PARIS: A stunning blue and white spiral spotted in skies across Europe late Monday was created by frozen fuel tumbling from a SpaceX rocket, according to weather forecasters and scientists.

The UK’s Met Office said on X it had received many reports of an “illuminated swirl” in the sky on Monday evening likely caused by a rocket that had blasted off earlier from Cape Canaveral in Florida.

“Don’t panic! No, it wasn’t a UFO but the degassing of a SpaceX Falcon 9 rocket,” said the French state weather forecaster Meteo France in the country’s central Loire Valley. Pictures of the vivid swirl were also posted by social media users in countries including Sweden, Poland, Hungary and Croatia.

People across Europe may have had the chance to see the phenomenon — as long as it was not obscured by clouds, planetary scientist James O’Donoghue of the UK’s University of Reading said. The spiral was created after the rocket’s first-stage booster, which blasted it off the ground, separated and the upper stage took over, he said.

As the booster fell back to Earth, it vented leftover fuel, which froze into reflective crystals. “These crystals caught the sunlight, creating the bright spiral pattern in the sky,” O’Donoghue said. “The spiral shape happened because the tumbling rocket was spinning as it released the fuel.”

The swirl was created by the launch of SpaceX’s NROL-69 mission. Exactly what it was carrying into space was classified. But the mission was conducted for the National Reconnaissance Office, which manages the US military’s spy satellites.

“The Falcon 9 reusable rocket booster returned safely to Landing Zone 1 after delivering the national security payload to orbit,” the office said in a statement. A similar spiral was spotted above New Zealand in 2022, also from the workhorse Falcon 9 rocket, according to reports at the time.

Published in Dawn, March 26th, 2025