恒星是如何形成的？

ABC，听好了。

ABC, listen.

你好。

Hello.

我叫Nidge。

My name is Nidge.

今晚在《想象一下》节目中，我们的目光聚焦于天空。

And tonight on Imagine This, we've got our eyes on the skies.

一闪一闪小针星，我真想知道你是什么。

Twinkle, twinkle needle star, how I wonder what they are.

我们一直好奇它们是什么。

We have been wondering what they are.

我们收到了很多关于星星的问题。

We've had a lot of questions about stars.

嗨。

Hi.

我叫内瓦，今年五岁。

My name's Neva, and I'm five years old.

我想知道星星是怎么形成的。

And I wanna know how a star is made.

你好。

Hello.

我叫埃迪。

My name is Eddie.

我五岁了，我想知道星星是由什么组成的。

I'm five years old, and I would like to know what a star is made of.

嗨。

Hi.

我叫俊泽，今年六岁。

I'm Juntse, and I'm six years old.

我想知道星尘是由什么组成的。

I wanna know what stardust is made of.

我叫洛伦佐，七岁。

My name is Lorenzo and I'm seven years old.

我想知道当星星……会发生什么。

I wanna know what happens when stardies.

我知道它们是由什么组成的。

I know what they are made of.

石头。

Rock.

我觉得它们是用亮片和金子做的。

I think they're made out of glitter and gold.

他们剪出一个星星的形状，然后让它发光。

They cut out a star shape and then they make it light up.

我知道谁能帮我们解答所有关于星星的问题，她自己就是一颗明星。

I know who can help us with all these star questions, and she's a bit of a star herself.

柯尔斯滕博士是一位天体物理学家。

Doctor Kirsten is an astrophysicist.

天体物理学家？

Astrophysicist?

天体物理学家研究关于恒星、太空中的事物以及宇宙的奥秘。

Astrophysicists learn all about the stars, things in space, and the mysteries of our universe.

我想我知道去哪儿找她，但我们最好带个手电筒。

I reckon I know where to find her, but we should probably bring a torch.

嘿，班克斯博士。

Hey, doctor Banks.

你好，尼德。

Hi, Nidj.

大家好。

Hi, everyone.

你好，基尔丝滕。

Hi, Kirsten.

你好。

Hello.

嗨，班克斯博士。

Hi, doctor Banks.

我就知道会在外面找到你。

I knew we'd find you out here.

你抓到我了。

You got me.

在夜空下用望远镜。

Under the night sky with a telescope.

基尔丝滕，我们对太空有很多问题。

Kirsten, we've got lots of questions about space.

你觉得你能帮帮我们吗？

Do you think you could help us out?

当然可以。

Of course.

恒星是怎么形成的？

How are stars made?

恒星是做什么的？

What star does?

恒星是怎么死亡的？

And how do stars die?

这是一连串的问题，答案就在那里。

That is a whole constellation of questions, and the answers lie right up there.

我认出那个星座了。

I recognize that constellation.

我能看到瑞安的腰带。

I can see Ryan's belt.

那是什么？一个锅？

It's a What's a saucepan?

你知道的，用来做饭的。

You know, to cook with.

就是一个锅。

It's a pot.

哦，对。

Oh, yeah.

像煎锅吗？

Like a frying pan?

那个

That

这组恒星有很多名字。

cluster of stars has lots of names.

对我们Wiradjuri族群来说，它是Bayami，我们的创世神灵。

To my Wiradjuri mob, it's Bayami, our creator spirit.

我还能看到他的膝盖和盾牌。

I can also see his knee and his shield.

你想仔细看看吗？

Do you wanna take a closer look?

怎么看？

How?

我们的想象力。

Our imagination.

是的。

Yeah.

走进我的宇宙飞船。

Step into my spaceship.

正在进行最终检查。

Initiating final checks.

主引擎点火。

Main engines firing.

检查完毕。

Check.

火箭助推器。

Rocket boosters.

检查完毕。

Check.

宇航服。

Space suits.

检查完毕。

Check.

那搭扣呢？

How about snaps.

检查完毕。

Check.

