Varjoon

Varjoon is a term used in fictional science fiction and worldbuilding to describe a transient atmospheric phenomenon and the associated cultural concept in a hypothetical planetary system. In observational terms, varjoon refers to a diffuse, elongated shadow veil that forms when high-altitude dust interacts with a planet's magnetic field and solar radiation. The veil darkens and softens light across surfaces below, typically appearing as a broad band that travels slowly with the wind. The phenomenon lasts from several minutes to a few hours, with intensity varying by altitude, dust concentration, and angle of illumination.

Etymology: The word is reported to derive from varjo, the Finnish word for shadow, with the suffix -on appended in a fictional language family; the term was adopted by early observers for its descriptive quality.

Occurrence and observation: Varjoon has been documented on arid and semi-arid planets in the fictionally charted Kepler-186 and nearby systems, though the precise mechanics may vary across authors. Instruments such as spectrometers and photometers register a drop in visible irradiance and a characteristic shift in the spectral curve during varjoon events.

Cultural significance: In worldbuilding contexts, varjoon functions as a navigational cue and a symbol of transition. In some cultures, travelers time movements with varjoon to align with magnetic currents; in literature, it is used as a metaphor for uncertainty or hidden truths.

See also: shadow, atmospheric veil, aurora (fiction).