Gabriela González: How LIGO discovered gravitational waves (with English subtitles) | TED

譯者: Candy Chow 審譯者: Helen Chang

A little over 100 years ago, in 1915,

大約一百多年前，在 1915 年，

Einstein published his theory of general relativity,

愛因斯坦發表了他的廣義相對論，

which is sort of a strange name,

這個理論命名有點奇怪，

but it's a theory that explains gravity.

但它的說明對象是重力。

It states that mass -- all matter, the planets -- attracts mass,

這個理論指出質量── 所有物質和星球──會互相吸引，

not because of an instantaneous force, as Newton claimed,

並非基於牛頓所提出的瞬時力，

but because all matter -- all of us, all the planets --

而是因為所有物質， 包括我們人類和所有星球，

wrinkles the flexible fabric of space-time.

使富彈性的時空結構出現了皺摺。

Space-time is this thing in which we live and that connects us all.

我們活在時空中， 時空聯繫我們所有人，

It's like when we lie down on a mattress and distort its contour.

情況好比我們躺在牀墊上， 使其形狀發生改變。

The masses move -- again, not according to Newton's laws,

我重申，質量移動 並非基於牛頓定律，

but because they see this space-time curvature

而是基於時空曲率，

and follow the little curves,

物質跟隨那些微弱的曲線移動，

just like when our bedmate nestles up to us

就好像牀墊凹了下去，

because of the mattress curvature.

使枕邊人向我們靠攏一樣。

(Laughter)

（笑聲）

A year later, in 1916,

一年後，在 1916 年，

Einstein derived from his theory

愛因斯坦從自己的理論

that gravitational waves existed,

推論出重力波的存在，

and that these waves were produced when masses move,

重力波在質量移動時產生，

like, for example, when two stars revolve around one another

比如當兩個星體互繞著對方轉動，

and create folds in space-time which carry energy from the system,

在時空造成帶有系統能量的摺皺，

and the stars move toward each other.

星體便互相靠近。

不過，他預計

However, he also estimated

that these effects were so minute,

其作用太微小，

that it would never be possible to measure them.

不大可能加以測量。

I'm going to tell you the story of how,

但我想告訴你

with the work of hundreds of scientists working in many countries

上百名在眾多國家工作的科學家

over the course of many decades,

是怎樣埋頭苦幹數十載，

just recently, in 2015,

終於在最近 2015 年，

we discovered those gravitational waves for the first time.

首次觀測到重力波。

It's a rather long story.

這是個漫長的故事，

It started 1.3 billion years ago.

一切從 13 億年前開始。

A long, long time ago,

很久很久以前，

in a galaxy far, far away --

在一個遙遠的星系，

(Laughter)

（笑聲）

two black holes were revolving around one another --

兩個黑洞互繞著對方轉動，

"dancing the tango," I like to say.

我會說它們就好像在「跳探戈」。

It started slowly,

剛開始速度很慢，

but as they emitted gravitational waves,

但隨著它們釋放重力波，

they grew closer together, accelerating in speed,

它們加速接近對方，

until, when they were revolving at almost the speed of light,

直至彼此都以光速轉動，

they fused into a single black hole

最終融合成一個黑洞，

that had 60 times the mass of the Sun,

它的質量是太陽的 60 倍，

but compressed into the space of 360 kilometers.

但給壓縮成 360 公里的空間，

That's the size of the state of Louisiana,

正是我所定居的 路易斯安那州的面積。

where I live.

This incredible effect produced gravitational waves

這個奇妙的作用產生了重力波，

that carried the news of this cosmic hug to the rest of the universe.

把黑洞融合的消息傳開去。

It took us a long time to figure out the effects of these gravitational waves,

我們花了很長時間才發現重力波，

because the way we measure them is by looking for effects in distances.

因為我們須找出距離的變化 才能測量重力波。

We want to measure longitudes, distances.

