与摩根·弗里曼一起穿越虫洞（2010）

我们在粒子产生之前就让它分散开
according to the time on our clocks, before it was produced.
目前，大型强子对撞机不是用来
Currently, the L.H.C. isn't set up
在碰撞发生之前观察的
to look at collisions before they happen.
一个标准的协议就是，在粒子产生之前
One of the standard protocols is that decay of recollisions
碰撞的衰变不会发生
don't happen before the particle is produced.
我们也许无意地创造出了希格斯单线
Unwittingly, we may be creating higgs singlets,
汤姆相信这种神秘的粒子
and tom believes his mysterious particle
可以最终引领我们回到过去
could eventually lead us backward in time.
如果你控制了这个东西，你起码可以
Well, if you could control this thing, you could, at a minimum,
像莫尔斯电码一样发送这些粒子
send the particles as morse code.
你可以向过去发送一个信♥号♥♥
You could send a signal to the past.
你甚至可以用它给年轻的你发送消息
You could even use it to send your younger self a message.
嘿，是我
Hey, this is me.
你把钱包忘在桌子上了
You left your wallet on the table.
别忘了拿
don't forget to pick it up.
与过去的交流也许已经存在了
Communication links into the past may already exist,
这位理论物理学家
and this theoretical physicist
认为他已经搞懂如果创造这样的交流
thinks he's figured out what it takes to make one.
我们真的能建立时间机器吗？
Can we, in fact, build a time machine?
我想拥有一台时间机器
I would love to have a time machine
能够重新经历那些宝贵的时刻
to be able to relive treasured moments
有机会再做一次一些事情
or maybe to have a chance to do some things over.
时间旅行可以在虫洞的帮助下实现
Time travel could be possible with the help of a wormhole...
一个穿越时空的宇宙捷径
...a cosmic shortcut through space and time.
没人见过虫洞
No one has ever seen a wormhole,
所以我们需要造一个
so maybe we'll just have to build one.
卢克·布彻是苏格兰爱丁堡大学的
Luke Butcher is a theoretical physicist
一名理论物理学家
with the university of Edinburgh in Scotland.
他研究时空的扭曲
He studies distortions of space-time,
能量如何翘曲宇宙的结构
how energy warps the fabric of the universe.
爱因斯坦的方程
Einstein's equations,
宇宙的能量和物质
our relation between the energy and matter of the universe
与物质产生的曲率之间的关系
and the curvature that that matter causes.
你把能量注入平坦的地方
You go from a flat thing, you put some energy in,
爱因斯坦说空间会弯曲
and Einstein says that the space will curve.
你注入了越多的能量，空间就越弯曲
And the more energy you put in, the more curved it gets.
虫洞是时空的极端扭曲
Wormholes are extreme distortions in space-time.
理论上，他们可以把不同的空间点、
They can, theoretically, link two different points in space
不同的时间点连接起来
and two different points in time.
虫洞还没有被发现
So wormholes have not been observed,
但我们可以在数学上研究它们
but we can study them mathematically.
如果把你认为时空的形状写下来
If you write down the shape you think space-time might be,
你可以把它们放入爱因斯坦的方程
then you can put them into Einstein's equations.
这些方程就可以计算出
And what those equations will spit out
让这个时空稳定存在
is the sorts of energy you need
所需要的能量
for that space-time to exist and to be stable.
卢克开始计算将一片时空
Luke started calculating what it would take
翘曲成让人通过的虫洞
to warp a patch of space-time into a wormhole
需要多少能量
someone could travel through.
这需要一种特殊形式的能量，叫做负能量
It needs a particular form of energy called negative energy.
想象负能量最好的方法是
So, the best way of thinking about what negative energy is
考虑什么是零能量
is to think about what zero energy is.
零能量就是真空
Zero energy is the vacuum.
但“真空”其实是假空
But the vacuum is not truly empty.
它充斥着量子微粒
It's filled with quantum particles
不断出现或消失
popping in and out of existence.
如果我们可以摆脱这些量子波动
If we can get rid of some of those quantum fluctuations,
我们就可以获得负能量
we'll end up with negative energy.
科学家已经在实验室中
Scientists have been able to create
成功地创造了一些负能量
small doses of negative energy in the lab.
他们把两个导电的金属板放得非常近
They place two conducting plates very close together
来限制它们的间隙中的
to constrain the quantum fluctuations
量子的波动
in the gap between them.
