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Hey Crazies.
嘿疯狂的人们
This piece of paper looks about as white as white can get.
这张纸看上去就是白色的
But what if I told you the color white doesn’t exist?
但假如我说 根本不存在白色这种颜色呢
Do you really expect me to believe that?
你觉得我会相信吗？
Not without an explanation.
没有解释是不会信的
Obviously.
这很明显啊
Ok,so the reason we see anything at all is because of light,
嗯 我们之所以能看见一切 是因为有光
so let’s start there.
就从光开始讲起
The word “light” applies to anything on the EM spectrum.
“光”这个词适用于电磁波谱上的任何东西
These category names are adjectives:
这些类别名称作为形容词修饰光：
Radio light, infrared light, ultraviolet light.
无线光 红外光 紫外光
The universe is full of light.
宇宙充满了“光”
It’s just that we can’t see most of it.
只是大部分我们看不见
The only type of light we can see
我们能看见的那类光
is this little tiny sliver right here,
只是这里的小小一段
which we call visible light for obvious reasons.
理所当然我们称之为可见光
We see almost none of the light in the universe.
我们几乎看不到宇宙中的任何光
But we do see enough to, you know,
但是我们确实看到了很多
function on a daily basis.
每天都能见到的光
I mean, the vast majority of the light emitted by the sun
我的意思是 太阳发出的绝大部分光
is visible,
是可见的
so it shouldn’t be surprising
所以不必惊讶
that animals evolved to see light in or near this range.
动物能看见这个范围内或附近的光 这是正常的
Seeing in x-rays or radio just wouldn’t be that useful.
再说能看见x射线或无线电波没那么有用
Anyway,specific colors are kind of like sub-categories.
总之 特定的颜色就像是一种特定的类别
If we zoom in on the visible part of the spectrum,
如果我们放大光谱中可见的部分
we can see how the frequency or wavelength of light corresponds to color.
就能理解光的频率或波长如何与颜色相对应
Do you see any white in here? I don’t.
你看到这里有白色的吗 我没有
Check!Mate!
看吧！伙计！
White does not exist!
白色根本不存在
Wait a minute!
等一下
How the heck is your lab coat white then?
奇怪的是你的实验服怎么是白色的？
Ok,I suppose I could elaborate.
好吧 我想我能解释一下
Sure,we assign colors to each of these wavelengths.
当然 每段波长都会有与之匹配的颜色
but does that mean these wavelengths are those colors?
但这是否意味着这些波长就是这些颜色呢
There are plenty of colors we can see
我们可以看到很多颜色
that don’t correspond to a single wavelength of light.
但它们不对应于单个波长
Black, white, and magenta are three big examples.
黑色 白色和洋红色就是三个典型例子
So clearly there’s more to color than just light.
所以颜色不等同于“光”
Hmm. Well,
嗯 好吧
we know light is necessary.
我们知道光是不可或缺的
Without it, all we see is black.
没有它 我们就只能看到黑色
Black is the absence of light. So,
缺少了光就会是黑色 所以
we definitely need a source of light
我们肯定需要一个光源
like the Sun or a bulb or something.
比如太阳或者灯泡之类的
Then we need the thing we’re trying to see,
然后我们需要我们想要看到的东西
and then our eye balls, and then our brains.
然后是我们的眼球 之后是我们的大脑
This is getting overwhelming.
这渐渐让人感到不知所措了
Let’s look at this as one big process.
让我们把它看作是一个主要过程
Lots of light is emitted by the Sun.
太阳发出许多光
Some of that light will reflect off of this leaf.
有些光从这片叶子上反射回来
Even less of that light actually enters your eyes,
实际上 进入你眼睛的光更少
which then send signals to your brain,
进入眼睛的光会传送信号到大脑
which in turn, has to interpret those signals.
接下来 大脑要翻译这些信号
Let’s start with that reflection.
让我们从反射开始
Remember the Sun emits all the colors in the visible spectrum.
别忘了太阳能发出可见光谱中的所有颜色
The reason this leaf looks green is
这片叶子看起来是绿色的
because that’s the color the leaf reflects.
因为那是树叶反射的颜色
Let me repeat that for everyone in the back.
我给后面的同学重复一遍
Objects do not have color.
物体没有颜色
Light has color.
光有颜色
Objects just absorb some colors and reflect others.
物体只是吸收一些颜色并反射其他颜色
I’m totally serious. My phone case isn’t red.
我是认真的 我的手机壳不是红色的
It just reflects red light.
它只是反射了红光
If you put it under different colored light,
如果你把它放在不同颜色的光下
it’ll be a different color.
颜色会不一样
If something looks white,
如果某个东西看起来是白色的
that just means it reflects all the colors,
这就意味着它反射了所有的颜色
but that can also happen with things that are transparent.
