According to The Sun, some users speculated it's where an alien spacecraft "decloaked", akin to starships in sci-fi movies like Star Wars and Star Trek.
"You can see a contrail right next to it," wrote Javier Rivera.
Others weren't so sure.
"This is not a UFO, this is the haarp weapon. Haarp means weather control," one user wrote, referring to a theory about a secret US government weapon that can manipulate the atmosphere.
Some believe it can disable satellites and even control minds.
It's not the first possible UFO sighting this year, and some have been closer to home.
Earlier this year, Kiwis in the South Island reported seeing a bright ball of fire, with a tail, flying across the skies. However, it was most likely debris from cargo sent up to the International Space Station.
In January, strange lights appeared on the horizon near Darwin. The phenomenon was captured on dashcam at a service station. Just six months later, Airport workers at Miami airport spotted something that looked like a UFO.
