Ever wonder why night vision goggles display everything in green? If so, it’s because the human eye can distinguish more shades of green than any other color. Night vision technologies can be broadly divided into three main categories: image intensification, active illumination and thermal imaging. The image is said to become “intensified” because the output visible light is brighter than the incoming IR light, and this effect directly relates to the difference in passive and active night vision goggles. Continue reading for more interesting facts.