Mirage of Chicago Skyline

Image: Sam Cornwell
September 10, 2008  

The image of Chicago hovering above Lake Michigan (above) is actually an atmospheric phenomenon known as an inferior mirage. The mirage is formed due to the slight temperature gradient of the atmosphere: cold air over warm air causes refraction of light upwards - so you look down to see light coming from the horizon or sky.

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Via my FB pal Hal