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We are all atomically connected. Fundamentally, universally. But what does that mean?
我们全都由原子连接在一起。这是放之四海皆准的基本规律。但这是什么意思呢？
I'm an astrophysicist, and as such, it is my responsibility to trace the cosmic history of every single one of your atoms.
作为一个天体物理学家，我的职责是，追溯构成你的每一个原子的宇宙历史。
In fact, I would say that one of the greatest achievements of modern astronomy
事实上，我应该这么说，现代天文学最伟大的成就之一
is the understanding of how our atoms were actually put together.
是理解我们的原子是怎样组装的。
While hydrogen and helium were made during the first two minutes of the big bang, the origin of heavy elements,
虽说氢和氦是在大爆炸的最初两分钟诞生的，重元素的起源，
such as the iron in your blood, the oxygen we're breathing, the silicone in your computers, lies in the life cycle of stars.
比如说血液中的铁，呼吸出的氧，电脑里的硅，都栖身于恒星的整个生命周期之中。
Nuclear reactions take lighter elements and transform them into heavier ones,
核反应将较轻的元素转换成更重的元素，
and that causes stars to shine and ultimately explode, therefore enriching the universe with these heavy elements.
这使得星辰闪耀，最终爆发，从而让宇宙充满了重元素。
So without stellar death there would be no oxygen or other elements heavier than hydrogen and helium,
如果没有恒星的死亡，也就不会有氧，或者其他比氢和氦更重的元素，
and therefore, there would be no life.
生命也就无从诞生。
There are more atoms in our bodies than stars in the universe. And these atoms are extremely durable.
我们身体中原子的数量比宇宙中星星的数量还多。而这些原子极其耐久。
The origins of our atoms can be traceable to stars that manufactured them in their interiors
我们的原子的起源可以追溯到数十亿年前，它们在恒星的内部被制造出来，
and exploded them all across the Milky Way, billions of years ago.
随后在爆炸中喷射到银河的各个角落。
And I should know this, because I am indeed a certified stellar mortician.
而我理应对此了如指掌，因为我是名副其实受认证的星星葬仪师。
And today, I want to take you on a journey that starts in a supernova explosion
今天，我想带领大家踏上一段旅程，由超新星爆炸开始，
and ends with the air that we're breathing right now.
在我们此刻呼吸的空气中结束。
So what is our body made of? Ninety-six percent consists of only four elements: hydrogen, carbon, oxygen and nitrogen.
我们的身体是由什么构成的？其中96%的组织仅由四种元素构成：氢、碳、氧、氮。
Now the main character of this cosmic tale is oxygen.
这个宇宙故事的主角是氧。
Not only is the vast majority of our bodies made of oxygen,
氧不仅是我们身体的主要成分，
but oxygen is the one element fighting to protect life on earth.
也是在地球上努力保护生命的那个元素。
The vast majority of oxygen in the universe
宇宙中绝大部分的氧
was indeed produced over the entire history of the universe in these supernova explosions.
确实是在整个宇宙的历史中，在这些超新星爆炸时制造出来的。
These supernova explosions signal the demise of very massive stars.
这些超新星爆炸宣告着非常巨大的恒星的逝去。
And for a brilliant month, one supernova explosion can be brighter than an entire galaxy containing billions of stars.
在这光辉炫目的一整个月中，一次超新星爆炸可能比包含了数十亿星星的整个星系还要明亮。
That is truly remarkable. That is because massive stars burn brighter and have a spectacular death, compared to other stars.
这真的令人叹为观止。那是因为比起其他星星，巨大的恒星燃烧得更加耀眼，死亡得也更加辉煌。
Nuclear fusion is really the lifeblood of all stars, including the sun,
核聚变可以说是所有恒星的命脉，包括太阳，
and as a result is the root source of all the energy on earth.
因此也是地球上所有能源的根源。
You can think of stars as these fusion factories which are powered by smashing atoms together in their hot and dense interiors.
你可以把恒星想象成核聚变工厂，在它们灼热而致密的内部，互相冲撞的原子为工厂提供着动力。
Now, stars like our sun, which are relatively small,
比较小的恒星，比如我们的太阳，
burn hydrogen into helium, but heavier stars of about eight times the mass of the sun
燃烧氢形成氦，但质量是太阳大约八倍的更重的恒星，
continue this burning cycle even after they exhausted their helium in their cores.
即使在耗尽了内核的氦之后，依然继续这个燃烧的循环。
So at this point, the massive star is left with a carbon core, which, as you know, is the building block of life.
