The northern lights look different depending on where you stand. Over the coast of Norway they hang above mountains and sea, over Fairbanks, Alaska, they can burst straight overhead, and from orbit they glow above the curve of the Earth. The two films here follow the lights over Fairbanks and from orbit.
What causes the northern lights
According to NOAA’s Space Weather Prediction Center, the aurora is produced when electrons from space stream down Earth’s magnetic field at about 20,000 km per second and crash into atoms and molecules in the upper atmosphere, more than 100 km above the ground. The collisions excite those atoms, which then give off light. The biggest displays follow coronal mass ejections, huge clouds of material thrown out by the Sun; high-speed solar wind from coronal holes brings moderate storms.
Why the aurora is green, red and purple
- Green, the most common colour, comes from atomic oxygen at about 120–400 km, glowing at a wavelength of 557.7 nanometres.
- Red also comes from oxygen, but only above about 300 km, where the excited atoms have time to release their light before colliding again.
- Purple comes from nitrogen at about 120–200 km and often shows as a fringe along the lower edge of the curtains.
Cameras often record stronger colours than the eye sees, which is why a time-lapse can look more vivid than the same sky watched live.
Aurora over Norway and Fairbanks, Alaska
The aurora appears in an oval around each magnetic pole, a band about 6 degrees of latitude wide centred near 67°N and 67°S. Northern Norway, beyond the Arctic Circle, and the interior of Alaska both lie close to it, which puts them among the best places to see the lights.
Fairbanks, at about 64°50′N, sees the northern lights on more than 200 nights a year on average; in summer the midnight sun hides them. Around the winter solstice it gets only about 3 hours and 41 minutes of daylight, and January averages −22 °C.
The Fairbanks clip, filmed on January 22, 2012, shows a coronal aurora. A corona forms when the display is directly overhead: the rays seem to spread out from a single point high in the sky, like the spokes of a wheel. It is the most striking of the ground-level forms, and a night’s aurora often builds towards it from a faint glow.
The northern lights from space
From orbit the view turns around: the dark planet fills the foreground and the aurora shows as a luminous band along the curved horizon, tracing the shape of the auroral oval. In September 2011 the Expedition 28 crew filmed the southern lights, the aurora australis, from the station.
Tips for seeing the aurora
- Go in the dark season. The lights need a dark sky, so plan for the long nights of autumn, winter and early spring. Geomagnetic storms are slightly more common around the equinoxes in March and September.
- Watch around midnight. Evening displays often start as a single arc; the brightest, most active forms usually appear near local midnight, and mornings tend to be patchy and pulsing.
- Check the Kp index. Kp 3–4 can still bring a good show near the auroral oval; Kp 7–9 means a strong storm that pushes the lights to lower latitudes.
- Get away from lights. Clear skies and a dark horizon matter more than anything else. Dress for deep cold if you head out in an Alaskan or Arctic winter.
Explore more: aurora from an aircraft window, and planning ground-based viewing without guarantees.
Related reading
- Kakslauttanen’s Glass Igloos: A Room with a Sky View
- The Arctic Light: Lofoten’s Long Spring Twilight
- Ten Northern-Lights Regions: Geography, Darkness and Realistic Expectations
Beauty
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