Giant atomic nuclei, only a few kilometers in diameter,

雖然巨型原子核的直徑只有幾公里

but as massive as stars.

但它們卻像恒星一樣龐大，它們的存在歸功於雄偉的事物的死亡

And they owe their existence to the death of something majestic.

由於脆弱的平衡而存在星星

[Intro music]

數以億億計的熱量

Stars exist because of a fragile balance.

等離子體被重力向內拉動，並以巨大的力將物質擠壓在一起，以致核子融合

The mass of millions of billions of trillions of tons of hot plasma

氫融合成氦

are being pulled inwards by gravity,

這會釋放出能量，從而克服重力並試圖逃逸。

and squeeze material together with so much force that nuclei fuse

只要存在這種平衡，恒星就相當穩定

Hydrogen fuses into helium.

最終氫氣將被耗盡

This releases energy which pushes against gravity and tries to escape.

像我們的太陽這樣的中型恒星經歷一個漫長的階段，在這個階段中他們將氦燃燒成碳和氧

As long as this balance exists, stars are pretty stable.

在他們最終變成白矮星之前

Eventually, the hydrogen will be exhausted.

但是在質量是我們太陽許多倍的恒星中，當氦耗盡時，事情變得有趣起來

Medium stars, like our Sun, go through a giant phase,

片刻之間，壓力與輻射之間的平衡崩潰，重力占據了優勢

where they burn helium into carbon and oxygen

擠壓使恒星比以前更緊凑，核心燃燒得更快更熱，且恒星的外層膨脹了數百倍

before they eventually turn into white dwarfs.

融合了越來越重的元素

But in stars many times the mass of our Sun,

數個世紀以來，碳燃燒成氖，一年內燃燒成氧氣，數月內燃燒成矽蒸氣

things get interesting when the helium is exhausted.

直到矽和鐵碰到的那一天

For a moment, the balance of pressure and radiation tips,

接著

and gravity wins, squeezing the star tighter than before.

是死亡

The core burns hotter and faster,

鐵是核灰，它沒有能量產生，也不能融合

while the outer layers of the star swell by hundreds of times,

融合突然停止，平衡結束，且沒有來自融合的向外壓力

fusing heavier and heavier elements.

核心被上方恒星的巨大重量壓碎

Carbon burns to neon in centuries,

現在發生的事情真是棒極了，而且驚人

neon to oxygen in a year,

像電子和質子這樣的粒子真的不希望彼此靠近

oxygen to silicon in months,

但是坍縮恒星的壓力是如此之大，以至於電子和質子融合成中子

and silicon to iron in a day.

然後，它們像原子核一樣緊緊地被擠壓在一起

And then…

一個地球大小的鐵球被擠成一個城市大小的純核物質球

…death.

但不僅是核心，整個恒星都會爆炸。重力以25％的光速拉動外層

Iron is nuclear ash.

這種內爆會從鐵芯上反彈，產生向外爆炸的衝擊波

It has no energy to give and cannot be fused.

並將其餘的部分彈射到太空

The fusion suddenly stops, and the balance ends.

這就是我們所說的超新星爆炸，它將超越整個星系

Without the outward pressure from fusion,

現在，恒星剩下的就是一個中子星

the core is crushed by the enormous weight of the star above it.

它的質量約為地球質量的一百萬倍，但被壓縮為約25公里寬的物體

What happens now is awesome and scary.

它是如此密集，以至於所有活著的人類的體重都可以容納在一立方釐米的中子星物質中

Particles, like electrons and protons, really don't want to be near each other.

在一個方糖大小的空間中大約有十億噸

But the pressure of the collapsing star is so great

換句話說，就是將珠穆朗瑪峰塞進一杯咖啡

that electrons and protons fuse into neutrons,

從外面看，中子星是

which then get squeezed together as tightly as in atomic nuclei.

令人難以置信的極端，它的重力是黑洞外最強的

An iron ball, the size of the Earth,

如果它更密集，它將成為一個黑洞

is squeezed into a ball of pure nuclear matter, the size of a city.

光在它周圍彎曲。意味著您可以看到正面和背面的一部分

But not just the core; The whole star implodes,

它們的表面達到一百萬攝氏度

gravity pulling the outer layers in at 25% the speed of light.

