What is the rarest color in nature? - Victoria Hwang

翻译人员: Xiang Li 校对人员: Yuwei Wu

Every color you see in front of you can be found in nature.

你眼前看到的所有颜色 都能在自然界中找到。

Some plant, animal, or mineral bears almost every hue imaginable.

植物、动物或者矿物质 让任何色彩都得以想象。

But which of these colors are you least likely to see in the natural world?

但是，哪种颜色是你最难在 自然界中看到的呢？

There are two factors that drive the rarity of color in nature:

有两个因素使一些颜色 在自然界中变得很稀有：

physics and evolution.

物理因素和生物进化因素。

Let’s start with physics.

我们从物理因素开始讲。

Colors are generated when wavelengths of light interact with objects,

色彩是由各种波长的光与物体 互相作用而产生的。

and most of the colors you’ve seen outside a screen

而大多数你在屏幕外看到的颜色

were produced in one of two ways.

是由两种方式的其中一种产生的。

In absorption-based colors,

对于以吸收光为基础的颜色，

certain wavelengths are absorbed by an object, while others are not.

某种特定波长的光被物体 所吸收，而其他的不会。

The result is a matte final color generated by these leftover light waves.

结果是未吸收的光波产生了一个 哑光的最终颜色。

Most naturally occurring colors fall into this category,

大多数自然产生的颜色 都是这种方式，

including those of many fruits and flowers.

包括各种水果和花朵。

Plants are full of compounds called pigments that absorb light waves

植物有一种丰富的色素化合物用于 吸收光波，一部分光波用于光合作用，

as part of photosynthesis,

the process by which they convert sunlight into energy.

它们利用光合作用将阳光转化为能量

While different plants have evolved different pigments

而不同的植物进化出了不同的色素

that result in different colors,

使它们展现出不同的颜色

higher energy wavelengths are more easily absorbed than lower energy ones.

高能量的波长比低能量的波更容易被吸收。

And blue light has some of the highest energy wavelengths

而蓝光在可见光光谱中 具有最高能量的波长

in the visible spectrum.

Numerous pigments have evolved to absorb blue light,

大量的色素参与了蓝光的吸收.

including chlorophyll, which absorbs blue and red wavelengths

包括叶绿素.

通过吸收蓝波和红波 来产生自然界标志性的绿色。

to produce nature’s trademark green.

However, green light is still fairly energetic,

但是，绿光仍然是相当有能量的,

and the most common class of pigments evolved to absorb these wavelengths

也是最常见的被色素吸收的光波。

as well.

There are over 1,100 types of carotenoids,

有超过 1100 种类胡萝卜素，

pigments which absorb high energy blue and green light,

这是一种吸收高能量的蓝光和绿光，

while leaving behind the lower energy red and yellow light.

而留下低能量的红、黄光的色素。

While carotenoids are present in most green plants,

然而，类胡萝卜素 在大多数绿色植物中都有，

they only become visible each fall when chlorophyll gets broken down

它们只有在叶绿素 都分解掉之后才能看见

to save energy for the winter.

从而为度过冬天保存能量。

But whether they’re working alone or side by side,

但是无论它们是单独工作， 还是一起工作

these pigments absorb blue light in virtually all plants.

这些色素几乎在 所有的植物中都吸收蓝光。

Even fruits and flowers that appear blue

甚至那些看上去是蓝色的水果和鲜花

actually have pigments that are red or purple,

实际上是含有红色或紫色的色素，

and only truly turn blue under specific chemical conditions.

只有在特定地化学条件下 才会真正转变为蓝色。

So, is blue the rarest color in nature?

那么，自然界 最稀有的颜色是蓝色吗？

Not quite.

不太是。

Absorption is just one of the two main ways light generates color.

吸收光只是光产生 色彩的两种方式之一。

In the second method, some wavelengths are scattered and amplified—

在第二种方式中， 一些波长的光会散射或者增强，

overpowering the others to determine an object's final color.

从而压倒其他光波， 来决定物体的最终颜色。

These structural colors occur

这些结构性的颜色产生

because some objects around us are made of microscopic particles

是因为我们身边的一些物体是由 许多微小颗粒组成的

which can form nanostructures that interfere with visible light.

这些微小颗粒可以形成 干扰可见光的纳米结构。

For example, this feather has no blue pigments in it.

例如，这片羽毛当中 并没有蓝色色素。

But when light strikes it, the electrons within its nanostructure

但是当光照射它时， 它的纳米结构中的电子

vibrate at the same frequency as the weight.

会以相同频率振动， 像波浪一样。

This makes the particles send out a new wave with the same frequency,

这使这些微粒发送了一种 有相同频率的新波，

starting a chain reaction that amplifies and scatters blue light.

形成了扩大和 散射蓝光的一连串反应。

Nanostructures of various shapes and sizes scatter different wavelengths,

各种各样结构和大小的纳米结构 散射不同波长的光，

but they typically scatter high-energy wavelengths most easily—

一般而言散射高能量的波长 是最容易的——

making blue the most common structural color.

这使蓝色成为 最常见的一种结构性颜色。

Meanwhile, low-energy wavelengths like red are only weakly scattered.

同时，低能量波长的光， 如红光，只有很微弱的散射。

Even when something evolves specific nanostructures

即使有一种生物进化出了 特别的纳米结构

that strongly scatter red light

可以强烈散射红光

they still resonate with other wavelengths,

这些红光也会与其他波长产生共振，

only appearing red at some angles of illumination and observation.

只有在一些特别的观察 和照射的角度才会展现红色。

This gives us two contenders for nature’s rarest color:

现在自然界中最稀有的颜色 有了两个竞争者：

absorption-based matte blues and structural iridescent reds.

吸收光为基础的哑光蓝色 和结构性闪烁红色。

Between these two, structural reds are much rarer.

这两者中，结构性红色更加稀有。

Only a handful of animals and rocks scatter red light

只有一小部分动物和矿石散射红光

and none of them scatter red light exclusively.

并且没有一种物体单独散射红光。

But since red and blue are rare in one way and common in another,

既然红色和蓝色都在一种方式中稀有 而在另一种方式里很常见，

we actually end up seeing both colors quite often.

所以我们事实上 经常可以看见这两种颜色。

So what color is least likely to be generated

所以到底哪种颜色

是结构性方式和吸收光方式 都最难产生的呢？

in structural and absorption-based forms?

The answer is violet.

答案是 蓝紫色。

Not to be confused with purple, which is just a combination of red and blue light,

不要和紫色弄混， 紫色是一种红光和蓝光的结合，

violet occupies a small portion of the visible light spectrum.

而蓝紫色只在可见光 光谱中占有很小的比例。

There are only a few nanostructures precise enough

只有极少的足够精细的纳米结构

to exclusively scatter violet light.

可以单独散射出蓝紫色的光。

And violet wavelengths are even more energetic than blue ones,

并且，蓝紫色的光波 甚至比蓝色光波更为高能，

making them likely to be absorbed by pigment.

使它更容易被色素吸收。

So if you ever stumble onto the iridescent violet wings

所以，如果你偶然遇到 紫色帝王蝶闪烁的紫色翅膀，

of a purple emperor butterfly,

take a second to appreciate one of nature’s rarest spectacles.

花些时间去好好欣赏 这自然界最稀有的光谱之一。