂的引力
that the sun creates in the spatial fabric.
就是說 保持地球在繞日軌道運行的引力
But the smooth, Gently curving image of space
只是地球在太陽製造的扭曲和波紋
predicted By the laws of general relativity
形成的特殊空間結構上的運動而已
is not the whole story.
但廣義相對論裡預言的
To understand the universe on extremely small scales,
平滑而起伏有致的空間
We have to use our other set of laws, quantum mechanics.
並不是宇宙的全部
And as we'll see,
要以極微觀的角度理解宇宙
Quantum mechanics paints a picture of space
我們得用上另一套定律 量子力學
So drastically different from general relativity
如我們即將所見
That you'd think they were describing
量子力學描繪的宇宙畫卷
two completely separate universes.
與廣義相對論的大不相同
To see the conflict between general relativity
甚至被認為二者描繪的是
And quantum mechanics
兩個完全不同的宇宙
We need to shrink way, way, way down in size.
要瞭解廣義相對論
And as we leave the world of large objects behind
與量子力學之間的矛盾
And approach the microscopic realm,
我們要變得 很小很小
The familiar picture of space In which everything behaves predictably
在我們離開龐然大物的世界
Begins to be replaced by a world
來到微觀粒子領域時
With a structure that is far less certain.
那幅萬物皆可預知的熟悉宇宙圖畫
And if we keep shrinking,
將逐漸被一個
Getting billions and billion of times
結構極不確定的世界取代
Smaller than even the tiniest bits of matter—
如果我們繼續縮小
Atoms and the tiny particles inside of them—
變得比最小的物質
The laws of the very small, quantum mechanics,
原子和原子中的微觀粒子
Say that the fabric of space becomes bumpy and chaotic.
還小上幾十億倍
Eventually we reach a world
描述微觀世界的量子力學表示
So turbulent that it defies common sense.
這時空間結構將變得波動而混亂
Down here,
最終我們來到了這個
Space and time are so twisted and distorted
喧囂而又違背常理的世界
That the conventional ideas of left and right, up and down,
在這裡
Even before and after, break down.
時間跟空間被扭曲變形
There's no way to tell for certain that I'm here,
傳統概念中的 左右 上下
Or here or both places at once.
甚至是時間的前後 都不復存在
Or maybe I arrived here before I arrived here.
這個世界裡 無法確定我是在這裡
In the quantum world you just can't pin everything down.
在這裡 還是同時處於兩個地方
It's an inherently wild and frenetic place.
又或者我來這裡之前 已經到了這裡
The laws in the quantum world
在量子的世界裡 沒什麼是確知無疑的
Are very different from the laws that we are used to.
這是個放蕩不羈 難以捉摸的地方
And is that surprising?
量子世界的定律
Why should the world of the very small, at an atomic level,
與我們習慣的定律截然不同
Why should that world obey the same kind of rules and laws
是不是非常令人驚訝
that we are used to in our world, With apples and oranges
為何原子層面的超微觀世界
And walking around on the street?
卻同樣遵守著
Why would that world behave the same way?
這個我們習慣的 有蘋果橙子
The fluctuating jittery picture of space and time predicted
還有人在街上走的世界的規則呢
By quantum mechanics
為何那個世界與我們的世界表現相同
is in direct conflict With the smooth, orderly,
這個時間跟空間劇烈動盪
Geometric model of space and time
由量子力學預言的世界
described by general relativity.
與那個平穩的 有條理的
But we think that everything,
廣義相對論描繪的幾何時空模型
From the frantic dance of subatomic particles
格格不入
To the majestic swirl of galaxies,
但我們認為 宇宙萬物
Should be explained by just one grand physical principle,
從亞原子粒子的瘋狂躍動
One master equation.
到星系的瑰麗漩渦
If we can find that equation,
應該由一套普適的物理學定律解釋
How the universe really works at every time and place
由一個主方程描述
Will at last be revealed.
若我們能找出這個方程
You see,
宇宙在何時何地如何運行的奧秘
What we need is a theory
終將揭曉
That can cope with the very tiny and the very massive,
你知道了
One that embraces both quantum mechanics and general relativity,
我們需要的是一套
And never breaks down, ever.
能在微觀和宏觀通用的理論
For physicists,
一套包含了量子力學和廣義相對論
Finding a theory that unites general relativity
永不崩潰的理論
And quantum mechanics is the holy grail,
對物理學家來說
Because that framework would give us a single mathematical theory
這套合併廣義相對論
That describes all the forces that rule our universe.
和量子力學的理論就像聖盃
General relativity describes
因為這套體系能帶來一套數學理論
The most familiar of those gravity.
可以描述所有規範宇宙的作用力
The quantum mechanics describes three other forces.
廣義相對論描述的是
The strong nuclear force
最為熟悉的作用力 重力
That's responsible for gluing protons and neutrons together inside of atoms;
量子力學則描述另外三種作用力
Electromagnetism,
強核力
which produces light, Electricity and magnetic attraction;
能使質子和中子在原子內結合
And the nuclear forces.
電磁力
That's the force responsible for radioactive decay.
能產生光 電 和磁吸引
Every event in the universe
還有核力
From the splitting of a atom, to the birth of a star
能導致輻射衰變
Is nothing more than these four forces into acting with manner
宇宙中的所有現象
Albert Einstein spent the last 30 years Of his life
從原子的分裂 到恆星的誕生
searching For a way to describe the forces Of nature
都不外乎是這幾種力的相互作用
in a single theory,
阿爾伯特·愛因斯坦 用他最後30年
And now string theory may fulfill
尋找能將自然界的所有作用力
His dream of unification.
用單一理論描述的方法
For centuries,
現在 弦理論也許能夠實現
Scientists have pictured the fundamental ingredients of nature
他理論大統一的夢想
atoms and the smaller particles inside of them
幾個世紀以來
As tiny balls or points.
科學家們把自然界的最基本元素
But string theory proclaims
原子和原子內的微觀粒子
That at the heart of every bit of matter
描繪為是小球體 或小點
is a tiny, Vibrating strand of energy called a string.
但弦理論宣告
And a new breed of scientist believes
一切物質的核心
These miniscule strings
都是微小振動的能量物質 叫做弦
Are the key to uniting the world of the large
新一代的科學家相信