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TEDxCaltech

Sean Carroll: Distant time and the hint of a multiverse

肖恩·卡罗尔:遥远的时间与多元宇宙的迹象

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在TEDx加州理工学院,宇宙学家肖恩·卡罗尔把我们带入一段娱乐性强且发人深省的,穿梭于时间与宇宙之间的旅程,目的是探究一个貌似简单的问题:为什么存在着时间?潜在的答案指向的对于整个宇宙以及宇宙中的我们的见解足以令人称奇。

- Physicist, cosmologist
A physicist, cosmologist and gifted science communicator, Sean Carroll is asking himself -- and asking us to consider -- questions that get at the fundamental nature of the universe. Full bio

The universe宇宙
宇宙
00:15
is really big.
非常大
00:17
We live生活 in a galaxy星系, the Milky乳白色 Way Galaxy星系.
我们生活在一个名为银河的星系
00:19
There are about a hundred billion十亿 stars明星 in the Milky乳白色 Way Galaxy星系.
银河系中有约一千亿颗恒星
00:22
And if you take a camera相机
如果你拿起相机
00:25
and you point it at a random随机 part部分 of the sky天空,
并把它指向空中的任何一处
00:27
and you just keep the shutter快门 open打开,
打开快门并让它开在那里
00:29
as long as your camera相机 is attached to the Hubble哈勃 Space空间 Telescope望远镜,
只要你的相机接通着哈勃天文望远镜
00:31
it will see something like this.
这就是它会看到的
00:34
Every一切 one of these little blobs斑点
这里的每一小点
00:36
is a galaxy星系 roughly大致 the size尺寸 of our Milky乳白色 Way --
都是与我们的银河系大小相当的星系
00:39
a hundred billion十亿 stars明星 in each of those blobs斑点.
每一小点中都有一千亿颗恒星
00:41
There are approximately a hundred billion十亿 galaxies星系
而在整个可见宇宙中
00:44
in the observable可观察 universe宇宙.
约有一千亿个星系
00:47
100 billion十亿 is the only number you need to know.
所以你记住一千亿这个数字就行了
00:49
The age年龄 of the universe宇宙, between之间 now and the Big Bang,
宇宙的年龄 自大爆炸以来
00:51
is a hundred billion十亿 in dog years年份.
在狗看来已过了一千亿年
00:54
(Laughter笑声)
(笑)
00:56
Which哪一个 tells告诉 you something about our place地点 in the universe宇宙.
这就告诉了你 我们在这宇宙中的位置
00:58
One thing you can do with a picture图片 like this is simply只是 admire欣赏 it.
面对这样的画面 你可以做的一件事便是欣赏
01:01
It's extremely非常 beautiful美丽.
它极其美丽
01:03
I've often经常 wondered想知道, what is the evolutionary发展的 pressure压力
我常想 在星系的照片还不存在的时候
01:05
that made制作 our ancestors祖先 in the Veldt大草原 adapt适应 and evolve发展
究竟是什么推动了我们远在非洲大草原的祖先
01:08
to really enjoy请享用 pictures图片 of galaxies星系
让他们适应 进化
01:11
when they didn't have any.
并欣赏这些星系的呢?
01:13
But we would also like to understand理解 it.
但除了欣赏 我们也想要了解它们
01:15
As a cosmologist宇宙学家, I want to ask, why is the universe宇宙 like this?
作为一个宇宙学家 我想问问 宇宙为什么是这样的呢?
01:17
One big clue线索 we have is that the universe宇宙 is changing改变 with time.
宇宙随着时间流逝的演变 是一条重要的线索
01:21
If you looked看着 at one of these galaxies星系 and measured测量 its velocity速度,
如果你选中一个星系并测量它的速度
01:24
it would be moving移动 away from you.
你会发现它正离你远去
01:27
And if you look at a galaxy星系 even farther更远 away,
而如果你选中的是一个更远的星系
01:29
it would be moving移动 away faster更快.
你会发现它正以更快的速度离你远去
01:31
So we say the universe宇宙 is expanding扩大.
所以说 宇宙正在膨胀
01:33
What that means手段, of course课程, is that, in the past过去,
当然 这就意味着过去所有的一切
01:35
things were closer接近 together一起.
彼此之间都比较接近
01:37
In the past过去, the universe宇宙 was more dense稠密,
曾经的宇宙密度比现在高
01:39
and it was also hotter.
它也比现在热
01:41
If you squeeze things together一起, the temperature温度 goes up.
如果你把东西紧捏在一切 温度便会上升
01:43
That kind of makes品牌 sense to us.
听起来有道理吧
01:45
The thing that doesn't make sense to us as much
而让我们觉得没道理的
01:47
is that the universe宇宙, at early times, near the Big Bang,
是宇宙初期 大爆炸之后那个
01:49
was also very, very smooth光滑.
极度光滑的宇宙
01:52
You might威力 think that that's not a surprise.
你或许觉得这并不值得惊讶
01:54
The air空气 in this room房间 is very smooth光滑.
这房间里的空气便十分光滑
01:56
You might威力 say, "Well, maybe things just smoothed平滑 themselves他们自己 out."
