了解宇宙是如何运行的（2010）

How the Universe Works S01E04

Part 3 April 18, 2021, 7:56 p.m.

以至几十亿年才能到达地球
even billions of years to reach us.
因此当哈勃太空望远镜
So when the Hubble Space Telescope
望向宇宙偏远的角落时
looks into the far
corners of our universe,
看到的是飞驰了几十亿年的光
it sees light that's been
travelling for billions of years.
今天看到来自船底座伊塔星的光
The light we see today from
Eta Carinae left that star
是远祖8000年前开始农耕时射来的
when our ancestors first
farmed the land 8,000 years ago.
参宿四的光在500年前…
Light from Betelgeuse has been travelling
since Columbus discovered America,
哥伦布发现美洲时已发射出来
500 years ago.
太阳的光也需要8分钟才传到地球
Even light from our own sun
takes eight minutes to reach us.
其实早在展开太空之旅前
But even before light starts
its journey through space,
光已飞驰了几千年
it's already been travelling
for thousands of years.
当太阳在核心把氢熔入氦之中
When the sir fuses hydrogen
into helium in its core,
就创造出光子
it creates a photon of light,
光的粒子
a particle of light
新光线要走很远才到达恒星表面
That new ray of light has a long way
to go just to reach the star's surface.
由于要穿越恒星
There's a whole star in its way,
所以, 光子诞生后, 走不了多远
and so when the photon is created,
it doesn't get very far before,
就撞向其它原子、光子、中子等等
it immediately slams into another atom,
another proton, another neutron, something.
被吸收, 再给射向另一个方向
It gets absorbed and then
shot off in another direction.
因此光子很任意的在太阳内移♥动♥
And so it's sort of randomly
moving around inside of the sun
很辛苦地逃出来
and it has to work its way out.
对光子来说
For the photons,
要撞上气体原子几十亿次
it's a wild ride smashing into
atoms of gas billions of times
才能千辛万苦的逃离恒星内部
as they struggle to escape
from inside the star.
整个过程有趣之处
What's funny about this whole process
是光子要花千千万万年
is that it takes the photon
thousands and thousands of years
才能从太阳核心去到表面
to get from the core of
the sin to the surface,
但一旦到达太阳表面
and yet once it hits the surface,
从那里到地球就只需要8分钟
it's only an eight-minute
trip from there to here.
光子提供光和热
Photons are the source
of light and heat,
但亦带来另一种更具破坏力的东西
but they also cause something
far more destructive:
太阳风
the solar wind.
到达表面时, 光子会加热太阳外层
As they reach the surface, photons
heat up the outer layers of the sun,
使之围绕恒星飞驰
sending it hurtling around the star,
形成强烈的湍流和强劲冲击波
creating extreme turbulence
and intense shockwaves.
狂暴得我们也听得到
It's so violent, we
can actually hear it.
由太阳和日球观测站人造卫星录得
Picked up by the
orbiting SOHO satellite,
这是太阳的声音
this is the sound of the sun.
高速飞驰的气体亦产生强大磁场
The speeding gases also generate
powerful magnetic fields.
恒星旋转时, 磁场相撞, 冲破表面
As the star rotates, the fields
clash and burst through the surface.
巨大磁环迸发进入太空
Giant, magnetic loops erupt into space.
有些大得能让地球穿过去
Some are so large, the Earth
could pass right through them,
周围还有几千英里空位
with thousands of miles to spare.
它们很壮观, 杀伤力极大
They are spectacular
and they are deadly,
把大量电粒子射到太空深处
blasting a stream of electrical
particles deep into space.
这就是太阳风
This is the solar wind.
它能破坏宇宙飞船和人造卫星
It can damage spaceships and satellites,
甚至危害航♥天♥员的生命
even put astronauts' I ives in jeopardy.
为了了解磁环怎样触发太阳风
To discover how the magnetic
