The Northern Lights take many forms in a single night — from a quiet arc to explosive curtains overhead. Those shapes are shaped by Earth's magnetic field and the energy of the solar particles.
Arcs and bands
A display often begins as a smooth arc low on the northern horizon — a calm, steady band of light following Earth's magnetic field lines.
Curtains and rays
As activity increases, the arc breaks into curtains and vertical rays that ripple and fold, tracing the magnetic field lines the particles spiral along.
Coronas and spirals
During a strong substorm, the aurora can appear directly overhead as a corona — rays radiating from a single point — or twist into dramatic spirals. This is the aurora at its most intense.
Reading the sky
Fast movement and overhead coronas signal a strong, active night. On a guided tour, your guide will explain what you're seeing as it unfolds.