你也许会说 “大概这些东西就是会自己慢慢平滑掉的”
01:58
But the conditions条件 near the Big Bang are very, very different不同
但大爆炸不久之后的环境 与这房间里的空气相比
02:01
than the conditions条件 of the air空气 in this room房间.
十分 十分的不同
02:04
In particular特定, things were a lot denser更密集.
特别是一切的密度
02:06
The gravitational引力 pull of things
当时的地心引力
02:08
was a lot stronger near the Big Bang.
比现在强很多
02:10
What you have to think about
我们不得不想想
02:12
is we have a universe宇宙 with a hundred billion十亿 galaxies星系,
这个宇宙里有一千亿个星系
02:14
a hundred billion十亿 stars明星 each.
而每个星系里都有一千亿颗恒星
02:16
At early times, those hundred billion十亿 galaxies星系
在宇宙初期 那一千亿个星系
02:18
were squeezed挤压 into a region地区 about this big --
被挤压到这么小的空间
02:21
literally按照字面 -- at early times.
毫不夸张 当初就这么小
02:24
And you have to imagine想像 doing that squeezing挤压
我们得想象一下这个挤压过程
02:26
without any imperfections缺陷,
这个完美的过程
02:28
without any little spots斑点
毫无瑕疵
02:30
where there were a few少数 more atoms原子 than somewhere某处 else其他.
这里比那里多一两个原子也不行
02:32
Because if there had been, they would have collapsed倒塌 under the gravitational引力 pull
如果真有任何瑕疵 地心引力也会把它们
02:34
into a huge巨大 black黑色 hole.
压成一个巨大的黑洞
02:37
Keeping保持 the universe宇宙 very, very smooth光滑 at early times
让初期的宇宙保持在极度光滑的状态并非易事
02:39
is not easy简单; it's a delicate精巧 arrangement安排.
这是个极为精细的布置
02:42
It's a clue线索
这条线索意味着初期宇宙
02:44
that the early universe宇宙 is not chosen选择 randomly随机.
并非任意选择的产物
02:46
There is something that made制作 it that way.
是某些东西把它造就成那样的
02:48
We would like to know what.
而我们想知道那是什么
02:50
So part部分 of our understanding理解 of this was given特定 to us by Ludwig路德维希 Boltzmann玻尔兹曼,
19世纪的奥地利物理学家路德维希·玻尔兹曼
02:52
an Austrian physicist物理学家 in the 19th century世纪.
给予了我们不少对此的了解
02:55
And Boltzmann's玻耳兹曼 contribution贡献 was that he helped帮助 us understand理解 entropy.
玻尔兹曼的贡献在于他帮助我们理解了熵
02:58
You've heard听说 of entropy.
你们听见过熵
03:01
It's the randomness随机性, the disorder紊乱, the chaoticnesschaoticness of some systems系统.
在某些系统中 它是随意性 是不规则 是混乱
03:03
Boltzmann玻尔兹曼 gave us a formula --
玻尔兹曼给了我们一条
03:06
engraved on his tombstone墓碑 now --
被刻在了他墓碑上的公式
03:08
that really quantifies量词 what entropy is.
让我们得以在数量上解释熵
03:10
And it's basically基本上 just saying
这条公式所说的 不过是
03:12
that entropy is the number of ways方法
我们可以重新组合
03:14
we can rearrange改编 the constituents成分 of a system系统 so that you don't notice注意,
构成一个系统的各个要素 而在宏观上
03:16
so that macroscopically宏观 it looks容貌 the same相同.
你看不出任何变化
03:19
If you have the air空气 in this room房间,
在感受这房间里的空气时
03:21
you don't notice注意 each individual个人 atom原子.
你不可能注意每一个原子吧
03:23
A low entropy configuration组态
如果能够组合出某个布局的方式屈指可数
03:26
is one in which哪一个 there's only a few少数 arrangements安排 that look that way.
那这个布局的熵值就会很小
03:28
A high entropy arrangement安排
反之 若能组合出某个布局的方式很多
03:30
is one that there are many许多 arrangements安排 that look that way.
这个布局的熵值就会很大
03:32
This is a crucially关键 important重要 insight眼光
对这一点的领悟极其关键
03:34
because it helps帮助 us explain说明
因为它帮助我们解释
03:36
the second第二 law of thermodynamics热力学 --
热力学第二定律——
03:38
the law that says that entropy increases增加 in the universe宇宙,
在整个宇宙 或是被隔离开的部分宇宙中
03:40
or in some isolated孤立 bit of the universe宇宙.
熵值只可增大
03:43
The reason原因 why entropy increases增加
熵值增大的原因很简单
03:45
is simply只是 because there are many许多 more ways方法
只因呈现出对应于大熵值的布局
03:47
to be high entropy than to be low entropy.
比呈现出对应于小熵值的布局的方式多得多
03:50
That's a wonderful精彩 insight眼光,
虽说领会到这些很奇妙
03:52
but it leaves树叶 something out.
