了解宇宙是如何运行的（2010）

How the Universe Works S08E07

Part 6 Jan. 30, 2022, 2:59 p.m.

an infinite number of galaxies
也可能有无数个没有生命的行星
that have planets with life,
an infinite number without life,
那么因为生命确实出现在地球上
then because life
did appear here on earth,
这在物理上是可能的
it's physically possible,
因此，它肯定会发生在
therefore,
it will definitely happen
宇宙的其他地方
elsewhere in the universe.
在平坦的宇宙中
Narrator: In a flat universe,
外星生命可能有无限多种形式
alien life could come in
an infinite number of forms,
这是一个完全陌生的保证
but there is an altogether
stranger guarantee.
如果宇宙没有边缘，这意味着
If the universe has no edge,
this means that
看起来不可能的事情就变成了可能了
things that seem like they are
impossible become possible.
每种可能的物质排列
Every possible arrangement
of matter,
每种可能的历史
every possible history.
某个星系中的太阳系，某个像地球一样的行星
A galaxy of a solar system
of a planet like earth
是有可能的
is possible
而且正在发生，就在那里的某个地方
and is happening right now
in parallel to us
与我们平行
somewhere over there.
弗里斯:所以这意味着一定有另一个地方
Freese: So that means that there
has to be another place
有一个和我们一样的星系
that has a galaxy just like ours
它也会有一个和我们一样的地球
and it would have an earth
just like ours.
会有人有另一个版本的你
It would have people who would
have another version of you,
另一个版本的我
another version of me.
这是100%的保证，有另一个马克斯·泰格马克在那里
It's 100% guaranteed that there
is another max tegmark out there
确定有这样的对话，事实上，有很多这样他们
having exactly this conversation
and in fact many of them.
一个无限的宇宙充满了马克斯·泰格马克
Narrator: An infinite universe
full of max tegmarks
也许这是一个奇怪的概念
may be a strange concept,
但真正令人费解的是去理解
but what's truly mind-bending
is understanding
一个平坦的宇宙的物理学
the physics of a flat universe.
如果宇宙是无限的，它在膨胀
If the universe is infinite
and it's expanding,
它会膨胀到什么程度，会从什么地方开始？
what's it expanding into
and what did it expand from?
宇宙曾经有过边缘吗？
Was there ever an edge
to the universe?
幸运的是，答案就是这个问题
Fortunately, the answer is that
it doesn't make sense
没有任何意义
to ask that question.
一切都在膨胀
Everything is expanding,
包括我们所在的宇宙
including the universe
that we exist within.
所以实际上，它没有膨胀成任何东西
So in fact, it's not expanding
into anything
因为它就是一切
because it is everything.
♪
为了帮助理解无限宇宙中
narrator: To help understand
what's going on
发生了什么
in an infinite universe,
我们需要回到大爆♥炸♥
we need to go back
to the big bang.
我们可以把大爆♥炸♥想象成空间中的爆♥炸♥
We want to think of the big bang
as an explosion in space,
就像它发生在某个地方一样
like it happened someplace,
但大爆♥炸♥之前没有任何地方
but there wasn't any place
before the big bang.
空间存在于大爆♥炸♥本身的内部
Space existed inside
of the big bang itself.
所以这不是在空间中的爆♥炸♥
So it's not an explosion
in space,
而是空间的爆♥炸♥
it's an explosion of space.
我们有时会被告知，在大爆♥炸♥中
We're sometimes told that
at the big bang,
宇宙开始非常非常小然后变得很大
the universe started out very,
very small and then got big,
但一个有限的点是如何变成无限的呢？
but how can a finite point
become infinite?
如果宇宙是无限的
Well, if the universe
is infinite,
那么大爆♥炸♥时也是无限的
then it was also infinite
at the big bang.
这是一件非常费解的事情
This is a tough thing
to think about.
可以这样想
Think about it this way.
在无限的宇宙中，星系永远存在
In an infinite universe,
the galaxies go on forever
而现在每个星系之间都有很长的距离
and now there's a great
distance between every galaxy.
但很久以前
But once upon a time,
星系之间的距离更近
the galaxies
were closer together,
距离只有现在距离的一半
say half their current
distance apart,
但它们仍然永远在继续
but they still went on forever.
宇宙仍然是无限的
The universe was still infinite.
在平面宇宙中
Narrator:
In a flat universe,
空间从一开始就是无限的
space was infinite
from the beginning.
宇宙中从来没有一个点
There was never
a single point in space
发生过大爆♥炸♥
where the big bang happened.
它的发生无处不在
It happened everywhere.
无限的宇宙提供了无限的可能性
An infinite universe offers
infinite possibilities
但空间没有边缘
but no edge to space.
但也许还有另一种边缘
But there may be
another kind of edge,
只有在宇宙消亡时才会显现出来
one that will only reveal itself
if the universe dies.
♪
我们生活在一个无限膨胀的宇宙中
narrator: We live in an infinite
and expanding universe.
空间没有边界它会一直延续下去
Space has no edge.
It goes on forever.
♪
但我们的宇宙可能存在另一种边缘
but there could be a different
kind of edge to our universe,
时间的边缘
an edge of time.
宇宙似乎始于138亿年前
The universe seems to have begun
所以人们倾向于认为
13.8 billion years ago
in the past,
宇宙在时间上
so there's some inclination,
some impression,
是有限的
that it's finite in time.
我们所说的大爆♥炸♥，就我们所知
What we call the big bang is,
as far as we understand it,
是一个开始，宇宙的开始
a beginning,
a start of the universe.
宇宙的年龄是有限的
The universe has a finite age.
那么，它在未来有边缘吗？
Now, does it have an edge
in the future?
我们曾经认为，时间总有一天
Narrator: We used to think
that time would someday
会和行星、星系
come to a catastrophic end,
以及宇宙中的所有生命一样
along with the planets,
galaxies,
走向灾难性的终结
and all life in the universe.
如果我们知道有一次大爆♥炸♥，如果我们知道宇宙有开始
If we know there's a big bang,
if we know the universe started,
有膨胀和冷却，我们就会很自然地想
it expanded and cooled,
it's very natural to wonder
是否有一天膨胀会停止，逆转
whether or not someday
the expansion will stop,
然后回来，这就是大收缩
reverse, and come back,
and that's a big crunch.
♪
在大收缩中
narrator: In a big crunch,
我们膨胀的宇宙会开始收缩
our expanding universe
would begin to contract.
恒星和行星会相互撞击
Stars and planets would smash
into each other.
星系会发生碰撞
Galaxies would collide,
宇宙中剩下的所有生命
and all of the life left
in space would be compressed
都会和其他物质一起被压缩成奇点
with all the other matter
into a singularity.
♪
如果这个理论是正确的
if this theory is true,
then the universe