Reuters' chief photographer Yannis Behrakis travelled to Balsfjord in the far north of Norway to capture these stunning Aurora Borealis displays. This is the ideal time of year to see the Northern Lights, as they occur most vividly around the spring and autumn equinoxes.

northern lights Norway
Yannis Behrakis/Reuters

Auroras occur when gaseous particles in the Earth's atmosphere collide with charged particles released from the sun's atmosphere.

They are most often seen above the magnetic poles of the northern and southern hemispheres. They are known as 'Aurora borealis' in the North and 'Aurora australis' in the South.

Auroras can be different colours, depending on the type of gas particles that are colliding. Green is the most common colour, produced by oxygen molecules located about 60 miles above the Earth.

Red auroras are produced by high-altitude oxygen molecules (at up to 200 miles above the Earth). Nitrogen produces blue or purple auroras.