检查完毕。

Check.

大家都准备好了吗？

Everyone done away?

好了。

Yep.

所有系统正常。

All systems are go.

天空晴朗，可以起飞。

Skies are clear to take off.

收到。

Roger.

开始倒计时。

Begin countdown.

五、四、三、二，我们

Five, four, three, two, We're

进入太空。

in space.

他们

They're

在睡觉。

sleeping.

谁在睡觉？

Who's sleeping?

什么在睡觉？

What's sleeping?

婴儿恒星。

The baby stars.

猎户座星云是我们最近的恒星育婴室。

The Orion Nebula is our closest star nursery.

哦，听起来挺

Oh, sounds pretty

可爱的。

cute.

它们其实不是在睡觉。

They're not really sleeping.

不是。

No.

但这里确实很梦幻。

But it is pretty dreamy up here.

是的。

Yeah.

它就像一朵发光的、五彩斑斓的旋涡状云。

It's like a glowing, colorful, swirly cloud.

是的。

Yes.

星云是太空中由气体和尘埃组成的云团，是恒星诞生的地方。

A nebula is a cloud of gas and dust in space, and it's where stars are born.

怎么做到的？

How?

所有的尘埃聚在一起就形成了恒星。

All the dust joins together and makes a star.

有点吧。

Kind of.

是的。

Yeah.

这里有一种重要的气体在旋转。

There's an important gas swirling around in here.

它是婴儿恒星的食物。

It's the food for a baby star.

它叫做氢。

It's called hydrogen.

氢？

Hydrogen?

听起来不太好吃。

That doesn't sound very yummy.

是啊。

No.

确实不好吃。

It doesn't.

当气体移动时，它会收集太空中漂浮的尘埃颗粒。

As the gas moves, it picks up bits of dust that are floating in space.

太空中有尘埃吗？

There's dust in space?

在星云里？

In a nebula?

没带扫帚。

Didn't bring a broom.

保佑你。

Bless you.

恒星尘埃很奇怪。

Stardust had very strange.

哦，不。

Oh, no.

太空过敏。

Space allergies.

这可不是我们家里那种灰尘。

It's not like the dust we get in our homes.

这些微粒非常特殊，比一粒沙子小得多。

These are very special specs, and they're much, much smaller than a grain of sand.

当它们在星云中聚集在一起时，一颗恒星婴儿就开始形成。

As they swell together in this nebula, a baby star starts to form.

是什么让这一切运动起来？

What's making it all move?

太空中没有风，对吧？

There's no wind in space, is there?

没有光。

No light.

当然有光。

Of course, there is.

这被称为恒星风。

It's called stellar wind.

来自附近所有恒星的能量，甚至其他婴儿恒星的打嗝和喷嚏，都能推动这些气态尘埃云并使其旋转。

Energy from nearby all the stars and even the burps and sneezes from other baby stars can push these gassy dust clouds and make them spin.

婴儿恒星打嗝。

Baby stars burp.

一个巨大的气球爆炸了。

A giant balloon pop off.

不好意思，恒星。

Excuse me, star.

当它们吸收这些宇宙物质、氢气和尘埃颗粒时，一切开始聚集在一起。

As they're feeding on all this cosmic material, hydrogen gas and grains of dust, everything starts clumping together.

随着越来越多的微粒粘合在一起，婴儿恒星变得越来越大、越来越重。

As more bits stick together, the baby star gets bigger and bigger and heavier and heavier.

嘿。

Hey.

我们在移动吗？

Are we moving?

它越大越重，引力就越强。

The bigger and heavier it gets, the more gravity it has.

引力

Gravity

当你向上走时，引力会把你拉下来。

pulls you down when you go up.

如果没有引力，你就可以漂浮起来。

And if there's no gravity, you could you just float.

是的。

Yeah.

引力是一种将物体相互拉向彼此的力。

Gravity is the force that pulls objects towards each other.

质量越大的物体，引力越强。

Heavier things have a stronger pull.

所以我们能待在地面上，是因为地球是一个巨大的行星，它的引力在把我们这些渺小的人类拉向它。

That's why we stay on the ground, because the Earth is a big planet, so its gravity is pulling us, little humans, towards it.

