The sun is entering solar maximum. Expect auroras and more

Those celestial fireworks were just the beginning of what could be a years-long series of similar displays. That’s because the sun is now approaching peak activity in its 11-year solar cycle — and it’s already much stormier than originally predicted.

Auroras occur when charged particles from the sun collide with oxygen and nitrogen molecules in Earth’s upper atmosphere. As atmospheric molecules shed the energy given off by such collisions, they emit light in a variety of colors. Because the planet’s magnetic field directs these charged particles toward the poles, auroras are mostly only seen at higher latitudes—unless storms are extremely powerful.

To find out what to expect over the next few years and understand how this period of high solar activity affects us, Scientific news spoke with Teresa Nieves-Chinchilla, acting director of NASA’s Moon-to-Mars Space Weather Analysis Office in Greenbelt, Md., and Shawn Dahl, a space weather forecaster at the National Administration’s Space Weather Prediction Center Oceanic and Atmospheric in Boulder, Colo. Conversations have been edited for clarity and brevity.

SN: What was going on with the sun in early May that caused so much excitement?

Nieves-Chinchilla: We are reaching the maximum of solar cycle 25 [the current solar cycle, which began in December 2019]. And as we get closer to that, we get more activity from the sun, especially on those May days.

Dahl: Basically, we had space weather activity in all three categories: from solar flares to radiation storms and, ultimately, to the geomagnetic storms that the world saw from May 10 to 11. There is no doubt that this was a historic storm, the same as the 2003 storm that caused some power outage problems in South Africa and Sweden.

SN: Much of this was caused by spots on the sun’s surface known as active regions. What are those?

Dahl: Active regions are strong areas of localized magnetic fields that appear on the Sun. They form deeper inside the sun and collide with the surface. Because they are so magnetically strong, they prevent the normal transfer of energy and light from deeper into the sun. So they appear darker and are much cooler than the surrounding surface of the sun. [The regions are as hot as 3,500° Celsius, whereas the rest of the surface is about 5,500° C.]

Nieves-Chinchilla: [In active regions], we can see many sunspots, these black areas in the sun. These regions accumulate a large amount of magnetic energy that must eventually be released.

SN: How did May 10 go?– 11 storm hits us on Earth?

Dahl: Satellite communications were degraded because the ionosphere – [part of the] the atmosphere through which communications must pass—was quite confused. GPS was a massive mistake for farmers [who use machines that rely on the technology and were] trying to plant crops, as an example. They had to be within inches of accuracy and were as far as 10 feet away. They had to stop their operations [May 10] because of this storm.

Launch operations were calling us – [folks] sending missiles – because they had concerns with GPS accuracy. Aviation was changing their flight routes further from the equator to avoid communication issues. We were talking to [NASA] for the benefit of astronauts on the space station. They were advised, when possible, to stay away from less protected areas of the space station [to avoid radiation].

The power grid had major effects throughout the system, seeing large amounts of induced currents that do not belong there from the storm. [Operators] there were devices in place to help ensure that there would be no major catastrophic collapse anywhere. And, as far as we can tell, there have been no system failures.

SN: How do we prepare for such solar storms?

Nieves-Chinchilla: It was very interesting because [by coincidence] we had a practice two days before the solar storm. And during this tabletop exercise, the agencies were working together to assess whether we were prepared for the storm. NOAA, for example, and [the Federal Emergency Management Agency] must speak to give notices to certain persons to be prepared for these things.

Dahl: Much work has been done over the past decade to learn more about space weather. All the technology providers we use in society today are aware of space weather and incorporate it into their planning and thinking. This was the most successfully mitigated extreme space weather storm in history for this reason. This is why we are not hearing about many confirmed impacts on our technologies.

SN: Solar cycle 25 was predicted to be relatively weak, right?

Dahl: The international panel of scientific experts who make these long-range solar cycle predictions – this was before 2019 – they predicted a mild solar cycle very similar to the previous one, which was not as active. We are well outside the original margin of error with that prediction. We expect the solar maximum at this point to be much more active than originally predicted. So throughout this year, throughout 2025, and even into 2026, we anticipate being at the highest risk for another such event.

SN: Those regions in the sun that caused the May storm will face Earth again. Can we expect similar events soon?

Nieves-Chinchilla: We don’t know yet. But I can tell you that there are some X-ray bursts coming from this region.

Dahl: Maybe we’ll see some more activity, but it certainly won’t be anywhere near what happened on May 10 or 11. People should always go to our website to find out the real story of what is actually happening and what we are predicting.