ballor/pancake.com

Open field guide / Earth's shape

Is Earth a ball—or a pancake?

A straightforward guide to the strongest arguments, the measurements behind them, and what you can check for yourself. Curiosity is welcome. Every claim gets a source.

Explore the claims Get the short answer

No blind trust. No false balance. Follow the measurements.

Field diagram 01Not to scale
The ballCurved in every direction
The pancakeA flat, extended plane
Two models. Make them explain the same observations.
Start with what you can observeMake a measurement

The short, honest answer

Earth is not a perfect ball. It is an oblate ellipsoid.

It bulges slightly at the equator and is slightly flattened at the poles. That globe-like shape is the best simple fit for measurements around the world—not a flat disk. The real surface and the gravity-based sea-level reference are more irregular still.

6,378.137 kmEquatorial radius
6,356.752 kmPolar radius
≈42.8 kmWider at the equator

Reference ellipsoid values (WGS 84). See NASA's Earth Fact Sheet and NOAA on geodesy.

The claims, made testable

Start with the strongest version of each question.

We selected recurring empirical arguments from IFERS, linked the original discussions, then asked what each model predicts and how a person could check it.

01Horizon & visibilityIf Earth is curved, why does the horizon look flat?A level-looking line is not a level measurement.

The forum argument

IFERS discussions argue that the horizon stays at eye level and looks flat from beaches, planes, and balloons.

Horizon Rises To Eye Level Earth’s Curvature From Your Airplane Window?

What to measure

A photo cannot tell whether the camera was tilted to keep the horizon centered. Record camera pitch against a calibrated level, observer height, lens, and atmospheric conditions. On a globe, the visible horizon sits below local horizontal, and the angle changes with elevation.

Where the evidence lands

A flat-looking local view is unsurprising on a planet thousands of kilometres wide. The useful test is a repeated, calibrated angle measurement—not a horizon cropped to the middle of a frame.

02Water & “level”Does water finding its level mean the oceans are flat?Level is local; sea level follows gravity.

The forum argument

IFERS threads use still oceans and the phrase “water finds its level” to argue that the surface must be one extended plane.

No Curvature On Bodies Of Water The Natural Physics of Water Prove Earth Flat

What to measure

At a pond, “level” is local: resting water follows an equipotential surface of gravity. The direction of local vertical changes from place to place. Mean sea level is modeled with a gravity-based geoid; a carpenter’s level compares nearby points, not continents.

Where the evidence lands

Local flatness and global curvature are compatible. Geodetic measurements describe a curved, gravity-defined reference surface rather than a single Euclidean plane.

03Sun, Moon & shadowsCould a nearby Sun explain the same sky?Angles across distance test the model.

The forum argument

IFERS topics question the measured size and distance of the Sun and Moon, and interpret everyday views of the sky as evidence for a nearby light source.

The Sun, Moon, and Stars Prove the Flat Earth The Size And Distance Of The Sun/Moon

What to measure

The IFERS post quotes historical estimates that differ. Compare the methods and uncertainty rather than treating old estimates as interchangeable. A daytime Moon is expected when the Sun and Moon are both above the horizon. For a repeatable geometry test, compare Sun angles from known north–south sites along the same meridian near local solar noon on the same date, then repeat in other seasons. A local-light model and a distant-Sun model predict different patterns.

Where the evidence lands

A single sunset, photo, or historical estimate is not a distance measurement. Better methods refine estimates; NASA’s Earth Fact Sheet lists Earth’s mean orbital semimajor axis as about 149.598 million km. Multi-site shadow-angle observations let you test the geometry directly and fit the globe model.

04Stars & latitudeWhat changes when you travel north or south?The visible sky tracks your latitude.

The forum argument

IFERS threads challenge where Polaris can be seen and whether star trails in the northern and southern skies fit a globe.

Polaris Seen From The Southern Hemisphere Star Trails In The Northern And Southern Hemisphere

What to measure

At a site with known latitude, record star positions through a full night. In the Northern Hemisphere, the north celestial pole’s altitude is approximately the observer’s latitude. South of the equator, Polaris is below the horizon while southern stars circle a different celestial pole.

