We are all atomically connected.

在原子上，我們都是相連的。

Fundamentally, universally.

根本上，宇宙上，都是。

But what does that mean?

但，那是什麼意思？

I'm an astrophysicist, and as such,

我是天體物理學家，因此，

it is my responsibility to trace the cosmic history

我的責任是要追蹤你的每一個原子

of every single one of your atoms.

背後的宇宙歷史。

In fact, I would say

事實上，我會說，

that one of the greatest achievements of modern astronomy

現代天文學最偉大的成就之一，

is the understanding of how our atoms were actually put together.

就是了解我們的原子 是如何形成的。

While hydrogen and helium were made

在大爆炸的前兩分鐘，

during the first two minutes of the big bang,

氫和氦就形成了，

the origin of heavy elements,

但，重元素如血液中的鐵、

such as the iron in your blood, the oxygen we're breathing,

我們所呼吸的氧氣、

the silicone in your computers,

電腦中用的矽，

lies in the life cycle of stars.

則起源於星星的生命循環。

Nuclear reactions take lighter elements and transform them into heavier ones,

核反應會把較輕的元素

and that causes stars to shine

轉換成較重的元素，

and ultimately explode,

那會導致星星的發光，

therefore enriching the universe with these heavy elements.

最終發生爆炸，

So without stellar death

因而讓宇宙中充滿了這些重元素。

there would be no oxygen

若沒有星星的死亡，

or other elements heavier than hydrogen and helium,

就不會有氧，

and therefore, there would be no life.

或者其他比氫和氦更重的元素，

There are more atoms in our bodies

因此，就不會有生命。

than stars in the universe.

在我們身體中的原子數

And these atoms are extremely durable.

比宇宙中的星星還多。

The origins of our atoms

這些原子非常耐久。

can be traceable to stars that manufactured them in their interiors

我們原子的源頭

and exploded them all across the Milky Way,

可追溯至星星在內部製造它們，

billions of years ago.

接著將它們炸出來，穿過銀河，

And I should know this,

這是數十億年前的事。

because I am indeed a certified stellar mortician.

我會知道這些，

(Laughter)

是因為我是有認證的 星星殯葬業者。

And today, I want to take you on a journey that starts in a supernova explosion

（笑聲）

and ends with the air that we're breathing right now.

今天我想要帶大家踏上一段旅程，

So what is our body made of?

從超級新星的爆炸開始，

Ninety-six percent consists of only four elements:

一直到我們現在呼吸的空氣為止。

hydrogen, carbon, oxygen and nitrogen.

我們的身體是什麼組成的？

Now the main character of this cosmic tale is oxygen.

其中 96% 只由四個元素組成：

Not only is the vast majority of our bodies made of oxygen,

氫、碳、氧、氮。

but oxygen is the one element fighting to protect life on earth.

這個宇宙故事的主角是氧。

The vast majority of oxygen in the universe

不僅我們的身體很大一部分 都是由氧所構成，

was indeed produced over the entire history of the universe

在地球上，氧也是 在努力保護生命的元素。

in these supernova explosions.

宇宙中大部分的氧

These supernova explosions signal the demise of very massive stars.

的確是在整個宇宙歷史中

And for a brilliant month,

從這些超級新星的爆炸製造出來。

one supernova explosion can be brighter than an entire galaxy

這些超級新星的爆炸， 表示有非常巨大的星星死亡了。

containing billions of stars.

在這明亮的一整個月中，

That is truly remarkable.

一個超級新星爆炸的亮度就超過了

That is because massive stars burn brighter

包含數十億顆星星的銀河。

and have a spectacular death, compared to other stars.

這真的很驚人。

Nuclear fusion is really the lifeblood of all stars,

這是因為巨大的星星 燃燒起來會更明亮，

including the sun,

且和其他星星相比， 它的死亡也更壯麗。

and as a result is the root source of all the energy on earth.

核融合是所有星星的命脈，

You can think of stars as these fusion factories

包括太陽，

which are powered by smashing atoms together

因此也是地球上所有能量的根源。

in their hot and dense interiors.

可以把這些星星想成是融合工廠，

Now, stars like our sun,

工廠的動力來源則是 在其又熱又密的內部

which are relatively small,

將原子彼此撞擊。

burn hydrogen into helium,

星星就像我們的太陽，

but heavier stars of about eight times the mass of the sun

它們相對很小，

continue this burning cycle

將氫燃燒成為氦，

even after they exhausted their helium in their cores.