但在太空中，更大的天体有着强得多的引力，比如恒星。

But in space, even bigger things have way stronger pulls, like stars.

是的。

Yes.

引力使地球和其他所有行星围绕太阳运转。

Gravity is what keeps the earth and all the other planets orbiting around the sun.

这个星云变得越来越大了。

This nebula is getting pretty big.

它是个饥饿的婴儿。

It's a hungry baby.

它拥有的引力越大，就会吸引越多的气体、尘埃和其他物质。

The more gravity it has, the more gas and dust and other objects it starts to pull in.

我们开始了。

We're starting.

我们正被

We're being

被这颗婴儿恒星的引力拉扯着。

pulled in by the baby star's gravity.

它看起来还不像一颗恒星。

It doesn't look like a star yet.

是的。

Yep.

当它旋转时，云团会扁平化成一个盘状。

As it spins, the cloud flattens out into a disc.

哇哦。

Woah.

哇哦。

Woah.

太旋转了。

It's too swirly.

我觉得我要吐了。

I think I'm gonna be sick.

来吧。

Come on.

我们去核心吧。

Let's head to the core.

哇。

Woah.

谢天谢地。

Thank goodness.

旋转停止了。

The spinning stopped.

我们在哪儿？

Where are we?

一颗年轻恒星的核心。

The core of a young star.

这个过程大约需要一百万年，但最终，那颗饥饿的婴儿恒星会吸入大量的气体和尘埃，不断成长，旋转速度也会逐渐减慢。

It takes about one million years, but eventually, that hungry baby star will pull in so much gas and dust that it grows and grows, and all that spinning slows right down.

它会变得多大？

How big does it get?

至少是木星体积的80倍。

At least 80 times the size of Jupiter.

真是个大宝宝。

That's a big baby.

这颗年轻的巨大恒星中，所有物质都在其自身巨大引力的压力下被挤压在一起。

Everything in this young massive star is getting squished together under the immense pressure of its own gravity.

温度在升高。

It's getting hot.

那是什么？

What's that?

一切东西。

Everything

物质被挤压得如此紧密，以至于氢原子开始融合在一起。

is being crushed together so tightly that the atoms of hydrogen are fusing together.

这就是恒星诞生的时刻。

This is the moment a star is born.

原子没有空间移动，所以它们结合在了一起。

There's no space for the atoms to move, so they're joining together.

这使得氢——这个饥饿的恒星婴儿的食物——转变成了氦。

That makes the hydrogen, which is the food for the hungry baby star, turn into helium.

氦？

Helium?

就像气球里让气球飘起来的那种东西？

Like the stuff in balloons that makes them float?

就是同一种东西。

The very same.

每个漂浮气球里的氦原子，都是由两个氢原子像这样猛烈碰撞而形成的。

Every bit of helium in a floating balloon was made by two hydrogen atoms smashing together just like this.

而且说那。

And says the.

没错。

Yep.

将氢转化为氦的过程被称为聚变。

Turning hydrogen into helium is called fusion.

它会产生大量的能量。

It creates a lot of energy.

它明亮而炽热，仿佛整颗恒星都试图向外爆炸。

It's bright and hot, and it's almost as if the whole star is trying to explode outward.

那它为什么不会直接炸开呢？

Why doesn't it just blow up?

引力。

Gravity.

引力在把它往下压，是吗？

The gravity is pushing it down, maybe?

是的。

Yes.

引力从各个方向向恒星施加压力。

Gravity is pushing down on the star from all sides.

正是这种向内的引力和向外的能量之间的平衡，使恒星保持形状和稳定。

It's this balance of gravity pushing in and energy pushing out that keeps the star in shape and stable.

就像无形的手将事物推回原位。

Like invisible hands pushing things back in.

这就是为什么恒星呈球形吗？

Is that why it's shaped like a ball?

没错。

Yep.

一旦恒星开始以氢为食并将其转化为氦，它就成熟了。

Once a star is feeding on hydrogen and turning it into helium, it's all grown up.

