Every glimmer of the northern lights begins as a spot on the sun’s surface. And if increased solar activity is any indication, the next year and a half will be filled with glimmers.
Sunspot observations, a key indicator of the likelihood of northern lights, have increased dramatically since the end of 2022, surpassing recent forecasts and in some cases increasing the area the phenomenon is visible from. Scientists say that if the trend continues, the next 18 months will bring the strongest northern lights activity of both the coming decade and the past 20 years, with the show being viewable more often and from more places on Earth.
“Skywatchers are excited,” said Mark Miesch, a research scientist at the University of Colorado - Boulder and the National Oceanic and Atmospheric Administration.
The Solar Cycle 25 Prediction Panel, an international scientific group sponsored by NASA and NOAA that forecasts sunspot activity, forecast in 2019 that the coming year would be below-average, with around 110 to 115 sunspots at its peak. But updated models from multiple scientists show the increase in solar activity could be much higher.
Solar activity is expected to steadily increase until fall 2024, when the likelihood of aurora borealis, also known as northern lights, is highest, Miesch said.
Sunspots — dark, lower temperature, strongly magnetic regions on the sun’s surface — create space weather when magnetic distortions hurl particles into space. This activity, called a coronal mass ejection, sends particles more than 94 million miles until they find vulnerabilities in the Earth’s magnetic field, where particles collide with the planet’s atmosphere and create the neon colors that fill the sky.
The northern lights are most visible near the North and South poles, where the Earth’s magnetic field is weakest. But the additional solar activity has already increased the range the lights can be spotted from this year: The northern lights could be seen as far south as Minnesota and Wisconsin on Monday night, and the Arizona Daily Star reported that northern lights were seen in the state in April.
Space weather isn’t the only factor: Autumnal and spring equinoxes lead to greater disruptions in the Earth’s magnetic field, Miesch said. This is because the orientation of the Earth’s magnetic field points its vulnerable part toward the sun, which allows space particles easier access to the Earth’s atmosphere.
“When there’s a big disturbance in the magnetic field, then you’re more likely to see aurora at lower latitudes,” Miesch said.
This will almost double the likelihood of northern lights in the coming days, Miesch said.
Sunspots are one of the longest-kept observational data sets, with record-keeping extending back to the 17th century.
“Sunspots are our window to the past to compare current activity to what it was centuries ago,” Miesch said.