loops trigger the solar wind,
加州理工学院一组科学家
a team of scientists at Caltech
在地球重塑恒星表面
recreate the surface of a
star, right here on Earth.
实在令人很兴奋
It's very exciting to be able...
在实验室里
to create in a laboratory
制♥造♥跟太阳表面…
the same sort of physics
相同的物理现象
that are on the solar surface.
我们无法前去, 无法派探测器去
We can't go there, we can't
even send probes there,
但我们能试着研究那里的情况
but we can try to study
what's happening there.
无空气舱模拟太空的真空状态
An airless chamber simulates
the vacuum of space.
庞大的电流
An enormous electric current
制♥造♥出一对人造磁环
produces a pair of
man-made magnetic loops.
我们在实验室制♥造♥的等离子环
The main difference between the
plasma loops we make in the lab
跟太阳表面那些的主要分别是大小
and the ones on the surface
of the sun is just their size.
我们在实验室制♥造♥的, 约这么大
The ones we make in lab are,
you know, about this big,
太阳表面的, 是地球大小的许多倍
and the ones on the surface of the sun
can be many times the size of the Earth.
实验显示当磁环在实验室内相撞
Their experiment reveals that when
magnetic loops clash in the lab,
就触发大量能量迸发
they trigger a massive burst of energy.
当巨型磁环在恒星表面相撞
When giant loops collide
on the surface of a star.
释放的能量令温度飙升
the energy released sends
temperatures soaring,
从1万度急升至1000万度
from 10,000 to 10 million degrees.
那股极大热力触发太阳风
That extreme heat
triggers the solar wind,
令数百万吨♥计的粒子涌进太空
sending millions of tonnes of
particles streaming out into space.
恒星越大, 太阳风的杀伤力就越大
The bigger the star,
the more deadly the wind.
若地球以相同距离
If we were orbiting a
star like Eta Carinae
围绕船底座伊塔星之类的恒星运转
at the same distance,
地球准会变成炼狱
it would be hell on
Earth, quite literally.
射向地球的能量
The amount of energy
blasting down on the Earth
能剥去大气层, 烧沸海洋, 熔掉表面
would strip away our atmosphere,
boil our oceans, melt the surface.
了解恒星的运作或能助我们自保
Understanding how stars work
could help us protect ourselves
方法是预测它们最大的破坏力
by predicting their
most destructive forces.
但当恒星消亡, 我们就无法自保
But there's nothing we can do to
protect ourselves when a star dies.
进入最后阶段, 恒星消灭周遭一切
In its final moments, it
annihilates everything around it
每颗新诞生的恒星都注定会消亡
From the moment of its birth,
every star is destined to die.
燃料会耗尽
Its fuel will run out
然后, 重力将战胜核聚变
Then, gravity will win
the battle with fusion,
触发连串摧毁恒星的事件
triggering a chain of events
that will destroy the star.
我们的太阳亦不例外
Our sir is no exception.
每一秒
Every second,
其核心燃烧6亿吨♥氢燃料
it burns through 600 million tonnes
of the hydrogen fuel in its core.
以这速度计算, 氢约70亿年就耗尽
At that rate, the hydrogen will run
out in about seven billion years.
随着氢渐少, 核聚变的速度亦减慢
As the hydrogen gets used up, it slows
down the fusion at the star's core.
这就让重力占上风
This gives gravity the edge.
随着核聚变往外推的力度减轻
With less fusion pushing outward,
重力挤压恒星向内压缩
gravity crushes the star in on itself.
但核聚变反击, 加热恒星外层
But fusion fights back heating
the star's outer layers.
给气体加热, 气体就会膨胀
When you heat up a gas, it expands,
因此太阳将会变大
and so the sin will actually expand up.
太阳直径不再是现在的100万英里
Instead of being a million
miles across like it is now,
它不断膨胀, 至直径约达1亿英里
it will swell up until it's about
a hundred million miles across.
我们的太阳将变成红巨星