英国皇家科学院圣诞讲座：让火花飞（2014）

好极了 你准备好了吗 露西
Great. OK, are you all ready, Lucy?
好了
Yes, I am.
好 请你站在那块板前面
OK. Right, so, if you stand in front of the board.
我们现在能在显示屏上看到露西了
Now, we should be able to see Lucy on the monitor.
我们现在要给你照个像
We're going to take an image of you now,
露西 请千万站着别动
Lucy, so stand very, very still.
好
Ok.
现在 电脑正在分♥析♥图像
Now, the computer's analysing that image
并圈出它认为露西所站的位置
and drawing a line around where it believes Lucy is standing.
好 看上去没错
OK, that looks about correct. Yes.
现在软件将控制枪
OK, now the software then tells the guns to fire
沿着露西的身体周围发射
all the way round Lucy's body,
希望别打中她
but hopefully not straight at her.
露西 你准备好把绿幕
So, Lucy, are you ready
从你身后拉下来了吗
just to pull that green down from behind you?
好 我觉得该倒数一下 大家一起
OK, this is it. I think this deserves a countdown, everybody.
从五开始 我退到一边去
So, from five, and I'm going to get out of the way.
准备好了吗
Ready?
五
Five,
四
four,
三
three,
二
two,
一
one,
开火
fire!
看上去棒极了 过来吧 露西
That looked amazing. Come on through, Lucy.
你觉得怎么样
How was that for you?
-有点紧张 -这不怪你
- A little nerve-racking. - Yeah, I don't blame you.
终于结束了
Just relieved it's over.
一点都不惊讶
It's not surprising.
所以我们能看到那里出现了一个轮廓
So we can see there's a bit of an outline
但我们也看到你有点被打到了
but we see it's also caught you a little bit there
可能明天会有点淤青
and might have a bit of a bruise there tomorrow,
但总体来说你毫发无损地出来了
but on the whole you've come out pretty unscathed,
非常感谢你对电脑程序的信任
so thank you so much for putting your trust in a computer programme,
也非常谢谢你 萨沙
and thank you very much, Sacha.
-不用谢 -谢谢
- No problem. - Thanks.
我希望大家看到的效果也不错
Now, I hope that looked good out here,
因为在里面看上去特别棒
cos that looked fantastic in there.
这不仅很有趣
Now, as well as being a lot of fun,
也证明电脑
this proves that a computer
不需要捕捉整个图像
doesn't have to capture the whole image.
只要使用合适的软件
But with the right software,
它就能开始处理那幅图像
it can start processing that image.
它可以提取出二维形状或是物体
It can pull out 2D shapes or objects,
也就是演示中的露西
or Lucy, in this case,
并告诉对象做出不同的反应
and tell the things how to react differently.
在构建真实的全息影像时
Now this is going to be crucial
这一步是至关重要的
in creating our convincing hologram.
我们应该能看到达拉斯在演播间就位了
So we should be able to see Dallas in position in the studio.
我们用一台相机
We have a camera that's lined up
从背景中抽取出达拉斯的高质量影像
to extract a high quality image of Dallas from that background
这样就能仅发送达拉斯的全息影像
so we can send the hologram of just Dallas
而不包括周围的家具
and not the surrounding furniture.
第一步完成了
So, step one complete,
我们已经成功捕捉到达拉斯的影像
we've managed to capture an image of Dallas.
第二步 如何发送这幅影像呢
Step two, how do we send that image?
我们要将那幅达拉斯的影像
We've got to take that hologram of Dallas
直接发送到皇家科学院来
and send it to right here at the Royal Institution.
这可能听上去是最难的一部分
Now, this probably sounds like it should be the hardest bit,
但实际上 这可能是最简单的一步
but, actually, it's probably the easiest.
我们只需要用互联网
We just use the internet, right?
用互联网就行
Just use the internet.
显然 我们觉得每天使用它理所当然
It's so obvious that we just take it for granted every day.
但实际上发生了什么呢
What is actually going on?
信息是如何从伦敦的一边
How do messages get sent from one side of London,
或是世界的一边发送到另一边的呢
or one side of the world, to another?
我们要使用的东西叫做光缆
Well, we use something called fibre optic cables.
你们对光缆应该很熟悉
And you will be very familiar with fibre optic cables.
