了解宇宙是如何运行的（2010）

How the Universe Works S01E02

Part 4 April 18, 2021, 7:55 p.m.

region right at the centre.
儿童常常问
Children ask the question:
月球绕着地球转, 地球绕着太阳转
"If the moon goes around the Earth,"
"the Earth goes around the sun,"
那么太阳绕着甚么转?
"then what does the sun go around?"
这问题很好
It's a good question,
天文学家也有同样疑问
and astronomers ask the same thing.
也许银河系中心有些东西
Maybe there was something going
on at the heart of the Milky Way,
或者中心存在一个黑洞
perhaps a black hole at the very centre.
但黑洞无法观测
But because we can't
actually see a black hole,
我们所能做的就是寻找蜘丝马迹
the best they could do was
look for telltale signs.
用红外线望远镜观测银河系中心
Using infrared telescopes, they
looked at the middle of the galaxy
发现一个高密度的恒星群
and discovered a densely packed
swarm of millions of stars,
但无法看到恒星群中心
but they couldn't see
what was at the centre.
一个科研团队已用了15年寻找线索
One team has spent 15
years looking for clues.
位于夏威夷莫纳克亚山
High above the clouds
on Mauna Kea, in Hawaii,
就是巨型的凯克望远镜
the giant Keck telescope
能够观测到银河系中心
has the power to see right through
to the centre of the Milky Way.
为证实黑洞的存在
The region which we have to study
我们必须研究的那个区域非常小
to prove that there's a black
hole is incredibly small.
这无异于♥大♥海♥捞针
It is absolutely the case of
looking for a needle in a haystack,
不同只是我们知道针的位置
except we know exactly
where the needle is.
格茨在寻找银河系黑洞的努力中
Andrea Ghez has spent countless nights
scanning the centre of the galaxy
度过了无数不眠之夜
for signs of a black hole.
要做这个实验, 我们需要观测到…
To be able to do this experiment,
one has to be able to see the stars
接近银河系中心的恒星
that are very close to
the centre of the galaxy
并对它们进行精确定位
and to position them
incredibly accurately,
这就好比我从洛杉矶
and this would be equivalent
to me in Los Angeles
看着身处纽约的你
looking at you in New York
和看到你手指的微小动作
and seeing you be able to
move your finger like this.
凯克望远镜一经启用
As the Keck kicks into action,
就探测到大气层中…
a laser beam detects tiny
disturbances in the atmosphere
使图像失真的微小扰动
that would distort the image.
直径30呎的镜面转动进行校正
Motors then adjust the huge
30-foot mirror to compensate.
图像极为清晰, 可以追踪到…
The image is clear
enough to track the stars
银河系中心的恒星
at the heart of our galaxy.
15年间格茨拍摄了数千张照片
Ghez has taken thousands of
images over the last 15 years.
这些照片揭示出一个惊人事实
And what they reveal is amazing.
银河系中心的恒星
The stars at the centre of the galaxy
以时速数百万哩高速移♥动♥
are moving at millions of miles an hour.
银河系中心是非常极端的环境
The centre of the galaxy is
a very extreme environment
恒星移♥动♥的速度
The speeds with which
stars move is much higher
比银河系任何地方都快很多
than anywhere else in our galaxy,
那绝对是黑洞的征兆
and that is absolutely the
signpost of the black hole.
它们看起来像小行星
They look like tiny planets
绕着隐形太阳高速旋转
racing around an invisible sun.
但它们不是行星, 而是恒星
But they're not planets, they're stars.
必须有强大引力牵引这些巨星
It takes a lot of gravity
to swing huge stars around
沿着靠近中心的轨道高速转动
in such fast, tight orbits.
宇宙只有一种物体有如此大牵引力
There's only one thing in the
universe with that much pull:
就是超大质量黑洞
a supermassive black hole.
这些恒星说明在银河系中心
Watching these things shows the
presence of a four million times