那么这时，巨大的恒星只剩下一个碳核心，我们都知道，碳也是生命的基石。
This carbon core continues to collapse and as a result, the temperature increases,
这个碳核心继续坍缩，造成温度升高，
which allows further nuclear reactions to take place,
进而导致更多核反应发生，
and carbon then burns into oxygen, into neon, silicon, sulphur and ultimately iron.
碳进一步燃烧成为氧，成为氖、硅、硫，最终形成铁。
And iron is the end. Why?
铁是整个过程的终点。为什么？
Because iron is the most bound nuclei in the universe, which means that we cannot extract energy by burning iron.
因为铁是宇宙中结合得最稳定的原子核，也就是说我们无法通过燃烧铁获取能量。
So when the entire core of the massive star is made of iron, it's run out of fuel.
当大恒星的整个内核充满了铁，它就耗尽了燃料。
And that's an incredibly bad day for a star.
对于一颗恒星来说，那可是相当糟糕的一天。
Without fuel, it cannot generate heat, and therefore gravity has won the battle.
没有燃料，它就无法产生热量，因此引力便在这场战斗中胜出。
The iron core has no other choice but to collapse, reaching incredibly high densities.
铁核心除了坍缩，达到异常高的密度之外别无选择。
Think of 300 million tons reduced to a space the size of a sugar cube.
想象一下三亿吨的质量压缩成一块方糖的大小。
At these extreme high densities, the core actually resists collapse,
在这极高的密度下，核心其实会反抗坍缩，
and as a result, all of this infalling material bounces off the core.
结果就是，所有这些坠落的物质会从核心反弹。
And this dramatic bounce, which happens in a fraction of a second or so,
而这戏剧性的反弹，发生在不到一秒的弹指间，
is responsible for ejecting the rest of the star in all directions, ultimately forming a supernova explosion.
它导致恒星的其余部分朝所有方向喷射出去，最终形成了超新星爆炸。
So, sadly, from the perspective of an astrophysicist,
从一个天体物理学家的角度来说，遗憾的是，
the conditions in the centers of these exploding stars cannot be recreated in a laboratory.
这些爆炸的星星的内部条件无法在实验室内重现出来。
Now, thankfully for humanity, we're not able to do that.
不过对于人类来说，这是值得庆幸的事。
But what does that mean? That means that as astrophysicists,
但这意味着什么？这意味着作为天体物理学家，
we have to rely on sophisticated computer simulations in order to understand these complex phenomena.
我们不得不依赖复杂的计算机模拟，以理解这些复杂的现象。
These simulations can be used to really understand how gas behaves under such extreme conditions.
我们可以通过这些模拟理解在这种极端条件下气体的表现如何。
And can be used to answer fundamental questions like, "What ultimately disrupted the massive star?"
我们也可以通过模拟，回答一些基本的问题，比如说，“归根结底，大恒星是怎么被瓦解的？”
"How is it that this implosion can be reversed into an explosion?"
“这样的向心爆炸是怎样被逆转变成向外爆炸的？”
There's a huge amount of debate in the field,
这个领域中有大量争论，
but we all agree that neutrinos, which are these elusive elementary particles, play a crucial role. Yeah?
但我们达成的共识是，中微子，也就是某种难以捉摸的基本粒子，在其中扮演了至关重要的角色。听上去如何？
I'm about to show you one of those simulations.
下面我要给大家演示其中一个模拟。
So neutrinos are produced in huge numbers once the core collapses.
中微子是在恒星内核坍缩时大量产生的。
And in fact, they are responsible for transferring the energy in this core.
事实上，它们担负着在内核中传递能量的职责。
Like thermal radiation in a heater, neutrinos pump energy into the core,
就像暖气机中的热辐射一样，中微子将能量朝内核中泵送，
increasing the possibility of disrupting the star.
增加了恒星被破坏的可能。
In fact, for about a fraction of a second, neutrinos pump so much energy that the pressure increases high enough
事实上，在几分之一秒的时间内，中微子输送的能量如此庞大，
that a shock wave is produced and the shock wave goes and disrupts the entire star.
使得压力升高到足以产生冲击波，而冲击波进一步将整颗恒星破坏。
And it is in that shock wave where elements are produced. So thank you, neutrinos.
正是在这个冲击波之中，各种元素诞生了。中微子，谢谢你们。
Supernovas shine bright, and for a brief period of time,
超新星非常耀眼，在一段短暂的时间里，
they radiate more energy than the sun will in its entire lifetime.