但还有被遗漏的部分
03:54
This insight眼光 that entropy increases增加, by the way,
值得提及的是 正是熵值的增大
03:56
is what's behind背后 what we call the arrow箭头 of time,
推动着我们的时间之箭
03:58
the difference区别 between之间 the past过去 and the future未来.
造就着过去与未来的不同
04:01
Every一切 difference区别 that there is
过去与未来
04:03
between之间 the past过去 and the future未来
它们之间的所有区别
04:05
is because entropy is increasing增加 --
都呈现于熵值的增大
04:07
the fact事实 that you can remember记得 the past过去, but not the future未来.
正如你能记得往事 却无法去记住将来所要发生的
04:09
The fact事实 that you are born天生, and then you live生活, and then you die,
又如你出生 成长 死亡的过程
04:12
always in that order订购,
这些不变的顺序
04:15
that's because entropy is increasing增加.
都源于熵值的增大
04:17
Boltzmann玻尔兹曼 explained解释 that if you start开始 with low entropy,
玻尔兹曼解释道 如果你从小熵值出发
04:19
it's very natural自然 for it to increase增加
它会很自然的增大
04:21
because there's more ways方法 to be high entropy.
因为处于大熵值状态的途径更多
04:23
What he didn't explain说明
但他并没有解释
04:26
was why the entropy was ever low in the first place地点.
为什么最初的熵值那么小
04:28
The fact事实 that the entropy of the universe宇宙 was low
宇宙初期的小熵值
04:31
was a reflection反射 of the fact事实
意味着的莫过于
04:33
that the early universe宇宙 was very, very smooth光滑.
初期的宇宙非常非常的光滑
04:35
We'd星期三 like to understand理解 that.
而我们想要理解它的原由
04:37
That's our job工作 as cosmologists宇宙学家.
那便是作为宇宙学家的我们的任务
04:39
Unfortunately不幸, it's actually其实 not a problem问题
遗憾的是 我们并没有
04:41
that we've我们已经 been giving enough足够 attention注意 to.
给予这个问题多大的关注
04:43
It's not one of the first things people would say,
如果你问一个现代宇宙学家
04:45
if you asked a modern现代 cosmologist宇宙学家,
“我们正研究着的问题有哪些?”
04:47
"What are the problems问题 we're trying to address地址?"
这不会是回答中你最先听到的问题之一
04:49
One of the people who did understand理解 that this was a problem问题
认识到这个问题的重要性的其中一人
04:51
was Richard理查德 Feynman费曼.
便是理查德·费曼
04:53
50 years年份 ago, he gave a series系列 of a bunch of different不同 lectures讲座.
50年前 他给了一系列的演讲
04:55
He gave the popular流行 lectures讲座
他面向大众的讲座
04:57
that became成为 "The Character字符 of Physical物理 Law."
成了《物理之美》
04:59
He gave lectures讲座 to Caltech加州理工学院 undergrads本科生
他面向加州理工学院本科生的讲课
05:01
that became成为 "The Feynman费曼 Lectures讲座 on Physics物理."
成了《费曼物理学讲义》
05:03
He gave lectures讲座 to Caltech加州理工学院 graduate毕业 students学生们
他面向加州理工学院研究生的讲课
05:05
that became成为 "The Feynman费曼 Lectures讲座 on Gravitation引力."
成了《费曼引力学讲义》
05:07
In every一切 one of these books图书, every一切 one of these sets of lectures讲座,
在上述的每本书 费曼的每个讲座中
05:09
he emphasized强调 this puzzle难题:
他都强调了这个难题
05:12
Why did the early universe宇宙 have such这样 a small entropy?
为什么初期的宇宙有着那么小的熵值?
05:14
So he says -- I'm not going to do the accent口音 --
我就不模仿他的口音了
05:17
he says, "For some reason原因, the universe宇宙, at one time,
他说:“虽说宇宙中包含着的能量巨大
05:19
had a very low entropy for its energy能源 content内容,
某些原因使它曾一度拥有小熵值
05:22
and since以来 then the entropy has increased增加.
而从那以后 熵值不断增大
05:25
The arrow箭头 of time cannot不能 be completely全然 understood了解
直至我们能够真正理解 而非单单推测
05:27
until直到 the mystery神秘 of the beginnings开始 of the history历史 of the universe宇宙
整个宇宙历史的 开端的秘密
05:30
are reduced减少 still further进一步
时间之箭
05:33
from speculation推测 to understanding理解."
便无法被完全理解”
05:35
So that's our job工作.
这就是我们的使命
05:37
We want to know -- this is 50 years年份 ago, "Surely一定," you're thinking思维,
这是费曼50年前说的 你也许在想:“那么久了
05:39
"we've我们已经 figured想通 it out by now."
我们现在弄清了吧”
05:41
It's not true真正 that we've我们已经 figured想通 it out by now.
错了 我们到现在也没弄清
05:43
The reason原因 the problem问题 has gotten得到 worse更差,
非但没把问题弄清
05:45
rather than better,
它还变得更糟糕了
05:47
is because in 1998
因为在1998年
05:49
we learned学到了 something crucial关键 about the universe宇宙 that we didn't know before.