但，比較重的星星 質量有太陽的八倍，

So at this point,

它們會持續這個燃燒循環，

the massive star is left with a carbon core,

即使在它們核心的氦 已經耗盡，仍會持續。

which, as you know, is the building block of life.

此時，

This carbon core continues to collapse

巨大的星星剩下一個碳核心，

and as a result, the temperature increases,

也就是建造生命的積木。

which allows further nuclear reactions to take place,

這個碳核心會持續崩塌，

and carbon then burns into oxygen,

因此，溫度會上升，

into neon, silicon, sulphur

讓進一步的核融核發生，

and ultimately iron.

接著，碳會燃燒成為氧，

And iron is the end.

成為氖、矽、硫，

Why?

最終成為鐵。

Because iron is the most bound nuclei in the universe,

鐵就是終點。

which means that we cannot extract energy by burning iron.

為什麼？因為鐵是 宇宙中最被束縛的核心，

So when the entire core of the massive star is made of iron,

意即，我們無法透過 燃燒鐵來取得能量。

it's run out of fuel.

當巨大星星的整個核心

And that's an incredibly bad day for a star.

都變成鐵做的，它就沒有燃料了。

(Laughter)

對星星而言，那是很糟糕的一天。

Without fuel, it cannot generate heat,

（笑聲）

and therefore gravity has won the battle.

沒有燃料，它就無法產生熱，

The iron core has no other choice but to collapse,

因此，引力就打贏了這場仗。

reaching incredibly high densities.

鐵核心沒有其他選擇，只能崩塌，

Think of 300 million tons

達到非常高的密度。

reduced to a space the size of a sugar cube.

想想看，三億公噸的重量，

At these extreme high densities, the core actually resists collapse,

縮小到一塊方糖的大小。

and as a result,

在這個極高的密度之下， 核心會抵抗崩塌，

all of this infalling material bounces off the core.

因此，

And this dramatic bounce,

所有這些下塌的物質 會被核心反彈。

which happens in a fraction of a second or so,

這戲劇性的反彈時間不到一秒鐘，

is responsible for ejecting the rest of the star in all directions,

但就造成星星的其他部分 朝向各個方向射出，

ultimately forming a supernova explosion.

最終，形成了超級新星爆炸。

So, sadly, from the perspective of an astrophysicist,

所以，感傷的是，

the conditions in the centers of these exploding stars

從天體物理學家的角度來看，

cannot be recreated in a laboratory.

我們無法在實驗室中重新創造出

(Laughter)

這些爆炸星星中心的條件。

Now, thankfully for humanity, we're not able to do that.

（笑聲）

(Laughter)

人類應該覺得謝天謝地 我們做不到這件事。

But what does that mean?

（笑聲）

That means that as astrophysicists,

但那就意味著天體物理學家

we have to rely on sophisticated computer simulations

必須要仰賴精密的電腦模擬

in order to understand these complex phenomena.

來了解這些複雜的現象。

These simulations can be used to really understand how gas behaves

這些模擬可以用來真正了解

under such extreme conditions.

氣體在這些極端條件下的行為。

And can be used to answer fundamental questions

也可以用來回答基礎的問題，

like, "What ultimately disrupted the massive star?"

如，「最終，巨大的星星 是被什麼瓦解的？」

"How is it that this implosion can be reversed into an explosion?"

「這種向內爆炸怎麼能夠 被反轉成向外爆炸？」

There's a huge amount of debate in the field,

在這個領域中有很多辯論，

but we all agree that neutrinos,

但大家都認同微中子，

which are these elusive elementary particles,

也就是這些很難捉摸的基本粒子，

play a crucial role.

扮演著關鍵的角色。

Yeah?

是吧？

I'm about to show you one of those simulations.

我等下會讓各位看其中一項模擬。

So neutrinos are produced in huge numbers once the core collapses.

一旦核心崩塌，就會有 大量的微中子產生。

And in fact,

事實上，

they are responsible for transferring the energy in this core.

在核心中能量的傳遞就要靠它們。

Like thermal radiation in a heater,

就像暖氣機中的熱輻射，

neutrinos pump energy into the core,

中子會把能量打入核心中，

increasing the possibility of disrupting the star.

增加瓦解星星的可能性。

In fact, for about a fraction of a second,

事實上，在大約一秒鐘的時間中，

neutrinos pump so much energy

中子會打入非常多能量， 讓壓力增加到

that the pressure increases high enough that a shock wave is produced

足以產生出衝擊波，

and the shock wave goes and disrupts the entire star.

