Aurora

The more dark, the brighter the aurora.

Northernlights

An aurora[a] (pl: auroras or aurorae),[b] also commonly known as polar lights or northern lights,[c] is a natural light display in Earth's sky.
Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky. — Wikipedia

Tips on how to find the northern lights

Aurora