我们天天都在用
We use these all the time.
它可以发送消息
And it sends information,
数字信息以光束的形式
digital information down a cable
在光缆中传递
in beams of light.
我用手电筒朝这根光缆照去
So you can see, I'm just shining a torch down this cable
你们可以在另一端看到光出来
and you can see the light at the other end.
在二十世纪五十年代
Now, this was actually originally developed in the 1950s
这是为了让医生看到人体内部而研发的
for doctors to see inside human bodies.
但在六十年代
But in the 1960s,
工程师用它
engineers then used it to
以光速传输电♥话♥信♥号♥♥
transmit phone calls at the speed of light.
正如我们刚才所见 我在一端照射
But we've just seen there that I shone a light
光从另一端出来 但这根光缆是弯曲的
and it came out of the other end and this cable is bending.
它弯曲缠绕 那到底怎么回事呢
It's twisting and turning, so how's that working?
因为我们都清楚 光沿直线传播
Because don't we all know that light travels in straight lines?
那么究竟是怎么回事呢
So how is this working?
我们再现一下
Well, let's recreate an experiment
约翰·丁达尔在1870年做的实验
that John Tyndall did in 1870.
我需要个志愿者来帮我
Now, I need one volunteer to help me with this.
就中间穿套衫的那位 来吧
So, you, right in the middle there, with the jumper on. Yeah.
-你叫什么 -露西
- OK, what's your name? - Lucy.
好 请站到这边 露西
Lucy, OK, if you want to stand this side, Lucy.
好 我要给大家说明下这里都有什么
OK, now, I'm going to explain to you what I've got here.
这有个桶 请你向桶内看一看 露西
What we have is a bucket, and if you just look inside, Lucy,
桶里面有一些反射膜
what we have is just some reflective film inside here.
这里有个小孔 你可以从里面看到它
And also, we have a little hole, and you can just see the inside.
这里有个小孔 目前它被胶带封住了
We have a hole here and we have it taped over at the moment.
我暂时把胶带揭掉
So, if I just take this tape off for now,
我们就能看见桶上有个小孔了
we can see we've got a little hole in our bucket.
我把这块瓷砖交给你
Now, I'm going to give you this tile
我要在这里点亮手电
and what I going to do is shine this torch in here
然后请你把这块瓷砖放在这边
and then I want you to put that tile on this side
放在你觉得光会出来的地方
where you think that light is going to come out.
光确实是沿直线传出来的
So, yeah, it's coming out in a straight line,
正如我们所料
and that's what we'd expect.
但我们再试一次 这次在桶里加水
But let's try it again and put some water in our bucket.
然后我们看看光路会如何变化
And let's see where the light goes then.
如果我们往桶里加水
So if we just add some water to our bucket
然后再次点亮手电
and then what I'm going to do is just shine the light again.
你准备好瓷砖
You get ready with your tile.
它会在这接住水
This is going to catch the water down here. OK?
然后我们看看光路如何
And then we'll see where the light goes.
好吗
Ok?
如果我揭开胶带...
Ok, so, if I then remove my tape...
有很多水 如果我在里面点亮手电
We've got a lot of water now, and if I shine my light in there,
然后你试试应该把瓷砖放在哪
and then if you just try and decide where that should be.
拿过来 你看见光束了吗
Bring it in. You see the beam of light now? Yeah?
光沿着水流出
So, the light is actually part of this water.
所以我们让光路弯曲了
So we're actually bending the light.
它之所以能发生
And the way that's working
是因为光在水流中
is the light is in that stream of water
我们利用水和空气的边界
so we're using the boundary of the water and the air
让光反射
for that light to bounce off.
我们就这样使光线弯曲 太神奇了
So we're bending light. It's amazing.
这就是光纤的工作原理
And this is the principle of how fibre optic works.
所以如果我想做根光缆
So if I want to be a fibre optic cable,
就得非常非常迅速地让光闪烁
I'm going to have to flash this really, really quickly
就像数字信♥号♥♥
just like digital signals.
那我能闪多快呢
So, how fast do think I could flash this?
大家觉得呢
Do you think?
也许是每秒几次 速度不快 是吗
A few times a second, maybe? Yeah? I'm not very fast, am I?
因为速度最快的光纤之一
Because one of the fastest demonstrated fibre optic cables