我們想要量度經度、距離。

When these gravitational waves passed by Earth,

當重力波經過地球，

which was in 2015,

時為 2015 年，

they produced changes in all distances --

它們改變了所有距離，

the distances between all of you, the distances between you and me,

包括你們所有人之間的距離， 你和我之間的距離，

our heights --

還有我們的高度，

every one of us stretched and shrank a tiny bit.

我們每個人都伸長又縮小了少許。

The prediction is that the effect is proportional to the distance.

科學家預測其變化與距離成正比。

But it's very small:

但變化很小，

even for distances much greater than my slight height,

即使是比我那細微的身高 變化大許多的距離，

the effect is infinitesimal.

其變化也是極微小的。

For example, the distance between the Earth and the Sun

假如地球和太陽之間的距離

changed by one atomic diameter.

僅改變了一原子直徑，

How can that be measured?

我們可以測量到這個變化嗎？

How could we measure it?

我們可以怎樣進行測量呢？

Fifty years ago,

50 年前，

some visionary physicists at Caltech and MIT --

加州理工學院和麻省理工學院 一些有遠見的物理學家，

Kip Thorne, Ron Drever, Rai Weiss --

例如：基普·索恩、 朗納·德瑞福、萊納·魏斯，

thought they could precisely measure distances

他們認為可以利用雷射

using lasers that measured distances between mirrors

量度公里以外的鏡子間的距離，

kilometers apart.

從而精確地測量距離。

It took many years, a lot of work and many scientists

為了發展這項科技和意念，

to develop the technology and develop the ideas.

科學家耗費了大量時間、人力和物力。

And 20 years later,

20 年後，

almost 30 years ago,

即大約 30 年前，

they started to build two gravitational wave detectors, two interferometers,

他們開始在美國建造兩座干涉儀，

in the United States.

它們是重力波探測儀器。

Each one is four kilometers long;

干涉儀每座長四公里；

one is in Livingston, Louisiana,

一座位於路易斯安那州利文斯頓，

in the middle of a beautiful forest,

在美麗的森林中央，

and the other is in Hanford, Washington,

另一座位於華盛頓漢福德，

in the middle of the desert.

在沙漠之中。

The interferometers have lasers

干涉儀備有雷射，

that travel from the center through four kilometers in-vacuum,

可從中心發送，

雷射通過四公里的真空距離後，

are reflected in mirrors and then they return.

給鏡子反射回原點。

We measure the difference in the distances

我們會計算兩臂所測量的距離的差。

between this arm and this arm.

These detectors are very, very, very sensitive;

這些探測儀非常，非常靈敏，

they're the most precise instruments in the world.

是世上最精密的儀器。

Why did we make two?

為什麼要有兩座？

It's because the signals that we want to measure come from space,

那是因為我們想要測量 來自太空的訊號，

but the mirrors are moving all the time,

而鏡子總是在移動，

so in order to distinguish the gravitational wave effects --

為了識別重力波的作用──

which are astrophysical effects and should show up on the two detectors --

重力波是天體物理學的作用，

會在兩座探測儀上顯現出來──

we can distinguish them from the local effects,

我們可以把重力波從分開出現的 局部作用中區分出來，

which appear separately, either on one or the other.

那些效果將在其中一座干涉臂可見。

In September of 2015,

在 2015 年九月，

we were finishing installing the second-generation technology

我們正在完成在探測儀上

裝置第二代技術的工作，

in the detectors,

and we still weren't at the optimal sensitivity that we wanted --

我們仍未取得期望的最佳靈敏度──

we're still not, even now, two years later --

即使兩年後的今天 仍未達至最佳效果──

but we wanted to gather data.

但我們希望收集數據。

We didn't think we'd see anything,

我們認為將不會有什麼發現，

but we were getting ready to start collecting a few months' worth of data.

但已準備要收集數個月份量的數據。

And then nature surprised us.

然後，大自然給我們送上驚喜。

On September 14, 2015,

在 2015 年 9 月 14 日，

we saw, in both detectors,

我們在兩座探測儀

a gravitational wave.

