TED2004
Steven Strogatz: The science of sync
斯托加茨谈“同步”
Filmed:
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数学家斯托加茨展示群居动物（如鸟、萤火虫和鱼）是如何在没有人发布命令的情况下同步行动的。这种强大的倾向在物质世界也有显现。
Steven Strogatz - Mathematician
In his work in applied mathematics, Steven Strogatz studies the way math and biology intersect. Full bio
In his work in applied mathematics, Steven Strogatz studies the way math and biology intersect. Full bio
Double-click the English transcript below to play the video.
00:19
I was trying to think, how is sync connected to happiness,
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当时我试着搞明白，“同步”和幸福的关系。
00:21
and it occurred to me that for some reason we take pleasure in synchronizing.
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我想到，我们在“同步”中感到快乐是有原因的。
00:28
We like to dance together, we like singing together.
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我们喜欢一起跳舞。我们喜欢一起歌唱。
00:31
And so, if you'll put up with this, I would like to enlist your help
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如果你们愿意，我想请求你们的帮助
00:36
with a first experiment today. The experiment is --
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来做一个实验。这个实验是——
00:40
and I notice, by the way, that when you applauded,
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其实我注意到，当你们鼓掌时，
00:43
that you did it in a typical North American way,
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你们是用北美人的方式，
00:45
that is, you were raucous and incoherent.
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那就是，以一种喧闹、不连贯的方式鼓掌。
00:49
You were not organized. It didn't even occur to you to clap in unison.
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没有人组织。你们甚至从没有想过要统一鼓掌。
00:54
Do you think you could do it? I would like to see if this audience would --
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但你们觉得你们可以做到么？我想看看我的听众们是否可以——
00:58
no, you haven't practiced, as far as I know --
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是的，据我所知，你们没有经过训练——
01:00
can you get it together to clap in sync?
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但你们可以同步鼓掌么？
01:04
(Clapping)
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（鼓掌）
01:14
Whoa! Now, that's what we call emergent behavior.
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哇！现在，这就是我们所说的应激行为。
01:16
(Laughter)
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（笑）
01:18
So I didn't expect that, but -- I mean, I expected you could synchronize.
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我并没有预料到，但是——我是说，我确实预见到你们可以同步。
01:22
It didn't occur to me you'd increase your frequency.
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但我并没有想到你们会提高频率。
01:25
It's interesting.
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那很有趣。
01:27
(Laughter)
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（笑）
01:30
So what do we make of that? First of all, we know that you're all brilliant.
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可我们是怎么做到的？首先，你们都是了不起的人物。
01:34
This is a room full of intelligent people, highly sensitive.
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这屋里满是智慧的人，非常敏感。
01:38
Some trained musicians out there.
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那里还坐着一些训练有素的音乐家。
01:41
Is that what enabled you to synchronize?
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可是，是这些使你们可以同步的吗？
01:43
So to put the question a little more seriously,
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或者更严谨的说，
01:46
let's ask ourselves what are the minimum requirements for what you just did,
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让我们想一下，什么是你们同步所需的
01:50
for spontaneous synchronization.
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最低要求。
01:53
Do you need, for instance, to be as smart as you are?
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举例来说，你们是不是需要如此聪明？
01:57
Do you even need a brain at all just to synchronize?
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甚至，你们是不是要有大脑才可以？
02:04
Do you need to be alive? I mean, that's a spooky thought, right?
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是否必须活着？我是说，那可是个鬼怪的想法。
02:09
Inanimate objects that might spontaneously synchronize themselves.
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但实际上，确实如此，没有生命的物体
02:14
It's real. In fact, I'll try to explain today that sync is maybe one of,
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确实可以达到同步。我正要试着向你们解释，同步或许是一种
02:21
if not one of the most, perhaps the most pervasive drive in all of nature.
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甚至可能是自然界中最普遍的力量之一。
02:25
It extends from the subatomic scale to the farthest reaches of the cosmos.
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它由亚原子尺度延伸至星系之间。
02:31
It's a deep tendency toward order in nature
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它是通往自然秩序的一种深刻的倾向。
02:35
that opposes what we've all been taught about entropy.
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正与熵增原理相反。
02:38
I mean, I'm not saying the law of entropy is wrong -- it's not.
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我并不是说熵增原理是错误的——它确定无疑。
02:41
But there is a countervailing force in the universe --
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但宇宙中还存在一种与之相消的力量——
02:43
the tendency towards spontaneous order. And so that's our theme.
