Revontulet: the fox fires of the north

The Sami called them guovssahasat — the lights you can hear. Folklore has it that you could hear the aurora crackle. Modern science says this is impossible at the altitudes involved, 100 km up. And yet the reports persist, from observers spread across centuries and cultures. The aurora still has things to explain.

The physics, briefly

The northern lights are caused by charged particles from the sun — a constant flow called the solar wind — interacting with gases in the earth's upper atmosphere. When the particles collide with oxygen and nitrogen atoms, the atoms release energy as light. Oxygen produces the green and red colours. Nitrogen produces blue and purple.

The reason auroras appear at the poles is the earth's magnetic field. The field funnels solar particles toward the polar regions, where they follow the field lines into the atmosphere. The oval where auroras most frequently appear — the auroral oval — sits roughly at the latitude of Lapland, Alaska, and northern Canada.

Solar activity follows an 11-year cycle. We are currently near a solar maximum, which means more and stronger auroras through the mid-2020s.

Where to see them

You need three things: darkness, a clear sky, and solar activity. Lapland provides the first two reliably from September through March. The third requires either luck or planning around solar weather forecasts (the Finnish Meteorological Institute publishes a free aurora forecast).

The best aurora experiences are away from any artificial light. The fells of Urho Kekkonen National Park — flat open plateau above the treeline, no nearby settlements — offer some of the darkest skies accessible by road in Finland. Muotkatunturi, the roadless wilderness on the Norwegian border, is darker still.

Lake Inari works differently. The lake's surface acts as a mirror, and in still, clear conditions, an active aurora reflects below you as well as above — a disorienting doubling that makes the usual sky-watching relationship feel reversed.

Saana Fell, above Kilpisjärvi, has the advantage of altitude and a treeless summit, but the area has a microclimate influenced by the nearby Norwegian coast that can bring cloud unpredictably.

The fox fires

The Sami legend — repaigeasa in Northern Sami, "foxfire" — describes a cosmic fox running across the fells, its tail brushing sparks from the snow as it runs. Each spark becomes a light in the sky. The tail is long; the fox is fast; the lights follow the movement.

What makes this legend worth knowing is not its charm but its accuracy. The aurora does move. The lights shift and ripple in a way that no static natural phenomenon does — it genuinely looks like something running. The Sami had no physics, but they had centuries of observation, and they described something real.