Not a UFO, this is the cause of the mysterious black circle in the sky of America

A black circle appeared in the sky, shaped like a trail of UFOs and was up to tens of meters in size, taken in Birkenshaw, Yorkshire, and the United States, causing controversy about its origin.

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There are many hypotheses given as black circles that are traces of an alien flying saucer, or a portal to another dimension or a mysterious natural phenomenon that humans not found .

But the truth is.

UFO, not. Some mysterious natural phenomenon, not always. According to Nigel Watson, a famous author, the black smoke ring was a trace left after firing a cannon during the nearby Yorkshire Wartime war reenactment.

When a cannon was fired, a swirl was created by the disturbance of the air around the barrel and in the gun. Then, the black smoke from the gunpowder curled up and flew up, forming a circle in the sky as we saw it.

Nigel Watson's explanation also received the approval of Nick Pope, one of the UFO experts at the US Department of Defense.

According to Nick Pope, we can easily create such smoke circles if we want, just let the air flow through a circular cylindrical structure.

Black circle in Kazakhstan in 2015.

In 2016, at Disneyland and in Kazakhstan, 2015 also recorded some mysterious black circles in the sky. But then, this phenomenon is not explained, leading to the emergence of a series of alien-related hypotheses.

Currently, the mystery of the mysterious black circle in the sky has the answer, by firing cannons, or from some chimney.