FE Meme
Plumb Lines Stay Level, Earth Does Not Bubble?
#156: Earth is not a globe that rises or bubbles upward; plumb lines and level references stay parallel locally, so curvature diagrams are fake physics.
The Meme
Black background diagram: red header "Earth is not a globe, the earth does not rise or bubble out like in this drawing"; blue upward arc with yellow level lines labeled "LEVEL" / "ALSO LEVEL" and green "PLUMB LINES" arrows.
Why It Spreads
The exaggerated blue bubble caricature of a rising globe is easy to mock, and labeling both sides level with plumb lines makes viewers think surveyors secretly agree the planet is flat. The caption claims smart people deny parallel plumbs, exploiting confusion between local tangent planes and global convergence toward Earth's center.
What It Gets Wrong
The red header insists "Earth is not a globe, the earth does not rise or bubble out like in this drawing" above a blue upward arc with yellow "LEVEL" lines and green "PLUMB LINES" arrows. Plumb bobs follow local gravity perpendicular to the geoid; on a sphere those normals converge slightly toward Earth's center over long distances, but over a few metres the tilt is microscopic on R ≈ 6371 km. Civil survey still closes on ellipsoid datums for long bridges and tunnels; the meme attacks a straw-man bubble cartoon instead of measured drop on kilometre baselines. TestTheGlobe's Water Finds Level Means Flat and TestTheGlobe's Gravity Direction Visualizer walk through the observations and predictions this image skips.
The Debunk
Gravity vectors converging toward Earth's center predict plumb lines parallel enough for construction over metres but measurably tilted over kilometre baselines on R ≈ 6371 km; that fits geodetic survey practice. Attacking a straw-man bubble-globe cartoon with "LEVEL" labels is inconsistent with logging distance and drop on real baselines. Use TestTheGlobe's Gravity Direction Visualizer to compare the meme's claim with a measurable prediction.
- TestTheGlobe's Gravity Direction Visualizer shows how gravity vectors tilt toward Earth's center, converging slowly with distance on R ≈ 6371 km.
- TestTheGlobe's Water Finds Level Means Flat page clarifies that local level means perpendicular to gravity, compatible with a large-radius sphere.
- TestTheGlobe's Water Finds Level Means Flat: plumb lines are parallel enough for construction pads over metres; geodetic surveys correct curvature on kilometre baselines.
- TestTheGlobe's Down Is The Same Everywhere: the meme draws a straw-man bubble globe with yellow level lines, then attacks the cartoon instead of logging distance and drop.