了解宇宙是如何运行的（2010）

How the Universe Works S01E03

Part 2 April 18, 2021, 7:56 p.m.

甚至几十亿年前遗留下来的
even billions of years ago.
经过那么久才传到来让我们看到
It's taken all that time to reach us.
今日见到的是那些星系的古老历史
So what we see today is the
ancient history of those galaxies.
我们在咍勃深空里见到一些小污点
When we look at the Hubble Deep
Field, what we see are little smudges.
一点不像今日见到的星系
They don't look much like
the galaxies we see today.
那些只是仅能辨别的小光点
They're just little smudges of
light that we can barely discern.
那些小光点里有数百万至数十亿颗
Those smudges of light contain
millions or billions of stars
刚开始聚集在一起的恒星
that have just begun to merge together.
这些微弱的光点就是最早的星系
These faint smudges are the
earliest galaxies of all.
它们大约在宇宙初开后十亿年形成
They were formed around one bi 11 ion
years after the beginning of the universe.
不过那只是哈勃能看到最远的情景
But that's as far
back as Hubble can see.
若想回到更久远的从前
If we want to go even
further back in time,
就需要另一种望远镜
we need a different kind of telescope,
这望远镜太大, 无法射上太空
one too big to launch into space.
我们在智利北部的沙漠上有一个
Well, now we have one in the
high desert of northern Chile.
这是ACT, 阿卡塔玛宇宙望远镜
This is ACT, the Atacama
Cosmology Telescope.
高1万7000呎
At 17,000 feet,
是全世界最高的地面望远镜
it's the highest ground-based
telescope in the world.
我很喜欢在ACT的极端环境下工作
I really like working in the
extreme environment of ACT.
经常非常寒冷, 风很猛烈
It's very, very cold often
and the wind blows violently.
不过好处是从我们的角度来说
But the good thing about
it from our point of view...
天空几乎所有时间都非常清晰
is that the sky is very, very
clear, almost all the time.
ACT的精确镜子要对准最早的星系
Clear skies are important
就一定要有清晰的天空
for ACT's precise mirrors to
focus on the earliest galaxies.
ACT让我们把某部分的天空放大
With ACT, we're able to zoom in
看到前所未见的细节
with unprecedented detail
on parts of the sky.
我们还可以研究结构的形成过程
We can also study the progress
of growth of structures,
像星系或星系团等结构
where structures or things like
galaxies or clusters of galaxies
看到极细微的细节
with a very fine scale detail.
ACT不是侦测可见光
ACT doesn't detect visible light
它侦测宇宙微波
It detects cosmic microwaves
追溯到宇宙只有几十万年历史之时
from the time the universe was just
a few hundred thousand years old.
这望远镜不只能侦测早期的星系
The telescope not only
detects early galaxies,
还能看到它们怎样成长
it actually sees how they grew.
我们可以追踪
We're able to track the progress
星系和星系团形成的过程
of the formations of galaxies
and clusters of galaxies.
看到由宇宙只有几十万年历史
We see the footprints
of all the galaxies
直到今天这段期间
that have grown in the time
所有星系留下的足印
between when the universe was a few
hundred thousand years old till now.
ACT帮助天文学家了解…
ACT has helped astronomers
understand how galaxies have evolved
由天地初开至今, 星系怎样演化
since almost the
beginning of time itself.
你可以开始回答这些问题:
You can start answering the question:
「星系年轻的时候是怎样的? 」
"What did galaxies look
like when they were young?"
「跟今日的星系有何分别? 」
"How did they compare
with modem day galaxies?"
「它们是怎样成长的? 」
"How have they grown?"
天文学家见到星系怎样由一群恒星
Astronomers are seeing how
galaxies evolve from groups of stars
演化成今日见到拼凑而成的星系
into the patchwork of
systems we see today.