一个关于宇宙的新发型展现在了我们面前
05:51
We learned学到了 that it's accelerating加速.
宇宙不仅在膨胀
05:54
The universe宇宙 is not only expanding扩大.
而且在加速膨胀
05:56
If you look at the galaxy星系, it's moving移动 away.
如果你看见一个星系正离你远去
05:58
If you come back a billion十亿 years年份 later后来 and look at it again,
十亿年后再回来看它时
06:00
it will be moving移动 away faster更快.
你会发现它远去的速度加快了
06:02
Individual个人 galaxies星系 are speeding超速 away from us faster更快 and faster更快
各个星系离我们远去的速度都在不断加快着
06:05
so we say the universe宇宙 is accelerating加速.
所以我们说这个宇宙正在加速膨胀
06:08
Unlike不像 the low entropy of the early universe宇宙,
与宇宙初期的小熵值不同
06:10
even though虽然 we don't know the answer回答 for this,
虽然我们没有答案 但要解释这现象
06:12
we at least最小 have a good theory理论 that can explain说明 it,
我们至少还有一套不错的理论
06:14
if that theory理论 is right,
如果那理论是正确的
06:16
and that's the theory理论 of dark黑暗 energy能源.
我是在说暗能量理论
06:18
It's just the idea理念 that empty space空间 itself本身 has energy能源.
它说 真空区自身便有能量
06:20
In every一切 little cubic立方体 centimeter厘米 of space空间,
这空间中的任何一立方厘米中
06:23
whether是否 or not there's stuff东东,
无论那里有没有东西
06:26
whether是否 or not there's particles粒子, matter, radiation辐射 or whatever随你,
无论那里有没有粒子 物质 辐射 或任何别的什么
06:28
there's still energy能源, even in the space空间 itself本身.
那里仍有能量 就这空间中便有
06:30
And this energy能源, according根据 to Einstein爱因斯坦,
在爱因斯坦看来
06:33
exerts发挥 a push on the universe宇宙.
这能量推动着宇宙
06:35
It is a perpetual永动的 impulse冲动
这是一股永恒的冲量
06:38
that pushes galaxies星系 apart距离 from each other.
使各星系之间的距离越来越大
06:40
Because dark黑暗 energy能源, unlike不像 matter or radiation辐射,
因为暗能量 与物质和辐射不同
06:42
does not dilute away as the universe宇宙 expands展开.
它不会因为宇宙的膨胀而被稀释
06:45
The amount of energy能源 in each cubic立方体 centimeter厘米
即便宇宙越来越大
06:48
remains遗迹 the same相同,
每立方厘米中的能量
06:50
even as the universe宇宙 gets得到 bigger and bigger.
都将保持不变
06:52
This has crucial关键 implications启示
这对宇宙未来的发展
06:54
for what the universe宇宙 is going to do in the future未来.
有着关键的影响
06:57
For one thing, the universe宇宙 will expand扩大 forever永远.
其中之一 便是宇宙会永远膨胀下去
07:00
Back when I was your age年龄,
当我像你们那么小的时候
07:02
we didn't know what the universe宇宙 was going to do.
我们并不知道宇宙是否会膨胀下去
07:04
Some people thought that the universe宇宙 would recollapse坍缩 in the future未来.
某些人认为 宇宙将会再坍缩
07:06
Einstein爱因斯坦 was fond喜欢 of this idea理念.
爱因斯坦就很喜欢这想法
07:09
But if there's dark黑暗 energy能源, and the dark黑暗 energy能源 does not go away,
但如果有暗能量 而暗能量又会永远留在那里
07:11
the universe宇宙 is just going to keep expanding扩大 forever永远 and ever and ever.
宇宙便会永不停息的 这样膨胀下去
07:14
14 billion十亿 years年份 in the past过去,
从140亿年前
07:17
100 billion十亿 dog years年份,
狗的一千亿年前
07:19
but an infinite无穷 number of years年份 into the future未来.
直至无数年以后 直至永恒的未来
07:21
Meanwhile与此同时, for all intents意图 and purposes目的,
在此期间 不论我们有什么意图或目的
07:24
space空间 looks容貌 finite有限 to us.
宇宙空间在我们看来都是有限的
07:27
Space空间 may可能 be finite有限 or infinite无穷,
宇宙或许有限 或许无限
07:29
but because the universe宇宙 is accelerating加速,
但因为它正在膨胀
07:31
there are parts部分 of it we cannot不能 see
我们看不到它的某些部分
07:33
and never will see.
也将永远无法看到
07:35
There's a finite有限 region地区 of space空间 that we have access访问 to,
能让我们获取信息的宇宙空间非常有限
07:37
surrounded包围 by a horizon地平线.
它被边界包围着
07:39
So even though虽然 time goes on forever永远,
所以即便时间不停下它的脚步
07:41
space空间 is limited有限 to us.
宇宙空间对我们来说还是有限的
07:43
Finally最后, empty space空间 has a temperature温度.