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一种通向同步与秩序的倾向。那正是我们的主题。
02:48
Now, to get into that, let me begin with what might have occurred to you immediately
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进入正题。让我由你们听到自然界的同步现象时
02:52
when you hear that we're talking about synchrony in nature,
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都会立即想到的开始，
02:56
which is the glorious example of birds that flock together,
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比如说群飞的鸟，
03:02
or fish swimming in organized schools.
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极有秩序游动的鱼群。
03:06
So these are not particularly intelligent creatures,
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这些并不是高度智慧的生物，
03:10
and yet, as we'll see, they exhibit beautiful ballets.
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但是从它们我们却看到美妙的舞步。
03:15
This is from a BBC show called "Predators,"
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这是来自BBC的《猎食者》，
03:17
and what we're looking at here are examples of synchrony that have to do with defense.
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我们看到的是与防御相关的同步现象。
03:23
When you're small and vulnerable, like these starlings,
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对于和这些椋鸟或者鱼一样，弱小而易受伤害的生物，
03:26
or like the fish, it helps to swarm to avoid predators, to confuse predators.
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群居或者去迷惑捕食者确实是一种有用的策略。
03:35
Let me be quiet for a second because this is so gorgeous.
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让我沉默一会儿，这是如此精彩。
03:53
For a long time, biologists were puzzled by this behavior,
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在很长一段时间内，生物学家对这种行为感到困惑，
03:56
wondering how it could be possible.
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觉得不可思议。
03:59
We're so used to choreography giving rise to synchrony.
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我们太过习惯于“同步”的来源——舞蹈。
04:03
These creatures are not choreographed.
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这些生物并未学过舞蹈。
04:05
They're choreographing themselves.
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它们是自觉地“舞蹈”。
04:09
And only today is science starting to figure out how it works.
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现在，只有科学能解释它们是如何做到的。
04:13
I'll show you a computer model made by Iain Couzin, a researcher at Oxford,
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我将展示Ian Kuzan，一位牛津大学研究员，设计的计算机模型。
04:19
that shows how swarms work.
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它告诉我们群飞现象的原理。
04:21
There are just three simple rules.
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只有三条简单的规则。
04:24
First, all the individuals are only aware of their nearest neighbors.
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第一，所有的个体只知道最靠近自己的近邻的行为。
04:29
Second, all the individuals have a tendency to line up.
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第二，所有的个体都有排成行的趋势。
04:33
And third, they're all attracted to each other,
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最后，它们之间互相吸引，
04:36
but they try to keep a small distance apart.
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但它们同时想保留小段距离。
04:39
And when you build those three rules in,
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当你写下这三条规则，
04:42
automatically you start to see swarms
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群飞现象自然而然地产生了。
04:44
that look very much like fish schools or bird flocks.
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与现实中的鱼群和鸟群完全一致。
04:48
Now, fish like to stay close together, about a body length apart.
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鱼比较倾向于靠近，间隔一个身长。
04:52
Birds try to stay about three or four body lengths apart.
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鸟会彼此间隔3、4个身长。
04:55
But except for that difference, the rules are the same for both.
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除了这些区别，两者都受那三条规则约束。
05:04
Now, all this changes when a predator enters the scene.
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现在，捕食者进入画面，一切都改变了。
05:09
There's a fourth rule: when a predator's coming, get out of the way.
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有了第四条规则：当捕食者出现，逃！
05:23
Here on the model you see the predator attacking.
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在这个模型里，可以看到捕食者正在进攻。
05:28
The prey move out in random directions,
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被捕食者四处逃窜。
05:30
and then the rule of attraction brings them back together again,
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之后“吸引法则”又把它们聚到一起，
05:33
so there's this constant splitting and reforming.
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所以产生了不断的分离与重组。
05:37
And you see that in nature.
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这在自然界也是常见的。
05:47
Keep in mind that, although it looks as if each individual is acting to cooperate,
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请记住，尽管个体之间看起来是在合作，
05:53
what's really going on is a kind of selfish Darwinian behavior.
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但实际只是自私的“达尔文”行为。
05:57
Each is scattering away at random to try to save its scales or feathers.
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每一次的分散都只是为了自己保命。
06:03
That is, out of the desire to save itself,
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是出自自我保护的欲望，
06:06
each creature is following these rules,
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所有的个体都遵循这些规则，
06:09
and that leads to something that's safe for all of them.
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结果却是集体都获得了安全。
06:11
Even though it looks like they're thinking as a group, they're not.
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它们并不是作为团队思考，但看起来却是如此。
06:32
You might wonder what exactly is the advantage to being in a swarm,
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你们可能会想：群聚对个体到底有何利处？
06:35
so you can think of several.
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确实有一些。
06:37
As I say, if you're in a swarm, your odds of being the unlucky one
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在群聚中，相比较处在一个较小的团体中，
06:41
are reduced as compared to a small group.
