What is the mechanism behind minor, non-heat-related visible light emissions like bioluminescence?

Answer

Specific chemical or electrical energy conversions releasing photons in the visible range.

Phenomena like bioluminescence are not due to high temperature but are a byproduct of chemical reactions, while lightning is due to electrical energy conversion resulting in visible light emission.

What is the mechanism behind minor, non-heat-related visible light emissions like bioluminescence?
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