Infrared (IR)

3 - 429 THz 100 - 0.7 ┬Ám
...are just under the visible spectrum, hence infra red (below red). Heatexchange happens through IR radiation. It's due to vibration or torsion of molecules (body, fire, temperature, ..)

Sources:

Stars, dust between stars, Sun, Blackbody radiation, Heat

Uses:

Heat seeking systems, electronic photography, remote controls or comm. devices (GSM, laptop, ..), fibre optics
Mobile phones, satellite communications, radar, TV, radio, ..

Interaction with matter:

Effects: