As water melts off the ice disc and sinks below it, it generates a "vertical vortex" under the disc that induces the ice block above to rotate.

Ice disc
Rare but natural phenomenon. Photo: City of Westbrook/Facebook

( — January 19, 2019) — The strange phenomena in Maine have been compared to crop circles where some believe aliens have landed the Science Alert reports.

A large round ice piece formed on the Prisampskot River in the US state of Maine which led some citizens to think the end is near or that they are being visited by aliens.

It is, however, a rare natural phenomenon and not a matter of extraterrestrial activities but a series of circumstances surrounding the natural phenomenon.

The piece of ice that spans slightly less than 300 feet broke away from the river. Only the surface of the river was frozen but the river itself continued to flow beneath the icy cap. Being too large to move the ice, the frozen chunk started rotating counter-clockwise because the force of the river current was pushing it, while the edges were constantly colliding with the river banks smoothing the edges into a circular shape.

The icy disc spooked some 17,500 residents of Westbrook, a suburb of Portland. Some of them we seriously frightened.

“Oh, no! The end of the world is approaching,” one of the citizens wrote on Facebook, commenting on the creation that was visible on the river.

Others just enjoyed watching ducks riding about on the frozen disc-shaped water. Local authorities took advantage of the situation and rushed tourists to come and take pictures while the occurrence lasts.

“Come down to the River Walk, take a selfie, and grab some lunch at one of our awesome nearby restaurants!” the Facebook post by local authorities reads reminding people that “the mysterious Ice Disk” is still spinning in Westbrook.

The same phenomenon has been recorded in other areas in the United States, but also around the world. Such a phenomenon was also seen in Michigan and North Dakota.

A 2016 experiment recreated this natural phenomenon in a lab, the Science Alert reports. According to the report scientists found out that it’s not just the river current but also something else that is contributing to the spin of the icy disk.

In that study, researchers discovered, as water melts off the ice disc and sinks below it, it generates a “vertical vortex” under the disc that induces the ice block above to rotate, the Science Alert reports.