都發現到重力波。

In both detectors, we saw a signal

在兩座探測儀，

with cycles that increased in amplitude and frequency

我們都看見了一個訊號，

振幅和頻率周期性上升然後下跌。

and then go back down.

And they were the same in both detectors.

而且兩座儀器 探測到的訊號都是一樣。

They were gravitational waves.

它們是重力波。

And not only that -- in decoding this type of wave,

分析這種波動不但讓我們得出結論：

we were able to deduce that they came from black holes

它們是在超過十億年前，

fusing together to make one,

多個黑洞合而為一時造成的，

more than a billion years ago.

And that was --

而且那是……

(Applause)

(掌聲)

that was fantastic.

那是非常美妙。

At first, we couldn't believe it.

最初，我們無法相信這是事實，

We didn't imagine this would happen until much later;

我們沒想像過會發生 這樣的事情，直至後來；

it was a surprise for all of us.

對我們來說，這是一個驚喜。

It took us months to convince ourselves that it was true,

我們花了數個月時間說服自己，

because we didn't want to leave any room for error.

因為我們不希望有任何出錯的地方。

But it was true, and to clear up any doubt

然而，那是真的，釋除疑惑後，

that the detectors really could measure these things,

探測儀真的能測量那些能量，

in December of that same year,

同年 12 月，

we measured another gravitational wave,

我們測量到另一重力波，

smaller than the first one.

比首次探測所得的波動小。

The first gravitational wave produced a difference in the distance

首次探測到的重力波 產生的距離相差為

of four-thousandths of a proton

每四公里四千分之一質子。

over four kilometers.

沒錯，第二次探測所得較為微小，

Yes, the second detection was smaller,

but still very convincing by our standards.

但按我們的標準來說， 結果仍是可信的。

Despite the fact that these are space-time waves and not sound waves,

雖然這些是時空波動，而非聲波，

we like to put them into loudspeakers and listen to them.

但我們喜歡用擴音器 來傾聽這些波動，

We call this "the music of the universe."

並稱之為「宇宙的音樂」。

I'd like you to listen to the first two notes of that music.

我希望你們也來聽聽這支音樂的首兩個音符。

(Chirping sound)

（鳴聲）

(Chirping sound)

（鳴聲）

The second, shorter sound was the last fraction of a second

第二個較為短促的聲音是

在一秒的最終的兩個黑洞，

of the two black holes which,

in that fraction of a second, emitted vast amounts of energy --

在那一瞬間，它們釋出巨大能量，

so much energy, it was like three Suns converting into energy,

能量之高好比 把三個太陽轉換成能量，

following that famous formula,

遵從那道有名的方程式：

E = mc2.

E = mc2.

Remember that one?

你還記得嗎？

We love this music so much we actually dance to it.

我們很喜歡這音樂，事實上還跳舞。

I'm going to have you listen again.

我將讓你再聽一遍。

(Chirping sound)

（嗚聲）

(Chirping sound)

（嗚聲）

It's the music of the universe!

這是宇宙的音樂！

(Applause)

（掌聲）

People frequently ask me now:

現在人們經常問我：

"What can gravitational waves be used for?

「重力波可以用來做什麼？」

And now that you've discovered them, what else is there left to do?"

「你現在已經發現了重力波， 還剩下什麼要做？」

What can gravitational waves be used for?

重力波可以用來做什麼？

When they asked Borges, "What is the purpose of poetry?"

人們問波赫士：「詩歌有何作用？」

he, in turn, answered,

他接著回答：

"What's the purpose of dawn?

「黎明有何作用？

What's the purpose of caresses?

愛撫有何作用？

What's the purpose of the smell of coffee?"

咖啡有何作用？」

He answered,

他回答：

"The purpose of poetry is pleasure; it's for emotion, it's for living."

「詩歌的作用是帶來愉悅；

為情感而存在，為生活而存在。」

And understanding the universe,

而去理解宇宙的慾望，

this human curiosity for knowing how everything works,

這種人類對萬物如何運作的好奇心

is similar.

