vihannestähteitä

Vihannestähteitä, a Finnish term, translates to "green stars" and refers to a phenomenon observed in the atmosphere. This refers to the brief, greenish flash that can sometimes be seen just as the sun either rises or sets. It is a visual effect caused by atmospheric refraction and dispersion of sunlight.

The green flash is most commonly seen when the sun is very low on the horizon, typically during sunrise or sunset. The Earth's atmosphere acts like a prism, bending (refracting) sunlight. Different wavelengths of light are bent at slightly different angles. Blue and violet light are refracted more than red and orange light. However, the blue and violet light are usually scattered away by molecules in the atmosphere before they reach the observer.

The remaining light, particularly the red and yellow hues, pass through more directly. However, just as the sun disappears below or appears above the horizon, a sliver of green light can be visible due to the way the atmosphere refracts and disperses the last or first rays of sunlight. This effect is enhanced by a clear, unobstructed horizon and a stable atmosphere. While often described as a "flash," it is a very brief visual phenomenon, lasting only a second or two. Vihannestähteitä is a poetic and descriptive term for this fleeting atmospheric spectacle.