BBC 地平线系列：时空谜团（2008）

然而却是天文学所揭示的奇怪的宇宙行为
but strange behaviour of the universe as revealed by astronomy.
因为我想说 啊 这个现在看上去像什么？
Because I'm trying to say, "Well, what does that look like now?"
现在看上去会是什么？
"What would that look like now?"
某种意义上 好像说的不对 是吧？现在看上去就是这个样子
In a sense, it's the wrong language to use, isn't it? That's what it looks like now.
对
That's right.
史蒂夫将他的图片做成了观看时光倒流的影片
Steve has turned his photo into a movie to journey back in time.
你看到这些小块向我们飞来？
You see these little pieces coming at us?
我们将进行时光倒流 你看到的是三维效果
We're going back in time. You can see the three-dimensional effect.
其中的一些还要往回退一点
Some of these others are a little farther back,
现在我们往回倒
but here we're going back,
我们现在大概回到了距现在30亿年了
we're probably back now about three billion years from the present.
我们继续下去 你就可以看到更小的东西
As we keep going and you get to the smaller ones,
你回到80到90亿年前了
you get back to about eight or nine billion years.
然后 我们看到了很小的相当遥远的东西
And then, when we get to the very tiny, most distant ones,
我们大概回到了100到110亿年前了
we'll be back probably 10 or 11 billion years in time.
我们进入了宇宙深处 看到了最小的结构
We're deep into the universe, looking at the smallest structures,
回到了约130亿年前了
back in time to about 13 billion years.
突然间 结束了
And, suddenly, we run out.
史蒂夫那惊人的图片让我们
Steve's amazing photo allows us
走过了几乎整个宇宙的历史
to travel back through almost the entire history of the universe.
但是如果我们现在就要知道时间是什么
But if we want to know what time it is right now,
我们还必须比史蒂夫的图片所提供的再往前一点点
we have to go back a little further than Steve's picture allows.
我们需要回到时间本身开始启动的那个点
We need to get back to the point when time itself started ticking,
回到宇宙开始的那个瞬间
back to the moment the universe began.
宇宙大爆♥炸♥ 理论上这么认为 是万物的开端 - 包括时间
The Big Bang, so the theory goes, was the beginning of everything - including time.
一旦想起 所说的真是非同寻常的事
If you think about it, that's a remarkable thing to say.
这意味着宇宙的第一天是没有昨天的
It means that the first day of the universe didn't have a yesterday.
只要宇宙开始于大爆♥炸♥ 就不存在昨天
If time began at the Big Bang, then there was no yesterday.
什么都没有 根本没有时间
There was nothing, no time at all.
然后发生了大爆♥炸♥...
And then the Big Bang happened and...
这一切都出现了
all this appeared.
为了了解时间 我们就需要准确地知道宇宙的年龄
To know the time, we need to know precisely, how old is the universe?
大爆♥炸♥那一刻开始 宇宙一直在膨胀
Since the moment of the Big Bang, the universe has been expanding.
我们如果能够确切地计算出宇宙膨胀的速度
If we could work out exactly how fast the universe is stretching,
那么我们就能想象吧这个膨胀倒回去
then we could imagine rewinding this expansion
一直回到起点
all the way back to the beginning.
我来到了伯克利 就在旧金山的东部
I've come to Berkeley, just east of San Francisco,
去拜访索尔·普密特
to meet Saul Perlmutter.
几年前 他找到了一个聪明的办法 来计算万物开始的时间
A few years ago, he worked out a clever way to calculate when it all began.
你能叙述一下这个测量的具体细节吗？
So, could you describe to the nuts and bolts of the measurement?
我们着手研究所用到的工具是...
The tool that we started to work with is a...
一种爆发的恒星 超新星
kind of exploding star, a supernova.
有一种超新星 我们称之为1A型
And there's one kind of supernova, we call it the type 1A,
它们在爆发时 看上去总是达到相同的亮度 然后就消失了
which, when they explode, they always seem to reach the exact same brightness and then fade away.
