Fact check: Earth is flat

1. How modern statistics and geodesy put the flat-Earth claim to rest

A 2024 statistical study introduced a novel estimator that directly rejects the flat-Earth model by estimating Earth's curvature with quantified uncertainty, producing a curvature consistent with the orthodox spherical/oblate model (π/20,000 km) and enabling formal inference against flatness ^[1]. Geodesy and geomatics literature frame Earth’s shape as a measurable, parameterized object rather than a philosophical debate; modern techniques combine terrestrial surveying, satellite tracking, and statistical inference to produce reproducible curvature estimates. These quantitative methods convert everyday observations into rigorous statistical evidence that is incompatible with a flat plane.

2. Satellite-era measurements and the pear-shaped nuance that disproves flatness

Spaceborne observations since the mid-20th century have produced highly precise models of Earth's figure, revealing it to be oblate with a pear-shaped component, not flat or perfectly spherical ^[2]. Vanguard-era and subsequent satellite determinations measured gravitational harmonics and surface equipotential shapes, providing multiple independent datasets that align on an oblate/pear-shaped solution. Reviews in geomatics synthesize these findings and emphasize that Earth’s deviations from a perfect sphere are small but well-characterized, which is precisely the kind of complexity a flat-Earth model cannot accommodate ^{[3] [5]}.

3. Educational analyses show flat-Earth claims fail basic physics and trigonometry tests

Pedagogical treatments use flat-Earth assertions as exercises to demonstrate falsifiability: trigonometry, simple geometry, and basic physical laws falsify many common flat-Earth arguments, making the topic a vehicle for critical thinking in physics education ^[6]. Classroom experiments—horizon observations, ship disappearance geometry, and stellar parallax—are reproducible and align with a curved-Earth interpretation. These analyses stress that the scientific method prioritizes repeatable, falsifiable measurements, and flat-Earth models routinely fail those standards.

4. Comprehensive parameter compilations reinforce the non-flat reality

Compilations of Earth’s fundamental parameters consolidate mass distribution, atmospheric structure, and geophysical constants into datasets that presuppose and confirm a three-dimensional, rounded Earth; these compilations are used for Earth science modeling and mission planning, tasks untenable under a flat-Earth hypothesis ^[5]. The operational needs of navigation, satellite orbits, and climate modeling depend on precise ellipsoidal/geoids and their harmonics; engineering systems calibrated to these parameters routinely validate the same figure. Applied science thus provides continual, practical confirmation of Earth’s rounded shape.

5. Recent scholarly reviews and engineering perspectives close the empirical gaps

A 2025 review in geomatics explicitly frames the Earth-shape problem as settled by measurement and modeling, noting that modern instruments and analysis pipeline remove ambiguity that earlier generations faced ^[3]. Engineering and surveying communities rely on standardized reference ellipsoids and geoid models for map projections and infrastructure—if the Earth were flat, those entire systems would fail in predictable ways. This body of work consolidates decades of independent methods into a consistent picture, illustrating the interdisciplinary consensus against flatness.

6. Why belief persists: social, cultural, and cognitive mechanisms

Scholarly work on conspiracy belief shows that the flat-Earth movement functions as a cultural and psychological phenomenon, not a serious scientific alternative ^[7]. Analyses document how identity, mistrust of institutions, and narrative coherence drive adoption of the flat-Earth framework; scholars label aspects of the movement a "superconspiracy" that blends scientific-sounding claims with religious and epistemic distrust ^[4]. These studies explain persistence by highlighting non-epistemic drivers—community formation and anti-establishment sentiment—rather than any credible empirical challenge to curvature measurements.

7. Comparing the evidence and claims across time: newer studies reinforce earlier consensus

From pedagogical critiques ^[8] to statistical estimators ^[9] and geomatics reviews ^[10], the trajectory of research shows increasing precision and interdisciplinarity that all point away from flatness ^{[6] [1] [3]}. Satellite-era measurements in 2024–2025 refine earlier models by measuring subtle asymmetries (pear-shaped components) while statistical work formalizes hypothesis tests against flatness. The social science studies from 2024–2025 document cultural spread of the belief, clarifying that the persistence of flat-Earth claims is sociological, not empirical ^{[4] [7]}. Recent work deepens and broadens the refutation rather than overturning it.

8. Bottom line for readers: empirical certainty and the nature of the disagreement

The multidisciplinary, dated evidence—statistical curvature estimates, satellite-derived shape models, compiled geophysical parameters, and educational refutations—forms a coherent, high-confidence rejection of the flat-Earth claim; there is no empirical support in the reviewed literature for a flat plane model ^{[1] [2] [5] [6]}. The disagreement exists primarily in cultural and epistemic domains, where identity and mistrust sustain the belief despite measurable, repeatable contradictions documented across fields. Understanding both the scientific evidence and the sociocultural drivers is essential to addressing why the claim endures.