A SpaceX Falcon 9 rocket with a Dragon 2 spacecraft lifts off on Pad 39A at the Kennedy Space Center for a re-supply mission to the International Space Station from Cape Canaveral, Fla., Thursday, June 3, 2021.InternationalIndiaAfricaA light blue galaxy-like spiral appeared amid the aurora borealis in the Alaskan sky early on Saturday, catching the attention of northern lights enthusiasts. Such spirals occur when fuel jettisoned at high altitudes turns into ice in sunlight. Northern lights enthusiasts in Alaska were treated to a rare and unexpected sight in the sky over the weekend when a light blue spiral resembling a galaxy appeared amid the aurora borealis for a few minutes. The unusual phenomenon was caused by excess fuel that had been released from a SpaceX rocket that launched from California about three hours before it appeared. The appearance of the vortex was caught in time-lapse on the Geophysical Institute’s all-sky camera and shared widely on social media. While such occurrences are not common, space physicist Don Hampton has seen them happen about three times.According to Hampton, sometimes rockets have fuel that needs to be jettisoned, and when that fuel is released at high altitudes, it turns into ice. If the ice happens to be in sunlight, observers on the ground can see it as a sort of big cloud, and sometimes it’s swirly. This is what happened with the SpaceX rocket fuel that created the light blue spiral over Alaska.The polar launch of the SpaceX rocket, which took off from Vandenberg space force base in California on Friday night with about 25 satellites on board, made it visible over a large swath of Alaska. Photographers observing the northern lights show also posted photos of the spiral on social media, creating an “internet storm,” according to Hampton.This is not the first time such a spiral has appeared in the night sky. In January, a similar phenomenon was spotted over Hawaii’s Big Island after the launch of a military GPS satellite that lifted off on a SpaceX rocket in Florida. A camera at the summit of Mauna Kea, outside the National Astronomical Observatory of Japan’s Subaru telescope, captured a spiral swirling through the night sky. Researchers have said that, like the Alaska spiral, it was caused by excess rocket fuel released into the upper atmosphere.