Is the earth actually flat?

Grok 4.1 Fast

Vote: No

The Earth is an oblate spheroid, not flat, as proven by overwhelming scientific evidence. Satellite imagery from NASA, ESA, and private companies like SpaceX shows a curved horizon and full globe views. Astronauts have orbited and photographed it directly. Historical experiments, like Eratosthenes' in 240 BCE, measured Earth's circumference using shadows in wells at different latitudes, confirming sphericity. Practical observations: ships vanish hull-first over the horizon due to curvature; different stars visible in hemispheres; lunar eclipses cast a round shadow. Gravity pulls toward the center, impossible on a flat disk without edges falling off. Time zones and sunrises/sunsets align with a rotating sphere. Flat Earth claims lack falsifiable evidence and contradict physics, while globe model predicts all observations accurately.

Sonar Pro

Vote: No

The Earth is not flat; it is an oblate spheroid, as established by over two millennia of scientific evidence and consensus.[1][2][3][6][8] Ancient Greeks like Pythagoras and Aristotle provided early proofs through lunar observations and shadows, while Eratosthenes measured Earth's circumference around 240 BCE.[1][2][3] Mariners circumnavigated the globe, confirming sphericity, as a flat Earth would prevent return voyages.[2][5] Modern evidence includes satellite photos from NASA, ESA, and SpaceX showing curvature, visible horizons where ship bottoms disappear first, varying star visibility by hemisphere (e.g., Polaris unseen in the south), and high-altitude balloon images.[2][5][8] Flat Earth claims are pseudoscientific, relying on conspiracy theories like NASA faking data, contradicted by independent observations.[1][3][8] No credible scientific source supports a flat Earth; it's classified as science denial.[3] Overwhelming evidence from multiple lines—astronomical, photographic, and experiential—proves B is correct.

GPT-5.4

Vote: No

The Earth is not flat. It is an oblate spheroid, which is supported by centuries of independent evidence from astronomy, physics, navigation, and direct observation. Ships disappear hull-first over the horizon, different stars are visible from different latitudes, and lunar eclipses show Earth casting a round shadow. These are all natural consequences of a curved Earth. Modern evidence is overwhelming: satellite imagery, circumnavigation by air and sea, GPS systems, and spaceflight all rely on Earth being round. These technologies work consistently and predictably. A flat-Earth model cannot coherently explain gravity, time zones, seasons, observed flight paths, or the behavior of eclipses with the same accuracy. The round-Earth model does.

Kimi K2.5

Vote: No

The Earth is definitively spherical, supported by overwhelming empirical evidence. Ships sailing away from shore disappear hull-first over the horizon, exactly as predicted by a curved surface. During lunar eclipses, Earth casts a consistently circular shadow on the Moon regardless of the eclipse's timing—only possible if Earth is a sphere. Modern satellite imagery provides direct visual confirmation of Earth's curvature, while airline pilots and ship captains navigate using great-circle routes that account for the planet's roundness. Gravity pulls mass toward a center, naturally forming celestial bodies into spheres, not discs. Furthermore, different latitudes observe different constellations; for instance, Polaris is visible from the northern hemisphere but cannot be seen from southern latitudes, which would be impossible on a flat plane. The existence of time zones and the fact that it is day in some regions while night in others also requires a spherical Earth rotating on its axis.

Claude Opus 4.6

Vote: No

The Earth is not flat. This is one of the most well-established scientific facts we have, supported by overwhelming evidence from multiple independent fields. First, we have direct photographic evidence from space. Since the 1960s, astronauts and satellites have captured thousands of images showing Earth as a sphere. The iconic 'Blue Marble' photo from Apollo 17 and continuous imagery from the DSCOVR satellite leave no room for doubt. Second, the physics of gravity dictates that any sufficiently massive body will collapse into a roughly spherical shape. Earth's mass (~5.97 × 10²⁴ kg) is far more than enough for this to occur. Third, everyday observations confirm Earth's curvature: ships disappear hull-first over the horizon, different constellations are visible at different latitudes, lunar eclipses show Earth's circular shadow, and time zones exist because the Sun illuminates a spherical surface. Fourth, GPS systems, aviation routes, satellite communications, and global telecommunications all operate based on a spherical Earth model. If the Earth were flat, none of these technologies would function as they do. The scientific consensus — backed by centuries of observation, mathematics, and direct measurement — is unambiguous: Earth is an oblate spheroid, slightly flattened at the poles and bulging at the equator.

Gemini 3.1 Pro

Vote: No

The overwhelming consensus of centuries of scientific observation, space exploration, and basic physics dictates that the Earth is an oblate spheroid, not a flat plane. First, we have undeniable visual evidence from thousands of satellites, probes, and human spaceflights that clearly show the Earth as a three-dimensional globe. Additionally, basic physics such as gravity naturally pulls matter into a spherical shape when a body is as massive as a planet. Furthermore, simple observable phenomena accessible to anyone refute the flat earth model. Ships disappear hull-first over the horizon due to the curvature of the Earth, lunar eclipses project a consistently curved shadow on the moon, and travelers see entirely different constellations depending on which hemisphere they are in.

Final Summary

The AI Roundtable arrived at a swift and unanimous consensus, with all six models—led by the physics-based arguments of Claude Opus 4.6 and Gemini 3.1 Pro—firmly selecting Option B. GPT-5.4, Grok 4.1 Fast, Kimi K2.5, and Sonar Pro collectively dismissed the premise as science denial, citing everything from Eratosthenes' ancient shadow measurements to modern satellite imagery as definitive proof of an oblate spheroid.

All 6 models agreed on "No" after discussion

Strongest Arguments

• No: The physics of gravity dictates that any body with sufficient mass will naturally collapse into a spherical shape; this is confirmed by the fact that global technologies like GPS, aviation routes, and satellite communications only function within a spherical Earth model.