Last few nights have been great for watching the northern lights dancing high up in the sky above Isafjordur. The weather has been great and stable and not a cloud in the sky for five days.
Aurora (short for polar aurora) is a glow in the sky, seen often in a ring-shaped region around the magnetic poles ("auroral zone") and occasionally further equatorward. The name comes from an older one, "aurora borealis," Latin for "northern dawn," given because an aurora near the northern horizon (its usual location when seen in most of Europe) looks like the glow of the sky preceding sunrise. The lights are commonly called "northern lights" (aurora borealis) in the north and "southern lights" (aurora australis) in the south.
Northern lights originate from our sun. During large explosions and flares, huge quantities of solar particles are thrown out of the sun and into deep space, making auroras visible at regions far from the pole, where they are rarely seen. The aurora is generally caused by fast electrons from space, guided earthward by magnetic field lines, and its light comes from collisions between such electrons and the atoms of the upper atmosphere, typically 100 km (60 miles) above ground.
Auroral oval is the region in which aurora can be seen at any single time, as observed (for instance) by satellite cameras. It resembles a circle centered a few hundred kilometers nightward of the magnetic pole, and its size varies with magnetic activity.