Huge ship appears to fly through the sky in one of nature's most incredible optical illusions

Video captured just off the coast of Kent, United Kingdom, last week shows a large container ship appearing to fly through the sky, floating just above the water.

Some experts have weighed in, calling the visual experience a Fata Morgana. The phenomenon is a rare optical illusion because the atmospheric conditions have to be just right. As AccuWeather Lead International Forecaster Jason Nicholls explained, "A Fata Morgana occurs because rays of light are bent when they pass through air layers of different temperatures in a steep thermal inversion where an atmospheric duct has formed."

Essentially, a Fata Morgana is a superior mirage that occurs because of the weather condition known as a temperature inversion. Cold air lies close to the sea with the warmer air above. Since cold air is denser than warm air, it bends light toward the eyes of someone standing in the distance making the mirage appear. Usually, the mirage is based on a real object, like a ship off in the distance.

Ship appears to float several feet above the ocean off the coast of Kent, U.K. (Reuters)

Others believe there may be other optics going on to cause this ghostly ship phenomenon.

"Enhancing the contrast on the photo, you can see the actual horizon that the ship is traveling on, so this may simply be a 'false horizon' effect -- an optical illusion that the color of the ocean happens to be a very similar color as the sky," AccuWeather Senior Weather Editor and Meteorologist Jesse Ferrell said, "and fog or sea spray can add to that illusion."

Ferrell hypothesized a few different factors that may be at play in causing the ocean to appear the same color as the sky. "It could be sunlight, differing water colors or differences in wind disturbing the water's surface," adding that, "It could be caused by refracting or reflecting light, which would make it a mirage according to the book Color and Light in Nature, but not a Fata Morgana which typically involves a mirrored reflection of the object."

"'Occam's razor' would suggest that the simplest explanation is the correct one: it is just an optical illusion caused by the similar colors of the water and sky, causing the brain to be tricked into thinking the ship is 'floating,'" Ferrell concluded.

"Hovering Ship" optical illusion, contrast-enhanced to reveal actual horizon.

Nicholls noted that superior mirages can produce several different types of images. "When a real ship is out of sight because it is below the horizon line, a Fata Morgana can cause the image of the ship to be elevated, and then everything which is seen by the observer is a mirage. However, if the real ship is still above the horizon, the image of it can be duplicated many times and elaborately distorted by a Fata Morgana."

A Fata Morgana can appear on land or at sea but are most common at sea because water helps form the cool air layer required. The illusion is most common in polar regions but can appear in deserts and may involve almost any kind of distant object, including boats, islands, and the coastline. Sightings are fairly common among the Great Lakes in the United States where many people have also seen mirages of cities or parts of the coastline.

The term Fata Morgana, according to Encyclopedia Britannica, is inspired by the name of King Arthur's sorceress sister, Morgan Le Fay, who, Arthurian legend has it, created mirages that would appear in the Strait of Messina, between Italy and Sicily. According to legend, the mirages she created appeared as castles and other intricate objects floating in the air and were intended to lure sailors toward them. Many experts believe a Fata Morgana sighting may even be the source of the legend of the Flying Dutchman, a ghost ship doomed to sail the high seas for eternity.

A Fata Morgana is a startling phenomenon to witness. Facebook user Colin McCallum was stunned after spotting one and shared an image he captured at Banff, Aberdeenshire, in recent years.

"When I first saw the boat, I had to do a double-take because I genuinely thought it was floating. Upon further inspection, however, I noticed that it was in fact just a remarkable optical illusion," McCallum said while speaking to the Daily Mail in February.

As noted, a Fata Morgana superior mirage of a ship can appear many different ways and even when the boat doesn't seem to be floating it still looks ghostly and it can be difficult to ascertain which individual segment of the mirage is real and what isn't.

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