但这也可能发生在透明的东西上
Take a nice piece of plastic for example.
以塑料为例
You might be inclined to say “It doesn’t have color.
你可能会说“它没有颜色”
It’s clear.” But,
很明显它是没有 但是
if you fold it enough times, you’ll notice something weird.
你如果折叠很多次 就会注意到怪事发生了
It’ll start to turn white.
它会开始变白
This happens because transparent materials aren’t perfect.
这是因为透明材料并不完美
There’s always a little reflection.
总会有一些反射
If there’s only one layer of plastic, the reflection is insignificant.
如果只有一层塑料 反射效果就不明显
But every fold adds extra reflections.
但是每一次折叠都增加了额外的反射
Eventually,most of the light gets reflected instead of passing through.
最终 大部分的光被反射而不是通过
The same thing happens with polar bear fur.
同样的事情也发生在北极熊的皮毛上
It’s also transparent.
这也是透明的
It’s just that the fur is layered enough with air
皮毛有很多层而且夹着空气
to maximize reflections.
这导致反射强度达到了最大
You can turn the reflection back down a bit
你可以通过在气体空间填充其他东西 比如水
by filling the air spaces with something else, like water,
这样反射效果会被削弱
which is exactly how the wet t-shirt effect works.
这也是湿T恤会让你走光的原因
The point is: Objects don’t have color. Light does.
重点是 物体没有颜色 光有颜色
The next step in the process is
这个过程的下一步是
how our eyes actually respond to the light.
我们的眼睛对光线会有怎样的反应
It’s time for a crash course in human eye biology.
现在来快速普及一下人眼的生物构造
The inside back of the eye
眼睛的内后壁
is covered in cells called photoreceptor cells,
被称为感光细胞的细胞所覆盖
which literally means “light receiver.”
感光细胞字面意思是“光接收器”
It’s kind of nice when a scientific name actually makes sense.
科学术语有意义是一件好事
Those photoreceptor cells come in two types: rods and cones,
这些感光细胞有两种类型 杆状细胞和锥状细胞
which is literally a description of their shape.
也就是对它们形状的描述
The rods only detect the intensity of light,
杆状细胞只能探测到光的强度
so they’re not really useful with color vision.
所以它们对色觉没有帮助
The cones are where the magic happens.
视锥细胞才是真正起作用的
At the top of each cone is a stack of membranous
在每个圆锥体的顶部是一堆膜状的
containing tiny collections of a protein called iodopsin
含有一种叫做碘伏蛋白的微量蛋白质
This stimulates another protein called transducin
这会刺激另一种叫做转导蛋白的蛋白质
This enzyme degrades a secondary messenger chemical
这种酶降解一种次生信使化学物质
in the cone’s cytoplasm The decrease in cGMP closes
在锥体细胞质中…cGMP停止减少…
Thus hyper-polarizing We call this a cyclic Huh?What?What?What?
因此超极化我们称之为循环 啊什么什么？
OK, here’s what actually matters.
好吧 这才是真正重要的
Light hits the cones and a chemical process sends a signal to the brain.
光照射锥细胞发生化学反应 产生信号发送给大脑
That signal contains information about color
这个信号包含有关颜色的信息
because there are three different types of cones: red, green, and blue.
因为锥体有三种不同的类型 红色 绿色和蓝色
They’re not actually that color.
它们实际上不是那种颜色
Most things in the human body are roughly the same pinkish-brown color.
人体中的大多数物质都是相同的粉褐色
These types of cones are called red, green, and blue cones
这些类型的视锥细胞被称为红 绿和蓝锥细胞
because that’s the type of light they each respond to.
这是用它们敏感的光来命名的
Wait wait, our eyes can only see red, green, and blue? Yeah,
等等 我们的眼睛只能看到红色 绿色和蓝色吗？ 是的
pretty much.
差不多
Then how does our brain know about the other colors?
那么我们的大脑是如何知道其他颜色的呢？
Mixed signals!
混合信号
This is one of those rare cases when mixed signals are a good thing.
混合信号竟然是好事 这挺少见
If you map out the sensitivity of cone cells against the visible spectrum,
如果你将视锥细胞的敏感程度与可见光谱对照画出
you get something like this.
你会得到这样的结果
Now let’s say orange light enters your eye.
现在假设橙色的光进入你的眼睛
That light will activate the red cones and green cones
橙光会激活红色和绿色的视锥细胞
by a very specific amount,
使其非常活跃
which sends a unique mixed-signal to the brain.
视锥细胞会向大脑发出独特的混合信号
No other color creates that signal combination.
没有其他颜色会产生这种信号组合
The same is true for every other color on the visible spectrum.
可见光谱上的其他颜色也是如此
But here’s the thing:
但问题是
There are signal combinations the brain can receive
大脑可以接收到多种信号组合
that aren’t created by a single wavelength of light.
