A puzzling event left many in awe in Great Britain as a large, spiraling blue-white light was seen twirling through the skies last Monday night (March 24).

Confused, witnesses quickly took to social media to share pictures of the mesmerizing sight, with many speculating it could be signs of alien life, a dangerous solar flare, or even a gateway to another realm.

“The truth is out there,” one netizen wrote. “There’s definitely something sinister going on here. People should stay indoors.”

Beyond humorous remarks and outlandish speculation, the strange phenomenon motivated dozens of conspiracy theories—from governments spraying new strains of deadly viruses to agencies testing new technologies in front of everyone.

That is—until experts revealed the true cause of the light.

Experts revealed the true cause of a mysterious blue spiral that was spotted in the skies above Britain

Image credits: LJSSockmonkey

“Just saw the most bizarre spiral of light in the sky while stargazing with my son. Aliens or rocket launch?!” one stargazer posted on X.

Many others echoed similar sentiments, sharing photos from locations across the country, including Yorkshire, Bristol, and Wales.

Image credits: Joshua Wheeldon/Facebook

As the hours went by, the UK’s Met Office was forced to issue an explanation after receiving numerous reports about the mysterious light, later confirming that the unusual spiral was the result of frozen fuel from a SpaceX rocket launch. 

“This stunning spiral was caused by excess fuel venting from the Falcon 9 rocket,” the post read.

Image credits: Tobytobytobyy

The fuel ejected from a fast-rotating Falcon 9 rocket froze in the high atmosphere, creating the dazzling, light-reflecting spiral that both captivated and scared viewers this week.

The frozen plume remained in the atmosphere until it caught the sunlight and its heat, allowing it to glow before ultimately turning into vapor.

The spiral was the result of the final stages of the launch of the SpaceX Falcon 9 rocket

Image credits: albierowlett1

The rocket responsible for the fuel ejection was SpaceX’s Falcon 9, which embarked on a classified NROL-69 US Government mission that day, landing in Florida shortly after.

Described as a reusable, two-stage rocket, the Falcon 9 was designed for the “reliable and safe transport of people and payloads into Earth orbit and beyond.”

Its cutting-edge design allows SpaceX to “refly the most expensive parts of the rocket, driving down the cost of space access.”

We’ve received many reports of an illuminated swirl in the sky this evening 💫

This is likely to be caused by the SpaceX Falcon 9 rocket, launched earlier today. The rocket’s frozen exhaust plume appears to be spinning in the atmosphere and reflecting the sunlight, causing it to… pic.twitter.com/4a9urgZceR

— Met Office (@metoffice) March 24, 2025

Since its inaugural launch on June 4, 2010, the Falcon 9 has embarked on 449 missions, 377 of which have been reflights. The cost of each launch is estimated to be around $69.75 million.

Image credits: U.S. Air Force

Now referred to by some as the “SpaceX spiral,” the phenomenon is the result of the upper stage of the Falcon 9 separating from its first-stage booster.

The upper stage then continues its course, while the lower stage falls back to Earth, retrieved minutes after launch. The upper stage then releases its cargo and falls to Earth as well, spiraling and dumping the remains of its fuel simultaneously.

Similar events have occurred in the past, with frozen rocket fuel creating spirals that have captivated onlookers

Falcon 9 lifts off from pad 40 and returns to LZ-1 in Florida pic.twitter.com/zC7PlEogcE

— SpaceX (@SpaceX) March 24, 2025

This isn’t the first time a similar event has been reported. In 2022, an almost identical sighting made headlines in New Zealand after a SpaceX rocket dumped fuel into the atmosphere, forming a glowing blue swirl in the sky.

In 2021, a similar spiral was linked to a Chinese rocket, the Long March 2C, which vented fuel as part of a satellite launch operation.

Image credits: burns_alasdair

Astrophysicist Simón Ángel, Scientific Director of Manuel Foster Observatory in Chile explained the phenomenon in detail to Bored Panda.

“This phenomenon falls under an umbrella term in English called the ‘twilight phenomenon,’ where the Earth’s surface is already dark, but higher layers of the atmosphere are still receiving sunlight,” he said.

“As a result, trails left by recent launches remain illuminated, making them visible from Earth.”

Image credits: View of Plaški, Croatia

According to Ángel, the freezing occurs primarily due to the temperature at which the layers of the atmosphere are, as well as the change in environment—from high pressure inside the rocket to the lower pressure of the atmosphere.

Image credits: View of Plaški, Croatia

On Earth, wind and friction would distort the spiral pattern, as was observed over Norway in 2009, when a failed Russian missile test produced a short-lived blue spiral that vanished into a smoke-shaped trail soon after.

The astrophysicist took the chance to assure the public that these events are do not have negative effect on health. “These phenomena occur high in the atmosphere, so they don’t affect people.”

“A job for the Avengers!” netizens joked, comparing the phenomenon to something straight out of a fantasy movie

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