Residents of Northwest China saw the strange spiral on June 18. Images shows a white object spinning above the clouds, expanding in size before vanishing.
Hours after China launched its Long March 2C from the Xichang Satellite Launch Center, Pacific Islanders and Chinese residents saw the pneumonia.
The Caledonian Astronomical Association shared on Facebook: “Strange spiral in the skies of New Caledonia and Vanuatu June 18th around 18pm.
“Several witnesses in Yate, Thio, La Tontouta and Vanuatu have seen this strange phenomenon.
“We don’t have an explanation but we are far from specializing in this kind of phenomenon.”
However, American astronomer Jonathan McDowell told MailOnline the sighting was not mysterious, and was merely because of China’s rocket launch.
He told the website: “The spiral happens when the rocket is tumbling end over end while venting its fuel – it’s then exactly like a garden sprinkler.
“Except that because it is in space the spiral stays perfect over hundreds of miles because there is no air to mess up the shape.
“That’s why it looks surprising to us, we’re not used to seeing such perfect geometries because on Earth there’s always wind or friction to distort things.”
A similar sighting was also reported on May 7, when China launched a Long March 2C rocket to deliver new Yaogan-30 satellites into orbit.
Mr McDowell previously told MailOnline about this sighting, and said: “Given the time it happened, I look to see if there was a rocket launch at that time. Indeed there was – the only space launch that day took off from China just 15 minutes or so earlier.
“We know the orbit of that rocket because the US space force tracked it once it reached orbit.
“I was then able to use standard orbit math to plot the trajectory – latitude and longitude of the rocket versus time – and confirmed that the track passed directly over New Caledonia and Vanuatu (where the spiral was seen), and not only that, it passed over those places within a couple of minutes of when the reports said the spiral was seen (and the reports were only accurate to a few minutes anyway).
“So, perfect agreement in space and time – case closed, it was the Yaogan 30 launch, and furthermore the timing is right for the rocket to be venting excess propellant after having deployed the satellites it took to orbit.”
The latest spiral sighting came as China launched its first ever crew to its space station earlier on June 17.
Three men, Nie Haisheng, Liu Boming and Tang Hongbo, took off in the Shenzhou-12 capsule, atop its Long March 2F rocket on Thursday.
It marks China’s longest crewed space mission to date and the first in nearly five years.
The take-off marks China’s longest crewed space mission to date and the first in nearly five years.
The crew took off from the Jiuquan satellite launch centre in the Gobi desert at 9:22am local time (1:22am GMT).