Mysterious floating city in China: Just another Fata Morgana
Residents of Foshan and Jiangxi, China have reported a floating city appearing in the clouds. The sight spawned a host of theories ranging from dimensional portals to NASA hologram. In reality, it's an autumnal optical illusion.
Fata Morgana: An optical illusion created by a temperature inversion.
The Weather Channel
If you suddenly see a city floating in the early morning or evening sky it鈥檚 not aliens, Arthurian legends, or a holographic trick, but an atmospheric event known as "Fata Morgana."
Residents and聽聽outlets in the cities of Foshan and聽Jiangxi in China have reported a floating city appearing in the clouds which has launched a host of theories ranging from dimensional portals and parallel universes to those who claim that聽聽using something conspiracy theorists have dubbed the聽.
According to atmospheric scientists this is the season for the Fata Morgana optical illusion, which typically takes place as temperatures cool rapidly. In summertime, you might see the illusion of heat haze over a hot road with phantom water shimmering on the surface. The apparition of a city or cliff in the sky is one of autumn鈥檚 more common optical illusions in the United States as well as China.
笔谤辞蹿.听 an atmospheric scientist in 聽department of geosciences, says in an interview that the phenomenon Fata Morgana gets its Italian name from聽, the sorceress of medieval Arthurian legend. Le Fay was said to have cast an illusion or multiple buildings and cliffs over the聽Straight of Messina聽in Italy to lure sailors to their death.
Professor Bowman says this optical illusion is not tied to pollution, global warming, or even vengeful fairies, but a common atmospheric set of conditions.
鈥淭he illusion is due to a slightly unusual temperature structure in the lower part of the atmosphere,鈥� says Bowman. 鈥淣ormally the atmospheric density decreases as you move up away from the surface. It鈥檚 the density of the air that determines the refracted index. So that鈥檚 what makes it behave somewhat like a lens.鈥�
Therefore, a Fata Morgana 鈥渋s the result of a big temperature inversion in the atmosphere,鈥� Bowman says. Normally, the air cools the further away you move from the Earth's surface. But with a temperature inversion, the air closest to the Earth's surface is cooler than the air further from the surface.
鈥淵ou can get inversions when temperatures get cold, the ground can cool off faster than the air that鈥檚 up above it. Especially in the fall and winter, you can get these shallow inversions.鈥�
Another way is when the air moves in different directions from different levels, and when a warm air mass moves over cold air.
These temperature inversions bounce light rays in unusual ways.
鈥淲e鈥檙e moving into winter season here so we鈥檙e starting to get cold air from the north and it鈥檚 going to get cold here in the Northeast here this week so you can get a large cold air inversion like this,鈥� Bowman says. 鈥淏ut when you get this unusual temperature structure in the atmosphere you can get light rays where light scatters off the surface and goes up into the atmosphere and is refracted back down to the surface again."
鈥淚t鈥檚 not exactly a reflection because it鈥檚 not a mirror but it鈥檚 like looking through a lens and you鈥檙e seeing the surface at a long distance away but it looks like it鈥檚 floating up in the atmosphere," Bowman says.
The Fata Morgan often appears to be shifting rapidly, from a "ship" or "island"聽right side up, and seconds later, upside down.聽
鈥淚n fact, they鈥檙e commonly seen over water,鈥� he says. "Exactly what鈥檚 happening in China, I really can鈥檛 tell without the weather maps, but it鈥檚 more common near large bodies of water, or over water.鈥�
Asked if he thought it was a NASA projection, Bowman says, 鈥淣o, that falls into the category of wacko.鈥