UFO sightings are often explained as misunderstood weather phenomenon, so it's not surprising that NASA is getting ribbed for using that approach in addressing a strange halo seen over China.
It appeared in August over Pu'er in the Yunnan Province (north of Laos) and resembled a rainbow-colored tower sitting atop a cloud of dark exhaust.
NASA shared a photo Sept. 6 and offered an explanation that involved clouds, uniformly sized water droplets and diffracted sunlight.
More than 62,000 reactions and 1,400 comments later, it's clear not everyone is convinced it was natural or accidental.
However, many more had no doubt it was a UFO and they suggested a government cover-up.
"Aliens are in that cloud," Marjana N Manny Perez wrote.
"It's either a man-made substance used to cover up advanced military technology, or aliens. You pick," Andreja Depiazzi said.
"Weird how I haven't seen or heard of these my entire life," Cassi Idle posted.
NASA did not address the theories but did offer a more detail explanation of what it called "an iridescent pileus cloud," which it conceded was a bit "unusual."
"Behind this darker cloud, is a pileus iridescent cloud, a group of water droplets that have a uniformly similar size and so together diffract different colors of sunlight by different amounts," NASA wrote.
"Also captured (in the photo) were unusual cloud ripples above the pileus cloud. The formation of a rare pileus cloud capping a common cumulus cloud is an indication that the lower cloud is expanding upward and might well develop into a storm."
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