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你被捕食的机会将大大降低。
06:45
There are many eyes to spot danger.
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有许多双眼睛去发现危险。
06:48
And you'll see in the example with the starlings, with the birds,
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以鸟为例，
06:55
when this peregrine hawk is about to attack them,
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当这只游隼准备攻击它们时，
06:57
that actually waves of panic can propagate,
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那些不断增长的惊恐的浪潮
07:00
sending messages over great distances.
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将危险的信号传递到极遥远处。
07:03
You'll see -- let's see, it's coming up possibly at the very end -- maybe not.
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你们将会看到——让我们看看，它将传到尽头——或许没有。
07:12
Information can be sent over half a kilometer away
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通过这种机制，在极短的时间里，
07:15
in a very short time through this mechanism.
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信息可以跨越半公里以上。
07:20
Yes, it's happening here.
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是的，就是这样。
07:22
See if you can see those waves propagating through the swarm.
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试着观察群中不断增长的浪潮。
07:26
It's beautiful. The birds are, we sort of understand, we think,
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很美。通过那个计算机模型，
07:30
from that computer model, what's going on.
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我们在某种程度上了解了这些鸟的行为。
07:32
As I say, it's just those three simple rules,
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正如我之前所说，只是由三条简单的规则，
07:34
plus the one about watch out for predators.
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加上一条关于捕食者的。
07:36
There doesn't seem to be anything mystical about this.
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没有任何神奇之处。
07:39
We don't, however, really understand at a mathematical level.
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可事实并非如此，从数学层面上说，我们并不了解。
07:42
I'm a mathematician. We would like to be able to understand better.
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我是一个数学家。我们总是希望更好的理解。
07:46
I mean, I showed you a computer model, but a computer is not understanding.
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我是说，这里有一个计算机模型。但它并不是理解。
07:49
A computer is, in a way, just another experiment.
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从某种程度上说，它只是另一种实验。
07:52
We would really like to have a deeper insight into how this works
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我们总是渴望更深刻地理解，
07:55
and to understand, you know, exactly where this organization comes from.
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去理解这种组织是如何形成的。
08:00
How do the rules give rise to the patterns?
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规则如何带来模式？
08:02
There is one case that we have begun to understand better,
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我们已经开始理解一个实例，
08:05
and it's the case of fireflies.
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是关于萤火虫。
08:08
If you see fireflies in North America,
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北美的萤火虫，
08:10
like so many North American sorts of things,
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就如同北美的其他东西一样，
08:12
they tend to be independent operators. They ignore each other.
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总是分头行动，忽视其他个体。
08:16
They each do their own thing, flashing on and off,
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总是干自己的，忽明忽暗，
08:18
paying no attention to their neighbors.
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完全不理会周围。
08:20
But in Southeast Asia -- places like Thailand or Malaysia or Borneo --
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可是在东南亚——比如泰国或马来西亚——
08:25
there's a beautiful cooperative behavior that occurs among male fireflies.
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雄性萤火虫之间有美妙的合作。
08:30
You can see it every night along the river banks.
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河岸边，每晚都可以看见。
08:33
The trees, mangrove trees, are filled with fireflies communicating with light.
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美洲红树上满是以光亮交流的萤火虫。
08:38
Specifically, it's male fireflies who are all flashing in perfect time together,
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特别的，那些雄性萤火虫完全同步的闪烁
08:43
in perfect synchrony, to reinforce a message to the females.
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来向雌性传递信息。
08:47
And the message, as you can imagine, is "Come hither. Mate with me."
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正如你们所想，那信息就是“来吧！和我约会！”
08:52
(Music)
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（音乐）
08:59
In a second I'm going to show you a slow motion of a single firefly
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一会儿我将展示一只萤火虫的慢镜头，
09:03
so that you can get a sense. This is a single frame.
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这样你们就可以感觉到我所说。这是一个单镜头。
09:06
Then on, and then off -- a 30th of a second, there.
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亮，暗——这是三十分之一秒。
09:11
And then watch this whole river bank, and watch how precise the synchrony is.
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然后让我们看看这整个河岸，看看这精确的同步。
09:18
On, more on and then off.
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明明暗暗。
09:27
The combined light from these beetles -- these are actually tiny beetles --
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这些虫身上汇聚的光亮——这些小虫啊——
09:30
is so bright that fishermen out at sea can use them
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是如此明亮，连海上的渔民都可以看见。
09:33
as navigating beacons to find their way back to their home rivers. It's stunning.
