ljósgjafa
Ljósgjafa is an Icelandic term that translates to "light source." In its broadest sense, it refers to anything that emits light. This encompasses a wide range of phenomena and objects, both natural and artificial. Natural ljósgjafar include the sun, stars, lightning, and bioluminescent organisms such as fireflies and some deep-sea creatures. Artificial ljósgjafar are objects created by humans to produce light, such as incandescent bulbs, fluorescent tubes, LEDs, lasers, and candles.
The study of light sources is fundamental to physics and optics. Understanding how different ljósgjafar produce