What happened in the arctic sky?

Aurora lovers and viewers were in for a surprise when they watched the green lights dance across the Alaskan sky: A pale blue, galaxy-like spiral appeared in the middle of the aurora borealis for a few minutes early Saturday.

The reason was nothing exceptional. Not a portal or alien invasion. It was excess fuel released from a SpaceX rocket that launched from California about three hours before the helix appeared in the sky.

A giant spiral appears amidst the Northern Lights in the Alaskan night sky https://t.co/vS0bGwMKNK pic.twitter.com/MFEuDjJ9N6

—David Papp (@DavidPapp) April 17, 2023

A strange, glowing “vortex” seen in the sky over Alaska baffles locals pic.twitter.com/CpFULO3uMj

– DailyLoud April 17, 2023

Sometimes rockets contain fuel that needs to be disposed of, space physicist Don Hampton, an associate professor at the University of Alaska’s Fairbanks Institute of Geophysics, told The Associated Press.

Too nice not to share. photos for @tweet @tweet I set off last night from my old hometown of Fairbanks, Alaska. Rocket launched from Vandenberg, California. The photo was taken at 1:55 am KSA. (Image credit: The Alaska Frontier Group) pic.twitter.com/e4c4h637nQ

—Brian Fleming (@_BrianFlemming) April 17, 2023

“When they do it at high altitudes, that fuel turns into ice,” he said. “And if you happen to be in the sunlight, when you are in the dark on the ground, you can see it as kind of a big cloud, and sometimes it’s a whirlpool.”

Alien invasion? No, it’s science. Experts say the mystery spiraling over the Alaskan sky Saturday during the northern lights — captured at this time lapse — was a trail of steam from a SpaceX rocket launch. https://t.co/6G6cf6oHaC pic.twitter.com/IQM39aHmNk

—Associated Press (AP) April 17, 2023

The rocket that lifted off from Space Force Base Vandenberg in California Friday night had about 25 satellites as payload. It was a polar launch, making it visible over a large swath of Alaska.