A video of a mysterious floating cityscape above a town in China has gone viral this week.
The footage captured by a local resident appears to show a city hovering in the clouds. Explanations for the occurrence range from an elaborate hoax to a secret NASA project to an actual atmospheric phenomenon.
Experts are hesitant to confirm if the video is real. In the words of atmospheric scientist Peggy LeMone, of the National Center for Atmospheric Research in Boulder, Colorado, “It looks almost too good.”
“If it is real,” states Jill Coleman, another atmospheric scientist at Ball State University in Muncie, Indiana, “It’s called a superior mirage, which just means it’s an upward projecting mirage. It could be something called a fata morgana, which is a certain kind of atmospheric mirage.”
Fata morgana occurs when air temperature at the surface is cooler than the air above, resulting in objects appearing like they are stacked on top of one another. Or, in this particular video’s case, a city floating in the clouds.
The atmospheric mirage usually occurs over large bodies of water since the air tends to be relatively cooler close to an ocean or lake, but it can also form over land. This kind of air layering bends light rays as they pass from one air mass into the next, tricking our brains into thinking an object is higher than it really is. And because the appearance of a fata morgana depends on a person’s perspective, the further away the individual is from an object, the taller the object will appear.
Perhaps this explains China’s floating cloud city.