Infrared — everything warm is broadcasting

Above visible red the spectrum becomes heat's own voice: every body radiates with a peak set by Wien's law, λ_peak·T = 2898 µm·K. Sealed: at body temperature (310 K) you glow brightest at 9.3 µm — which is exactly where thermal cameras look: https://narrowhighway.com/s/2e10f3cd833c0da8ed1973eeb517c9de779e8956cd7d04eeee423aab280c4455 . Remote controls (~940 nm), night vision, and the greenhouse effect all live here — CO2 and water vapor absorb in these bands, which is honest empirical spectroscopy, measured line by line. The photon picture is arriving but gentle: an IR photon carries ~0.1 eV, enough to wiggle molecules (heat), far too weak to break them.