Are northern lights happening more frequently? What’s behind the recent activity.

Skies over North America erupted this week with shimmering colors: Shades of pink, purple and green swayed across the skies in northern as well as some southern states. It followed two similarly prolific auroral displays in North America in October and May of 2024.

The sudden spate of auroral activity may leave some Americans wondering what the deal is. Are the northern lights becoming more common? Has something changed?

The high-end geomagnetic storms that fuel northern lights are rare, but they have always happened. However, one factor contributing to the recent activity is the natural ebb and flow of an 11-year solar cycle. We are in the peak of that cycle, which means there are more opportunities to witness the aurora. There are more sunspots, more magnetic explosions on the sun and, subsequently, more energetic strikes hitting the Earth.

During each recent event, social media was ablaze with talk of the aurora and geomagnetic storms.

This week, as skies lit up above parts of New England, the Great Lakes, the Upper Midwest and the northern Rockies, and last year as the same was spotted all the way down to Oklahoma and Arkansas, stylized maps and thousands of pictures cluttered social media timelines, a hodgepodge of blurred iPhone shots and professional photos alike.

The light show brought by the aurora borealis (and aurora australis in the Southern Hemisphere) is caused by the interaction of solar energy with Earth’s magnetic field. As high-energy particles and magnetism bombard Earth, our magnetic field shields us, transforming that energy into harmless visible light.

The magnetic field is greatest near the poles, which is why the aurora is most common at high latitudes in the Arctic and Antarctic. But if enough solar energy bombards Earth, that light spills closer to the equator.

Those energetic bombardments from the sun are called CMEs, or coronal mass ejections. They are explosions that accompany bursts of light from sunspots, or bruise-like discolorations on the solar surface that throb and pulsate with energy. Most CMEs miss us. But if a CME is aimed toward Earth, it causes a disturbance, having impacts all around the globe.

The most significant CMEs cause so-called geomagnetic storms, which occasionally disrupt power grids, satellite communications and GPS navigation systems. Farmers in Iowa wound up with crooked rows of crops last year due to subtle fluctuations in the GPS system used by planting equipment.

The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center ranks geomagnetic storms on a 1-through-5 scale. A G5 geomagnetic storm, the most extreme, happens only once or twice a decade on average. Last May’s storm was a G5; this week’s was a G4.

Before the May 2024 event, you’d have to go back to late October-early November 2003, when extreme geomagnetic storms raged for days. The aurora dipped into the Mediterranean, with vibrant colors seen in California and Florida. An estimated 59 percent of satellites were affected, and airlines had to reroute flights to avoid “radiation storms” over the poles.

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A peak of solar activity

Even as the sun reached peak activity last year, solar activity was expected to remain high into 2025 and even 2026. Because we’ll be at peak for the next year or so, we might get another couple of significant solar storms.

During the quieter parts of a solar cycle, weeks or even months can pass without a single sunspot; space weather flatlines, and so too do chances of catching the aurora at the midlatitudes.

The last solar cycle (Cycle 24) peaked in April 2014, but it was a relatively tame one without any notable G5 storms. Solar Cycle 23, which peaked in November 2001, went gangbusters.

So the reason we’re seeing so much solar activity is simply that we’re at that point of the solar cycle.

But the amount of activity online and on social platforms also helps make it seem more active; such platforms were not active 20 years ago during the high-end solar storms of the last peak. What’s more, our predictive abilities were not as strong then.

By 2027, we’ll start to simmer as we slump back down toward what’s known as solar minimum.

After that, the cycle will start to climb again in the mid- to late 2030s.

That means you should seize every opportunity you can to check out the aurora. It will require patience, a strong geomagnetic storm and some luck.