Why the Northern Lights Are Having a Moment

Humans have been looking up at glowing skies for a very long time. One of the earliest recorded observations of the aurora borealis dates back to 567 BC, when a clay tablet described a mysterious “red glow” appearing in the night sky (Stephenson et al. 2004). These events were important enough to be documented by official astronomers, long before anyone understood what caused them. Today, we know these shimmering lights as auroras, and while they’re no longer mysterious omens, they’re still one of the most beautiful reminders that Earth is deeply connected to the Sun.

What Are Auroras, Anyway?

Earth doesn’t exist in isolation. It’s surrounded by a constantly changing environment of charged particles or plasmas and magnetic fields that together produce what scientists call space weather (Newell et al. 2001). Auroras are one of the most visible effects of this space weather in Earth’s atmosphere (Vázquez et al. 2016).

Rather than appearing randomly, auroras typically form diffuse bands of light that wrap around Earth’s magnetic poles, creating oval-shaped rings known as auroral ovals. During periods of increased solar activity, such as solar or geomagnetic storms, these ovals can expand, allowing auroras to be seen farther from the poles than usual (Vázquez et al. 2016).

What Causes an Aurora?

Auroras occur when Earth’s magnetic environment interacts with the Sun. More specifically, they arise when the connection between Earth’s magnetic field and the Sun’s magnetic field, called the Interplanetary Magnetic Field (IMF), becomes distorted (Vázquez et al. 2016).

This distortion is usually triggered by two main solar processes:

• Coronal mass ejections (CMEs): Enormous bursts of ionized particles hurled into space from the Sun.

• High-speed solar wind streams: Fast flows of solar particles that originate from coronal holes, regions where the Sun’s magnetic field opens outward toward Earth.

When these solar disturbances sweep through the Earth’s magnetic field, they collide with oxygen and nitrogen particles in the upper atmosphere (NASA 2004). These air particles gain energy from these collisions, which they then release as a colourful glow. Strong geomagnetic storms, especially those driven by CMEs, can push auroras to much lower latitudes than normal, making them visible to people who rarely see them (Vázquez et al. 2016).

Why Have the Northern Lights Been So Visible Recently?

If it feels like the northern lights are showing up more often lately, that’s not just your imagination. The Sun goes through a repeating cycle of activity roughly every 11 years, a pattern first identified in the 1840s by Heinrich Schwabe through long-term observations of sunspots (Norton et al. 2023). Sunspots are regions on the Sun’s surface with especially strong magnetic fields, and their number rises and falls over the solar cycle. 

During 2024–2025, the Sun reached the maximum of this cycle, a period when solar activity peaks. Around solar maximum, the Sun produces more solar flares, coronal mass ejections, and bursts of high-speed solar wind than at other times in the cycle (Norton et al. 2023). This also coincides with a reversal of the Sun’s magnetic poles, a large-scale magnetic reorganization that happens approximately every 11 years (BBC 2024).

With more frequent and more powerful solar eruptions interacting with Earth’s magnetic field, geomagnetic storms became more common during this period. The result was auroral ovals that expanded farther toward the equator, allowing the northern lights to be seen at much lower latitudes than usual. In other words, the aurora displays of the past year were a natural consequence of the Sun being at its most active.

As the solar cycle now moves away from its peak, auroras haven’t disappeared, but the especially widespread and intense displays seen in 2024–2025 are likely to become less frequent until the Sun ramps up again in the next cycle.

Auroras are more than just a beautiful light show, they’re a glowing reminder that Earth is part of a much larger, dynamic system shaped by the Sun. So the next time the sky lights up in green, pink, or red, don’t forget that you’re watching space weather in action.

References

BBC. (2024, October 12). Why are we seeing the Northern Lights so often lately? https://www.bbc.com/news/articles/cdjepzxjrjgo

NASA. (2004). Space Technology: How Auroras Form. https://www.jpl.nasa.gov/nmp/st5/SCIENCE/aurora.html

Newell, P. T., Greenwald, R. A., & Ruohoniemi, J. M. (2001). The role of the ionosphere in aurora and space weather. Reviews of Geophysics, 39(2), 137–149. https://doi.org/10.1029/1999RG000077

Stephenson, F. R., Willis, D. M., & Hallinan, T. J. (2004). The earliest datable observation of the aurora borealis. Astronomy & Geophysics, 45(6), 6.15-6.17. https://doi.org/10.1046/j.1468-4004.2003.45615.x

Vazquez, M., Vaquero, J., Gallego, M., Cortes, T., & Pallé, P. (2016). Long-Term Trends and Gleissberg Cycles in Aurora Borealis Records (1600 – 2015). Solar Physics, 291. https://doi.org/10.1007/s11207-016-0849-6