最后 真空区有它的温度
07:45
In the 1970s, Stephen斯蒂芬 Hawking霍金 told us
在70年代 斯蒂芬·霍金告诉我们
07:48
that a black黑色 hole, even though虽然 you think it's black黑色,
虽然你认为黑洞是黑的
07:50
it actually其实 emits发射 radiation辐射
它其实会辐射
07:52
when you take into account帐户 quantum量子 mechanics机械学.
如果把量子力学考虑进去的话
07:54
The curvature曲率 of space-time时空 around the black黑色 hole
黑洞周围的空间曲率
07:56
brings带来 to life the quantum量子 mechanical机械 fluctuation波动,
是会导致真空量子涨落的
07:59
and the black黑色 hole radiates辐射.
黑洞也就会辐射
08:02
A precisely恰恰 similar类似 calculation计算 by Hawking霍金 and Gary加里 Gibbons吉本斯
根据霍金与加利·基本斯的 一个类似的精确计算
08:04
showed显示 that if you have dark黑暗 energy能源 in empty space空间,
如果真空区里有暗能量
08:07
then the whole整个 universe宇宙 radiates辐射.
整个宇宙便会辐射
08:10
The energy能源 of empty space空间
真空区的能量
08:13
brings带来 to life quantum量子 fluctuations波动.
带来量子涨落
08:15
And so even though虽然 the universe宇宙 will last forever永远,
所以虽然宇宙是永恒的
08:17
and ordinary普通 matter and radiation辐射 will dilute away,
而且一般的物质和辐射会被稀释
08:19
there will always be some radiation辐射,
但某些辐射会永远留下
08:22
some thermal fluctuations波动,
某些热涨落
08:24
even in empty space空间.
即便那是真空区
08:26
So what this means手段
这也就是说
08:28
is that the universe宇宙 is like a box of gas加油站
宇宙好比一盒气体
08:30
that lasts持续 forever永远.
永恒的气体
08:32
Well what is the implication意义 of that?
这又意味着什么呢?
08:34
That implication意义 was studied研究 by Boltzmann玻尔兹曼 back in the 19th century世纪.
玻尔兹曼在19世纪对此进行了研究
08:36
He said, well, entropy increases增加
他说 熵值只会增大
08:39
because there are many许多, many许多 more ways方法
因为让宇宙处于大熵值状态的方式
08:42
for the universe宇宙 to be high entropy, rather than low entropy.
比让它处于小熵值状态的方式 多得多
08:44
But that's a probabilistic概率 statement声明.
但那是一个概率性的称述
08:47
It will probably大概 increase增加,
它可能会增大
08:50
and the probability可能性 is enormously巨大 huge巨大.
而且这可能性奇大无比
08:52
It's not something you have to worry担心 about --
我们不需要担心
08:54
the air空气 in this room房间 all gathering搜集 over one part部分 of the room房间 and suffocating令人窒息 us.
这房间里的空气不会挤到一处 并让我们窒息
08:56
It's very, very unlikely不会.
这可能性极小极小
09:00
Except if they locked锁定 the doors
但如果门被锁上
09:02
and kept不停 us here literally按照字面 forever永远,
我们被关在这里直至永远
09:04
that would happen发生.
这便会发生
09:06
Everything that is allowed允许,
所有被允许的
09:08
every一切 configuration组态 that is allowed允许 to be obtained获得 by the molecules分子 in this room房间,
这房间里的分子的布局
09:10
would eventually终于 be obtained获得.
都终究会出现
09:13
So Boltzmann玻尔兹曼 says, look, you could start开始 with a universe宇宙
所以玻尔兹曼说 你可以从一个
09:15
that was in thermal equilibrium平衡.
处于热平衡状态的宇宙出发
09:18
He didn't know about the Big Bang. He didn't know about the expansion扩张 of the universe宇宙.
他没听说过大爆炸 也没听过宇宙膨胀
09:20
He thought that space空间 and time were explained解释 by Isaac艾萨克 Newton牛顿 --
他以为牛顿对时空做出了充分的解释
09:23
they were absolute绝对; they just stuck卡住 there forever永远.
时空是绝对的 它被永恒的固定在那里
09:26
So his idea理念 of a natural自然 universe宇宙
所以他在眼中的自然宇宙里
09:28
was one in which哪一个 the air空气 molecules分子 were just spread传播 out evenly everywhere到处 --
空气中的分子都平均的分散在各处
09:30
the everything molecules分子.
所有的分子
09:33
But if you're Boltzmann玻尔兹曼, you know that if you wait long enough足够,
但如果你是玻尔兹曼的话 你知道 如果你等的够久
09:35
the random随机 fluctuations波动 of those molecules分子
那些分子无规则的涨落
09:38
will occasionally偶尔 bring带来 them
会偶尔使它们
09:41
into lower降低 entropy configurations配置.
处于小熵值的布局
09:43
And then, of course课程, in the natural自然 course课程 of things,
但肯定的是 在那之后 随着自然规律
09:45
they will expand扩大 back.
它们会涨回到分散的状态
09:47
So it's not that entropy must必须 always increase增加 --
所以说 并非是熵值必须要增大
09:49
you can get fluctuations波动 into lower降低 entropy,
涨落会带来小熵值
09:51
more organized有组织的 situations情况.