我们把恒星的成年期称为主序阶段。

We call a star's adult life its main sequence.

主序阶段能持续多久？

How long does the main sequence last?

较小的恒星可以在主序融合阶段持续数十亿年。

Smaller stars can stay in their main sequence of fusion for billions of years.

一旦它们吃光了所有的氢，就会开始把氦当作能量来消耗，但最终也会耗尽氦。

Once they gobble up all the hydrogen, they start munching on the helium as energy, but they eventually run out of that too.

然后灯就灭了？

And then the lights go off?

差不多吧。

Kind of.

是的。

Yeah.

较小的恒星会冷却并逐渐熄灭。

Smaller stars will cool down and fizzle out.

但这颗星可不是小恒星。

But this is no small star.

让我们跳过几百万年，看看会发生什么。

Let's jump ahead a few million years and see what happens.

那是什么声音？

What's that sound?

我们的幼星已经成长为一颗红超巨星。

Our baby star has grown up into a red supergiant.

红巨星？

A red giant?

哎呀。

Whoops.

这是对巨大恒星的称呼。

It's the name of really big stars.

巨大的恒星。

Gigantic star.

没错。

Yep.

超巨星的体积可以超过我们太阳的1000倍，而它们的结局只有一种。

A supergiant can be over 1,000 times the size of our own sun, and they only go out one way.

哎呀。

Uh-oh.

我想我知道接下来会发生什么。

I think I know what's coming next.

启动护盾。

Engage the shields.

我们即将发生超新星爆发。

We're about to go supernova.

大家系好安全带。

Buckle up, everyone.

大质量恒星的寿命通常比小而稳定的恒星短得多。

Massive stars tend to have much shorter lives than smaller, stable stars.

它们燃烧得又热又快。

They burn hot and fast.

你不是说需要几百万年吗？

Didn't you say it took a few million years?

在恒星的时间尺度上，这不过是眨眼之间。

It's the blink of an eye in star time.

为什么它们会爆炸，而不是像较小的恒星那样冷却下来？

Why do they blow up instead of cooling down like smaller stars?

它们如此巨大且强大，即使在氢和氦气体耗尽后，仍能持续进行核聚变。

They're so big and so powerful that they keep that fusion going long after the hydrogen and the helium gases run out.

它们开始使用其他元素作为燃料，情况就开始变得危险了。

They start using other elements for fuel, and things start to get dicey.

最终，向外推的能量与向内拉的引力之间的平衡被打破。

Eventually, that balance of energy pushing out and gravity pushing in gets unbalanced.

哪一方会赢？

Which side wins?

引力。

Gravity.

它会爆炸吗？

Is it gonna explode?

更准确地说，它是向内坍缩。

It's more like it implodes.

核心停止产生足够的能量向外推，恒星因此向内坍缩。

The core stops making enough energy to push outwards, and the star collapses in on itself.

坍缩发生得如此迅速，恒星的质量如此巨大，以至于它向宇宙中释放出一股巨大的能量、光和物质冲击波。

The collapse happens so fast, and the weight of the star is so massive that it sends a huge shockwave of energy and light and matter out into the universe.

快，大家把太阳镜系好安全带。

Quick, put your sunnies on seat belts, everyone.

这可真够混乱的。

That was hectic.

呼。

Phew.

嘿。

Hey.

我们回到星云里了吗？

Are we back in the nebula?

那些闪亮的东西是什么？

What are those sparkly thing?

我认为这确实展示了另一个星云，而它又孕育了一颗新恒星。

I think it really shows another nebula, which starts another star.

当一颗恒星死亡时，新的一颗便诞生了。

When a star dies, a new one comes to life.

没错。

Yep.

这是伟大的宇宙循环。

It's the great cosmic cycle.

一颗垂死的恒星会将它数百万年来所形成的物质全部释放回宇宙中。

A dying star sends everything it's made over millions of years back out into the universe.

这些宇宙尘埃不仅仅是普通的岩石。

That space dust isn't just a bit of rock.

它还包含碳、金、铁、氧——所有构成生命所需的元素。

It's also carbon, gold, iron, oxygen, all the things you need to make life.

哇哦。

Woah.

