As the air warmed over Lake Michigan, a light fog developed on the horizon. This created a mirage of the distant Chicago skyline some 40 miles across the lake from our vantage point.
Called a superior mirage, it is created when cold air is near the surface, and warmer air is above. The atmosphere acts like a lens, inverting the skyline. If you look closely around the horizon, you will see the tops of some shorter buildings upside-down in the mirage.
Because of this mirage, objects that are usually hidden by the curvature of the earth can be seen above the horizon, only upside down. The Chicago skyline is usually visible from this vantage point, but the numerous other small buildings are never seen, unless displayed by a superior mirage.
Looking up the shoreline toward Michigan City, the lighthouse is visible, but generally nothing beyond. It's unusual to see any land beyond the lighthouse, but the superior mirage along the horizon refracted the objects below the horizon, and displayed them above, just inverted.
An interesting effect created by the perfect weather conditions.
Posted by Tom Gill at Sunday, April 02, 2017