On the long side of the visible spectrum, Infrared is "hot light" growing from 750 nanometers up to 1mm in wavelength. Here Infrared meets those special radio waves used for satellite communications and cooking food, called Microwaves. On the short side of the visible spectrum, extending from 400 nanometers down to 1 nanometer is the region called Ultra Violet Light. Beyond Ultra Violet Light, are the X rays which extend down to 1 picometer in wavelength. Overlaping X rays, Gamma rays begin at 10 picometers and extend down to 10 micro-nanometers.

Light waves are "electro-magnetic" disturbances where an initial "electrical field" or "magnetic field" collapses, causing the build up of the alternate type of field, which itself must collapse when the initial field has completely collapsed. Of course the alternate type of field builds up a new model of the initial type of field that created it while collapsing, and the disturbance races out to infinity.

An important property of any light wave is its Color Temperature. The whole electromagnetic continuum may be regarded as the "radiant heat spectrum." Heat and light are not however the same thing. I would suggest though, that heat is the principle means by which all light interacts with matter. To my mind, photons are virtual particles that have no real existence until a light beam strikes a material body. If I picture every cycle of a light wave as a virtual photon, I have no difficulty understanding how the shorter wavelengths posses higher color temperatures. The shorter wavelengths have higher frequencies with more complete cycles per unit time, equating to more photon collisions with matter per unit time, therebye raising the energy content of the struck body proportionately,- raising its temperature.