相比之下，我們的太陽只有六千度

This implosion bounces off the iron core,

好吧，讓我們看一下中子星的内部

producing a shock wave that explodes outwards

儘管這些巨大的原子核在許多方面都算作恒星，但它們更像是在液核上有硬殼的行星

and catapults the rest of the star into space.

地殼非常堅硬

This is what we call a supernova explosion, and it will outshine entire galaxies.

最外層是由超新星遺留下的鐵製成的，擠在一起形成晶格，大量的電子流過它們

What remains of the star is now a neutron star.

往深處，重力將原子核擠壓在一起。我們發現越來越少的質子是因為大多數融合成兩個中子，

Its mass is around a million times the mass of the Earth

直到我們到達地殼的底部，這裏的原子核被牢牢地擠壓在一起，以至於它們開始接觸

but compressed to an object about 25 kilometers wide.

質子和中子重新排列，形成長圓柱體或薄片，具有數百萬個質子和中子的巨大核子

It's so dense that the mass of all living humans

形狀像義大利麵條和千層面，物理學家稱之為核麵食

would fit into one cubic centimeter of neutron star matter.

核麵食是如此稠密，以至於它可能是宇宙中最堅固的物質，基本上是堅不可摧的

That's roughly a billion tons

中子星內部的麵食團塊甚至可以使山頂高出幾釐米，但質量卻和喜馬拉雅山接近

in a space the size of a sugar cube.

最終，在麵食下方，我們到達了核心

Put another way, that's Mount Everest in a cup of coffee.

我們真的不確定當如此大力地擠壓物質時，它們的性質會是什麼

From the outside, a neutron star is unbelievably extreme.

質子和中子可能會溶解在誇克的海洋中，即所謂的誇克膠子等離子體

Its gravity is the strongest, outside black holes,

其中一些誇克可能會變成奇怪的誇克

and, if it were any denser, it would become one.

用非常極端的性質來講述一件奇怪的事情，以至於我們製作了一個完整的視頻

Light is bent around it,

也許他們只是留下質子和中子。沒有人可以確認。這就是為什麼我們從事科學

meaning you can see the front and parts of the back.

那都是字面意義上很重的東西。所以我們回到太空

Their surfaces reach 1,000,000 degrees Celsius, compared to a measly 6,000 degrees for our Sun.

當中子星第一次坍塌時，它們開始非常快地旋轉，就像芭蕾舞女演員將手臂伸進去一樣

Okay, let's look inside a neutron star.

中子星是天文學的芭蕾舞演員，每秒旋轉多次

Although these giant atomic nuclei are stars,

這會產生脈衝，因為它們的磁場會產生一束無線電波，每次旋轉時都會通過

in many ways, they're also like planets,

這些射電脈衝星是最著名的中子星類型

with solid crusts over a liquid core.

銀河系中已知有2,000個

The crust is extremely hard.

這些磁場是宇宙中最強的，在它們誕生後比地球要強大四千萬倍

The outermost layers are made of iron left over from the supernova,

他們被稱為磁星，直到它們稍微平靜下來

squeezed together in a crystal lattice,

但是最好的中子星是其他中子星的朋友

with a sea of electrons flowing through them.

引力波在時空中波動時輻射出能量

Going deeper, gravity squeezes nuclei closer together.

它們的軌道可能會衰減，並且會撞出一場千新星爆炸殺死彼此，從而散播一些他們的能量

We find fewer and fewer protons, as most merge to neutrons.

當它們發生時，條件變得如此極端，以至於一會又產生了重核

Until we reach the base of the crust.

這次不是聚變使原子核聚在一起，而是重中子富集物質散開並重新組裝

Here, nuclei are squeezed together so hard

直到最近，我們才知道這可能是宇宙中大多數重元素如金的起源

that they start to touch.

鈾和鉑金等等

Protons and neutrons rearrange,

所以現在，他們這兩個中子星坍塌並變成了一個黑洞，再次消失

making long cylinders or sheets,

不僅兩個恒星必須死去創造元素。他們必須死兩次

enormous nuclei with millions of protons and neutrons

在數百萬年的時間裏，這些原子將重新混入銀河系

shaped like spaghetti and lasagna,

但是它們中的一些最終變成了雲層，重力將雲層拉在一起形成一圈恒星和行星

which physicists call nuclear pasta.