衝擊波便會瓦解整個星星。

And it is in that shock wave where elements are produced.

而元素正是在 那衝擊波當中產生的。

So thank you, neutrinos.

所以，謝謝你，微中子。

(Laughter)

（笑聲）

Supernovas shine bright,

超級新星很明亮，

and for a brief period of time,

在一段很短暫的時間中，

they radiate more energy than the sun will in its entire lifetime.

它們放射出的能量超過 太陽一生所放射出的能量。

That point of light that you see there,

各位看到的這個光點，

which was certainly not there before,

它以前肯定不在那裡，

burns like a beacon,

它燃燒起來亮得像燈塔一樣，

clearly indicating the position where the massive star has died.

清楚指出巨大星星死亡的位置。

In a galaxy like our own Milky Way,

在像我們這樣的銀河中，

we estimate that about once every 50 years,

我們估計，大約每五十年

a massive star dies.

就有一個巨大星星死亡。

This implies that somewhere in the universe,

這就表示，每一秒鐘左右，

there's a supernova explosion every second or so.

在宇宙中的某處 就有一個超級新星爆炸。

And thankfully for astronomers,

對天文學家而言，謝天謝地，

some of them are actually found relatively close to earth.

當中有些還非常靠近地球。

Various civilizations recorded these supernova explosions

在早望遠鏡發明之前，

long before the telescope was invented.

就有許多文明記載了 超級新星爆炸的記錄。

The most famous of all of them

當中最有名的，

is probably the supernova explosion that gave rise to the Crab Nebula.

可能就是形成蟹狀星雲的 那個超級新星爆炸。

Yeah?

對吧？

Korean and Chinese astronomers recorded this supernova in 1054,

1054 年，韓國和中國的天文學家

as did, almost certainly, Native Americans.

就記錄下了這個超級新星，

This supernova happened about 5,600 light-years away from earth.

幾乎可以肯定， 美國原住民也有這項記載。

And it was so incredibly bright

這顆超級新星在距離地球 大約五千六百光年的地方。

that astronomers could see it during the day.

它非常亮，

And it was visible to the naked eye for about two years in the night sky.

天文學家在白天就能看見它。

Fast forward 1,000 years or so later, and what do we see?

有大約兩年的時間， 晚上都可以用肉眼看見它。

We see these filaments that were blasted by the explosion,

快轉一千年左右，我們看到什麼？

moving at 300 miles per second.

我們看到爆炸炸開的這些光絲，

These filaments are essential for us to understand

移動速度為每秒鐘三百英里。

how massive stars die.

若我們要了解巨大星星如何死亡，

The image that you see there

這些光絲就非常重要。

was assembled by the Hubble Space Telescope

各位看見的這張影像 是用哈伯太空望遠鏡

over a span of three months.

收集了三個月時間的成果。

And it is incredibly important to astronomers

它對天文學家非常重要，

because it ultimately carries the chemical legacy

因為，最終，它帶著 爆炸星星的化學遺產。

of the star that exploded.

各位看見的橘色光絲

The orange filaments that you see there are the tattered remains of the star,

是星星的破爛殘駭，

and are made primarily of hydrogen,

主要是由氫所構成，

while the blue and red filaments that you see

至於藍色和紅色的光絲

are the freshly synthesized oxygen.

則是剛合成的氧。

So studying supernova remnants, like the Crab Nebula,

所以，天文學家透過 研究超級新星的殘餘物，

allowed astronomers to firmly conclude

比如蟹狀星雲，就能肯定地下結論

that the vast majority of oxygen on earth was produced by supernova explosions

認為地球上絕大部分的氧氣是由

over the history of the universe.

宇宙歷史上的超級新星 爆炸所產生的。

And we can estimate

我們可以估計，

that in order to assemble all the atoms of oxygen in our body,

要集合出我們身體中 所有的氧原子，

it took on the order of a 100 million supernova.

會需要大約一億個超級新星。

So every bit of you, or at least the majority of it,

所以，各位的全身上下， 至少絕大部分，

came from one of these supernova explosions.

都來自其中一個超級新星爆炸。

So now you may be wondering,

現在，各位可能會納悶，

how is it that these atoms

在這些極端的條件下 產生出來的原子

that were generated in such extreme conditions

最終怎麼會進到我們的身體？

ultimately took residence in our body?

我想請大家來做一個思想實驗。

So I want you to follow the thought experiment.

想像我們銀河出現了一顆超級新星。

Imagine that we're in the Milky Way, and a supernova happens.

