Board Thread:Off Topic/@comment-24993958-20150629203847/@comment-24891101-20150703204048

Thermal is a subset of EM. Night vision can be distinct from thermal, in that night vision can also simply be a very sensitive detector with better acuity than the eye, which then ups intensity for you. It can also throw a NIR spotlight on a thing and detect that. Or it can be detecting IR passively. More info here.