In 2024, we can expect to see more vibrant northern lights than we have in the past decade.
Usually, people have to travel to faraway places like Iceland or the tip of Norway to catch a glimpse of this celestial spectacle. However, this year, the northern lights might appear closer to home for many, even in southern Europe, treating the skies to enchanting displays like those witnessed in November 2023.
Now, let’s understand what the northern lights are. The bright ribbons of red, green, and magenta are caused by particles from the sun, known as the solar wind, interacting with the Earth’s atmosphere. When these particles reach our planet, they are directed by the Earth’s magnetic field toward the polar regions, typically visible only over the Arctic Circle in the northern hemisphere.
Sometimes, the northern lights become visible further south. Last November, skies from southern England to Slovenia were illuminated with magenta and fuchsia hues due to an unusually strong aurora borealis. This event was triggered by a large eruption on the sun’s surface, leading to increased geomagnetic activity in the following days.
Auroras usually occur in a band called the annulus, centered on the magnetic pole. The arrival of a Coronal Mass Ejection (CME) from the sun’s atmosphere can cause the annulus to expand, bringing the aurora to lower latitudes. In 2023, this resulted in the lights being visible in the UK and even further south in Europe, capturing the attention of photographers in Italy and Greece.
The colors of the auroras depend on the gas molecules in the atmosphere and their altitude. Oxygen produces green light at around 100 km above the Earth and all-red auroras at 160-320 km, while nitrogen causes the sky to glow blue, with a purple hue at higher altitudes.
So, why are the northern lights stronger this year? The sun is currently more active, leading to brighter aurora displays. This increased activity is part of the sun’s natural ‘solar cycle,’ where its magnetic field flips every 11 years. As we approach the peak in 2024 or 2025, there’s been a significant rise in ‘sunspots,’ indicating how active the sun is.