索尔利用这些特别的超新星
Saul uses these special supernovae
来测量宇宙膨胀的速度
to measure how fast the universe is expanding.
这些特殊的恒星现象总是以同样的方式爆发
These particular stellar phenomena always explode the same way,
发出特定的蓝♥光♥
giving out light with a particular blue colour.
然而这个光抵达我们这里需要花时间 而在那段时间里
But it takes time for this light to reach us and, in that time,
宇宙在继续膨胀
the universe continues to expand.
随着宇宙的膨胀 这个光的光波会被拉长
As the universe expands, the wave length of the light gets stretched.
就会将原来的蓝色变成红色
This turns the original blue colour into red.
在不断膨胀的宇宙中 宇宙拉伸的量恰好等于
In an expanding universe, the amount that the universe stretches is exactly the same amount
超新星发出的光在传播到我们这里 波长拉伸的量
that the light from the supernova has its wavelength stretched while it's travelling to us.
所以我们回头在找附近差不多那种颜色的东西
Ah, so we look back and we see that the nearby ones are pretty much the colour that they were.
没错 看上去蓝色的 然后它们远去.. 越来越红
That's right, they look blue, right? And then further away... Redder and redder.
它们随着光被拉长越来越红 没错
They go redder and redder as the light is stretched. Exactly.
现在你可能会提出 那我们现在来描述所有这些
And now you can start asking, "Let me now map out the history
各种延伸的过程 过程中的各个时段
"of all those different stretches, all those different
宇宙究竟膨胀了多少
"times in history, how much the universe has expanded. "
到回去计算所有一切刚好相互碰在一起的时间
And back calculate when was everything right on top of each other?
什么时候 所有之间的距离为零
When were all the distances at zero?
那个就是我们所说的宇宙的起点
And that's what we call the beginning of the universe.
利用索尔的观察资料 我们能够把宇宙爆♥炸♥
Using Saul's observations, we can reverse the expansion
倒回到万物开始的起点
of the universe to arrive at the point it all began.
我们现在知道这一刻就在大约137亿年前
We now know this time was roughly 13.7 billion years ago,
启动了空间 启动了时间
the start of space and the start of time.
那么应对问题“时间是什么”
So the answer to the question, "What time is it?"
不是2008年或其它历法的随意数字
is not 2008 or any other arbitrary number on a calendar.
而是137亿年
It's 13.7 billion years.
是不是啊？
Or is it?
你所看到的这些非常精确的探测数据
You get these very precise sounding numbers
137亿年 正负百分之一 这个令人印象深刻
like 13.7 plus or minus a percent. And that sounds very impressive.
然而那肯定不是万物的开端
But that doesn't have to be the beginning of everything.
那只是我们通过观察宇宙的膨胀
That's just the beginning of this period that we can learn about
所能获得的这个过程的开端
by watching the expansion of the universe.
万物开始于大爆♥炸♥的概念
The idea that everything began at the Big Bang
引出了科学上一个最深刻的问题 -
leads to one of the most profound questions in science -
究竟是什么引发了宇宙的启动？
what exactly triggered the beginning of the universe?
假如大爆♥炸♥之前存在着什么
If there was something before the Big Bang,
那么会包括时间之类的东西吗？
might that something include time?
现在公认的观点是不存在时间
The orthodox view today is that there was no time.
时间始于大爆♥炸♥ 时间起点
Time began at the Big Bang, time zero.
但是也有理论认为 某种意义上 宇宙在此之前或许就存在了
But there are theories that suggest that maybe the universe existed before then in some sense.
或许时间一直存在 而我们所看到的大爆♥炸♥
Maybe time has existed for ever, and what we see as the Big Bang
仅仅创造了我们这一点空间和时间
is just the creation of our little bits of space and time.
我来到剑桥 来探寻大爆♥炸♥之前的情况
I've come to Cambridge to find out what happened before the Big Bang.
