时差N小时 黄色太阳镜（在线收听）

Look at a cloud-filled sky, then look again through a pair of amber sunglasses.

观察那布满云彩的天空，再戴上黄色镜片的眼镜去观察。

You'll be surprised to see the hazy, bluish clouds jump suddenly into focus, revealing a world of unexpected detail.

你会惊讶得发现，蔚蓝朦胧的云朵突然聚焦于眼球，呈现出一个无比精准的视界。

Many skiers use amber sunglasses too, to help see detail in white banks of snow.

许多滑雪者也使用黄色的眼镜，用以看清白茫茫雪地。

On today's Moment of Science, we'll learn how amber-tinted sunglasses make things appear so much sharper.

今日时差N小时，我们将学习黄色眼镜怎样将视像变得更清晰。

The answer has as more to do with your eyes than it does with the sunglasses.

相比眼镜，我们更应该从眼睛成像原理出发找答案。

Behind the pupil of your eye is a natural lens like a tiny bag of transparent jello.

人眼瞳孔之后是透明的果冻似的自然晶状体。

This lens focuses images on the back of your eyeball the same way a camera's lens focuses images onto film.

就像照相机镜头可以把图像聚焦在胶片上，晶状体则把图像聚焦到眼球的后部。

Unfortunately, even healthy eyes can't focus everything perfectly.

不幸的是，即使是正常的眼睛也不能十分完美得聚焦图像。

This is because each color of light focuses slightly differently through a lens.

这是因为每一种不同颜色的可见光在透过晶状体聚焦时有微小的差别。

Imagine a slide projector showing a red and a blue image on the same screen.

想象一个幻灯放映机在屏幕上同时放映红色和蓝色的图像。

If you focus the red image sharply, the blue one will be slightly blurry.

如果你专看红色的图像，蓝色的图像会显得模糊。

If you twist the knob to focus the blue image, the red one will drift slightly out of focus.

如果你转动旋钮，目光集中在蓝色的图像上，红色的图像会轻轻漂出视线。

You can only get ultra-sharp focus of one color at a time.

人眼一次只能聚焦一种颜色。

Healthy eyes are set to focus yellow, the middle of the color spectrum.

健康的眼睛注定要聚焦位于光谱中间的黄色。

This is great for yellow--and pretty good for green and orange--but it makes red and blue appear slightly out of focus.

人眼看黄光会显得非常清晰，看绿光和橙色光也很清楚，但是看红光和蓝光似乎显得模糊。

White sunlight contains all the colors, so the red and blue extremes will make any white object seem somewhat hazy.

白光包含了所有颜色的单色光，所以临界的红光和蓝光会让任何白色的物体看起来模糊。

Amber sunglasses block the blue and red parts of sunlight, letting you concentrate on the yellow colors that are easier to focus.

黄色镜片则阻挡红光和蓝光，提高对比度，让眼球聚焦在黄光上。

Without blue and red, everything seems sharper.

没有红蓝两色，一切似乎显得清晰起来。