You asked us, how does night vision technology work?
Our eyes allow us to see a wide range of lights. When the sun goes down, our ability to make out stuff drops off quickly - colors fade, things get fuzzy, till our eyes become useless and we're what goes bump in the night.
Cue night vision technology.
There are two very cool types. The first is thermal imaging. It registers on the upper portion of the infrared light spectrum. Invisible to humans, this kind of light is emitted as heat by things like warm bodies, recently driven cars and even some chemicals. Thermal imaging devices can see through the fog, smoke and dust.
Type number two amplifies available light from the visible spectrum as well as some infrared light, making things look brighter than they appear to the naked eye. Most night vision equipment uses this imaging enhancement technology, though it's useless if it's pitch black.
Originally developed to spot enemy targets, night vision is now used for all kinds of things - from military to baby monitors. Because you know, you've got to get the upper hand on these babies.