Infrared light is just past red — invisible to your eyes but detected as warmth.
Why can a TV remote control 'see' across a dark room when you can't?
Light you feel as warmth
Infrared sits between visible red light and microwaves on the spectrum. Anything warmer than its surroundings glows in infrared — that's exactly what thermal cameras and night-vision goggles pick up.
Longer wavelength means lower energy. Infrared photons can't sunburn you or break DNA bonds — they mostly just make molecules jiggle, which we sense as heat.
Remote controls, fibre-optic internet, weather satellites spotting cloud temperatures, astronomers peering through dust clouds, building heat-loss surveys — infrared is everywhere once you have a detector for it.
Remote controls, night-vision goggles and thermal imaging all use infrared.