revontulia

Revontulia is the Finnish term for the aurora borealis, the natural light display that appears in high-latitude night skies. The name translates to “fox fires,” reflecting a Finnish folklore explanation in which a fox sweeping its tail across the snow creates sparks that light the sky.

In Finnish folklore, revontulia are often described as vivid, shifting curtains and arcs of light that dance across the horizon. The phenomenon is explained in myth as the result of a fox’s tail brushing the snowy landscape, a story that accompanies the long polar nights in northern regions.

Scientifically, revontulia are caused by charged particles from the Sun interacting with Earth’s magnetosphere and upper atmosphere. When these particles collide with atmospheric gases, they excite atoms and emit light. The most common green colors arise from oxygen at altitudes of roughly 100 to 300 kilometers; red aurorae appear at higher elevations, while purples and pinks can come from ionized nitrogen.

Revontulia are most visible in high-latitude regions, particularly within the Arctic Circle, and are commonly observed in Finland’s northern areas during winter when nights are longest and skies are clear. Observers are advised to seek dark, away-from-town locations with minimal light pollution and to account for local weather conditions.

Activity levels vary with the solar cycle and space weather; stronger displays accompany periods of high solar activity and are tracked by indices such as the Kp-index. Observations can range from faint glows to dynamic, pulsating curtains that shift across the sky, offering frequent opportunities for photography and tourism in northern Finland.