带来更规则的状态
09:54
Well if that's true真正,
就这样
09:56
Boltzmann玻尔兹曼 then goes onto invent发明
玻尔兹曼接着发明了
09:58
two very modern-sounding现代冠冕堂皇 ideas思路 --
两个听上去很现代化的概念
10:00
the multiverse多重宇宙 and the anthropic人为 principle原理.
多元宇宙与人择原理
10:02
He says, the problem问题 with thermal equilibrium平衡
他说 热平衡的问题在于
10:05
is that we can't live生活 there.
我们无法生活在这样的状态下
10:07
Remember记得, life itself本身 depends依靠 on the arrow箭头 of time.
记得吗 生命本身便依赖于时间之箭
10:09
We would not be able能够 to process处理 information信息,
如果我们生活在热平衡的状态下
10:12
metabolize代谢, walk步行 and talk,
我们将无法处理信息
10:14
if we lived生活 in thermal equilibrium平衡.
没法新陈代谢 没法走路 没法说话
10:16
So if you imagine想像 a very, very big universe宇宙,
如果你想象一个很大很大的宇宙
10:18
an infinitely无限地 big universe宇宙,
一个无限大的宇宙
10:20
with randomly随机 bumping碰撞 into each other particles粒子,
粒子间无规律的碰撞
10:22
there will occasionally偶尔 be small fluctuations波动 in the lower降低 entropy states状态,
会偶尔带来小熵值下的小涨落
10:24
and then they relax放松 back.
然后它们会复原
10:27
But there will also be large fluctuations波动.
但也会存在大涨落
10:29
Occasionally偶尔, you will make a planet行星
偶然造出个行星
10:31
or a star or a galaxy星系
恒星 星系
10:33
or a hundred billion十亿 galaxies星系.
或是一千亿个星系
10:35
So Boltzmann玻尔兹曼 says,
所以玻尔兹曼说
10:37
we will only live生活 in the part部分 of the multiverse多重宇宙,
我们只可能生活在多元宇宙里
10:39
in the part部分 of this infinitely无限地 big set of fluctuating波动 particles粒子,
这无限大的涨落中的粒子群里
10:42
where life is possible可能.
允许生命的那部分
10:45
That's the region地区 where entropy is low.
也就是有着小熵值的区域
10:47
Maybe our universe宇宙 is just one of those things
也许我们宇宙的诞生不过就是
10:49
that happens发生 from time to time.
那些时而发生的事之一
10:52
Now your homework家庭作业 assignment分配
你们的回家作业
10:54
is to really think about this, to contemplate沉思 what it means手段.
是去好好想想这些 这到底意味着什么
10:56
Carl卡尔 Sagan萨根 once一旦 famously著名 said
引用卡尔·萨根的名言
10:58
that "in order订购 to make an apple苹果 pie馅饼,
“要做个苹果派
11:00
you must必须 first invent发明 the universe宇宙."
你必须先造出个宇宙”
11:02
But he was not right.
但他说错了
11:05
In Boltzmann's玻耳兹曼 scenario脚本, if you want to make an apple苹果 pie馅饼,
根据玻尔兹曼 如果你想要做个苹果派
11:07
you just wait for the random随机 motion运动 of atoms原子
你只需等着 让原子不规则的运动
11:10
to make you an apple苹果 pie馅饼.
帮你做个苹果派
11:13
That will happen发生 much more frequently经常
这比等着原子不规则的运动
11:15
than the random随机 motions运动 of atoms原子
造出个苹果园
11:17
making制造 you an apple苹果 orchard果园
造出些糖和烤箱
11:19
and some sugar and an oven烤箱,
然后再帮你做个苹果派
11:21
and then making制造 you an apple苹果 pie馅饼.
可能性大得多
11:23
So this scenario脚本 makes品牌 predictions预测.
这论点包含着某些预测
11:25
And the predictions预测 are
这些预测包括
11:28
that the fluctuations波动 that make us are minimal最小.
造出我们的是最小限度的涨落
11:30
Even if you imagine想像 that this room房间 we are in now
即便你想象我们现在的这个房间
11:33
exists存在 and is real真实 and here we are,
真实的存在着 而我们也就在这里
11:36
and we have, not only our memories回忆,
我们不仅有着我们的回忆
11:38
but our impression印象 that outside there's something
也坚信着这房间外面还有东西
11:40
called Caltech加州理工学院 and the United联合的 States状态 and the Milky乳白色 Way Galaxy星系,
有加州理工学院 有美国 有银河系
11:42
it's much easier更轻松 for all those impressions印象 to randomly随机 fluctuate波动 into your brain
让这些想法通过不规则的涨落进入你的大脑
11:46
than for them actually其实 to randomly随机 fluctuate波动
比起让这些涨落真正造出加州理工学院
11:49
into Caltech加州理工学院, the United联合的 States状态 and the galaxy星系.
造出美国 造出银河系 要容易得多
11:51
The good news新闻 is that,
好消息是
11:54
therefore因此, this scenario脚本 does not work; it is not right.
这论点行不通 是错误的
11:56
This scenario脚本 predicts预测 that we should be a minimal最小 fluctuation波动.
