A storm from the broiling sun turned the chilly northernmost skies of Earth into an ever-changing and awe-provoking art show of northern lights on Tuesday.
Even experienced stargazers were stunned by the intensity of the aurora borealis that swept across the night sky in northern Scandinavia after the biggest solar flare from the sun in six years.
"It has been absolutely incredible," British astronomer John Mason cried from the deck of the MS Midnatsol, a cruise ship plying the fjord-fringed coast of northern Norway.
"I saw my first aurora 40 years ago, and this is one of the best," Mason told the Associated Press, his voice nearly drowning in the cheers of awe-struck fellow passengers.
An aurora appears when a magnetic solar wind slams into the Earth's magnetic field, exciting electrons of oxygen and nitrogen. Even before particles from the solar storm reached the Earth on Tuesday, the latest aurora was dancing across the sky as far south as Ireland and England, where people rarely get a chance to catch the stunning light show.
Those northern lights were likely just variations in normal background solar wind, not the solar storm that erupted Sunday, said physicist Doug Biesecker at the U.S. Space Weather Prediction Center in Boulder, Colo.
Tuesday's colorful display may not have moved that far south, limiting its audience, but those who got to see it got brilliance in the sky that had not been around for years. "It was the biggest northern lights I've seen in the five-six years that I've worked here," said Andreas Hermansson, a tour guide at the Ice Hotel in the Swedish town of Jukkasjarvi, above the Arctic Circle. He was leading a group on a bus tour in the area.
Geomagnetic storms cause awesome sights, but they can also bring trouble. According to the National Oceanic and Atmospheric Administration, problems can include current surges in power lines and interference in the broadcast of radio, TV and telephone signals. No such problems were reported Tuesday.