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他们把这光作为回家指路的灯塔。这真惊人。
09:37
For a long time it was not believed
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很长时间内都没有人相信，
09:39
when the first Western travelers, like Sir Francis Drake,
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当德雷克爵士等西方旅行家来到泰国
09:42
went to Thailand and came back with tales of this unbelievable spectacle.
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回去时讲述这一不可思议的景象时，
09:46
No one believed them.
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没有人相信。
09:48
We don't see anything like this in Europe or in the West.
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在欧洲或西方我们从来没有见过这类事。
09:51
And for a long time, even after it was documented,
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就连被录制成纪录片之后很久，
09:54
it was thought to be some kind of optical illusion.
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仍只被认为是某种光学幻觉。
09:56
Scientific papers were published saying it was twitching eyelids
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科学论文中论述它是由于眼睑的眨动。
09:59
that explained it, or, you know, a human being's tendency
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可是你们知道，人类总是想要
10:03
to see patterns where there are none.
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在没有模式处发现模式。
10:05
But I hope you've convinced yourself now, with this nighttime video,
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但我希望在看过这些之后，你们已经信服
10:08
that they really were very well synchronized.
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这确实是非常完美的同步了。
10:11
Okay, well, the issue then is, do we need to be alive
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那么，现在的问题是，是不是一定要有生命
10:14
to see this kind of spontaneous order,
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才可以达到这种同步。
10:16
and I've already hinted that the answer is no.
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我已经暗示答案是否定的。
10:21
Well, you don't have to be a whole creature.
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你根本不需要是一个生命体。
10:23
You can even be just a single cell.
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你甚至可以只是单个细胞。
10:25
Like, take, for instance, your pacemaker cells in your heart right now.
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就好像你心脏里的起搏细胞一样。
10:28
They're keeping you alive.
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没有它们，你我可活不下去。
10:30
Every beat of your heart depends on this crucial region, the sinoatrial node,
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心脏的每一次跳动都取决于这个关键的部位，窦房结，
10:35
which has about 10,000 independent cells that would each beep,
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大约一万个相互独立的细胞
10:39
have an electrical rhythm -- a voltage up and down --
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以一种电流的韵律——电压起伏——“鸣叫”。
10:42
to send a signal to the ventricles to pump.
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以此来发出让心室运作的信号。
10:45
Now, your pacemaker is not a single cell.
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你的起搏器并不是单一细胞。
10:48
It's this democracy of 10,000 cells that all have to fire in unison
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正是个10000个细胞统一的合作
10:51
for the pacemaker to work correctly.
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才使得起搏器正常工作。
10:54
I don't want to give you the idea that synchrony is always a good idea.
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我并不是想让你们觉得同步总是个好主意。
10:57
If you have epilepsy, there is an instance of billions of brain cells, or at least millions,
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如果你患有癫痫症，那么大约有10亿，至少几百万的脑细胞，
11:02
discharging in pathological concert.
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“同步”失效。
11:06
So this tendency towards order is not always a good thing.
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所以这一倾向秩序的趋势并不总是好的。
11:10
You don't have to be alive. You don't have to be even a single cell.
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其实你甚至不需要是一个细胞。你不需要活着。
11:13
If you look, for instance, at how lasers work,
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举例来说，如果你们知道激光是如何工作的，
11:16
that would be a case of atomic synchrony.
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那就是一个原子层面上的同步例子。
11:19
In a laser, what makes laser light so different from the light above my head here
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我头顶的光线是杂乱的——
11:23
is that this light is incoherent --
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有许多不同的颜色和频率，
11:25
many different colors and different frequencies,
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有点像你们一开始时的鼓掌——
11:28
sort of like the way you clapped initially --
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但激光和这不同，
11:31
but if you were a laser, it would be rhythmic applause.
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它是“有节奏”的“鼓掌。”
11:34
It would be all atoms pulsating in unison,
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是所有原子按照同一个频率震动，
11:36
emitting light of one color, one frequency.
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发射出同一色的单频率光线。
11:40
Now comes the very risky part of my talk,
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现在到了我演讲中最有风险的一部分，
11:43
which is to demonstrate that inanimate things can synchronize.
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来展示没有生命的物体也可以达到同步。
11:47
Hold your breath for me.
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请为我摒住呼吸。
11:49
What I have here are two empty water bottles.
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我这里有两个空水瓶。
11:56
This is not Keith Barry doing a magic trick.
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我并不是Keith Barry，也不会变魔术。
11:58
This is a klutz just playing with some water bottles.
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我就是一个拿着两个水瓶的普通人。
12:03
I have some metronomes here.
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我有一些节拍器。
12:08
Can you hear that?
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你们可以听到吗？
12:12
All right, so, I've got a metronome,
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我将使用一个节拍器，
12:14
and it's the world's smallest metronome, the -- well, I shouldn't advertise.