有一个质量为太阳400万倍的黑洞
the mass of our sun black hole located
right at the heart of our galaxy.
这是个重大发现
It is a huge discovery.
银河系里的一切, 包括太阳系
Everything in our galaxy,
including our own solar system,
都在绕着一个超大质量黑洞运行
orbits around a supermassive black hole.
但黑洞并非只存在于银河系中心
But the Milky Way isn't the only
galaxy with a black hole in the middle.
宇宙中很多星系的中心
There are super massive black holes
都存在超大质量黑洞
at the heart of most
galaxies in the universe.
仙女星系是离我们最近的邻居
The Andromeda galaxy is
our closest neighbour.
它绕着一个比太阳…
It circles around a
supermassive black hole
重1.4亿倍的黑洞旋转
weighing 140 million
times more than our sun.
其它星系, 像这个眺7
Other galaxies, like this one, M87,
有相等于太阳重量200亿倍的黑洞
have black holes weighing
as much as 20 billion suns.
黑洞是怎样变得如此巨大
How do black holes get so big,
它们为何存在于星系的中心?
and what are they doing
at the centre of galaxies?
为了找到答案, 我们需要追溯到…
For answers,
140亿年前宇宙刚诞生的时候
we have to go back nearly 14 billion
years, to the beginning of the universe.
那时宇宙充满大爆♥炸♥残留的气体云
Back then, the universe was a filled
with clouds of gas from the big bang.
在一些地方, 气体够浓厚
In some places, the gas was thick enough
从而形成数百万颗恒星
for millions of stars to form.
最初的恒星中多数都是超巨星
Most of the first
stars were supermassive.
温度极高, 燃烧速度也快
They burned hot and fast,
它们在爆♥炸♥后产生大量黑洞
and then exploded creating
lots of black holes.
早期宇宙是个野蛮疯狂的地方
The early universe was
a wild and crazy place
大范围的物质土崩瓦解
where huge regions of mass
were collapsing catastrophically
从而制♥造♥出黑洞
producing black holes.
其实早期宇宙
And in fact, the early universe
可能处处充斥着新生黑洞
might have been full of
emerging black holes everywhere.
引力将许多黑洞牵引到一起
Gravity pulled many of them together.
它们相互合并形成更大的黑洞
All over the early universe they merged,
creating larger and larger black holes.
数亿年间, 黑洞不断增长
Over hundreds of millions of
years, each black hole grew
产生更大引力吸入更多星际气体
producing stronger gravity and
pulling in more and more gas.
新恒星从气体诞生, 形成原始星系
New stars were born from the
gas, forming primitive galaxies.
黑洞不断吸入气体直到容不下为止
But the black hole kept on sucking
in gas until it could take no more.
点燃宇宙中最强大喷火器
Igniting the most powerful
flame thrower in the universe.
一个年轻星系就是一个星团…
A young galaxy is a
vast cluster of stars,
由气体中诞生的恒星所构成
stars that formed from clouds of gas.
新星系中心有个年轻超大质量黑洞
At the centre of the new galaxy
is a young suoermassive black hole
通过吞噬气体而不断成长
feeding on the gas,
getting bigger and bigger.
若你能想象当星系很年轻正在成形
If you can imagine when a galaxy
is very young and still forming,
中心形成了一个超大质量黑洞
there's a supermassive black
hole forming at the core
而气体不断坠落其中
and the gas is still falling into it
继续形成这一星系
and still forming the galaxy.
在中心黑洞附近, 物体变得非常热
Well, near that central black
hole, things are getting very hot,
物质不断升温
that material's heating up.
气体高速进入黑洞
Gas is speeding into the black hole,
但黑洞超载
but it overloads,
没有空间供多余炙热气体进入
and there's no room for
all that excess hot gas.
无法进入的气体被黑洞吐出
It has nowhere to go but out.
喷入太空形成巨大能量流
It's blasted into space
in huge jets of energy.
每道能量流都比太阳系宽20倍
Each jet is 20 times