它把大量的氧原子炸出來，

It blasted tons and tons of oxygen atoms

進入空蕩蕩的太空中。

almost into empty space.

當中少數組合成了星雲。

A few of them were able to be assembled in a cloud.

四十五億年前，

Now, 4.5 billion years ago,

某樣東西動搖了 那星雲，讓它崩塌，

something unsettled that cloud and caused it to collapse,

在其中心形成了太陽以及太陽系。

forming the sun in its center and the solar system.

所以，太陽、行星， 以及地球上的生命

So the sun, the planets and life on earth

都要仰賴這個美麗的循環：

depend on this beautiful cycle

恆星誕生、恆星死亡、恆星再生。

of stellar birth, stellar death and stellar rebirth.

因此，宇宙中的原子回收 也持續進行下去。

And this continues the recycling of atoms in the universe.

因此，天文學和化學 有著密切的關聯。

And as a result, astronomy and chemistry are intimately connected.

我們這種生命形式，

We are life forms that have evolved to inhale the waste products of plants.

演化成會吸入植物的廢棄產物。

But now you know

但，現在各位知道我們也會 吸入超級新星爆炸的廢棄產物。

that we also inhale the waste products of supernova explosions.

（笑聲）

(Laughter)

所以，花點時間，深深吸口氣。

So take a moment, inhale.

氧原子剛進入了你的身體。

An oxygen atom has just gone into your body.

可以肯定，那氧原子

It is certain that that oxygen [atom]

記得它曾待在一個星星的內部，

remembers that it was in the interior of a star

且它很可能是由 超級新星爆炸所產生的。

and it was probably manufactured by a supernova explosion.

這個原子可能穿過了整個太陽系，

This atom may have traveled the entire solar system

才落在地球上，

until it splashed on earth,

又過了好長的時間才遇到你。

long before reaching you.

當我們呼吸時，

When we breathe,

每天要用掉數百公升的氧。

we use hundreds of liters of oxygen every day.

所以，我非常幸運能夠 站在這群美好的觀眾面前，

So I'm incredibly lucky to be standing in front of this beautiful audience,

但我其實是在偷你們的氧原子。

but I'm actually stealing your oxygen atoms.

（笑聲）

(Laughter)

因為我在對各位說話，

And because I'm speaking to you,

我會把一些曾經在 我體內的氧原子還給你們。

I'm giving you some of them back, that once resided in me.

所以，呼吸吧，

So breathing, yeah,

參與這美好的原子交換。

participates in this beautiful exchange of atoms.

接著，各位可以問：

And you can then ask,

「我們體內有多少原子

"Well, how many atoms in our body once belonged to Frida Kahlo?"

曾經屬於芙烈達卡蘿（畫家）？」

(Laughter)

（笑聲）

About 100,000 of them.

大約十萬個。

100,000 more probably belonged to Marie Curie,

可能還有十萬個是屬於居禮夫人，

100,000 more to Sally Ride,

另外十萬個屬於 莎莉萊德（物理學家），

or whoever you want to think of.

或其他你想到的人。

So breathing is not only filling our lungs with cosmic history,

所以，呼吸讓我們的肺部

but with human history.

不僅充滿宇宙的歷史，

I would like to end my talk by sharing a myth

也充滿人類的歷史。

that is very close to my heart.

我想分享一個和我關係密切神話， 作為這場演說的結尾。

A myth from the Chichimeca culture,

這個神話來自奇奇梅克文化，

which is a very powerful Mesoamerican culture.

它是個非常強大的中美洲文化。

And the Chichimecas believe

奇奇梅克相信，

that our essence was assembled in the heavens.

我們的本質是在天上合成的。

And on its journey towards us,

在來到我們這裡的路上，

it actually fragmented into tons of different pieces.

破成了非常多不同的碎片。

So my abuelo used to say,

我祖父以前常說：

"One of the reasons you feel incomplete

「你會感到不完整，理由之一

is because you are missing your pieces."

是因為你少了你的碎片。」

(Laughter)

（笑聲）

"But don't be fooled by that.

「但，別被它騙了。

You've been given an incredible opportunity of growth.

你得到了非常棒的成長機會。

Why?

為什麼？

Because it's not like those pieces were scattered on earth

因為並不是那些碎片散在地球各地，

and you have to go and pick them up.

而你得去把它們撿回來。

No, those pieces fell into other people.

不，那些碎片落到了其他人身上。

And only by sharing them you will become more complete.

只有透過分享，你才會變得更完整。