As you’ve probably seen by now, the entire internet is more or less losing its crap over an illusion that showed a flying city over China. Have the Chinese invented anti-gravity technology? No, it’s a specific type of optical illusion called a Fata Morgana. Here’s what you need to know.
But somebody told me on Facebook that…
Let me stop you right there; by now, you should be fully aware that most of what you read on Facebook is crap. But some basic physics will tell you that your mind is being fooled. Look at the photos again:
Notice how the city underneath is not covered in a pool of shadow? Unless this is a flying city made of glass or its anti-gravity system gives off sunlight, that’s not a flying city, no matter what your mind tells you.
Okay, so what is it?
A Fata Morgana, a specific type of optical illusion created by the weather. It needs a thermal inversion, that is, warmer air sitting on top of cooler air. If you remember your basic physics, you know this doesn’t happen often. When it does, it creates an atmospheric duct, a phenomenon that serves as a sort of lens for various wavelengths of radiation. Most importantly to us, it refracts light and tends to create a sharp, delineated image. There are plenty of examples all over the internet; my personal favorite gives the illusion of a flying sailboat.
So, wait, basically a Chinese city had a whole bunch of these atmospheric ducts appear over it at once?
Yep. Of course, the fact that this happened over Foshan, which is about 30 miles from the nearest ocean, and that these atmospheric ducts are relatively rare away from the sea, does raise its own set of questions. But don’t worry, whatever else might be happening in China, they haven’t built a flying city. A dam that literally shakes the Earth, yes, but not a floating city. Yet.