了解宇宙是如何运行的（2010）

How the Universe Works S08E07

Part 1 Jan. 30, 2022, 2:58 p.m.

岛屿有边缘
Narrator: Islands have edges.
行星有边缘
Planets have edges.
甚至星系也有边缘
Even galaxies have edges.
但是宇宙呢？
But what about the universe?
作为探险家，作为好奇的人类
As explorers,
as curious humans that we are,
我们对界限和限制着迷
we're obsessed with boundaries
and limits.
我们想知道
And we want to know,
“整个宇宙是否有极限？”
"does the whole thing,
the universe, have a limit?"
宇宙有边缘吗？好吧，答案是既肯定又否定
does the universe have an edge?
Well, the answer is yes and no.
这取决于你所说的边缘是什么意思
It depends on
what you mean by edge.
我们能看到边缘吗？
Narrator:
The edge of what we can see?
我们能到达边缘吗？
The edge of where we can go?
还是现实本身就有边缘？
Or the edge of reality itself?
泰勒:观察宇宙的边缘
Thaller: Looking out to the edge
of the universe
对于理解我们在宇宙中的位置
is tremendously important
to understand
是非常重要的
our place
in the universe itself.
布洛克:我们说的是我们的宇宙边缘
Bullock: We're talking
about our universe.
我们谈论的是我们存在的东西
We're talking about the thing
that we exist within.
事实上是
The most fundamental
thing there is,
我们被迫地去理解它
we're driven to understand it.
人们总是渴望把知识推向边缘
There is always a desire to push
the knowledge to the edge.
那么，我们能找到
Narrator:
So, can we ever find
宇宙的边缘吗？
the edge of the universe?
宇宙是如何运行的
第八季第7集宇宙的边缘
♪
2016年，哈勃太空望远镜
2016,
the hubble space telescope
转向大熊星座的
turned toward
a dark patch of sky
一片黑暗的天空
in the constellation ursa major.
它捕捉到了一个模糊的光点
It captured an image
of an indistinct blob of light.
这束光来自一个名为 gn-z11 的遥远星系……
The glow is from a distant
galaxy called gn-z11...
♪
……这是我们观测到的最遥远的星系
...The most distant galaxy
we've ever observed.
但这是宇宙的边缘吗？
But is this the edge
of the universe?
泰勒:我们周围的宇宙充满了星系
Thaller: The universe all around
us is filled with galaxies,
所以我们很自然地会说，“会有最后一个星系吗？”
so it's kind of natural to say,
"would there be a final galaxy?
“如果你旅行到足够远的地方”
If you traveled far enough away,
“你最终会在宇宙的最后一个星系”
would you finally be at the very
last galaxy in the universe
“向空无一物的空间望去吗？”
looking out into empty space?"
这是个很难回答的问题
narrator: That's a difficult
question to answer.
因为我们能看到的距离是有限的
Because there's a limit
to how far we can see.
这一切都归结于光速
It all comes down
to the speed of light
和宇宙的年龄
and the age of the universe.
了解宇宙边缘的关键在于
The key to understanding
the edge of the universe
光的传播速度非常非常快
is that light travels
very, very fast,
但不是无限快
but not infinitely fast.
从宇宙的一个地方
It takes time for it
to get from one place
到另一个地方需要时间
in the universe to the other.
你打开窗帘，光线充满整个房♥间
You open the curtains,
light fills the room.
它似乎根本不会移♥动♥
It doesn't seem
to travel at all.
但在浩瀚的宇宙中
But over the vast distances
of the universe,
你会注意到这个旅行的时间
you actually notice
this travel time.
即使是9300万英里（约1亿5000万公里）外的太阳
Even the sun
93 million miles away,
光也需要8分钟才能到达我们这里
the light takes eight minutes
to get to us.
当你看星星的时候，我们开始用光年
When you look out at the stars,
we start to think of distance
来测量距离，因为光从那些星星
in terms of light-years
because it takes years
到我们这里需要很多年
for the light
to get from those stars to us.
当你观察星系时，你所观察的星系有
Then when you look at galaxies,
then you're talking about
数百万或数十亿光年远
millions
or billions of light-years.
当我们看到 gn-z11 星系发出的光时
Narrator: When we look at the
light from galaxy gn-z11,
我们看到的是134亿年前发出的光
we're seeing light emitted
13.4 billion years ago.
你找不到
You can't really
even find a galaxy
比这更远的星系了
too much farther away than that
因为宇宙只有138亿年的历史
because the universe
is only 13.8 billion years old,
而星系的形成需要一定的时间
and it takes a certain amount of
time for galaxies to even form.
所以我们不会发现
So we're not going to find
too many more galaxies
比这个更远的星系
farther away than this.
如果物体足够远，那么在宇宙的年龄时间内
If things are far enough away,
there is no way that light
光是不可能到达我们这里的
can get to us
in the age of the universe.
这意味着我们所能看到的宇宙的边缘
What this means
is there's a hard limit
存在一个严格的限制
to the edge of the universe
that we can see,
这是由宇宙的年龄所决定的
and this is set
by the age of the universe.
Gn-z11 在宇宙早期
Narrator: Gn-z11 sparked
into life
就被点燃了
early in the history
of the universe,
在大爆♥炸♥后4亿年
just 400 million years
after the big bang.
在那之前，没有发光的星星
Before that, there were no stars
to send out light.
泰勒:如果你朝任何方向看
Thaller: If you look
in any direction at all,
你就会回到没有恒星、没有星系的时候
you get all the way back to
when there were no stars,
只有非常非常热的气体
no galaxies,
nothing but very, very hot gas,
这些气体在我们周围形成了一个壳
and that sort of forms
a shell around us.
外层是宇宙微波背景
Narrator: That outer shell is
the cosmic microwave background.
它是宇宙中最古老的光
It is the oldest light
in the universe,
是宇宙诞生和大爆♥炸♥的
the echo of the birth
of the universe,
回声
the big bang.
我们宇宙的边缘
The edge of our universe,
我们能看到的最远的东西
the very furthest thing
that we can see,
是宇宙本身形成的
is one of the earliest relics
最早遗迹之一
of the formation
of the universe itself.
这就是宇宙微波背景
That is the cosmic microwave
background.
我们称之为可观测宇宙的边缘
Narrator: We call this the edge
of our observable universe.
所以我们有一个可观测的宇宙
So we have an observable
universe, but beyond that,
但除此之外，即使有东西存在
even if there
are things out there,
我们也不可能看到它们
there's no way we can see them
因为光到现在还不可能到达我们这里
because the light just could
not have gotten to us by now.
顾名思义，可观测宇宙
Narrator: As the name states,
the observable universe
就是我们能看到的宇宙的一部分
is simply the part
of the universe we can see.
我们可以把可观测宇宙