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这是世界上最小的节拍器——哦，我不应该做广告。
12:18
Anyway, so this is the world's smallest metronome.
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可这确实是世界上最小的节拍器。
12:21
I've set it on the fastest setting, and I'm going to now take
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我已经将它调至最高档。我把另一台
12:24
another one set to the same setting.
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也调到同样。
12:28
We can try this first. If I just put them on the table together,
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我们可以先试试这个。我只是把它们一起放在桌上，
12:33
there's no reason for them to synchronize, and they probably won't.
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它们好像没有什么理由会同步，也许它们不会。
12:42
Maybe you'd better listen to them. I'll stand here.
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你们可能最好听着。我站在这里。
12:49
What I'm hoping is that they might just drift apart
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我只是希望它们分开
12:51
because their frequencies aren't perfectly the same.
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因为它们的频率并不是一模一样。
13:01
Right? They did.
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是吧？它们分开了。
13:03
They were in sync for a while, but then they drifted apart.
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它们同步了一段时间，但之后又分开。
13:07
And the reason is that they're not able to communicate.
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原因是它们之间没有办法交流。
13:09
Now, you might think that's a bizarre idea.
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现在你们或许觉得这是个怪主意。
13:11
How can metronomes communicate?
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节拍器要怎么交流？
13:14
Well, they can communicate through mechanical forces.
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它们可以通过机械力交流。
13:17
So I'm going to give them a chance to do that.
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现在我就是给它们一个机会去这么做。
13:19
I also want to wind this one up a bit. How can they communicate?
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我还将对这个略作调整。它们怎么交流？
13:22
I'm going to put them on a movable platform,
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我将它们放到一个可移动的平台上，
13:24
which is the "Guide to Graduate Study at Cornell." Okay? So here it is.
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就是《康奈尔大学研究生学习指导》。可以吗？就在这里。
13:33
Let's see if we can get this to work.
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让我们试试是否可行。
13:37
My wife pointed out to me that it will work better if I put both on at the same time
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我的妻子指出，如果我可以同时打开它们，那么将会更好。
13:41
because otherwise the whole thing will tip over.
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否则周期会无法对应。
13:43
All right. So there we go. Let's see. OK, I'm not trying to cheat --
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好了，我们开始。让我们悄悄。好的，我并不是要作弊——
13:50
let me start them out of sync. No, hard to even do that.
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让它们刚开始时不要同步。不，这将更难。
14:08
(Applause)
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（掌声）
14:12
All right. So before any one goes out of sync, I'll just put those right there.
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好的。在它们失去同步之前，我要把它们摆到那里。
14:17
(Laughter)
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（笑）
14:18
Now, that might seem a bit whimsical,
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这一切看起来似乎有点神奇，
14:20
but this pervasiveness of this tendency towards spontaneous order
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但这一种强大的对同步的倾向
14:25
sometimes has unexpected consequences.
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有时候会有意想不到的结果。
14:29
And a clear case of that,
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举例来说，
14:31
was something that happened in London in the year 2000.
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2000年时在伦敦，
14:34
The Millennium Bridge was supposed to be the pride of London --
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千年桥本应成为伦敦的骄傲——
14:37
a beautiful new footbridge erected across the Thames,
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一座横跨泰晤士河的美丽的桥，
14:41
first river crossing in over 100 years in London.
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在100年里第一座。
14:45
There was a big competition for the design of this bridge,
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为了争取桥的设计权，产生了激烈的竞争。
14:48
and the winning proposal was submitted by an unusual team --
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获胜的是由一只古怪队伍提交的设计——
14:52
in the TED spirit, actually -- of an architect --
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很有TED精神——的建筑师——
14:55
perhaps the greatest architect in the United Kingdom, Lord Norman Foster --
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可能算英国最伟大的建筑师，福斯特爵士——
14:59
working with an artist, a sculptor, Sir Anthony Caro,
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和一位雕塑家卡若爵士
15:04
and an engineering firm, Ove Arup.
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以及Ove Arup工程公司合作而成。
15:08
And together they submitted a design based on Lord Foster's vision,
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他们以福斯特的创意为基础，提交了一份设计。
15:13
which was -- he remembered as a kid reading Flash Gordon comic books,
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他的灵感来自于小时候读到Flash Gordon的漫画书，
15:17
and he said that when Flash Gordon would come to an abyss,
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他说当Flash Gordon来到一处深渊，
15:20
he would shoot what today would be a kind of a light saber.
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他会发射一种类似于今天所说“激光剑”的东西。
15:23
He would shoot his light saber across the abyss, making a blade of light,
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他会把激光剑射过深渊，形成一道光的刀锋，
15:27
and then scamper across on this blade of light.