我們的太陽系就是一個例子，而擺在我們面前的那些中子星的殘骸都在我們周圍

Nuclear pasta is so dense that it may be the strongest material in the universe,

整個現代技術世界都是由遠古的中子星產生的元素構成的

basically unbreakable.

在一百三十億年的旅程中將這些原子送去，使我們和我們的世界聚在一起

Lumps of pasta inside a neutron star

那很酷

can even make mountains

在那之前，我們可以在紙上看它們

at most a few centimeters high,

一千二百二十個人類太空時代的日曆已經到來。您可以立即訂購，直到我們售罄，然後不會再有了

but many times as massive as the Himalayas.

參觀水星上陰沉的維納斯·戴森（Venus Dyson），越過太陽系的邊界

Eventually, beneath the pasta, we reach the core.

首次從美國和歐洲運輸，但我們可以將貨物運送到世界各地

We're not really sure what the properties of matter are when they're squeezed this hard.

您還可以得到毛絨或連帽衫或海報。我們為您提供一些優惠

Protons and neutrons might dissolve into an ocean of quarks,

為您的朋友家人和孩子們過聖誕節，或者從現實中讓自己分散注意力

a so-called quark-gluon plasma.

1000億個類地行星，位於可觀測宇宙中太陽類恒星的可居住區域

Some of those quarks might turn into strange quarks,

最近幾年，您將永遠不會訪問任何一個。我們已經把它們全部賣掉了，所以不要著急，但是時間在流逝

making a sort of strange matter, with properties so extreme,

從我們的商店買東西是支持我們的最佳方法之一

that we made a whole video about it.

因為有了您，我們可以讓所有人免費觀看此頻道，並製作更漂亮的內容

Or, maybe they just stay protons and neutrons.

12020星際新年快樂！

No one knows for sure, and that's why we do science.

That's all pretty heavy stuff, literally, so let's go back out into space.

When neutron stars first collapse,

they begin to spin very, very fast, like a ballerina pulling her arms in.

Neutron stars are celestial ballerinas, spinning many times per second.

This creates pulses

because their magnetic field creates a beam of radio waves,

which passes every time they spin.

These radio pulsars are the best-known type of neutron star.

About 2,000 are known of in the Milky Way.

These magnetic fields are the strongest in the universe,

a quadrillion times stronger than Earth's after they're born.

They're called magnetars until they calm down a little.

But the absolute best kind of neutron stars are friends with other neutron stars.

By radiating away energy as gravitational waves, ripples in spacetime, their orbits can decay,

and they can crash into and kill each other in a kilonova explosion that spews out a lot of their guts.

When they do, the conditions become so extreme

that, for a moment, heavy nuclei are made again.

It's not fusion putting nuclei together this time,

but heavy neutron-rich matter falling apart and reassembling.

Only very recently,

we've learned that this is probably the origin of most of the heavy elements in the universe,

like gold, uranium, and platinum, and dozens more.

So there now two neutron stars collapse and become a black hole, dying yet again.

Not only do stars have to die to create elements, they have to die twice.

Over millions of years, these atoms will mix back into the galaxy,

but some of them end up in a cloud, which gravity pulls together to form stars and planets, repeating the cycle.

Our solar system is one example,

and the remains of those neutron stars that came before us are all around us.

Our entire technological modern world was built out of the elements neutron stars made in eons past,

sending these atoms on a thirteen-billion-year journey to come together and make us and our world.

And that's pretty cool.

Until then, we can look at them on paper.

The 12,020 Human Space Era Calendar has arrived.

You can order it now until we sell out,

and then never again.

Visit the cloudy cities of Venus,

Dyson swarm assembly on Mercury,

and cross the borders of our Solar System.

Shipping from the US,

and from Europe for the first time,

but we deliver to every country all over the world.

You could also get a plushie or hoodie or poster.

We have some sweet deals for you.

Get it for Christmas for your friends, families, and kids,

or to distract yourself from the fact that there are

100 billion billion Earth-like planets in the habitable zone of Sun-like stars in the observable universe…

…and you will never visit any of them.

The last few years, we've sold them all,

so no rush, but the clock is ticking.

Getting stuff from our shop is one of the best ways to support Kurzgesagt.

Because of you, we can keep this channel free for everyone,

and make more beautiful things.

A happy interstellar year 12,020.

[Outro music]