了解宇宙是如何运行的（2010）

How the Universe Works S08E07

Part 7 Jan. 30, 2022, 2:59 p.m.

那么宇宙将有时间的开始和结束
would have both a beginning
and an end of time.
如果我们生活在一个会膨胀
If we live in a universe
that will expand,
停止膨胀，然后回到紧缩的宇宙中
stop expanding,
and then go back into a crunch,
那么它实际上就有两个边界
then it has,
in effect, two edges.
但还有一种更奇怪的可能性
Narrator: But there's a much
stranger possibility.
也许结束只是一个开始
Perhaps the end is
but a beginning,
在那里宇宙是一个振荡的宇宙
where the universe
is a oscillating universe.
它有一个大爆♥炸♥的开始
It has a big bang
like beginning,
它膨胀到最大
it expands to a maximum size,
然后回到大收缩
and then goes back
into a big crunch
如此一遍又一遍反复
and does that over and over.
我们可能是一个由另一个
Narrator: We could be residents
of a universe
宇宙的灰烬所创造出来的宇宙的居民
created from the ashes
of another,
也可能是一串跳动的宇宙中的一个宇宙……
a single universe in a stream
of bouncing universes...
……每一个宇宙都充满了星系、行星和生命
...Each full of galaxies,
planets, and life.
但是，我们最近对宇宙的观察表明
But our most recent observations
of the universe suggest
大坍缩是不可能的
a big crunch isn't in the cards.
再一次，暗能量是关键
Once again, dark energy is key.
有一段时间，我们不知道宇宙的膨胀
For a while we didn't know
if the expansion of the universe
是否会因为引力而减速、停止
was going to slow, stop,
并自我逆转
and reverse itself
because of gravity.
宇宙中有很多这样的星系
There are all these galaxies
in the universe
它们通过引力相互拉拽
and they're pulling on
each other by their gravity.
如果膨胀速度不够快
And if the expansion
isn't fast enough,
引力可能会强大到足以阻止膨胀
that gravity might be strong
enough to stop the expansion
并重新坍缩宇宙
and re-collapse the universe.
现在有了暗能量
Now with dark energy,
我们知道这是不可能发生的
we know that there's no way
that can happen.
宇宙将永远膨胀下去
The universe is going
to expand forever
因为暗能量在不断地加速
because dark energy is
pumping it full of acceleration.
如果要有一次大的收缩
In order for there
to be a big crunch,
我们对暗能量的理论必须有很大的改变
our understanding of dark energy
would have to change a lot.
也就是说，暗能量必须是非常奇怪的
That is, dark energy would have
to be extremely weird
并且以某种非常有趣的方式关闭
and turn off in some very funny
way for the universe
宇宙才能突然停止膨胀并重新崩溃
to suddenly stop expanding
and re-collapse.
没有大坍缩
Narrator:
Without a big crunch,
时间就没有未来的边缘
there is no future edge to time.
卡罗尔:宇宙不仅在膨胀
Carroll: The universe is not
only expanding,
而且在暗能量的驱动下
but it's being driven
by dark energy
膨胀得越来越快，据我们所知
to expand faster and faster
and the dark energy
暗能量并没有被稀释掉
doesn't dilute away,
as far as we can tell.
所以最简单的观点是
So the simplest idea
is that the universe
宇宙会继续向未来无限扩张
will simply continue to expand
eternally toward the future.
就像空间一样，时间是永恒的
Narrator: Just like space,
time will go on forever.
这听起来像是生命和宇宙的更好命运
That might sound like a better
fate for life and the universe,
但事实并非如此
but it's not.
弗里斯:暗能量导致
Freese: One of the consequences
of this dark energy
宇宙加速的后果之一是
that's causing the acceleration
of the universe
我们最终会走向“热寂”
is that we eventually are
headed towards the big chill.
我应该说"我们最终会走向严寒"
I should say, "we're eventually
headed towards the big chill."
所以宇宙会变得越来越冷
so the universe is getting
colder and colder
事物会变得越来越分散
and things are getting more
and more spread out.
因此，我们宇宙的加速
So the accelerated and continual
持续和永远的膨胀
and forever expansion
of our universe
可能会导致时间本身的一个令人沮丧的结局
might make for a frankly
depressing end to time itself.
宇宙最终基于熵的热死亡
The ultimate entropy-based
heat death of the universe
你走出去看不到天空中的星星
where you would walk out
and see no stars in the sky,
什么都看不到
see absolutely nothing.
总有一天，宇宙中最后一颗恒星会熄灭
There will come one day when the
very last star in the universe
就这样死寂
just fizzles out and that is it.
在未来
Narrator: In the future,
空间将是一个寒冷、黑暗和无限的虚空
space will be a cold, dark
and infinite void,
在那里时间将永远流逝
where time goes on forever.
除了在永恒的苍穹中受苦
There will be nothing to do
什么也做不了
but suffer
in the eternal expanse.
宇宙中时间没有未来的边缘
It's our inevitable fate
that there's no future edge
是我们不可避免的命运
of time in the universe.
但即使宇宙没有边缘
But even if there isn't an edge
to the universe,
宇宙内部会有边缘吗？
could there be edges
within the universe?
如果你想去宇宙边缘
If you wanted to visit the edge
of the universe,
那就去找离你最近的黑洞，然后跳进去
then go find your nearest
black hole and jump on in
因为这是单程旅行
because that's a one-way trip.
如果你越过这条边缘，你将永远不会回来
Narrator: If you cross this
edge, you will never return.
♪
[掌声]
[ applause ]
2019年4月
narrator: April 2019,
一个国际天文学家团队
an international team
of astronomers
做出了一个特别的声明
makes a special announcement.
今天我们很高兴能向大家报告
And we are delighted to be able
to report to you today
我们看到并拍摄了一张黑洞的照片
that we have seen and taken
a picture of a black hole.
在这儿
Here it is.
[掌声]
[ applause ]
♪
这是一张超大质量黑洞的照片
narrator: It's a picture
of a supermassive black hole
位于5400万光年远的 m87 星系中心
at the center of the m87 galaxy
54 million light-years away.
它也可能是宇宙中第一张边缘的图像
It may also be the first image
of an edge in the universe.
当我们想到空间和有边缘的宇宙时
Black holes create
a really interesting scenario
黑洞创造了一个非常有趣的场景
when we think about space
and the universe having edges.
黑洞内外空间之间的边缘
Narrator: The edge between space
outside and inside a black hole
称为视界
is called the event horizon.
布洛克:黑洞的视界是这样一个区域
Bullock: The event horizon
of a black hole
一旦你穿过视界
is a region within which,
once you cross inside,
它的引力是如此强大
the gravitational tug
is so strong
以至于连光都无法逃脱，这意味着
that even light cannot escape,
which means nothing can escape
一旦你穿过视界，任何东西都无法逃脱
once you cross
inside the event horizon.
这确实是一个边缘
So that really