Empirical Earth · The Boomerangs — Flat-Earth Proofs That Backfire

The long flat bridge & the salt flats

The claim

“The flattest places on Earth — a 24-mile causeway, the Bonneville Salt Flats — are dead level, with no curve at all.”

What is measured

The exhibits flat-Earthers love most turn on them. Across Lake Pontchartrain, ~16 miles of identical, equally tall towers visibly curve down as their bases drop behind the bulge. The Bonneville Salt Flats, level to within ~8 inches, follow Earth’s curved “level” surface, with Interstate 80 plainly bending when viewed with zoom from the hills. More on refraction and the curve.

Sources

1. Power lines over Lake Pontchartrain. A ~16-mile straight line of identical, evenly spaced transmission towers; photographed end-on with a telephoto, the bases of distant towers drop behind t link
2. Bonneville Salt Flats: levelness vs. curvature. The National Geodetic Survey records only ~7.874 in of height variation across the flats, while a sphere’s drop over a 10-mile span is ~66.9 f link
3. Lake Pontchartrain power-line geometry. A ~16-mile straight run of equal-height transmission towers ~287 m apart; photographed by “Soundly” (from June 2017) with a ~480 mm-equivalent telepho link
4. Bonneville Salt Flats: flatness and the geoid. The National Geodetic Survey measures ~7.874 inches of height variation across the flat; the surface conforms to a gravitational equipotential. link
5. Bonneville: “level, not flat,” and the I-80 curve. Roads spanning ~47 miles of the flats change elevation ~53 feet (~0.02% grade) — level tracking the curve, not a plane. From the hills west link

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