i was taught from grade school on that all light gives off heat, but i’ve recently seen a television program that stated there were fish that live in the deepest parts of the oceans that create their own light source called bio-luminesence (illuminesence?), and that this form of light does not create any heat. how can that be?

Fish and inverts that produce bioluminescence generally do so through a chemical reaction (luciferin + O[sub]2[/sub] —> oxyluciferin + light … occurs in the presence of luciferase) that releases a photon from the activated form of oxyluciferin. The chemical energy of the reaction is released as that photon, rather than as kinetic energy of atoms (heat). The photon could later strike something and heat it up, so the light from bioluminescence can heat up objects, but heat is not a direct result of the chemical reaction.

The photon released is not special or different from other photons, it’s like those photons released by the sun that also heat things up.