A ghostly blue spiral spotted in the sky over Hawaii could be related to a SpaceX satellite launch.

The National Astronomical Observatory of Japan spotted the mysterious spiral through its Subaru Telescope on January 18, just after SpaceX launched a Falcon 9 rocket carrying a large military satellite for the US Space Force.

Ichi Tanaka, a researcher with the Subaru Telescope, was busy doing other work that night and didn't notice the otherworldly shape forming in the telescope's view, he told The Guardian. Then someone sent him a screenshot from the YouTube livestream.

"When I opened Slack, that is what I saw and it was a jaw-dropping event for me," Tanaka told The Guardian.

On Twitter, the observatory shared an image of the cosmic whirlpool and posted a video of the spiral formation flying over the Mauna Kea volcano, then dissipating.

"The Subaru-Asahi Star Camera captured a mysterious flying spiral over Maunakea, Hawai`i," the Subaru Telescope said on Twitter on January 19. "The spiral seems to be related to the SpaceX company's launch of a new satellite."

The launch occurred in Cape Canaveral, Florida, but satellite tracker Scott Tilley replied to the tweet saying that the location of the spiral over Hawaii closely matched the location of the second stage of the Falcon 9 rocket at the time.

That's the portion of the rocket that pushes its passenger satellite all the way into Earth's orbit, after the rocket booster (first stage) separates and falls back to Earth.

SpaceWeather.com, which tracks sightings of phenomena like this, speculated that the mystery spiral came from that Falcon 9's first stage dumping fuel as it descended.

This isn't the first time a spiral has been spotted in the sky after a SpaceX launch. After a Florida launch in June 2022, a similar spiral was seen over Queenstown, New Zealand, The Washington Post reported.

These SpaceX spirals are "becoming commonplace over the Pacific" as the company increases the pace of Falcon 9 launches, according to SpaceWeather.com.

Falcon 9 rockets have made other colorful and ethereal formations in the sky, too. The launch that could have produced the New Zealand spiral may have also created a "smoke ring" formation in the skies above the central US, according to SpaceWeather.com.

The SpaceX rocket is also known for the "space jellyfish" it often paints across the sky as it climbs through the atmosphere.

This article was originally published by Business Insider.