If Earth curved, you couldn’t see the Chicago skyline across Lake Michigan.
Quick reality-check: That famous photo is a superior mirage: cold air hugging the lake refracts light upward, lifting the image of buildings that are actually hidden below the curve. Take the same shot on a day with no inversion and only the tops are visible.
Why is this claim made?
The claim is based on a misunderstanding of how light and atmospheric conditions can affect what is visible. Flat-Earth proponents assume that if you can see the skyline, the lake must be flat.
Why the claim doesn’t work
Superior mirages are well-documented optical phenomena caused by temperature inversions. On days without an inversion, only the tops of distant buildings are visible, matching predictions for a curved surface.
Evidence against the claim
- Physics World and other science outlets explain mirages and atmospheric refraction.
- Repeated observations show the skyline is only fully visible during temperature inversions.
- Watching ships disappear hull-first is a classic demonstration of the curve.
DIY test: Watch a ship sail away through binoculars—the hull disappears first; zooming back in doesn’t bring it back because it’s below the curve, not just “too small to see.”
Summary
Atmospheric refraction explains the rare full skyline view. On most days, the curve hides the lower floors—just as globe geometry predicts.
Links to additional resources