Arcs, rippling curtains, spirals, even a crown directly overhead — the aurora takes many forms in a single night. Each shape is drawn by Earth's magnetic field.
Here's what the shapes mean.
Arcs and bands
The most common form is a smooth arc stretching across the northern sky. As activity rises it breaks into bands that fold and ripple. These trace the magnetic field lines high above.
Curtains and rays
The famous curtains form because charged particles pour down along vertical field lines, creating fluted, rippling drapes with visible rays like folds in fabric.
The corona
When the aurora is directly overhead, the rays appear to radiate from a single point — a corona, or crown. It's a perspective effect (like looking up at parallel rails) and one of the most spectacular sights.
Reading the display
Smooth arcs often mean a building, quieter phase; fast, folding curtains and a corona mean an active substorm. On a guided hunt we help you read what's coming next.