The sun is at its 11-year maximum. That means another year of eruptions that can endanger satellites, ground flights, and spark stunning auroras.

But solar eruptions can also endanger satellites, astronauts, and even power grids here on Earth.

NASA expects a lot of those explosions in the next six months to a year along with the geomagnetic storms they cause in Earth’s upper atmosphere. That’s how much longer the sun will likely be at maximum, but there’s still potential for big eruptions in the ensuing years as the sun winds down.

“We anticipate additional solar and geomagnetic storms leading to opportunities to spot aurora over the next several months, as well as potential technology impacts,” Kelly Korreck, a program scientist in NASA’s Heliophysics Division, said during the announcement on Tuesday.

The problem with the aurora

Solar eruptions, like solar flares or coronal mass ejections, don’t directly harm anyone on Earth, but they disrupt a layer of the upper atmosphere called the ionosphere.

Some technologies, such as GPS and high-frequency radios used for navigation, rely on the ionosphere and experience blackouts during some solar storms.

That can delay flights, since planes use both satellite and radio communications. Indeed, a 2023 study found that flights were 21% more likely to be delayed by at least 30 minutes during solar storms.

Solar storms can also push satellites out of orbit.

In very severe cases, solar storms can affect power grids. In 1989, a geomagnetic storm wiped out Quebec’s electricity and caused other power-system issues in the US, UK, and Sweden.

Nothing that major has happened in a while. But this solar maximum has been one for the books. In May, an extreme geomagnetic storm brought the northern lights as far south as Arkansas.

“There’s more sunspots emerging, the magnetic field has more chances to interact and increase the probability of having a significant geomagnetic storm,” Lisa Upton, the co-chair of the Solar Cycle 25 Prediction Panel, which is an international panel of experts who have been keeping tabs on the sun, said during the announcement on Tuesday.

NASA scientists couldn’t confirm that the sun had reached maximum until they’d seen the number of sunspots start to plateau.

“It’s by looking at the shape of that cycle, how it’s progressed so far, and how we know that solar cycle progresses from our observations of the last 25 solar cycles, that we can really say that we’re at the maximum phase now,” Upton said.

Eventually, scientists will be able to pinpoint an exact peak of the entire solar cycle, but not until many months after the maximum phase ends.