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然后踏着光穿过深渊。
15:29
He said, "That's the vision I want to give to London.
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他说：“那就是我想给伦敦的创意。
15:31
I want a blade of light across the Thames."
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我想在泰晤士河上建一道’光剑‘。“
15:35
So they built the blade of light,
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于是他们建起了”光剑“，
15:37
and it's a very thin ribbon of steel, the world's --
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它是一层非常薄的金属之”虹“，或许是世界上——
15:43
probably the flattest and thinnest suspension bridge there is,
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最平坦最薄的桥，
15:46
with cables that are out on the side.
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由绳索在两侧牵挂。
15:49
You're used to suspension bridges with big droopy cables on the top.
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一般的索桥都由很粗大的绳索从上端牵挂。
15:52
These cables were on the side of the bridge,
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而这些绳索从两侧固定桥，
15:55
like if you took a rubber band and stretched it taut across the Thames --
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就好像有人取了一块橡胶并将它平铺在泰晤士河上——
15:59
that's what's holding up this bridge.
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那就是固定住桥的东西。
16:01
Now, everyone was very excited to try it out.
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所有人都跃跃欲试把它建起来。
16:03
On opening day, thousands of Londoners came out, and something happened.
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在开幕礼上，千万伦敦人来观看，发生一些事。
16:08
And within two days the bridge was closed to the public.
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两天内桥就对公众关闭了。
16:12
So I want to first show you some interviews with people
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先来看一些采访
16:17
who were on the bridge on opening day, who will describe what happened.
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由那些在开幕式上参观桥的人来形容发生了什么。
16:20
Man: It really started moving sideways and slightly up and down,
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男人：桥突然开始左右摇摆并开始上下震动，
16:25
rather like being on the boat.
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好像身处船上。
16:28
Woman: Yeah, it felt unstable, and it was very windy,
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女人：是的。感觉非常不稳定。那天风很大。
16:31
and I remember it had lots of flags up and down the sides, so you could definitely --
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我记得桥两边有许多旗帜。你可以确定——
16:35
there was something going on sideways, it felt, maybe.
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你可以感觉到桥在倾斜。
16:38
Interviewer: Not up and down? Boy: No.
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记者：没有上下震动吗？男孩：没有。
16:40
Interviewer: And not forwards and backwards? Boy: No.
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记者：也没有前后摇摆？男孩：没有。
16:42
Interviewer: Just sideways. About how much was it moving, do you think?
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记者：只是侧移。那么大概多大幅度？
16:45
Boy: It was about --
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男孩：大概——
16:47
Interviewer: I mean, that much, or this much?
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记者：我是说，多大幅度，这么大？
16:49
Boy: About the second one.
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男孩：差不多是第二个。
16:51
Interviewer: This much? Boy: Yeah.
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记者：大约有这么多？男孩：是的。
16:53
Man: It was at least six, six to eight inches, I would have thought.
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男人：至少有六到八英尺。
16:56
Interviewer: Right, so, at least this much? Man: Oh, yes.
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记者：是的。至少这么多？男人：对。
16:58
Woman: I remember wanting to get off.
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女人：我记得我想赶快下去。
17:00
Interviewer: Oh, did you? Woman: Yeah. It felt odd.
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记者：是吗？女人：是的。那感觉很奇怪。
17:02
Interviewer: So it was enough to be scary? Woman: Yeah, but I thought that was just me.
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记者：那么那已经有些吓人了？女人：是的。但我当时以为只有我这么觉得。
17:08
Interviewer: Ah! Now, tell me why you had to do this?
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记者：啊！告诉我你为什么要这么做？
17:11
Boy: We had to do this because, to keep in balance
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男孩：为了保持平衡。
17:13
because if you didn't keep your balance,
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如果你不能保持平衡，
17:15
then you would just fall over about, like, to the left or right, about 45 degrees.
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那你就会向左或右倾倒大概45度。
17:21
Interviewer: So just show me how you walk normally. Right.
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记者：不过给我看看你们平时是如何走路的。好。
17:26
And then show me what it was like when the bridge started to go. Right.
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现在给我看看在桥开始移动时你们是怎么走的。好。
17:31
So you had to deliberately push your feet out sideways and --
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所以你们必须特意将脚向两侧摆，并且——
17:35
oh, and short steps?
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哦，步伐很小？
17:37
Man: That's right. And it seemed obvious to me
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男人：是的。当时我觉得很明显
17:40
that it was probably the number of people on it.
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一定是因为桥上人太多。
17:44
Interviewer: Were they deliberately walking in step, or anything like that?
