BBC.地平线.2012.宇宙何其大

you would like to be able to use an object
已知亮度的天体
that's of known brightness.
我们将
We call anything
任何亮度已知的天体称为标准烛光
that we know the brightness of a Standard Candle.
标准烛光的亮度相同
A Standard Candle always has the same brightness -
你可以借此精确测量距离
so you can use it to measure distance very precisely.
距离越远
The further away it is,
在我们的望远镜中就会显得越暗淡
the dimmer it will appear in our telescopes.
但是烛光难以捉摸
But candles are elusive objects.
我们寻觅有固定规律的
We hunt, for what astronomical object could you possibly use,
可见的天体
that will behave in this very regular way,
由此可以真正对比距离
so that you can actually compare the distances.
星系本身不好用
The galaxies themselves are no good.
它们的形状尺寸差异很大
They come in many different shapes and sizes
而且在这种距离下 非常暗淡
and at this distance, they're so dim
我们几乎看不到
we can barely see them.
我们说的距离
We're talking about distances
比过去天文学所研究的要更遥远
that are even more vast than usual for astronomy.
现在我们得观察宇宙中最遥远的某些天体
Now we need to look at some of the most distant objects in the universe
因此它们本身必须非常明亮
so these had to be very bright objects.
索尔有个非常聪明的想法
Saul had a very bright idea.
借助垂死恒星发出的光
He would find his way by the light of a dying star.
超新星
A supernova.
当一颗超新星爆♥炸♥时
When one of these supernovas explode,
恒星本身的亮度可以与由数千亿颗恒星
that one star can be as bright as the entire galaxy
构成的整个星系相媲美
of a hundred billion other stars.
所以这是一个非常明亮的单独个体
So this is a remarkably bright, single event.
索尔知道有一种特殊的超新星
Saul had a special kind of supernova in mind.
当垂死的恒星
A Type Ia is triggered
吸积周围物质 将会变成Ia型超新星
when a dying star draws in mass from its neighbour.
恒星到达临界质量的一瞬
Just at the point where there's a critical mass,
会发生大规模核聚变 产生爆♥炸♥
there will be a runaway thermonuclear explosion.
这意味着每当达到同样质量 就会触发爆♥炸♥
So that means that it's triggered at the same mass every time.
质量相同就代表着每次亮度相同
Same mass every time means same brightness every time.
它们是完美的标准烛光
They're perfect standard candles.
但是索尔首先要找到它们
But Saul had to find them first.
如果在这世界上 你还能借助别的对象
If you could work with anything else in the world
进行研究 你是绝对不会选择超新星的
besides a supernova to do your research you would.
研究它们真的很让人头痛
They're just a real pain in the neck to work with.
它们很稀少 很随机 还很短暂
They're rare, they're random and they're rapid.
一颗超新星只能明亮地燃烧三个星期
A supernova only burns brightly for three weeks.
而且在所有已知的星系
And in any given galaxy,
大约每隔三百年就会毫无征兆地
they explode without warning
发生一次爆♥炸♥
roughly once every 300 years.
这种几率下 你不能在世界最好的望远镜上
With those odds, you can't book valuable time
给它们预订宝贵的观测时间
on the world's best telescopes.
要是你说 在未来几百年里
It makes a terrible proposal, if you were to say that,
在这个星系的某处 会有一颗Ia型超新星
"Sometime in the next several hundred years,
以防万一 我申请3月8日晚上观测
"a Type Ia supernova, might explode, somewhere in this galaxy.
那么这个观测计划糟透了
"I would like the night of March the 3rd, just in case."
但索尔有个计划能使发现几率让他满意
But Saul had a plan to get the odds working in his favour.
在可观测宇宙里有数十亿的星系
With billions of galaxies in the observable universe -
所以每天晚上会出现几十颗超新星
there are dozens of supernovae every night.
索尔的团队花了六年的时间
Saul's team spent six years
来完善一个全新的超新星即时反应系统
perfecting a new system for supernovae on demand.
他们一次拍下几千个星系的照片
They took snapshots of thousands of galaxies at once,
然后在两周半后 重复拍摄
then repeated them two and a half weeks later.
起初你看不到超新星
First you don't see a supernova.
现在能看到了
Now you do.
这两个半星期的时间非常重要
That's very important, that two and a half weeks,
因为这确保了
because that guarantees,
你所发现的东西
that everything you find,
在第二次拍摄时都会比第一次要亮
that's brighter, on the second night than the first,
这是一个上升的过程
is on the way up.