它们辐射出的能量比太阳在生命周期内释放的还多。
That point of light that you see there, which was certainly not there before,
你们在那里看到的光点，之前绝对不存在，
burns like a beacon, clearly indicating the position where the massive star has died.
它现在像灯塔一样熊熊燃烧，清楚地标示着巨大恒星死去的位置。
In a galaxy like our own Milky Way, we estimate that about once every 50 years, a massive star dies.
在一个像我们的银河系一样的星系里，我们估计大约每50年就有一颗大恒星死亡。
This implies that somewhere in the universe, there's a supernova explosion every second or so.
这意味着大约每一秒钟，宇宙中的某处就有一次超新星爆发。
And thankfully for astronomers, some of them are actually found relatively close to earth.
对于天文学家来说，谢天谢地的是，其中一些的发生位置离地球相对比较近。
Various civilizations recorded these supernova explosions long before the telescope was invented.
早在天文望远镜被发明之前，许多文明已经对这些超新星爆炸有所记载。
The most famous of all of them is probably the supernova explosion that gave rise to the Crab Nebula. Yeah?
其中最著名的当属诞生了蟹状星云的那场超新星爆炸。对吧？
Korean and Chinese astronomers recorded this supernova in 1054, as did, almost certainly, Native Americans.
韩国和中国的天文学家在1054年记录了这颗超新星，基本可以肯定美国原住民也对此进行了记录。
This supernova happened about 5,600 light-years away from earth.
这次超新星爆炸发生在距离地球约5600光年的地方。
And it was so incredibly bright that astronomers could see it during the day.
它如此明亮，天文学家们在白昼也能看到它。
And it was visible to the naked eye for about two years in the night sky.
在大约两年的时间里，它在夜空中裸眼可见。
Fast forward 1,000 years or so later, and what do we see?
向前快进约1000年，我们看到了什么？
We see these filaments that were blasted by the explosion, moving at 300 miles per second.
我们看到这些因爆炸迸发的光丝，以每秒300英里的速度移动。
These filaments are essential for us to understand how massive stars die.
这些光丝对于我们理解大恒星如何死亡至关重要。
The image that you see there was assembled by the Hubble Space Telescope over a span of three months.
大家看见的这幅图像，是由哈勃天文望远镜耗时三个月收集的。
And it is incredibly important to astronomers because it ultimately carries the chemical legacy of the star that exploded.
它对于天文学家非常重要，因为归根结底，它承载的是发生爆炸的星体的化学遗产。
The orange filaments that you see there are the tattered remains of the star, and are made primarily of hydrogen,
这些橘色的光丝是那颗恒星残破的遗骸，主要由氢构成，
while the blue and red filaments that you see are the freshly synthesized oxygen.
而蓝色和红色的光丝，是新鲜生成的氧。
So studying supernova remnants, like the Crab Nebula, allowed astronomers to firmly conclude
因此，研究像蟹状星云那样的超新星的残留物，能让天文学家得出坚定的结论：
that the vast majority of oxygen on earth was produced by supernova explosions over the history of the universe.
地球上绝大部分氧元素都是在宇宙的历史长河中由超新星爆炸产生的。
And we can estimate that in order to assemble all the atoms of oxygen in our body,
我们可以估算，为了组装我们身体里所有的氧原子，
it took on the order of a 100 million supernova.
需要上亿的超新星。
So every bit of you, or at least the majority of it, came from one of these supernova explosions.
因此大家的全身上下，至少是其中的绝大部分，都来自这些超新星爆炸中的一个。
So now you may be wondering,
那么现在各位可能会纳闷，
how is it that these atoms that were generated in such extreme conditions ultimately took residence in our body?
这些在如此极端条件下产生的原子，最终是怎样在我们的身体里定居的？
So I want you to follow the thought experiment.
我想让各位进行一个思想实验。
Imagine that we're in the Milky Way, and a supernova happens.
想象一下我们在银河里，一场超新星爆炸开始了。
It blasted tons and tons of oxygen atoms almost into empty space.
它将无数氧原子轰进了空空如也的太空。
A few of them were able to be assembled in a cloud.
其中少数被聚集成为星云。
Now, 4.5 billion years ago, something unsettled that cloud and caused it to collapse,
45亿年前，某种东西扰乱了那片星云，使其土崩瓦解，
forming the sun in its center and the solar system.
在它的中心形成了太阳和太阳系。
So the sun, the planets and life on earth depend on this beautiful cycle of stellar birth, stellar death and stellar rebirth.
因此太阳、行星和地球上的生命，都仰赖这个美丽的循环：恒星诞生、恒星死亡、恒星重生。
And this continues the recycling of atoms in the universe.