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记者：他们是故意这么走吗？
17:48
Man: No, they just had to conform to the movement of the bridge.
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男人：没有。他们只是想要使桥的运动平缓。
17:52
Steven Strogatz: All right, so that already gives you a hint of what happened.
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斯托加茨：好了。这些足以是你们明白发生了什么。
17:55
Think of the bridge as being like this platform.
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把那座桥想像成这个平台。
17:59
Think of the people as being like metronomes.
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人们就是节拍器。
18:02
Now, you might not be used to thinking of yourself as a metronome,
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可能把自己想象成节拍器会有难度。
18:05
but after all, we do walk like -- I mean, we oscillate back and forth as we walk.
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但毕竟，当我们走路时确实像节拍器，——我是说，走路时我们前后摆动，
18:09
And especially if we start to walk like those people did, right?
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特别是当我们像那些人那样走时。
18:12
They all showed this strange sort of skating gait
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桥刚开始震动，
18:16
that they adopted once the bridge started to move.
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他们倾斜得就像滑雪一般。
18:19
And so let me show you now the footage of the bridge.
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现在来看看桥的”步伐“。
18:22
But also, after you see the bridge on opening day, you'll see an interesting clip
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但同时，在看过大桥开幕礼后，让我们来看一段有趣的视频，
18:26
of work done by a bridge engineer at Cambridge named Allan McRobie,
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它关于剑桥以为名叫Allan McRobie的桥梁工程师的工作。
18:31
who figured out what happened on the bridge,
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他指出了大桥究竟发生了什么。
18:33
and who built a bridge simulator to explain exactly what the problem was.
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他还建起了一座桥的模拟器来解释问题究竟是什么。
18:37
It was a kind of unintended positive feedback loop
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那是一种在行人和桥梁运动之间的
18:41
between the way the people walked and the way the bridge began to move,
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出人意料的正反馈循环。
18:44
that engineers knew nothing about.
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当时的工程师对此一无所知。
18:46
Actually, I think the first person you'll see
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实际上，你们最先看到的将是
18:48
is the young engineer who was put in charge of this project. Okay.
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负责这个工程的年轻工程师。好的。
18:53
(Video) Interviewer: Did anyone get hurt? Engineer: No.
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（视频）记者：有人受伤吗？工程师：没有。
18:55
Interviewer: Right. So it was quite small -- Engineer: Yes. Interviewer: -- but real?
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记者：那很好。这很小。工程师：是的。记者：但却可以模拟真实的桥？
18:58
Engineer: Absolutely. Interviewer: You thought, "Oh, bother."
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工程师：完完全全。记者：你会想：“哦，真麻烦！”
19:01
Engineer: I felt I was disappointed about it.
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工程师：我有些失望。
19:04
We'd spent a lot of time designing this bridge, and we'd analyzed it,
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在设计桥上我们花了很多时间，也分析过它。
19:08
we'd checked it to codes -- to heavier loads than the codes --
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我们检验过负重了——我们用超过最高载重的重量检验过了——
19:11
and here it was doing something that we didn't know about.
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然后发生了一些我们当时根本不知道的事。
19:14
Interviewer: You didn't expect. Engineer: Exactly.
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记者：你们完全没有预料到。工程师：的确。
19:16
Narrator: The most dramatic and shocking footage
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旁白：最动荡的一次震动中
19:19
shows whole sections of the crowd -- hundreds of people --
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成百上千人
19:22
apparently rocking from side to side in unison,
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一起从桥的一侧到另一侧，
19:24
not only with each other, but with the bridge.
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并不只是所有人一起动，桥也在一起震动。
19:27
This synchronized movement seemed to be driving the bridge.
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这种同步的运动似乎正在驱使桥移动。
19:31
But how could the crowd become synchronized?
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但是人群是怎么同步的？
19:34
Was there something special about the Millennium Bridge that caused this effect?
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千年桥是不是隐藏着导致这种效果的特殊原因？
19:38
This was to be the focus of the investigation.
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这成为调查的焦点。
19:42
Interviewer: Well, at last the simulated bridge is finished, and I can make it wobble.
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记者：好了。模拟桥终于建成了，我可以使它摆动。
19:49
Now, Allan, this is all your fault, isn't it? Allan McRobie: Yes.
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现在，Allan，这都是你造成的吗？Allan McRobie：是的。
19:53
Interviewer: You designed this, yes, this simulated bridge,
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记者：你设计了，这座模拟桥。
19:55
and this, you reckon, mimics the action of the real bridge?
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你认为它可以模拟真实的桥？
19:58
AM: It captures a lot of the physics, yes.
