Unraveling the Mystery of Alaska's Sky Spiral.

A light blue spiral resembling a galaxy appeared in the Alaska skies amid the aurora, surprising northern lights enthusiasts. The cause was excess fuel released from a SpaceX rocket that launched from California about three hours earlier. The fuel turned into ice and was visible as a big cloud in the sunlight. The timing of the fuel dump and the fact that it was a polar launch made the blue spiral visible over a large swath of Alaska. This is not a common sight, but space physicist Don Hampton has seen such occurrences about three times.