Where the evidence lands

Latitude-dependent star heights and opposite directions of star-trail rotation are predicted by a spherical Earth. Compare time-stamped observations from both hemispheres, not a single image.

05Lunar eclipsesWhat shape is Earth’s shadow on the Moon?A repeating shadow is a useful cross-check.

The forum argument

The IFERS archive includes a challenge about the March 2025 total lunar eclipse and broader disputes about lunar geometry.

Total Lunar Eclipse — March 14, 2025 NASA: Lunar Eclipses

What to measure

Track the curved edge of Earth’s shadow over a full eclipse, compare the timing with published predictions, and check observations from more than one location. A single snapshot is suggestive, not decisive.

Where the evidence lands

A sphere casts a circular shadow from every orientation, matching repeated lunar eclipses and their predicted paths. It is one strong strand of evidence, not the whole case by itself.

06Flights & engineeringWould pilots and builders need to “correct for the curve”?Local level is not one global plane.

The forum argument

IFERS posts argue that aircraft would have to keep pitching downward and that canals, bridges, railways, and surveys do not account for curvature.

Flight Routes, Shipping Routes, Under Sea Cables Architects and Engineers for Flat Earth Truth

What to measure

“Level” in flight and surveying refers to local gravity and a chosen altitude datum; it does not mean pointing toward one global plane. Small projects use local planar approximations. Long-distance geodesy and GPS use Earth-centered reference systems and an ellipsoid.

Where the evidence lands

A pilot does not need a continuous manual nose-down correction to stay at altitude. The relevant check is the reference system and scale used—not whether a short bridge looks straight.

07Photos & trustWhat if a space photo is edited or distorted?No single image carries the case.

The forum argument

The forum collects images presented as flat-Earth evidence and questions lens distortion, image stitching, and official space imagery.

Flat Earth Image Proofs IFERS: Reference Materials and Maps

What to measure

For any image, ask for the camera, lens, tilt, location, date, and original file. Then compare it with observations that use different instruments and methods.

Where the evidence lands

We do not ask anyone to accept a single agency photo. A disputed image can weaken that image; it does not erase independent shadow measurements, star positions, geodesy, or eclipse predictions.

IFERS is a user-run discussion forum, not a scientific journal. A link means “this is where the claim appears,” not “this claim has been verified.”

Try a simple measurement

Let two shadows measure a world.

Eratosthenes-style reasoning uses the difference in Sun angles at two known locations to estimate Earth's circumference. Compare north–south sites along the same meridian, or adjust for longitude, near each site's local solar noon on the same date. The same sunlight meets the ground at different angles because the ground curves.

See how we evaluate a test
Shadow checkIllustrative values
800 km

Choose the north–south distance between two observation points.

7.2°

Choose the difference in the measured Sun angle at local noon.

Estimated circumference40,000 km

Example: 800 km between sites and a 7.2° angle difference gives about 40,000 km. Use a known north–south distance along the same meridian (or adjust for longitude), readings near local solar noon on the same date, and repeat the measurement. Real results depend on uncertainty and the locations chosen.

How we keep it transparent

A test should be open to anyone.

We do not score claims by popularity or by who says them. We ask which model makes the clearest prediction—and whether the result can be repeated.

01

State the claim fairly.

Use the strongest version people actually make, not a caricature.

02

Ask what it predicts.

A useful model should say what someone will observe before the test.

03

Show the method.

Record location, time, instrument, assumptions, and uncertainty.

04

Invite a repeat.

Prefer independent measurements over credentials, slogans, or a single image.

What would change our mind?

Repeatable measurements showing that one flat-disk model predicts horizon angles, shadows, star positions, eclipses, and long-distance routes more accurately than the ellipsoid model. We would publish the data, method, and uncertainty—and update this page.

Follow the sources

Open references

Read the claims. Check the measurements.

Source check · 3 Nov 2026

The discussion · IFERS

User-authored forum threads, linked as the origin of the arguments—not as scientific verification.

Measurement & reference

Public science and geodesy references for checking the numbers and observing the sky.

This guide summarizes recurring, testable themes from the supplied IFERS forum. The forum is user-generated and not peer-reviewed. We separate what its posters claim from what independent measurements show, and we welcome corrections with sources and reproducible methods.