時差N小時:當天空變成綠色時

It sounds like something from a fairy tale.

這聽起來就像是個童話故事。

If you look at the horizon at sunset–exactly as the last sliver of sun disappears–you might see aflash of brilliant green blaze across the sky.

日落的時候如果你看看地平線，尤其是在太陽的最后一縷銀光消失的時候，你可能會看到一束耀眼的火焰劃過天空。

Indeed, an old Scottish proverb maintains that whoever sees this flash will always be lucky inlove. 的確，有一句古老的蘇格蘭諺語這么說，看見這道光焰的人總是會在愛情上交好運。

While we can't confirm the lucky-in-love part of this, there is a scientific explanation for theflash of green light.

盡管我們無法證實會有桃花運，但對于這束綠光倒有一個科學的解釋。

As sunlight enters our atmosphere, it bends slightly.

當陽光進入大氣層，光線會發(fā)生輕微的彎曲。

This is due to refraction, the same thing that makes a pencil look slightly askew when youstick it half way into a glass of water.

這是折射的作用，就象把鉛筆的一半插入一玻璃杯水中，鉛筆會看起來有點傾斜。

The atmospheric bending of light rays is greatest when the sun is right along the horizon, atsunrise or sunset.

日出日落時分，太陽恰好貼著地平線的時候就是光線折射作用最強的時候。

How does bending sunlight create a green flash?

但彎折的太陽光又是怎樣產生綠光的呢?

When sunlight is bent by refraction, it separates into different colors, just like light through aprism.

當日光由于折射而彎曲時，光線就會分解成不同的顏色，就像通過棱鏡發(fā)射不同的光一樣。

While a prism can make a dramatic rainbow, atmospheric refraction isn't that strong.

然而三棱鏡可以折射出漂亮的七色彩虹，而大氣的折射作用卻沒有那么強。

It doesn't turn the sun into a rainbow, but it makes the lowest part of the sun seem a bitmore red, and the top of the sun seem greenish blue.

它不會將太陽光折射成彩虹，但是它可以使最底部的光變得更紅一些，而最頂部的光看上去像藍綠色。

The effect is so subtle, you'd never notice it.

這個變化非常微妙，你可能從來都未曾注意。

Except, of course, at sunset or sunrise.

當然，除了在日出或日落的時候。

For a split second, when most of the sun's globe is below the horizon, the only part showing isthat blue-green sliver along the top.

只有那么一瞬間，當太陽的大部分輪廓低于水平線，僅有的露出來的部分就是頂部的藍綠色長條。

Blue light is scattered by the atmosphere, so what's left is a brief flash of green, the onlyillumintion in the sky!

藍光被大氣層分散，剩下的就是一縷縷的綠光，天空唯一的光亮處。

Please remember, this happens immediately after a sunset. Never look directly at the settingsun.

請記住，這種現(xiàn)象只在日落后的一瞬間發(fā)生。要記著可別一直盯著落日看。