Odd spiral emerges amid Alaska’s northern lights

A swirl appeared during Alaska’s northern lights on Saturday. The uncommon sight was caused by fuel released from a SpaceX rocket which turned to vapor that reflected the sunlight.

Sometimes rockets have fuel that needs to be jettisoned, said space physicist Don Hampton, a research associate professor at the University of Alaska Fairbanks Geophysical Institute.

"When they do that at high altitudes, that fuel turns into ice," he said. "And if it happens to be in the sunlight, when you’re in the darkness on the ground, you can see it as a sort of big cloud, and sometimes it’s swirly."