Here are five sources of light that are not hot:
Bioluminescence: This is the production and emission of light by living organisms, such as fireflies, glowworms, or deep-sea creatures like anglerfish. Bioluminescent organisms produce light through chemical reactions without generating significant heat.
LEDs (Light-Emitting Diodes): LEDs are electronic devices that emit light when an electric current passes through them. Unlike traditional incandescent bulbs, LEDs convert electrical energy into light efficiently, producing minimal heat.
Fluorescent lights: Fluorescent lights generate light by passing an electric current through a gas that contains phosphorescent material. This causes the material to emit visible light. While they do generate some heat, the majority of the energy is converted into light rather than heat.
Chemiluminescence: This is a process where light is emitted as a result of a chemical reaction, without significant heat being produced. Glow sticks and certain chemical reactions in nature, such as the bioluminescence mentioned earlier, are examples of chemiluminescence.
Electroluminescence: Electroluminescent materials emit light when an electric current is applied to them. This phenomenon is used in devices like electroluminescent panels, which are commonly found in electronic displays and backlighting applications.
These sources of light do not rely on the intense heat associated with incandescent sources like the Sun or a traditional light bulb, but rather on other mechanisms to produce visible light.