它预测我们应该是个小涨落
11:59
Even if you left our galaxy星系 out,
即便你忽略我们的星系
12:02
you would not get a hundred billion十亿 other galaxies星系.
你也没法弄到一千亿个其他星系
12:04
And Feynman费曼 also understood了解 this.
费曼也明白这一点
12:06
Feynman费曼 says, "From the hypothesis假设 that the world世界 is a fluctuation波动,
他说:“假设这世界便是涨落
12:08
all the predictions预测 are that
那这也就意味着 如果我们
12:12
if we look at a part部分 of the world世界 we've我们已经 never seen看到 before,
对从未观测过的那部分世界进行观测
12:14
we will find it mixed up, and not like the piece we've我们已经 just looked看着 at --
我们会发现它很混乱 与我们之前观测的
12:16
high entropy.
大熵值的部分不同
12:18
If our order订购 were due应有 to a fluctuation波动,
如果我们的秩序来自于涨落
12:20
we would not expect期望 order订购 anywhere随地 but where we have just noticed注意到 it.
我们便不会认为除了刚注意到的秩序 另外还有秩序
12:22
We therefore因此 conclude得出结论 the universe宇宙 is not a fluctuation波动."
所以我们断定 宇宙并非涨落
12:24
So that's good. The question is then what is the right answer回答?
这算是好了 但正确的答案又是什么呢?
12:28
If the universe宇宙 is not a fluctuation波动,
如果宇宙不是涨落
12:31
why did the early universe宇宙 have a low entropy?
初期宇宙的熵值为什么那么小?
12:33
And I would love to tell you the answer回答, but I'm running赛跑 out of time.
我很乐意回答你 但我没时间了
12:36
(Laughter笑声)
(笑)
12:39
Here is the universe宇宙 that we tell you about,
我们告诉你的宇宙 对应着
12:41
versus the universe宇宙 that really exists存在.
真正存在着的宇宙
12:43
I just showed显示 you this picture图片.
我刚刚给你们看过这画面
12:45
The universe宇宙 is expanding扩大 for the last 10 billion十亿 years年份 or so.
一百多亿年来 宇宙不断膨胀着
12:47
It's cooling冷却 off.
它也冷却着
12:49
But we now know enough足够 about the future未来 of the universe宇宙
但我们现在对宇宙的了解
12:51
to say a lot more.
足够让我们说出更多的
12:53
If the dark黑暗 energy能源 remains遗迹 around,
如果暗能量留在周围不动
12:55
the stars明星 around us will use up their nuclear fuel汽油, they will stop burning燃烧.
我们周围的恒星将用尽他们的核子燃料 它们将停止燃烧
12:57
They will fall秋季 into black黑色 holes.
它们会变成黑洞
13:00
We will live生活 in a universe宇宙
我们将生活在一个 除了黑洞
13:02
with nothing in it but black黑色 holes.
空空如也的宇宙
13:04
That universe宇宙 will last 10 to the 100 years年份 --
那宇宙将会存在10的100次方年
13:06
a lot longer than our little universe宇宙 has lived生活.
比我们的小宇宙长寿多了
13:10
The future未来 is much longer than the past过去.
为了比过去长得多
13:12
But even black黑色 holes don't last forever永远.
但就连黑洞也不是永恒的
13:14
They will evaporate蒸发,
它们会蒸发
13:16
and we will be left with nothing but empty space空间.
除了一个真空宇宙我们将一无所有
13:18
That empty space空间 lasts持续 essentially实质上 forever永远.
这真空宇宙将会是永远的
13:20
However然而, you notice注意, since以来 empty space空间 gives off radiation辐射,
但你意识到 因为真空区也会有辐射
13:24
there's actually其实 thermal fluctuations波动,
所以热涨落其实存在着
13:27
and it cycles周期 around
它以存在于真空区中的
13:29
all the different不同 possible可能 combinations组合
有着各种不同组合的
13:31
of the degrees of freedom自由 that exist存在 in empty space空间.
自由度之间 不断的循环着
13:33
So even though虽然 the universe宇宙 lasts持续 forever永远,
所以即便宇宙将永远的存在下去
13:36
there's only a finite有限 number of things
能够在宇宙中发生的事
13:38
that can possibly或者 happen发生 in the universe宇宙.
却是有限的
13:40
They all happen发生 over a period of time
它们都在10到10的120次方年
13:42
equal等于 to 10 to the 10 to the 120 years年份.
这段时间内发生
13:44
So here's这里的 two questions问题 for you.
我想问你们两个问题
13:47
Number one: If the universe宇宙 lasts持续 for 10 to the 10 to the 120 years年份,
第一:如果宇宙会存在10到10的120次方年
13:49
why are we born天生
我们为什么出生于
13:52
in the first 14 billion十亿 years年份 of it,
最初的140亿年间
13:54
in the warm, comfortable自在 afterglow余辉 of the Big Bang?
出生于这大爆炸带来的温暖 舒适的环境中?
13:57
Why aren't we in empty space空间?
我们为什么不在真空区?