这个过程循环往复，将宇宙中的原子回收再利用。
And as a result, astronomy and chemistry are intimately connected.
因此，天文学和化学是紧密联系的。
We are life forms that have evolved to inhale the waste products of plants.
我们这种生命形态，演化到要依靠植物的废弃产物来呼吸。
But now you know that we also inhale the waste products of supernova explosions.
不过现在大家也了解了，我们同时也呼吸着超新星爆炸的废弃产物。
So take a moment, inhale. An oxygen atom has just gone into your body.
所以花点时间，深吸一口气吧。一个氧原子刚刚进入了你的身体。
It is certain that that oxygen remembers that it was in the interior of a star
可以肯定的是，那个氧原子记得它曾身处某颗恒星的内部，
and it was probably manufactured by a supernova explosion.
也记得它很可能是在一场超新星爆炸中被制造出来的。
This atom may have traveled the entire solar system until it splashed on earth, long before reaching you.
这个原子或许历经了跨过整个太阳系的跋涉，才溅落在地球上，又过了很久很久才和你相遇。
When we breathe, we use hundreds of liters of oxygen every day.
我们呼吸时，每天都消耗掉数百升氧。
So I'm incredibly lucky to be standing in front of this beautiful audience, but I'm actually stealing your oxygen atoms.
所以我今天非常幸运能站在这群美妙的观众面前，但我其实是在偷你们的氧原子。
And because I'm speaking to you, I'm giving you some of them back, that once resided in me.
而因为我在和你们交谈，我会归还给你们一些曾经住在我体内的氧原子。
So breathing, yeah, participates in this beautiful exchange of atoms.
所以没错，通过呼吸，参与到这场美丽的原子交换之中。
And you can then ask, "Well, how many atoms in our body once belonged to Frida Kahlo?"
接下来你就可以发问，“那么，我们体内有多少原子曾经属于弗里达·卡罗？”
About 100,000 of them. 100,000 more probably belonged to Marie Curie,
大约有10万个。还有10万个或许曾属于居里夫人，
100,000 more to Sally Ride, or whoever you want to think of.
另外10万个曾属于萨莉·莱德，或者任何一位你想起的人。
So breathing is not only filling our lungs with cosmic history, but with human history.
所以呼吸为我们的肺部充满的不仅是宇宙的历史，也是人类的历史。
I would like to end my talk by sharing a myth that is very close to my heart.
我想分享一个藏在我内心的传说，以此结束这次演讲。
A myth from the Chichimeca culture, which is a very powerful Mesoamerican culture.
一个来自奇奇梅克文化的传说，这是一种非常强大的中美洲文化。
And the Chichimecas believe that our essence was assembled in the heavens.
奇奇梅克人相信我们的本质是在天上组装的。
And on its journey towards us, it actually fragmented into tons of different pieces.
而在朝我们前进的路途上，它破裂成了无数不同的碎片。
So my abuelo used to say, "One of the reasons you feel incomplete is because you are missing your pieces."
我的祖父曾经说过，“你感到自己不完整的原因之一是因为你确实确实了一些东西。”
"But don't be fooled by that. You've been given an incredible opportunity of growth. Why?
“但不要为此所欺骗。你获得了难以置信的成长机会。为什么？
Because it's not like those pieces were scattered on earth and you have to go and pick them up.
因为那些碎片并不是散落在地球各处，你要去把它们捡起来。
No, those pieces fell into other people. And only by sharing them you will become more complete.
不，那些碎片落在了别人身上。只有通过分享碎片，你才会变得更加完整。
Yes, during your life, there's going to be individuals that have these huge pieces that make you feel whole.
没错，在一生之中，你会遇见拥有巨大碎片的人，他们会让你感到完整。
But in your quest of being complete, you have to treasure and share every single one of those pieces."
但在你追寻完整的旅途中，你必须珍视并分享每一片碎片。”
Sounds a lot like the story of oxygen to me.
我觉得这听起来很像氧原子的故事。
Which started in the heavens in a supernova explosion, and continues today, within the confines of our humanity.
氧原子的故事在天空中伴随着超新星爆炸开始，并持续至今，在人类的界限之内继续书写。
Our atoms in our body have embarked on an epic odyssey, with time spans from billions of years to mere centuries,
我们身体里的原子踏上了一场史诗般的长途冒险，历时横跨数十亿年到仅仅几个世纪，
all leading to you, all of you, witnesses of the universe. Thank you.
全都指引向你的身边，你们所有人身边，你们是宇宙的见证人。谢谢大家。