尼尔·图尔克是世界领先的宇宙学家
Neil Turok is one of the world's leading cosmologists and he believes
他认为公认的时间始于大爆♥炸♥的观点是完全错误的
the accepted view that time began at the Big Bang is completely wrong.
我要说那个标准的前提
I would say the standard hypothesis,
宇宙突然出现在137亿年前
that the universe sprang into existence 13.7 billion years ago,
怎么也说不通
doesn't make any sense.
什么东西神秘地发生在137亿年前
Something mysterious happened 13.7 billion years ago
而我们却不知道那是什么
and we do not yet know what that was.
尼尔有个什么导致了大爆♥炸♥的理论
'Neil has a theory for what caused the Big Bang.
如果他是对的 那就意味着时间的存在 要比原先所认为的长的多
'If he's right, it would mean that time has been around a lot longer than originally thought. '
如果你想解释大爆♥炸♥ 最简单的办法就是究竟是什么引起的
If you want to explain the Big Bang, the simplest option is that something caused it.
那么 如果是什么引起的 那么大爆♥炸♥之前就存在时间了
And, if something caused it, there was a time before the Big Bang.
所以 只要来看一下宇宙
So, if you look at the... the universe,
只要我们来画一个时空的图表
and if we try to draw a graph of time and space,
我们来跟踪一下大爆♥炸♥产生的粒子
and we follow the particles emerging from the Big Bang,
它们产生于137亿年前的那个事件
then they come out of this event 13.7 billion years ago.
在那个事件中 所有的粒子相互紧挨着
And, at that event, all the particles were
没有任何空间
on top of each other and space had shrunk to no size at all.
密度无穷大 空间无从谈起
So the density was infinity, there is no space to talk about.
那么 这一点就是时间的开端吗？
So, that's the point at which time began?
不 根本不是
No! Not at all.
尼尔想出了一个聪明 但难以理解的解决方案
'Neil has come up with a clever, if mind-boggling, solution.
借助最不可理解的弦理论引出的数学
'With maths drawn from the almost unintelligible realm of string theory,
他认为解决方案在于空间额外的维度里
'he believes the solution lies in additional dimensions of space
存在平行的世界 他称之为膜（membranes）
'and the existence of parallel worlds that he calls membranes,
或简称膜（branes）
'or branes for short. '
那么 我们怎样来描绘这个我们这个空间的起点
How, then, can we picture this, the beginning of our bit of space
如果时间早就存在的话？
if time has gone on for ever?
我们用弦理论拿出的第一个具体的模型
The first concrete model we could come up with, coming out of
是一个叫做膜世界的特殊的结构
string theory, was a particular set-up called brane worlds.
发生在膜世界里的就是我们生存的三维空间
And what happens in a brane world is that the three dimensions of space we live in,
这里我要画一个二维图表 这就是我所能画出的图像
which I'll draw as a two-dimensional sheet, just so that I can draw a picture of it.
你要把这想象成我们的三维世界
You're to imagine that this is our three-dimensional world
我们画上一些粒子 它们可以在这个世界里移♥动♥
and we're made out of particles which can travel within that world.
确实是 你 我 所有一切 我们的宇宙
Literally, well, you and me and everything? Our universe.
对 在这个世界里
Yes, is within this world.
弦理论所说的就是 这里不光有这个三维世界
So, what string theory says is that there's not just this
或者我画的图表
three-dimensional world or sheet in my picture of it.
还有其它的东西 以细小的间隙把我们分开
There's another one, separated from ours by a very tiny gap
这个细小的间隙就是空间的第四维
and that tiny gap is a fourth dimension of space.
所发生的就是这两个膜世界可以相互接近和碰撞
So what can happen is that these two brane worlds can move towards each other and hit.
随着它们相互接近 就融为一体了
So as they move towards each other, they become one.
在尼尔的模型里 我们看到 我们周围的一切都完全在他的膜里了
In Neil's model, everything we see around us exists entirely on one of his branes.
然而宇宙中还有其它的膜
But there are other branes in the universe,