Fieröintiä

Fieröintiä is a Finnish term that describes the phenomenon of light scattering from airborne particles, often seen as a faint, diffuse glow in the atmosphere. It is typically observed at twilight, during dawn or dusk, and is most noticeable when the sun is below the horizon. The light from the sun, passing through the atmosphere at an oblique angle, is scattered by tiny particles such as dust, water droplets, or ice crystals. This scattering redirects the light in multiple directions, making the sky appear illuminated even when the direct sunlight is not visible.

The intensity and color of fieröintiä can vary depending on the size and composition of the particles in the atmosphere, as well as the angle of the sun. Finer particles tend to scatter shorter wavelengths of light, resulting in a bluish hue, while larger particles can scatter longer wavelengths, producing reds and oranges. Urban environments, with higher concentrations of dust and pollutants, may exhibit more pronounced or varied fieröintiä compared to cleaner, rural areas. This atmospheric effect is a natural process and is distinct from other light phenomena such as aurora borealis or light pollution.