BOULDER, Colo. ‒ Skygazers eager to catch the northern lights have a powerful ally: a small group of space weather forecasters who monitor the sun for significant solar explosions.

Last month's spectacular aurora display, visible as far south as Florida, was highly unusual. However, experts predict that the next several years could bring even more impressive shows as the sun reaches the peak of its typical 11-year sunspot cycle.

In a secure facility in Boulder, forecasters at the federal Space Weather Prediction Center are closely watching for the sun’s next move. This center, part of the National Oceanic and Atmospheric Administration, uses giant screens to display images of the sun through various filters, from visible light to its intense magnetic field and the solar flares constantly erupting from its surface.

We're always just trying to figure out what's going to hit our little blue marble," said senior forecaster Shawn Dahl.

Extra-strong sunspots, often accompanied by massive ejections of superheated plasma from the sun, can trigger stunning auroras but also pose risks to satellites, airplanes, GPS navigation, and the power grid.

Typically, people living near the poles — in regions like Alaska, Iceland, Finland, New Zealand, and Australia — can witness the aurora during the winter. However, last month's display was unusual as it was visible in many places that don't typically experience such sights, especially during late spring.


Experts predict that typical viewing patterns will persist, but the presence of a large sunspot increases the likelihood of another massive display occurring soon across vast areas of the United States.

While typical aurora displays are forecasted with only a few hours' notice, larger events like last month's are caused by solar explosions that forecasters can detect days before they light up the Earth's atmosphere.

Utilizing data from a constellation of sun-focused satellites, forecasters are closely monitoring the sunspot group known as Region 3697, along with solar flares and coronal mass ejections—massive plasma eruptions powerful enough to have their own magnetic fields.

Appearing as a gray disturbance on the sun's surface, the scale of this sunspot cluster is astonishing: it is 15 times larger than Earth. And the sun itself is 93 million miles away.

From 93 Million Miles to a Field Near You


Dahl noted that while the center's forecasts have long been utilized by electric utilities, satellite operators, and other large organizations, they are only recently becoming known to the general public.

On May 10, just as the aurora display was starting, Dahl received a call from his nephew in North Dakota, who was doing spring planting. The GPS on his tractor, usually accurate to a centimeter, was off by 12 feet.

"This is the first time in my life I've received a space weather report from a family member," Dahl said. "I'm used to being asked about snow forecasts or hail threats, but my nephew told me their system was taking them in circles."

During last month's event, the plasma impact was so strong that it temporarily pushed Earth's magnetic field closer to the planet, causing some satellites to lose their orientation. Government-funded satellites are typically designed to withstand solar storms and have multiple redundant navigation systems, but smaller, cheaper ones may not be as resilient.


The Environmental Defense Fund, which launched a methane tracking satellite from California earlier this year, temporarily halted some calibration work on its $88 million device during the storm, according to Peter Vedder, senior director of mission systems for MethaneSAT. Built in Colorado, the 770-pound satellite is still reaching its operational position about 360 miles above Earth.

While light from solar flares and coronal mass ejections reaches Earth in about 8 minutes and charged particles known as protons arrive in 15 minutes, ejected particles take two to four days to hit and be deflected by Earth's magnetic field. Auroras are usually most pronounced around the poles due to the shape of Earth's magnetic field.

"You can't navigate around it or fly past it. You have to design the satellite to be robust enough to handle it," Vedder said. "Typically, you turn off some of the more sensitive electronics and wait it out for a day."

Interfering with communication systems

Starlink, the company led by Elon Musk, which has deployed over 4,000 satellites to offer global internet coverage, reported that it successfully weathered the May storm without any issues. "Starlink satellites are under significant pressure, but holding up well so far," Musk posted on his social media platform, X, on May 11.

In 2022, 38 newly launched Starlink satellites burned up due to unexpected conditions in the Earth's upper atmosphere caused by a mild solar storm. Since then, Starlink and forecasters at the prediction center in Boulder have been working more closely to monitor potential disruptions, particularly during satellite launches.

Starlink satellites orbit closer to Earth compared to many other satellites, and scientists have found that solar storms can temporarily increase the density of the surrounding area, leading to unexpected drag.

Solar flares and coronal ejections can also impact long-distance power lines used for electricity transmission. These solar storms can disturb the Earth's magnetic field, causing power surges that damage transformers and other equipment.

In 1989, approximately 6 million Canadians and residents of northern New England experienced a nine-hour power outage due to solar-induced surges. With advance notice, utilities can implement measures to minimize the damage. Recently, one of the largest transmission groups installed a pioneering system designed to automatically safeguard its power lines.


The most intense geomagnetic storm on record, the Carrington Event of 1859, ignited auroras so brilliant that they allegedly roused gold miners from their tents in Australia, fried telegraph equipment, and illuminated the sky to a brightness surpassing that of the full moon.

Solar storms also disrupt the propagation of radio waves through the atmosphere and can interfere with radar and radio communications.

Dahl explained that during solar storms, commercial airliners often need to follow longer routes nearer to the equator to maintain reliable radio communications with air traffic control. Additionally, aircraft on polar routes may need to divert to avoid heightened radiation exposure.

Forecasting space weather presents significant challenges.

In anticipation and during the May storm, space weather forecasters conducted routine briefings with power utilities and other relevant groups, addressing queries. Six hours before the storm's "strong, sudden arrival," they emphasized the impending strength.

"That provided them with a six-hour window to prepare and acknowledge the magnitude of the event," Dahl explained. "And they were prepared. Despite experiencing various effects and remaining occupied, fortunately, there were no reported instances of significant system-wide impact.

In the coming years, Dahl mentioned that space weather forecasters are likely to become involved in safety considerations for space tourism and in NASA's missions to return to the moon and send astronauts to Mars. He highlighted that upcoming launches of scientific satellites will enhance the center's space forecasts but acknowledged the significant challenges in accurately predicting Earth's weather.

"Forecasting events from 93 million miles away presents immense difficulties, and our scientific understanding is limited," Dahl explained. "While we can effectively predict the likelihood and potential intensity of solar flares and radiation storms, we currently lack the capability to anticipate imminent flare occurrences. That aspect of the science remains elusive; we must wait for these events to unfold.

Dahl, an enthusiast of astronomy and a photographer of the night sky, regretfully missed the May 10 display due to work commitments. Nevertheless, he remains optimistic about the prospect of witnessing a new spectacle. Dahl also pointed out that sunspot activity is projected to rise over the next year before gradually diminishing, promising skywatchers ample opportunities for further displays.