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太阳闪烁绿光是真的 – 译学馆
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太阳闪烁绿光是真的

It's True: The Sun Really Does Flash Green

序曲
[♪INTRO]
日落时神秘的绿光
Ah, the mythical green flash during a sunset.
最初是儒勒·凡尔纳在他1882年的一部小说中
It was first made popular by Jules Verne
使这种说法变得流行 并且还通过个别海盗电影的续集
in an 1882 novel, and it ’ s still leaking into
渗透了一些流行文化
pop culture through an occasional pirate moviesequel.
但这并不是一个神话
Except it’s not actually a myth.
我知道那有点怪
I know, it’s weird.
通常我们会推翻人们认为是正确的事情
Usually we ’ re debunking things people think are true,
而不是支持他们
not the other way around.
但绿光是一种真实存在的光学现象
But the green flash is a real optical phenomenon,
而且不仅仅发生在日落后
and it doesn ’ t just happen right after the sun sets.
你也可以在日出前看到它
You can see it right before sunrise, too.
你甚至可以在地球上任意海拔 任何地方看到它
You can see it from any altitude, and from anywhere in the world.
但你得有合适的时机
But you have to have the right conditions.
你也许会认为
You might think that
除去那几朵蓬松的云
the Earth’s air is pretty uniform.
地球上的大气成分完全一样
minus the occasional puffy cloud or two.
但其实大气层也有很多不可见层
But there are a bunch of invisible layers in the atmosphere,
每一层都有差别细微的
each with slightly different
温度和密度
temperatures and densities.
阳光从一层穿到另一层时
As sunlight travels from one layer to another,
会发生轻微的
the light refracts, or bends,
折射或弯曲
just a teeny tiny bit.
这和你水杯中
It ’ s the same principle that
看起来像是“折断”了的吸管
makes your straw look like it ’ s bent
是一个道理
below the water in your glass.
但是光的折射程度取决于其波长
But the amount of refraction depends on the wavelength.
因此
And therefore,
光就有了不同的色彩
the color of the light.
最终 太阳光中不同颜色的色光是
So the different colors end up separating out
从白光中分离出来并进入大气层中形成的
from the white sunlight that enters the atmosphere.
光的色散的最好证明
The most obvious way to see this separation is
就是彩虹 尽管它是由于
in a rainbow, although that comes from
更大的密度差形成的
a much more dramatic change in density —
——从空气到小水滴
from air to water droplet — so it ’ s a much
效果就更加明显
more obvious effect.
波长越短的光线越容易被折射
And the shorter the wavelength, the more thelight is refracted.
而蓝光波长较短
Bluer light has a shorter wavelength,
所以太阳下山后 仍可在地上看到影子
so as the sun sets, those shades will stay visible
你可以看到影子的时间更长 因为光线在地平线之下更加弯曲
longer because they can be bent further aroundthe horizon.
这想起来有点怪 但基本上
It ’ s kind of weird to think about, but basically,
太阳下山时先是红色部分
the red image of the sun sets first, followed
然后是橙色 黄色等等
by orange, yellow, and so on.
可见的红光和紫光之间
There ’ s a second or two delay
只会停留一两秒
between the last visible red sunlight and the violet.
时间很短
It ’ s not a lot of time,
但如果你知道何时何地去看那就够了
but it ’ s enough if you know when and where to look.
日出时恰好相反
And it works exactly in the opposite direction,too, with sunrises.
太阳的蓝光和紫光
But if the blue and violet shades of the sun
先穿越地平线
are also above the horizon
为什么这些光是绿的?
Why are these flashes green? Well,
波长越短的光与空气中的
shorter wavelengths of light are scattered
微粒碰撞后散得更远了
more after colliding with molecules in the air
这就是天蓝的原因
that’s why the sky is blue.
但那也说明紫光和蓝光
But that also means violet and blue light
更容易从你的视野里消失
are more likely to be scattered away from
所以你就看见了绿光
your line of sight, so you see the sun asgreen.
如果空气超级洁净 那你就能看见蓝光
If the air is super clear, though, you can see blue flashes.
相反地 如果空中雾多
And if it ’ s super hazy,enough green
绿光可能就会离开
might be scattered to make the flash
光反而变得更黄了
look yellow, instead.
但你在日出和日落时
But there ’ s a reason you don ’ t see a flash
并看不到彩色的光
with every sunrise and sunset — by itself,
是因为这样的折射程度
this refraction isn ’ t enough
并不足以让你用肉眼
for you to actually be able to see the flash with your
观察到这些光
own eyeballs.
不同色光中的色散程度不够大
The physical separation between the differentcolors isn’t large enough.
而海市蜃楼将之放大了
So we also need a mirage to magnify the effect.
海市蜃楼是大气折射形成的多个像的叠加
Mirages are just multiple images formed byatmospheric refraction.
你可能会说这些像只有一个是真的 剩的都是假像
You might think one of those images is ‘ real ’ and the rest are ‘ fake ’,
但是
but that ’ s
并不是这样的
not the case.
它们都源于同一处
They all come from a single source.
这里的海市蜃楼就像另一个太阳
The mirage in this case looks like a secondsun.
你知道这些日落的景象
You know those pictures of sunsets where it looks
看起来太阳像是变大了
like the sun grows a little stand at
在落下时
the bottom?
那其实是两个海市蜃楼重叠了
That ’ s actually two mirage images overlapping,
那就是让我们看见绿光的东西
and it ’ s what allows us to see green flashes.
看日落时
And during sunsets,
有一个器官能帮我们放大效果
there ’ s also a physiological component that can amplify the effect.
当你看红色的落日时
When you look at a reddish sunset,
眼的视觉细胞识别红光的能力变得更敏锐
the receptors in your eyes that detect red light get so
当光线消失时
used to being activated that when the source goes away,
所有的事物和它自身相比
everything looks more green than
会看起来更绿
it really is.
但日出时不会这样
But this doesn ’ t happen in sunrises,
因为你看不到红色的太阳
because there ’ s no red sun too look at — the green
“绿色的”太阳首先升起
rises above the horizon first.
从理论上讲 在地球上每年的任何时刻
While green flashes can theoretically be seen anywhere
到处都能看见绿光
on Earth at any time of year, they ’ re
在空气清洁并且相对稳定的
best spotted above an unobscured horizon,
无遮蔽的地平线上能够更好地观察绿光
where the air is clean and relatively stable.
这就是许多这样的故事来于船员或旅客的原因
Which is probably why so many stories of them come from people on boats.
所以如果你找对了地方
So if you find the right spot,
那你就可以看到儒勒·凡尔纳所描述的
you might just get a glimpse of what Jules Verne described
“真正的绿色希望”
as “the true green of Hope. “
感谢你观看这段《科学秀》
Thanks for watching this episode of SciShow!
如果你像儒勒·凡尔纳喜欢绿色的太阳一样喜欢科学
If you love science as much as Jules Verne apparently loved the green sun, well,
那么
you ’ ve
你来对了
come to the right place!
如果你想每天都能看到新的视频
And if you want a new video every day,
就去YouTube上订阅Scishow
just go to youtube.com/scishow and subscribe.
结尾
[♪OUTRO]

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视频概述

这个视频解释了太阳在升起和落下时产生绿光的原因

听录译者

收集自网络

翻译译者

Stacey

审核员

审核员 AF

视频来源

https://www.youtube.com/watch?v=nMq3cqO__Yw

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