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It's the mother of all questions!
这个问题是所有问题的起源
Well, except maybe What's the Meaning of Life? -- which we actually have our own scientific answers to …
不是"人生的意义是什么?" －因为这个问题我们每个人都有自己的 答案......
Or What Is Love? -- We have some thoughts on that, too.
或者“什么是爱？”－我们对此也都有不同的理解
But one of the most googled questions in the English-speaking world is the one that kids are famous for asking --
但在讲英语的国家中 搜索最多的那个问题是孩子们 超爱问的－
and grown-ups are notorious for avoiding, because they just don't know.
但大人们却避之不及的 因为他们 真的不知道
Why is the sky blue?
天空为什么是蓝色的?
Just give me a couple minutes and I'll let you know why.
几分钟内我就会让你明白究竟是为什么
This is the World's Most Asked Questions!
这里是世界上被问的最多的问题!
The sky is blue because of three things:
天空是蓝色的原因有三个因素：
light from the sun, particles in our atmosphere, and the fact that you're a human.
阳光 大气中的微粒 以及你是人类
I'll get to that last part in just a minute.
一分钟后我就会讲最后一个因素
But let's start with how sunlight interacts with particles in the sky.
我们先来看阳光是如何同大气中的微粒发生反应的
I'm not talking about dust or water droplets or other big particles,
我指的不是尘埃 水滴 或其它大的微粒
which are sometimes mistakenly used to explain the sky's blueness.
它们常被 误用来解释天空为什么是蓝色的
Instead, it's the very small particles in our atmosphere that make the sky look blue.
相反 大气中的极小微粒才是天空看起来是蓝色的原因
I'm talking about molecules of the air itself, mostly molecular oxygen and nitrogen -- O2 and?N2.
我是指是空气自身所包含的分子 大部分是氧气分子和氮气分子--O2 和 N2
These molecules are super-abundant in our atmosphere and so small that they're even smaller than wavelengths of visible light!
它们在大气中的含量十分丰富 而且很小 甚至比可见光的波长还要小
And that's the key.
而这就是关键
Visible light consists of a range -- or spectrum -- of different wavelengths.
可见光光谱由不同波长的光组成
Light with the longest wavelengths are at the red end of the spectrum,
波长最长的光在光谱红色末端
and light with the shortest wavelengths are at the blue and violet end.
波长最短的在光谱蓝色和紫色末端
Since the blue wavelengths of light are shorter,
因为蓝光波长更短
they're more likely to strike those tiny molecules of oxygen and nitrogen more often,
它们更容易撞击那些 氧气和氮气的微小分子
and when they do, they get scattered in all directions.
之后分子就会四处 散射
This effect is known as Rayleigh scattering, because it was first described by John William Strutt,
这种现象叫做瑞利散射 是由约翰·威廉·斯特拉特
aka the Third Baron Rayleigh, who in 1871 published his mathematical proof that
也叫瑞利男爵三世 他在1871年首次发表了数学证据证明
blue wavelengths of light in the atmosphere are scattered 16 times more than red wavelengths.
大气中 蓝光散射的频率是红光散射的16倍多
But violet light has the shortest wavelength of all visible light,
但紫光在可见光中波长最短
and it's scattered even more strongly by tiny particles -- so why isn't the sky purple?
更容易被 小微粒阻挡而发生散射 那为什么天空不是紫色的
Well, this is where being human comes into play.
这就讲到了人的因素了
Our human eyes perceive the middle of the spectrum most sharply which is why blue is way easier to see than violet.
人眼对光谱中间的颜色最敏感 所以 人类更容易看见蓝光
So even though violet light is being scattered around like crazy,
就算紫光四处散射
we just don't detect it as well as we detect the blue.
我们也很难像察觉到蓝光一样 察觉到紫光
And that's why the violet band of the rainbow is often the hardest for us to make out.
所以我们很难看到彩虹的紫色色带
So SciShow viewers are in luck, because when we surveyed you, the most popular favorite color from the rainbow was blue.
科学秀 (SciShow) 的观众们很幸运 因为我们调查显示 彩虹颜色中大家最喜欢的就是蓝色
33.55% of survey takers reported blue as their favorite color, while yellow was the least favorite at only 2.8%.
33.55%的受访者表示最爱蓝色 而只有2.8%的表示最爱黄色 最少
Poor yellow.
可怜的黄色
But, there are other animals that can see all the way into the ultraviolet end of the spectrum,
但有些动物能够看到光谱的所有颜色 包括紫外线
like honeybees and some birds. So maybe they like yellow.
如 蜜蜂和一些鸟类 它们可能喜欢黄色
And maybe the sky looks completely different to them.
它们看见的天空也许也完全不同
Of all the fascinating questions in the world, what question do you want answered most?
大千世界无奇不有 你最想知道什么
Let us know on Facebook or Twitter or in the comments down below,
在脸书 推特 或视频下方留言 我们会尽力
and we will try to answer those questions in a new video at the end of the month.
在本月末的新视频中给你答案
And don't forget to use hashtag #WMAQ and stay tuned for more answers to the World's Most Asked Questions.
记得加标签#WMAQ 继续关注 世界上问得最多的问题 我们给你答案
