From late September through early March, a remarkable natural display unfolds in the polar regions. In the northern parts of the Northern Hemisphere, the spectacle is known as the polar aurora, while in the southern hemisphere, viewers can glimpse it over Australia. Throughout history, many cultures believed these lights served as a bridge between gods and the earthly realm or as the spirits of ancestors, unborn children, dragons, or flying serpents made visible in the sky.
So what exactly are polar auroras? Simply, they arise when highly charged particles from the sun, the solar wind, collide with Earth’s atmosphere and illuminate the night. Billions of excited atoms release tiny flashes of light, painting a vast palette that shifts from green to pink and purple. Witnesses describe the experience as magical and electrifying—a nighttime show on a grand scale.
A Reykjavík Cathedral silhouette glows beneath the Northern Lights in Iceland. Getty
A study published last year in Nature Communications showed that the brightest polar auroras originate from strong electromagnetic waves during geomagnetic storms. Researchers aimed to understand how electrons accelerate before colliding with the ionosphere to produce the aurora’s glow. They point to Alfven waves, rapid disturbances traveling along magnetic fields from the Sun, as the force that accelerates electrons toward Earth, pushing particles to speeds that can exceed 70 million kilometers per hour and generate the characteristic luminescence.
Particles from the Sun
Energetic particles expelled from the Sun during eruptions and solar flares spiral along Earth’s magnetic field lines into the upper atmosphere, colliding with oxygen and nitrogen molecules to excite them. As these molecules relax, they emit light, giving the aurora its vibrant hues at altitudes around 100 kilometers above sea level.
Northern Lights over Greenland are frequently captured by visitors under the night sky. These luminous bands, sometimes visible during daylight hours, have long fascinated observers.
The aurora phenomenon carries a long history. It was named in 1619 after the Greek dawn goddess Aurora and Boreas, the north wind. For centuries red-dominated auroras were sometimes interpreted as omens. They were believed to foretell events such as Julius Caesar’s death or the American Civil War, illustrating how people associated these lights with fate and myth.
The first clear scientific explanation came from Norwegian scientist Kristian Birkeland, though recognition arrived only after his death. Each aurora begins with its own character. Common forms include arcing or twisting bands and a green stripe across the sky, varying in appearance and intensity with solar activity and with the orientation of Earth’s magnetic field.
Two observers capture a boreal aurora from a distant vantage
Whether auroras will appear is not something scientists can predict with certainty. They are a natural phenomenon, like the weather. Yet there are places and moments when the odds of seeing them clearly are higher.
Where to see the Green Lady
Ideal locations in the Northern Hemisphere for viewing include Alaska, Canada’s northern territories, Iceland, Norway’s Lofoten islands, the Northern Cape, Kiruna in Sweden, Finnish Lapland, northern Siberia in Russia, Scotland’s Shetland Islands, Svalbard, and Greenland, where auroras begin to be seen in August. In some regions locals refer to the aurora as the green lady because green is typically the dominant hue.
Growing interest and visitor numbers have spurred new accommodation ideas in these regions. Glass-ceiling rooms, ice hotels in remote areas, and guided safaris focused on spotting the northern lights have become popular. Norway, Sweden, and Iceland especially attract travelers keen on chasing the light.
Common questions about the northern lights include why they move, when the best months to see them are, what time frames maximize viewing, and why the chances are higher on cold nights. Aurora activity occurs when high-energy electron beams pass through the upper atmosphere, and as these beams travel, the aurora shifts. Statistics indicate spring and autumn bring the most activity, though auroras can appear in late autumn, winter, and early spring. The peak viewing window is typically from sunset to dawn, with the best chances around 22:00 to 23:00. The likelihood rises on cold nights because the clarity of the sky improves when cloud cover diminishes farther above the atmosphere. A recent study on polar auroras offers further reading.