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AM：它模拟了大桥的许多物理特征，是的。
20:00
Interviewer: Right. So if we get on it, we should be able to wobble it, yes?
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记者：好的。所以如果我们站上去，我们可以摆动它，是吗？
20:06
Allan McRobie is a bridge engineer from Cambridge who wrote to me,
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Allan McRobie是一位剑桥来的桥梁工程师。
20:09
suggesting that a bridge simulator ought to wobble
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他写信给我，建议建一座模拟桥
20:12
in the same way as the real bridge --
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来模拟真实的桥的摆动——
20:14
provided we hung it on pendulums of exactly the right length.
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前提是我们把它悬挂在实际长度的摆挂上。
20:16
AM: This one's only a couple of tons, so it's fairly easy to get going.
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AM：这一座只有几吨重，所以很容易就可以被摆动。
20:19
Just by walking. Interviewer: Well, it's certainly going now.
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只需要在上面走走。记者：好的。很明显已经开始了。
20:22
AM: It doesn't have to be a real dangle. Just walk. It starts to go.
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AM：并不需要特意去摇晃，只需要走走。它就会开始摆动。
20:25
Interviewer: It's actually quite difficult to walk.
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记者：实际上很难走。
20:28
You have to be careful where you put your feet down, don't you,
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你必须小心注意自己向哪里迈步。
20:31
because if you get it wrong, it just throws you off your feet.
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因为一旦你走错，就会摔倒。
20:34
AM: It certainly affects the way you walk, yes. You can't walk normally on it.
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AM：震动当然会影响你的走动。你不能像平时那样走。
20:39
Interviewer: No. If you try and put one foot in front of another,
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记者：不行。如果你试着把一只脚放到另一支前面，
20:41
it's moving your feet away from under you. AM: Yes.
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其实就会把它放到另一只下面。AM：是的。
20:44
Interviewer: So you've got to put your feet out sideways.
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记者：所以你就必须把脚向两边伸展。
20:47
So already, the simulator is making me walk in exactly the same way
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所以这个模拟器已经是我按照真桥上
20:50
as our witnesses walked on the real bridge.
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目击者一样的方式行走了。
20:52
AM: ... ice-skating gait. There isn't all this sort of snake way of walking.
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AM：。。。滑雪式的倾斜。实际上没有人会这样像这样蛇行。
20:55
Interviewer: For a more convincing experiment,
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记者：为了使实验更加可信，
20:57
I wanted my own opening-day crowd, the sound check team.
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我想要我的“开幕礼”团队，第二支检验队伍。
21:00
Their instructions: just walk normally.
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他们得到的指示是：正常走。
21:12
It's really intriguing because none of these people is trying to drive it.
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这真的很神奇因为没有人会可以去驱使桥摆动。
21:16
They're all having some difficulty walking.
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他们都只是觉得走起来有点难。
21:19
And the only way you can walk comfortably is by getting in step.
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唯一可以使他们舒服走路的方式就是这样走。
21:22
But then, of course, everyone is driving the bridge.
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之后，当然，所有人都开始驱使桥。
21:27
You can't help it. You're actually forced by the movement of the bridge to get into step,
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人们没有办法控制，他们实际上使被桥的运动驱使这么走。
21:32
and therefore to drive it to move further.
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结果这更加剧了桥的运动。
21:38
SS: All right, well, with that from the Ministry of Silly Walks,
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SS：好了，那么，看过“愚蠢走路大使”之后，
21:42
maybe I'd better end. I see I've gone over.
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或许我最好停止。我已经超时了。
21:45
But I hope that you'll go outside and see the world in a new way,
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但我希望当你们走出去，你们可以以一种全新的视角看世界。
21:48
to see all the amazing synchrony around us. Thank you.
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去发现我们周围绝妙的同步现象。谢谢。
21:51
(Applause)
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（掌声）
ABOUT THE SPEAKER
Steven Strogatz - MathematicianIn his work in applied mathematics, Steven Strogatz studies the way math and biology intersect.
Why you should listen
Steven Strogatz studies some of the most interesting problems in applied mathematics -- such as the intersection of math and biology, looking for patterns in the human sleep-wake cycle or in swarms of blinking fireflies.
He's been looking at nonlinear dynamics and chaos applied to physics, engineering and biology, and branching out into new areas, such as explorating of the small-world phenomenon in social networks (popularly known as "six degrees of separation"), and its generalization to other complex networks in nature and technology.
Strogatz' work has been in the news as British engineers released the definitive paper on the Millenium Bridge wobble, and its roots in how people walk on an unpredictable surface.
In 2012, he re-examined the "birthday problem" >>
Steven Strogatz | Speaker | TED.com