A strange vortex invites itself into the aurora borealis

The Northern Lights are a sight in themselves. But when a strange blue swirl is added, the fireworks are incomparable, immediately raising questions about the origin of such an event. Dan Hampton, chief scientist at the Boker Flat Research Range Astronomy Observatory in Alaska, offered an explanation that undercuts even the most arcane speculation.

The vortex in question, photographed by several aurora borealis enthusiasts, appeared just after 9 a.m. on April 15 in the still-dark skies of Alaska, hours after the SpaceX Falcon-9 launched from a base in Vandenberg, California. Rocket. It launched 51 satellites into polar orbit. Its first stage landed at its launch point, while the second stage, having accomplished its mission, was destined to fall back into the Pacific.

“The cloud appeared after all the mission payloads were usedNotes Dan Hampton, In Proceedings of the Geophysics Institute, University of Alaska, Fairbanks. So it’s rocket exhaust, or excess propellant exhaust. The swirl pattern indicates a second stage swirling while expelling the gases. » The American astronomer noted that at this height all the water vapor turned to ice, which reflected the sun’s light, forming a magnificent cloud visible from Alaska, plunged into darkness as the sun was still below the horizon. “This cloud looks really bright in these photos, but it’s only a few pounds of water.”Says the analyst.

The phenomenon is not new. In January, another vortex was observed over Hawaii. The image was captured by a Japanese Subaru telescopic camera, at the top of Maunakea. Researchers attributed this spin to the launch of a military GPS satellite by a SpaceX rocket.