是很相像的。

Since time immemorial, humanity -- all of us, everyone, as kids --

自古以來，人類──

當我們所有人 每個人還是孩子時──

when we look up at the sky for the first time and see the stars,

首次仰望天空，看見星星，

we wonder,

我們好奇：

"What are stars?"

「星星是什麼來的？」

That curiosity is what makes us human.

那種好奇心是人的特性，

And that's what we do with science.

也是我們發展科學的原因。

We like to say that gravitational waves now have a purpose,

我們會說重力波現在有用途了，

because we're opening up a new way to explore the universe.

因為我們開拓了探索宇宙的新方式。

Until now, we were able to see the light of the stars

之前我們能夠使用電磁波

via electromagnetic waves.

來觀測星光，

Now we can listen to the sound of the universe,

現在，我們能夠聽到宇宙的聲音，

even of things that don't emit light, like gravitational waves.

即使那些東西並不會放光，

比如像重力波。

(Applause)

（掌聲）

Thank you.

謝謝。

(Applause)

（掌聲）

But are they useful?

但它們實用嗎？

Can't we derive any technology from gravitational waves?

我們不能用重力波開發任何科技嗎？

Yes, probably.

能夠的，

But it will probably take a lot of time.

但需要很長時間。

We've developed the technology to detect them,

我們已經發展了技術去探測重力波，

but in terms of the waves themselves,

但就重力波而言，

maybe we'll discover 100 years from now that they are useful.

可能我們將在 一百年後才發現其用處。

But it takes a lot of time to derive technology from science,

從科學到科技需要大量時間，

and that's not why we do it.

但並非我們實行的原因。

All technology is derived from science,

所有科技都從科學而來，

but we practice science for the enjoyment.

但我們從事科學是為了享受。

What's left to do?

還剩下什麼要做？

A lot.

很多。

A lot; this is only the beginning.

很多；這只是個開始。

As we make the detectors more and more sensitive --

隨著我們使探測儀更趨靈敏──

and we have lots of work to do there --

那已經是很大的工作量，

not only are we going to see more black holes

我們不單會看見更多黑洞，

and be able to catalog how many there are, where they are

能夠紀錄黑洞的數量、位置和大小，

and how big they are,

we'll also be able to see other objects.

我們還能夠看見其他物體。

We'll see neutron stars fuse and turn into black holes.

我們將可以看見中子星 融合並轉化為黑洞。

We'll see a black holes being born.

我們將可以看見黑洞誕生。

We'll be able to see rotating stars in our galaxy

我們將可以看見銀河的星星旋轉，

produce sinusoidal waves.

產生正弦波。

We'll be able to see explosions of supernovas in our galaxy.

我們將可以看見超新星 在我們的銀河爆炸。

We'll be seeing a whole spectrum of new sources.

我們將會看見新事物的完整波譜。

We like to say

我們想說

that we've added a new sense to the human body:

我們為人類增加了新感官：

now, in addition to seeing,

現在，除了看得見，

we're able to hear.

我們能聽得見。

This is a revolution in astronomy,

這在天文學是一項革新，

like when Galileo invented the telescope.

像伽利略發明了望遠鏡一樣。

It's like when they added sound to silent movies.

情形好比人們為默片增加了聲音。

This is just the beginning.

這只是個開始。

We like to think

我們認為

that the road to science is very long -- very fun, but very long --

科學的路很漫長──

很有趣，但很漫長，

and that we, this large, international community of scientists,

而我們這些科學家 是一個龐大的國際性團體，

working from many countries, together as a team,

來自眾多國家，組成一個團隊，

are helping to build that road;

正協助建設這條路；

that we're shedding light -- sometimes encountering detours --

我們照亮道路—儘管有時會遇上此路不通 —

and building, perhaps,

並且建設一條可能是

a highway to the universe.

直達宇宙的高速公路。

Thank you.

多謝各位。

(Applause)

（掌聲）