The sun is more active than experts predicted. It could mean more grounded flights, downed satellites, and stunning aurora.

Not all sunspots will produce an eruption and, when they do, not all eruptions pose a threat because they might miss Earth, Alex James, a solar physicist at the University of College London, told Business Insider over email.

Still, learning to predict solar storms ahead of time is an important field of ongoing research because it could give us more lead time to prepare, James said.

The sun is more active than we thought

But those high-energy particles are also like little gremlins that can cause all sorts of mayhem to high-frequency radio emissions that the military, airlines, and GPS systems rely on, Gerrard said.

Since January, geomagnetic storms have caused radio blackouts on four continents: North and South America, Europe, and Africa. This can make your GPS temporarily act up. It can also lead to power outages as well as grounded flights and flight delays since the Federal Aviation Administration won’t allow planes to fly without both radio and satellite communications.

Another concern is spacecraft. “If there’s a coronal mass ejection, and if that material gets to the Earth, it’s going to make the densities in Earth’s upper atmosphere higher,” Gerrard said. “And that’s going to create more drag, and more drag is going to bring down spacecraft.”

In February 2022, a geomagnetic storm contributed to 38 Starlink satellites coming down from orbit. The satellites were in a lower, transitional orbit and hadn’t yet reached their final destination. Scientists suspect that lower orbit combined with a geo-storm, causing them to fall from space and burn up in Earth’s atmosphere.

And last May, the largest geomagnetic storm to reach Earth in two decades led to degraded service from Starlink. No satellites fell out of orbit during that storm.

The sun is reaching solar maximum

The sun’s activity is expected to continue to increase until it reaches peak activity levels, which scientists call solar maximum.

“Current predictions suggest solar maximum will occur in the second half of 2025, but we’ll only really know when the true maximum has occurred after the activity starts to decline again,” James said.

Though this cycle’s solar maximum is projected to be stronger than scientists initially predicted, it’s “looking fairly average in a more historical context,” Mathew Owens, professor of space physics at the University of Reading, told BI over email.

Still, we’re likely more prone to the effects of solar maximum now than ever before because of our growing dependence on satellite technology, James said.