它们不是由单一波长的光产生的
What if the blue and red cones activate intensely at the same time?
如果蓝色和红色的视锥细胞同时活跃呢
None of the colors on the visible spectrum are going to do that,
没有一种颜色在可见光谱上是这样的
but if your brain gets that signal,
但是如果你的大脑收到这个信号
it’s got to make sense of it somehow.
大脑还是会翻译它
So it makes it look like this: magenta.
所以大脑让其看起来是洋红色
Your brain literally made up a color
你的大脑确实创造了一种颜色
for a hypothetical signal combination
为了解释一个信号组合
and that’s not the only color it made up!
而且这不是它唯一创造的颜色
What if all three types of cones activate intensely at the same time? Well,
如果这三种细胞同时变得非常活跃会怎样
that’s what your brain calls white.
这就是你的大脑所认为的白色
So,if you total up all
实际上 如果你把
the possible signal combinations the brain can receive,
大脑可能接收到的信号组合全部加起来
you get about 10 million different colors.
你能得到大概1000万种不同的颜色
Colors we can summarize with cool animations like this.
我们可以用这种酷动画来总结这些颜色
Actually,this reminds me of another point I should probably make.
实际上 这让我想起了另一个应该说的事实
This isn’t actually yellow.
这其实不是黄色
See,ten million different colors
你看 一千万种不同的颜色太多了
is a lot to engineer into an LCD screen
无法全部设计在一块液晶屏幕上
like the one you’re using to watch this video.
就像你用来看这个视频的屏幕
So we’ve designed screens to play tricks on your brain.
所以我们设计让屏幕来欺骗你的大脑
Your screen is made of a bunch of pixels.
你的屏幕是由一堆像素组成的
If you make those pixels small enough
如果让这些像素足够小
you get the illusion of a continuous image,
你会产生连续图像的幻觉
but what if you want a color image?
但如果你想要一个彩色图像呢
Your eyes can only see three types of colors: red, green, and blue;
你的眼睛只能看到三种颜色:红色 绿色和蓝色
so that’s all your screen has to display.
所以这就是屏幕全部需要显示的
Red and green set to full brightness
如果把红色和绿色调到全亮度
is going to look like yellow to your brain,
它看起来就像你大脑中的黄色
even if it isn’t yellow.
即使它不是黄色的
If each color in a pixel has 256 different brightness levels,
如果一个像素中的每种颜色有256种不同的亮度
the screen has a total
屏幕上一共能够显示
of 16,777,216‬ different colors it can display,
‬16777216种不同的颜色
which is well over the 10 million or so colors we can see.
这远远超过了我们能看到的1000万种颜色
The point is we already can’t see a bunch
事实上 我们已经看不到很多种
of the colors that your screens are displaying.
在屏幕上显示的颜色
Any additional colors marketed to you are a complete waste of your money.
推销给你任何额外的颜色 都是浪费你的钱
So is white a real color?
那么白色是真正的颜色吗
Not really.
不见得
You won’t find the color white on the visible spectrum
在可见光谱上 你找不到白色
like you wouldn’t most other colors.
就像你找不到其他多数颜色一样
It’s not a color connected to a single wavelength of light.
它不是一种与单一波长的光相连的颜色
But if something reflects enough different colors at the same time,
但如果某物同时反射足够多的不同颜色
all three different types of cones
在你眼睛后部的三种不同的椎体细胞
will activate at the back of your eye
都会变得活跃
and send a strong signal to your brain.
并向你的大脑发出强烈的信号
Your brain interprets that signal as white.
你的大脑将这个信号解读为白色
Your brain literally makes up colors
你的大脑实际上是在创造颜色
and white is one of those colors.
白色就是其中之一
So are you ever going to look at color the same way again?
所以你还会以同样的方式看待颜色吗
Please share in the comments.
请在评论区分享你的观点
Thanks for liking and sharing this video.
谢谢你喜欢和分享这个视频
Don’t forget to subscribe
别忘了订阅
if you’d like to keep up with us.
如果你想跟上我们的步伐
A special thanks goes out to Patreon patrons like William Morton
特别感谢Patreon的赞助人 比如William Morton
who help make this show possible with their generous support.
在他们慷慨的支持下 这个视频才能做成
And until next time, remember,
在下次课之前 记住
it’s OK to be a little crazy.
有点疯狂没什么大不了的
The featured comment comes from Monkey Business who asked:
这条特色评论来自Monkey Business 它问道
Why on Earth is this not taught in school?!
为什么学校不教这个
Honesty,I think it’s just
老实说 我认为
that old habits are hard to break.
旧习惯是很难改掉的
Also,changing official curriculum is not very easy.
同时 更改官方课程并不容易
You know, politics and stuff.
你知道的 政治啊什么的
Anyway,thanks for watching!
总之 谢谢收看