Is the Earth flat?
Written by AI from saved sources. A script checks every quote word for word, and a second AI compares each claim with its source. How we work and corrections
No: Earth is roughly spherical, or shaped like a ball, though not a perfect ball. Some globe images combine separate shots or sets of satellite data. But observations of ships, spacecraft photographs and flight-time comparisons support a curved Earth.
Checked against: NOAA, NASA, 2024 flight study, October 2026.
Why people believe it
Distrust deserves a hearing before an answer. Texas Tech reports a researcher’s statement that many flat-Earth believers distrust powerful institutions. A 2020 study abstract describes people interviewed at a conference who started out skeptical. They reported failing to disprove flat-Earth YouTube videos, then gradually changed their minds after watching them repeatedly.
A 2025 study interviewed four former members of conspiracy communities. One described months of videos while becoming a flat-Earth believer. The authors interpret the participants’ communities as offering a sense of identity and creating social and personal barriers to leaving. These four accounts cannot tell us why everyone believes.
“Without space photos, how would we know?”
NASA’s historical account describes an ancient estimate of the distance around Earth. The calculation used the noon Sun’s angle and the distance between two cities. The account also describes an ancient argument for a spherical Earth from its circular shadow on the Moon during a lunar eclipse. These are historical explanations, with limits. NASA and NOAA give different ancient distances and estimates of the distance around Earth.
“Things just get smaller in the distance”
NASA’s explanation of what observers see from shore describes a departing ship’s hull disappearing first. Its masts and sails disappear last. It says a ship that has vanished from shore becomes visible again from a nearby hill or tower.
Thinking tool: ask what each explanation predicts
NASA’s worksheet compares two predictions. On an ideal flat planet, a distant object shrinks. On a spherical planet, a departing ship disappears bottom first. Look for the difference between shrinking and being hidden from the bottom upwards. This is an idealized comparison between imagined flat and spherical planets.
Use it on other claims. Ask what you would expect to see under each explanation before choosing between them.
“But the pictures are made from other pictures”
Some are: NASA’s 2015 EPIC colour image combines red, green and blue images. NASA separately identifies an Apollo 17 photograph taken in December 1972 between Earth and the Moon. Its Earthrise Revisited page distinguishes an original Apollo 8 photograph from a recreated version. That recreation uses data about the Moon, past cloud observations and images of land.
“Could navigation work on a flat Earth?”
GPS.gov describes satellites in GPS (a system for finding locations) circling Earth twice daily. NIST explains how GPS receivers find their locations. They calculate distances from satellites using the speed of light and how long signals take to travel. They use those distances to find their locations.
NOAA links time differences to Earth’s daily spin. But it says countries change time-zone boundaries for convenience.
“What about flight routes?”
A 2024 paper compared flight times using 10 north–south routes and 10 east–west airport pairs. Its test decisively rejected the flat-Earth model tested in favour of its spherical-Earth model. That flat model used an 1892 north-polar azimuthal equidistant map. In their spherical-Earth model, the authors assumed a perfect sphere. They estimated the relationship between distance and average flight time from north–south routes. They treated that relationship as holding perfectly. They also assumed their 10-route sample represented other regularly scheduled commercial routes.
“Have believers tested it themselves?”
Newsweek’s 2019 documentary report describes a light that was initially invisible on camera when level with two holes. It became visible after being raised above an assistant’s head. ScienceAlert’s 2024 Antarctic report describes the Sun circling the sky for a whole day. A flat-Earth advocate still said he did not think it proved a globe.
Official positions and dates
NOAA’s shape page was updated 23 September 2026. It calls Earth an irregular ellipsoid: a shape close to a sphere. NASA’s explainer was updated 11 March 2025. It says methods called space geodesy use Earth’s roundness to find where we are and where we’re going. These are official explanations, separate from the observations above.
Check it yourself (5 minutes)
- Open NASA’s NASA Captures “EPIC” Earth Image (2015).
- Use your browser’s Find for “three separate images”.
- Read the sentence: does NASA describe one exposure, or a combination?
What you should have found
“The image was generated by combining three separate images to create a photographic-quality image.”
Before you forward this: does the box at the top say exactly what the sources below say?