我们现今的理解是恒星形成星群
Our current understanding
is that stars form clusters
星群形成星系, 星系形成星系团
that build into galaxies, that
build into clusters of galaxies,
星系团形成超星系团
that build into super
clusters of galaxies,
那是今日见到在宇宙里最大的结构
the largest structures we
observe in the universe today.
早期的星系很混乱
Early galaxies were a mess,
只是一团团的恒星、气体和尘埃
lumpy bunches of stars, gas and dust.
今日的星系看起来却整齐有序
But today galaxies
look neat and orderly.
混乱的星系怎会变成…
So how do messy galaxies transform into
漂亮的螺旋形和焰火轮?
beautiful spirals and pinwheels?
答案是引力
The answer is gravity.
引力塑造星系, 并控制它们的未来
Gravity shapes galaxies
and controls their future.
在大部分星系的中心
There is an unimaginably powerful and
incredibly destructive source of gravity
都有极强大且破坏力惊人的引力
at the heart of most galaxies.
在我们的银河系深处也有一股引力
And there's one very deep at
the centre of our own Milky Way.
星系存在了超过120亿年
Galaxies have existed
for over 12 billion years.
我们知道这些巨大的恒星帝国
We know these vast empires of stars
有各种不同的形状和体积
come in all shapes and sizes,
由旋转的螺旋形, 到巨大的球状
from swirling spirals
to huge balls of stars.
不过我们对星系仍所知不多
But there's still a lot
about galaxies we don't know.
星系怎会有现在的形状?
How did galaxies come to
have the shapes they do?
螺旋星系是不是一直是螺旋形状?
Was a spiral galaxy
always a spiral galaxy?
答案几乎肯定是不
The answer is almost certainly no.
很年轻的口星系是一团混乱无序的…
Very young galaxies
are messy and chaotic,
恒星、气体和尘埃
a jumble of stars, gas and dust
经过几十亿年后
Then, over billions of years,
演化成秩序井然的结构
they evolve into neat,
organised structures
像漩涡星系
like the Whirlpool galaxy.
或我们的银河系
Or our own Milky Way.
我们的银河系最初不是…
Our Milky Way began
一个单一的小星系, 而是很多个
not as a single baby galaxy but many.
今日的银河系曾经包含…
What is now our Milky Way was once
很多细小的结构
comprised of lots of small structures,
不规则形状的物体开始合并
irregularly shaped objects
that began to merge.
引力把那些细小的结构拉在一起
The thing that pulls the small
structures together is gravity.
逐渐地把恒星往内拉
Gradually, it pulls stars inward.
它们开始越转越快, 并变成圆盘
They begin spinning faster and
faster and flatten into a disk.
恒星和气体被卷成巨大的螺旋臂
Stars and gas are swept
into huge spiral arms.
这过程在宇宙里重复好几十亿次
This process was repeated billions and
billions of times across the universe.
这些星系各有不同
Each of these galaxies looks different.
却有一个相同之处
But they do have one thing in common,
它们都环绕中心运行
they all seem to orbit
something at their centre.
一直以来, 科学家都很想知道…
For years, scientists wondered
甚么巨大力量足以改变星系的行为
what could be powerful enough
to change how a galaxy behaves.
他们找到了答案
They found out.
黑洞
A black hole.
不是任何一种黑洞
And not just any kind of black hole.
而是超级巨大的黑洞
A super massive black hole.
超级黑洞存在的第一个迹象
The first clue that super
massive black holes existed
是在一些星系的中心
was at the heart of some galaxies,
有一股巨大的力量从中心散发出来
there was an immense amount of
energy emanating out from the centre.
我们见到这些黑洞…
What we're seeing is the black holes
和这些星系在吞食周围的物质
and these galaxies feasting
on the material around them.
像丰富的感恩节晚餐
So it's like having a
huge Thanksgiving dinner.
那些食物就是气体和恒星
The meal is gas and stars.
被那超级巨大的黑洞吞食