14:00
You might威力 say, "Well there's nothing there to be living活的,"
你也许会说:“那里根本没有活着的东西”
14:02
but that's not right.
但这不对
14:04
You could be a random随机 fluctuation波动 out of the nothingness虚无.
你可以来自空无一物中无规则的涨落
14:06
Why aren't you?
而你为什么不是呢?
14:08
More homework家庭作业 assignment分配 for you.
还有些回家作业要布置给你们
14:10
So like I said, I don't actually其实 know the answer回答.
如我所说 我并不知道答案
14:13
I'm going to give you my favorite喜爱 scenario脚本.
就让我来谈谈我最喜欢的情形吧
14:15
Either it's just like that. There is no explanation说明.
也许它本该如此 根本没有解释
14:17
This is a brute畜生 fact事实 about the universe宇宙
这就是个不容争议的关于宇宙的事实
14:20
that you should learn学习 to accept接受 and stop asking questions问题.
你必须接受它 并不再询问任何问题
14:22
Or maybe the Big Bang
或者说 大爆炸
14:26
is not the beginning开始 of the universe宇宙.
并非宇宙的开端
14:28
An egg, an unbroken绵绵 egg, is a low entropy configuration组态,
一只完整的鸡蛋 处于小熵值的状态
14:30
and yet然而, when we open打开 our refrigerator冰箱,
但当我们打开冰箱时
14:33
we do not go, "Hah, how surprising奇怪 to find
我们不会想:“哇 能在冰箱里看到这样一个
14:35
this low entropy configuration组态 in our refrigerator冰箱."
小熵值状态实在太惊人了“
14:37
That's because an egg is not a closed关闭 system系统;
那是因为一只鸡蛋并非一个封闭系统
14:39
it comes out of a chicken.
它是某只鸡生出来的
14:42
Maybe the universe宇宙 comes out of a universal普遍 chicken.
也许整个宇宙都是一只宇宙鸡生出来的
14:44
Maybe there is something that naturally自然,
也许通过物理定律的发展
14:48
through通过 the growth发展 of the laws法律 of physics物理,
某些东西会自然的导致
14:50
gives rise上升 to universe宇宙 like ours我们的
这个宇宙
14:53
in low entropy configurations配置.
以小熵值的形式诞生
14:55
If that's true真正, it would happen发生 more than once一旦;
如果那是正确的话 它不会只发生一次
14:57
we would be part部分 of a much bigger multiverse多重宇宙.
我们会是巨大的多元宇宙的一部分
14:59
That's my favorite喜爱 scenario脚本.
这便是我最中意的情形
15:02
So the organizers组织者 asked me to end结束 with a bold胆大 speculation推测.
组织者们让我以一个大胆的推测结束我的演讲
15:04
My bold胆大 speculation推测
我大胆的推测
15:07
is that I will be absolutely绝对 vindicated平反 by history历史.
便是我将会绝对的被历史维护
15:09
And 50 years年份 from now,
今后的50年间
15:12
all of my current当前 wild野生 ideas思路 will be accepted公认 as truths真理
我现在所有疯狂的想法都会
15:14
by the scientific科学 and external外部 communities社区.
被科学界以及整个社会 接受为现实
15:17
We will all believe that our little universe宇宙
我们将全都相信 我们的小宇宙
15:20
is just a small part部分 of a much larger multiverse多重宇宙.
不过是更大的多元宇宙中的一部分
15:22
And even better, we will understand理解 what happened发生 at the Big Bang
不仅如此 我们将理解大爆炸时发生的一切
15:25
in terms条款 of a theory理论
将有一套能够
15:28
that we will be able能够 to compare比较 to observations意见.
被观察支持的理论
15:30
This is a prediction预测. I might威力 be wrong错误.
这只是预测 我也许错了
15:32
But we've我们已经 been thinking思维 as a human人的 race种族
那么多年来 作为人类
15:34
about what the universe宇宙 was like,
我们不断思考着 曾经的宇宙
15:36
why it came来了 to be in the way it did for many许多, many许多 years年份.
是怎样的 而它又是怎么变成它当时的样子的
15:38
It's exciting扣人心弦 to think we may可能 finally最后 know the answer回答 someday日后.
令人兴奋的是 或许终有一天我们会找到答案
15:41
Thank you.
谢谢
15:44
(Applause掌声)
(掌声)
15:46
Translated by Lily Yichen Shi
Reviewed by Jenny Yang

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About the speaker:

Sean M. Carroll - Physicist, cosmologist
A physicist, cosmologist and gifted science communicator, Sean Carroll is asking himself -- and asking us to consider -- questions that get at the fundamental nature of the universe.

Why you should listen

Sean Carroll is a theoretical physicist at Caltech in Pasadena, California, where he researches theoretical aspects of cosmology, field theory and gravitation -- exploring the nature of fundamental physics by studying the structure and evolution of the universe.

His book on cosmology and the arrow of time, From Eternity to Here: The Quest for the Ultimate Theory of Time, was published in 2010. He keeps a regular blog at Cosmic Variance.

More profile about the speaker
Sean M. Carroll | Speaker | TED.com