時(shí)差N小時(shí):夜視 人類為何看不見顏色?

When we are in a fairly dark room, or outside atnight away from lights, we can still see, but wecan'tsee the colors of things very well. Why is that?

當(dāng)我們?cè)谝粋€(gè)非?；璋档姆块g或夜晚在無(wú)燈的戶外，我們?nèi)匀豢梢钥匆娢矬w，但很看不清楚物體的顏色，為什么會(huì)這樣呢?

There are two kinds of light-sensitive organs locatedin the backs of our eyes: rod-shaped andcone-shaped.

在我們眼睛的后部有兩種感光器官：桿狀體和錐狀體。

Both rods and cones are sensitive to light.

它們都對(duì)光線敏感。The difference between them is thattherods allow us to see in very dim light but don't permit detection of color, while the coneslet ussee color but they don't work in dim light.

而它們的差別就在于，桿狀體能讓我們看見昏暗的光線下的東西，但無(wú)法辨別顏色;而錐狀體能讓我們辨別物體的顏色，但在昏暗的燈光下卻無(wú)法發(fā)揮作用。

When it gets dark the cones lose their ability to respond to light.

當(dāng)光線變暗時(shí)，錐狀體失去對(duì)光線做出反應(yīng)的能力。

The rods continue to respond toavailable light, but since they cannot see color, so to speak,everything appears to be variousshades of black and white and gray.

而桿狀體繼續(xù)對(duì)光線做出反應(yīng)，但由于它不能幫助人們識(shí)別顏色，因此所有的物體看上去都是不同形狀的黑色、白色或者灰色。

A curious thing is that in dim light you can see more clearly out of the side of your eye,becausethe light-sensitive rods are more highly concentrated off to the side in the back ofyour eye.

奇特的是，在光線暗淡情況下，通過(guò)眼睛兩邊的余光你能看得更清晰，因?yàn)闂U狀體更集中地分布在眼睛后部的邊側(cè)。

So, next time you're out on a clear night, notice how little color you can see, and how you cansee objects like dim stars better out of the corner of your eye than from the center.

所以，下次在一個(gè)晴朗的夜晚外出，留意一下你是不是看不見什么顏色，并且關(guān)注一下用眼角的余光看東西，例如晦暗的星星，會(huì)不會(huì)比正視看效果更好。