Celestial sources of light include other stars, comets and meteors.
Other natural sources of light include lightning, volcanoes and forest fires.
There are also bio-luminescent light sources including some species of fish and insects as well as types of bacteria and algae.
Man-made light sources include:
Man-made light sources of the most simple type include natural tars and resins, wax candles, lamps that burn oil, fats or paraffin and gas lamps
Tungsten lights: These are a type of incandescent source which means they radiate light when electricity is used to heat a filament inside a glass bulb.
Halogen bulbs: These are more efficient and long-lasting versions of incandescent tungsten lamps and produce a very uniform bright light throughout the bulb’s lifetime.
Fluorescent lights: These are non-incandescent sources of light. They generally work by passing electricity through a glass tube of gas such as mercury, neon, argon or xenon instead of a filament. Fluorescent lamps are very efficient at emitting visible light, produce less waste heat, and typically last much longer than incandescent lamps.
LED lights: An LED (Light Emitting Diode) is an electroluminescent light source. It produces light by passing an electrical charge across the junction of a semiconductor. An LED light typically emits a single colour of light which is composed of a very narrow range of wavelengths.
Made-made lights can emit a single wavelength, bands of wavelengths or combinations of wavelengths.