现在我们能确定不会只有一颗Ia型超新星
We can now guarantee that there would not just be one Type Ia supernova,
而是有六颗
but there would be a half dozen.
现在索尔已经知道
Saul now knew exactly where to point
该把位于夏威夷 世上最强大的望远镜之一
one of the world's most powerful telescopes -
凯克天文台对准哪里
the Keck Observatory in Hawaii.
他终于准备好要测量宇宙的减速了
He was finally ready to measure the deceleration of the universe.
但是截至1997年底
But by late in 1997,
团队得到的都是一些奇怪的结果
the team was getting some very weird results.
那些点没有出现在预期的位置上
The points were not showing up where you would expect.
这很让人兴奋
This was exciting.
测量到的超新星距离
The supernovae distance measurements
与预测的减速没有对应上
didn't match the predicted deceleration.
我们面临疑问
We were then faced with the question,
想着到底还有哪里不对
"OK, what else could be going wrong?"
索尔和他的团队又度过了焦虑的五个月
Saul and his team spent five more anxious months,
致力于消除所有可能的错误来源
eliminating all possible sources of error.
到1998年1月他们最终决定发表结果
But by January 1998 they were finally ready to go public.
我们越是检查
The more we checked,
越是对计算中的每一步仔细研究
the more we fine tuned every little step of the calibration,
得到的结果就越是奇怪
the more the weird result didn't go away.
这一奇怪的结果
The weird result
从发表时起就引起了整个科学界的强烈反响
has reverberated through the world of science ever since.
2012年1月
In January 2012,
诺贝尔奖得主保留车位
诺贝尔物理学奖得主终身保留车位
索尔·珀尔马特被授予诺贝尔物理学奖
Saul Perlmutter won the Nobel Prize for Physics
这个停车位将永远为他保留
and booked a parking space for life.
最后 我们得出结论
At the end, we concluded that actually,
宇宙其实并没有降速
the universe really isn't slowing down,
事实上它是在加速膨胀
it's actually speeding up in its expansion.
这实在是让人震惊
And that was a big shock.
可以说这是现代宇宙学中
It's been described as one of the biggest shocks
最具震撼性的发现
in modern cosmology.
这是脱缰的宇宙
This is a Runaway Universe
不管你是否愿意
and everyone's on board -
每个人命运共系
whether we like it or not.
我们发现宇宙不仅是在膨胀
We find out that the universe is not just expanding,
而且膨胀的速度越来越快
but that it's getting faster and faster.
当结果出来时 宇宙学界
The cosmological community, when this result came out,
完全不相信
was completely incredulous.
我一开始听到这个消息的时候也不相信
I didn't believe it when I first heard about it.
我想我当时根本都没太注意这件事
I don't even think I paid very much attention to it at the time.
我们知道宇宙看上去不是这样的
We know the universe doesn't look like this.
观测里肯定是出了什么差错
There had to be something wrong with these observations.
我以为这种说法♥会♥渐渐消失 真的
I thought they would go away, I really did.
当然是我错了
Of course, I was wrong.
有时候犯错误也很有意思
It's sometimes really fun to be wrong.
欢迎来到全新的宇宙景象
Welcome to a very new picture of the universe.
但即使是专家们也很难相信这是真的
But even the experts can hardly believe it's real.
整个宇宙都在抗拒引力
The most famous force in physics has met its match -
物理学中最著名的力遇到了势均力敌的对手
because the entire universe is defying gravity.
这是说宇宙中
This was saying that there was something
充满了某种东西
that fills the universe,
从而造成了反引力
and causes an anti-gravity force.
这种东西造成了
Something that was causing
物体之间的推力
everything to push everything else apart,
使得宇宙膨胀的速度越来越块
and to make the universe bigger and bigger in an accelerated way.
引力就像是刹车
Gravity acts as a brake -
能够控制住宇宙的膨胀
pulling back on the expansion of the universe.
但现在我们知道了有另外一种更神秘的力量
But we now know there's another, more mysterious force -
正踩着油门
with its foot on the gas.
是什么力在向外推
What's doing the pushing?
是什么力使万物互相分离
What's that force that's forcing everything apart?
我们无从知晓 但我们想到了该如何称呼它
Well, we don't know, but we did work out what to call it.
我们给它取了个名字 叫做暗能量
We have a name for it. We call it dark energy.
宇宙学家不知道什么是暗能量
Cosmologists don't know what dark energy is.
他们只知道它有什么作用
They only know what it does.
引力使万物吸引