We can expect additional aurora displays and potentially more impacts to technology over the next year or two, according to NASA and the National Oceanic and Atmospheric Administration.
The sun has put on quite the show for Earthlings over the past few years, and now scientists have confirmed the sun has entered its most active period in 11 years, with more action still to come.
So far, large punches of solar particles have triggered purple and red auroras as far south as India and the Bahamas, but have also interrupted smaller satellite operations in space and disrupted GPS signals. Over the next year or two, NASA, the National Oceanic and Atmospheric Administration and the Solar Cycle Prediction Panel said we can expect additional widespread aurora displays and potentially more impacts to technology. That's because the sun has moved into a key period known as solar maximum -- the peak phase of activity in its solar cycle.
"What we are currently experiencing from the sun indicates that the sun has reached the maximum phase of the solar cycle," said Lisa Upton, co-chair of the Solar Cycle 25 Prediction Panel, an international panel of experts sponsored by NASA and NOAA, in a news conference on Tuesday. "We're about two years into the maximum period, so we are anticipating another year or so of maximum phase."
The sun's activity is not uniform. Every 11 years, the sun goes through a costume change, where its north and south magnetic poles flip. As the sun's inner magnetic dynamo rearranges, the level of activity at the surface also changes.
Activity is the lowest at the beginning in a stage called solar minimum and then slowly builds until it hits a peak. At this solar maximum, the sun sends off more eruptions in the form of solar flares or large clouds of particles called coronal mass ejections.
"The sun transitions from being rather sluggish to being really active and stormy," said Kelly Korreck, program scientist at NASA's heliophysics division. "The solar cycle is a natural cycle of the sun."
Currently, the sun is in its 25th solar cycle since regular recordkeeping began in 1755. Scientists observed the start of it in December 2021 but noticed activity started to ramp up in early 2023. One method to track the sun's activity is by monitoring dark splotches on the sun's surface, called sunspots. Sunspots are temporary regions on the sun, where the sun's magnetic field is extra strong. Magnetic field lines near these areas often tangle and cross, sometimes causing sudden explosions of energy on the surface.
"As the sun moves through this natural cycle in which activity rises and falls through the these 11 years, sunspot numbers rise and fall too," Korreck said.
The current cycle is also shaping up to be a bit below average. Across the last 24 solar cycles, the average number of sunspots at solar maximum was about 179 sunspots in the peak month. This cycle is predicted to be between 141 and 162, according to NOAA.
While scientists know the sun is currently in its maximum phase, Upton said they won't be able to confirm the exact peak month until about six months to a year after -- "because we need to track a consistent decline in solar activity first."
Smaller cycles though, Upton said, tend to have longer maximum phases -- lasting roughly three to four years. Given that the sun is about two years into its maximum phase, the number of sunspots will likely stay higher for another a year or two before declining.
But even once the maximum phase has passed, big storms are still likely.
In fact, some of the biggest solar storms on record that have hit Earth -- like the May 1921 storm that brought widespread aurora and damaged telegraph systems in New York -- occurred as the sun was coming out of solar maximum. That's because sunspots in the declining phase can be more magnetically complex, some scientists say.
So far in 2024, Earth has already seen impressive solar storm activity.
In May, the biggest solar storm in at least two decades hit -- rated a 5 out of 5 on the NOAA severity scale. It brought the best aurora displays in 500 years, bringing the lights to all 50 U.S. states to Jamaica to South Africa. The storm also disrupted precision GPS signals used for seed planting, tilling and irrigation in the agriculture industry, costing the industry about half a billion dollars, said Bill Murtagh, program coordinator at NOAA's Space Weather Prediction Center.
In October, another strong solar storm -- rated 4 out of 5 in severity -- brought another widespread aurora show across Earth, including in rare spots that don't often experience northern lights -- including Alabama, Mississippi, Texas and Arizona.
The May storm was "very rare," but Murtagh said storms at the October level are more common during solar maximum. Typically, he said there are several dozen at that strength, but we have experienced around 10 so far.
"There's going to be more geomagnetic storms at that G4 level," said Murtagh. "We will see the aurora extend into northern California and across that line of latitude due to the Carolinas, so more to come."