The Lights at Both Ends of the World

When the sky lights up green over northern Norway, the same storm is often painting the sky over the ocean south of Australia.

Auroras happen when charged particles from the Sun get funneled along Earth’s magnetic field and strike gases in the upper atmosphere. Field lines loop out from one end of the planet and back in at the other, so the particles can arrive at both ends at about the same time.

Two names for one show

The northern lights are the aurora borealis. The southern lights are the aurora australis. Scientists have photographed both from space during the same storm, and they often look like near mirror images, though the Sun’s wind can twist them out of alignment.

Where to see them

The north gets all the tourism, since far more people live close to the northern auroral zone. In the south, most of the zone falls over open ocean and Antarctica. Tasmania and the southern tip of New Zealand are good bets.

Green comes from oxygen around 100 kilometers up, with deep red higher up. Purple and blue come from nitrogen. Whichever end you are at, it is the same light show.