Aurora Borealis

The aurora borealis, also called the northern lights, is a natural light display that appears mainly in the night skies of high northern latitudes. It forms when electrically charged particles released by the Sun travel through space and are guided by Earth's magnetic field toward the polar regions.

There, these particles collide with atoms and molecules high in the atmosphere, transferring energy that is released as visible light. The colours depend on the type of gas and the altitude where the collisions occur. Oxygen often produces green or red light, while nitrogen can create blue, violet or pink shades.

Auroras usually appear as glowing arcs, curtains or moving bands that slowly change shape across the sky. Northern lights are most common in regions close to the Arctic Circle, including northern Canada, Alaska, Greenland, Iceland, Norway, Sweden and Finland. Their intensity increases during periods of strong solar activity, such as solar storms, although they can sometimes be seen farther south.

A similar phenomenon occurs around the South Pole and is known as the aurora australis, or southern lights. Scientists study auroras because they reveal how the Sun interacts with Earth's magnetic field and upper atmosphere. These observations also help improve forecasts of space weather, which can affect satellites, radio communications, navigation systems and electrical power networks.