因为里面的波动
Because the fluctuations inside
比外面的要弱
are weaker than the ones outside,
这个间隙就具有了负能量
the gap has negative energy.
如果可能的话，我们放大这个过程的尺度
If we can scale up this process, it's possible
制♥造♥足够多的负能量
that we could manufacture enough negative energy
建立一个虫洞，向过去打开一扇窗
to create a wormhole and use it to open a window to the past.
但这里有一个问题
But there's a problem.
数学家们说
The mathematics say
虫洞是极度不稳定的
that wormholes are incredibly unstable.
一量你进去了，它们马上就会关闭
Once you try to enter them, they close right up.
所以，如果你试图把这个当做时间机器
So, if you're trying to use this as a time machine
或者从a到b的一个捷径
or a shortcut from "a" to "b,"
根本没戏
there's gonna be no hope, right,
你从一端到达另一端之前
because this thing's gonna collapse
这玩意儿就崩塌了
before you get from one side to the other.
但当卢克挖掘地更加深入时
But as Luke dug deeper,
他发现也许有一种方法
he realized there might be a way
通过让虫洞变得苗条来延长它的生命期
to extend the life span of a wormhole by slimming it down.
虫洞有趣之处在于
The interesting thing about a wormhole is that
我们有两种不同类型的曲线
we have two different sorts of curvature going on.
一种是长的、纵向的曲线
There's this long, longitudinal curvature,
虫洞的曲线就像是这样
curvature through the wormhole like this.
也有一种绕着虫洞的曲线
And there's also curvature going around the wormhole.
一个细长的虫洞
A longer, thinner wormhole
不需要那麽多的负能量让它保持稳定
wouldn't need as much negative energy to stay open,
它的狭窄甚至使其自身就可以产生负能量
and its narrowness would even create some of its own,
让它变得更加稳定
making it far more stable.
本质上，这些纵向的曲线
Essentially, this longitudinal curvature here
需要和容纳它的东西相平衡
needs to be balanced by something that holds it in.
大体上来说
And so very roughly speaking,
沿这个方向编织的柳条
the wicker pattern weaved around this side
可以类比作负能量保持虫洞稳定时
is analogous to the role that negative energy plays
所扮演的角色
in keeping the wormhole stable.
紧紧围绕虫洞咽喉的
The tight circles of space-time
时空的圈
around the throat of the wormhole
产生了它们自己的负能量
create their own negative energy
支撑着出入口保持开放
and keep the portal propped open.
所以，如你所见，这个虫洞
So, this wormhole, as you can see,
比我们一开始用的
is quite a lot longer and thinner
典型的这个虫洞
than this wormhole that we started with,
更长更细
a typical wormhole.
相反，这个虫洞
This wormhole, on the other hand,
从头到尾弯曲地很平缓
is very gently curved from top to bottom
它的周长很小
and has a very tight circumference.
需要更少的负能量
It requires less negative energy
产生更多的负能量
and generates more negative energy,
它应该是更加稳定的
so it should be more stable.
卢克或许已经弄明白了如何创造一个更稳定的虫洞
Luke may have figured out how to create a more stable wormhole,
但仍然有问题，它能作为一个时间机器吗？
but the question remains, could it work as a time machine?
这处在我们知识的边缘
It's on the edge of our knowledge, really,
但它令人着迷，因为我们不能肯定这是错的
but it's tantalizing because it's not definitively no,
也不能肯定这是对的
and it's not definitively yes.
在我已经完成的计算中
In terms of the calculations I've done,
你可以发送一个物体
you could send an object through
快速地移♥动♥，接近光速
moving very close to the speed of light,
它将能够挤过去
and it would be able to squeeze through.
卢克的虫洞，从设计上来讲
Luke's wormhole is, by design,
太窄了，人类挤不过去
far too narrow for a person to squeeze through,
但一束光线还是可以的
but a light beam could probably make it.
这就够我们向过去发送消息了
And that's all we would need to send a message back in time.
也许未来的某一天，某人会发现一个新的弯曲
Maybe in the future, someone will discover a new twist
允许虫洞让更大的东西通过
that allows a wormhole to Usher through something bigger,
比如一个人
like a person.
看起来时间无休止地带着我们
It may seem that time relentlessly carries us
从过去奔向未来
from the past toward the future,
但宇宙并不真的是这样工作的
but that's not the way the universe really works.
过去发生的事
What takes place in our past