You know this already. There are longer wavelengths,

你们已经知道还有波长更长的辐射
there's longer wavelength radiation called infrared.

有叫做红外线的长波辐射
It has wavelengths that are longer than the--in the visible spectrum.

它的波长比可见光的波长要长
You can't see these but some cameras can see infrared.

你看不到红外线但是一些相机可以
That's how if you-- when you watch the films from the war in Iraq

这就是你在看某些伊拉克战争的影片中
where they have these sort of heat visualization goggles,

士兵们用到的热成像仪的原理
they're looking at infrared wavelengths.

热成像仪通过红外线来成像
There's something in the goggles that is sensitive to infrared light

成像仪中有可以感应红外线的装置
and it converts it into visible wavelengths which you can see.

继而把红外线转换成你能看到的可见光
Have you ever seen satellite pictures where--

你们看过卫星图片么
they used to do this, oil companies or electric companies

石油公司或者电力公司以前会
would take a picture of neighborhoods from the sky, infrared.

从空中用红外线对居民区进行摄影