什么？

What?

我们得到的黄金就是这样来的吗？

Is that how we get gold?

这是真的吗？

Is that true?

没错。

Yep.

哇。

Wow.

所以恒星是由气体和尘埃聚集在一起形成的一个巨大能量球体，它们的核心温度极高、亮度极强，从而开始制造元素。

So stars are born from gas and dust sticking together to make a big ball of energy, and they burn so hot and bright that they start to make elements in their core.

超新星爆发后，这些元素会被释放回宇宙，用于形成更多的恒星。

And after a supernova, those elements get released back into the universe to make more stars.

还有行星。

And planets.

还有你和我。

And you and me.

什么？

What?

地球上的几乎所有东西都起源于恒星的核心。

Almost everything on Earth has its beginnings in the core of a star.

我们都是由恒星尘埃构成的。

We're all made of stardust.

我们是星星做的？

We're made of stars?

哇。

Wow.

别开玩笑了。

Come on.

我们回到实地吧。

Let's head back to solid ground.

看起来快日出了。

Looks like it's almost sunrise.

哦，不。

Oh, no.

我现在能看到星星了。

I can see the stars now.

但你看。

But look.

我们的恒星来了。

Here comes our star.

如果我们的恒星爆炸了，生命就无法存在了，因为我们的太阳帮助我们生存。

If our star exploded, there'd be no more life because our sun helps us to be alive.

我们的太阳是一颗较小的稳定恒星。

Our sun is a smaller, stable star.

它们比超巨星燃烧得更久，长达数十亿年。

They burn bright for billions of years longer than a supergiant star.

它们永远不会超新星爆发吗？

And they never go supernova?

不会。

No.

我保证。

I promise.

地球绝对安全。

Earth is totally safe.

凯尔丝滕，非常感谢你向我们讲解恒星的生与死。

Kirsten, thank you so much for teaching us about the life and death of a star.

你真的是一颗明星。

You really are a star.

随时欢迎。

Anytime.

外面的宇宙非常广阔。

It's a big universe out there.

谁知道我们接下来会发现什么呢？

Who knows what we'll discover next?

外星人？

Aliens?

所以，俊成、Naver、洛伦佐和梅茜，恒星诞生于巨大的气体和尘埃云中

So Junsei, Naver, Lorenzo, and Maisie, stars are born in huge clouds of gas and dust

在星云中。

In a nebula.

其中微小的颗粒旋转并粘合在一起，直到变得越来越大、越来越大。

Where the tiny specks swirl around and stick together until they get bigger and bigger and bigger.

它们变得极其庞大。

They get massive.

引力将恒星挤压得如此紧密，以至于其核心中的原子结合在一起。

Gravity squeezes the star so tightly that the atoms in its core join together.

氢转化为氦。

Hydrogen turns to helium.

这

This

这被称为核聚变。

is called fusion.

这是恒星的能量来源。

It's the food that powers the star.

它使恒星变得如此炽热和明亮。

It makes it so hot and so bright.

当一颗小恒星耗尽能量时，它会冷却下来，并缓慢地将能量释放回太空。

When a small star runs out of food, it cools down and slowly releases its energy back out into space.

它熄灭了。

It fizzled out.

当一颗大质量恒星耗尽能量时，它会向内坍缩。

When a massive star runs out of food, it collapses in on itself.

它

It

爆炸并将恒星尘埃向宇宙各处喷射。

explodes and sends its stardust out in all directions across the cosmos.

碳、金、氧、铁。

Carbon, gold, oxygen, iron.

这些元素将继续形成新的恒星、行星，以及你和我。

These elements go on to create new stars and planets and you and me.

我们是由恒星尘埃构成的。

We're made of stardust.

恒星形成与死亡的这一循环已经持续了数十亿年。

This cycle of stars forming and dying has been going on for billions of years.

自宇宙诞生以来。

Since the beginning of the universe.

这正是地球上生命得以存在的原因——不仅造就了你和我，也造就了陆地、海洋以及其间的一切生命。

And it's how life on Earth is even possible, not just to make you and me, but all life on land and in the sea and everything in between.