Auroras: the northern and southern lights

What an aurora is

An aurora is a natural light display in the upper atmosphere. In the north it is called the aurora borealis, or northern lights; in the south, the aurora australis, or southern lights. Both happen at the same time, mirror images around the two magnetic poles.

Auroras can look like a quiet arc, rippling curtains, bright rays or a crown overhead. They shift and pulse, sometimes slowly over minutes, sometimes within seconds during strong activity.

From the Sun to our sky

The Sun constantly blows out a thin stream of charged particles called the solar wind, which travels at roughly a million miles per hour. Sometimes the Sun also throws out a huge cloud of plasma called a coronal mass ejection, or CME, which can reach Earth in one to three days.

Earth is wrapped in a magnetic bubble called the magnetosphere. It deflects most of the solar wind, but when the Sun's magnetic field links up with Earth's, energy and particles pour in. They are funneled along field lines toward the polar regions and slam into the upper atmosphere, roughly 60 to 190 miles up.

The collisions give energy to atoms and molecules of oxygen and nitrogen. As they settle back down, they release that energy as light, much like the gas in a neon sign.

Why the colors differ

The most common color is a pale green, made by oxygen atoms at about 60 to 150 miles altitude. Higher up, where the air is extremely thin, oxygen gives off a deep red light. Red auroras are often the ones seen from far away during big storms, because they sit so high they peek over the horizon.

Nitrogen produces blue and purple light, usually along the lower edge of a curtain. When colors mix, you may also see pink, yellow or white. Cameras often record colors more strongly than the eye, which is less sensitive to color in the dark.

Reading the Kp index

Space weather forecasters use the Kp index to sum up geomagnetic activity on a scale from 0 to 9. Kp 0 to 2 is quiet, and auroras stay close to the poles. Kp 5 marks a geomagnetic storm, and each step higher pushes the aurora farther toward the equator.

The NOAA Space Weather Prediction Center also uses a G scale from G1 (minor) to G5 (extreme). A Kp of 9 equals a G5 storm, which happens only a few times per 11-year solar cycle. Activity is generally higher around solar maximum; the current cycle peaked around 2024–2025, and strong storms remain fairly likely for a few more years as of 2026.

The May 2024 storm

On May 10–11, 2024, a series of CMEs from a very active sunspot group hit Earth and set off the first G5 storm since October 2003. Auroras were photographed across Europe, the southern United States, northern India and parts of Africa and South America.

Many people in Türkiye saw or photographed red and pink glows low in the northern sky, something very rare at about 36° to 42° north. Phone cameras helped, because their long exposures picked up faint colors that eyes barely noticed. Storms like this are exceptional, so do not expect them every year.

How to see an aurora

The most reliable places sit under the auroral oval, a ring around each magnetic pole: northern Norway, Sweden, Finland, Iceland, Alaska and northern Canada, or Antarctica and, on good nights, Tasmania and the south of New Zealand. The dark months, roughly September to March in the north, are best; summer nights there are too bright.

Get away from city lights, pick a clear night and look toward the pole, north in the Northern Hemisphere. Activity often peaks within a couple of hours of local midnight. Give your eyes 20 minutes to adjust and avoid looking at your phone screen.

Watch the NOAA aurora forecast and Kp predictions. From mid-latitudes such as Türkiye, only strong storms of about Kp 8 or 9 have a real chance, so set up an alert and be ready to drive to a dark spot with a low northern horizon.

For photos, use a tripod, a wide lens and exposures of a few seconds to about 15 seconds. Many phones have a night mode that works well.

Where and when to see the northern lights

The most reliable places to see the northern lights sit just under the auroral oval: northern Norway (Tromsø and the Lofoten Islands), Swedish and Finnish Lapland, Iceland, northern Canada (Yukon and the Northwest Territories) and Alaska. On a clear, dark night there, even a quiet Kp 2–3 often brings a display.

The season runs roughly from late September to late March. In summer the sky at these latitudes never gets properly dark, so any aurora is lost in the twilight. Activity tends to rise a little around the equinoxes in September and March.

The best hours are usually between about 9 p.m. and 2 a.m. local time. Get away from town lights, pick a spot with an open view to the north, and check the cloud forecast as closely as the aurora forecast: clouds hide even the strongest storm.

In the Southern Hemisphere the same glow is called the southern lights, or aurora australis. Tasmania, New Zealand’s South Island and Antarctica are the best-known places to watch it.

From mid-latitudes such as Türkiye, southern Europe or the southern United States, auroras are rare, but very strong storms like the one in May 2024 can show a reddish glow low in the north. When an alert comes, find a dark spot, face north and try a long exposure or your phone’s night mode; the camera picks up colors your eyes may miss.