luonnonvalonlähde
Luonnonvalonlähde refers to any source of light that originates from nature, as opposed to artificial lighting. The most prominent natural light source is the Sun. Its light travels vast distances to illuminate the Earth, driving weather patterns, enabling photosynthesis in plants, and providing the primary source of visible light for most life on the planet. The Sun's light is a complex spectrum of electromagnetic radiation, with visible light being just a portion of it.
Other natural light sources exist, though they are less significant in terms of overall illumination. The Moon,