flat Earth
-
What is the flat Earth theory?
The flat Earth theory is the belief that Earth is a flat disk rather than a sphere or ellipsoid. This idea was common in the ancient world but was replaced by the understanding that Earth is spherical due to empirical observation.
The modern resurgence of the flat Earth theory can be traced to the mid-19th century and has gained popularity through the Internet and social media. Modern flat Earth models include the idea of a circular disk with the North Pole at the center and a wall of ice at the edges. Some adherents believe that the Sun and Moon are small and circle above the disk. Others propose that Earth is a disk accelerating upward to create the illusion of gravity.
This theory persists despite scientific evidence and is often rooted in mistrust of science, conspiracy theories, and social media misinformation.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Who first believed that the Earth was flat?
Different ancient civilizations believed in a flat Earth. Ancient Egyptian and Mesopotamian records depict the world as a disk in the ocean with the heavens arching above it.
An Iraqi tablet, dating back to 1000 BCE, shows Babylon at the center of a flat disk. The Greek philosopher Anaximander (610–546 BCE) viewed Earth as a flat disk atop a cylinder. Some sacred texts in India describe the planet as stacked flat disks or a horizontal wheel on a vertical axle. In China, the Earth was described as flat and square until the 17th century, when Western science presented evidence of its spherical shape.
Pythagoras suggested Earth was spherical in the 6th century BCE, and Aristotle later provided arguments for this in the 4th century BCE.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What are some reasons people believed the Earth was flat?
Prior to the advances in science and technology, a few factors contributed to the belief that Earth was flat.
- Limited perspective From the surface, the world looks flat and stationary because ancient technology couldn't allow people to view Earth from a high enough altitude to see its curvature. To observe Earth’s curved horizon, one must be at least 10,668 metres (about 35,000 feet) above its surface.
- Celestial movement The Sun and Moon appear to rise in the east and set in the west relative to a flat horizon. Similarly, the stars seem to rotate in a dome overhead, reinforcing the perception of a flat, unmoving Earth.
- Cultural descriptions Ancient civilizations like the Egyptians and Mesopotamians depicted the world as a disk in the ocean with the heavens arching above. Likewise, a tablet from Iraq dated to 1000 BCE shows Babylon at the center of a flat disk.
- Mistrust of science Some people resist scientific findings and prefer to rely on their own observations. This can be due to a general mistrust of official scientific sources, the perpetuation of conspiracy theories, loyalty to specific groups, and the spread of misinformation through social media.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How did scientists prove the Earth is round?
Early evidence that the Earth is curved came from ancient Greek philosophers. Pythagoras, in the 6th century BCE, noted the spherical nature of the Moon and Sun and reasoned that Earth was also spherical. In the 4th century BCE, Aristotle estimated Earth's circumference.
Later, sailors observed stars shifting as they traveled and saw ships appearing in stages over the horizon, indicating Earth's curvature. In 240 BCE, Eratosthenes used geometry based on shadows and their angles relative to the Sun to estimate Earth’s circumference.
Today, geodesy, the science of determining Earth's size and shape, uses satellite data to map the geoid, which is the average sea level across the globe. These satellites use techniques to measure the drift rates of continents and define the global gravity pattern.
4 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Why do some groups still support flat Earth ideas today?
Belief in a flat Earth persists due to mistrust of science, conspiracy theories, community loyalty, and social media misinformation. The modern flat Earth concept emerged in the 1950s and gained traction through the Internet in the early 2000s.
Flat Earth models vary, with some echoing ancient views of Earth as a disk beneath a rotating dome of stars. Others propose the Sun and Moon are small and close, or that Antarctica surrounds the world. Some reject gravity, suggesting Earth accelerates upward to simulate it.
Scientists address this by debunking models online and restoring trust in science through respectful engagement with flat Earth adherents. You can explore more on this topic at flat Earth.
1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What evidence do people use to argue for or against the flat Earth theory?
The flat Earth theory is the idea that Earth is a flat disk, despite evidence to the contrary. This perception existed in the ancient world until empirical observations proved Earth is a sphere.
Arguments for a flat Earth often involve mistrust of scientific sources, embracing conspiracy theories, and community loyalty. Proponents suggest the horizon appears flat, the Sun and Moon are small and close, and gravity is an illusion caused by Earth accelerating upward.
However, scientific evidence overwhelmingly supports a spherical Earth. Observations by ancient Greeks, such as Pythagoras and Anaxagoras, noted curved shadows during lunar eclipses and changing star locations as one travels. Additionally, the fact that ships disappear hull first over the horizon demonstrates Earth's curvature.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
flat Earth, the perception that Earth exists as a flat disk, either circular or square-shaped. This view persisted in the ancient world until empirical observations revealed that Earth’s shape was spherical or ellipsoidal. In modern times, however, the notion of a flat Earth has been revived and promoted on social media despite scientific evidence to the contrary.
Traditional conceptualizations
To observe Earth’s curved horizon, one must be at least 10,668 metres (about 35,000 feet) above its surface. Since the technology of ancient cultures was insufficient to allow people to reach such heights, the world around them appeared to be flat and stationary. Their perceptions were further reinforced by the movements of the Sun and the Moon, which appear to rise in the east and set in the west relative to a flat horizon, and of the stars, which appear to rotate in a dome overhead.
Different descriptions of a flat Earth can be found in the annals of ancient civilizations worldwide. For example, ancient Egyptian and Mesopotamian records describe the world as a disk in the ocean with the heavens arching above it. An Iraqi tablet dated to 1000 bce shows Babylon at the centre of a flat disk, and the Greek philosopher Anaximander (610–546 bce) perceived Earth as a flat disk perched at the top of a cylinder. In Norse cosmology, Earth’s flat plane is encircled by an ocean, with a world tree or pillar at the centre. In India some sacred texts describe the planet as a series of stacked flat disks, while others describe it as a horizontal wheel set on a vertical axle. In China Earth was described as flat and square into the 17th century, at which time Western science introduced evidence for the planet’s spherical shape (see also spherical Earth).
" height="20" alt="HEW Logo">
Contemporary revival
The idea that Earth is flat seems to have an enduring hold on human imagination. In the 1830s a commune in Britain, led by British writer Samuel Birley Rowbotham, resurrected the concept as backlash against rapid scientific progress. Members believed that Earth was a circular disk with the North Pole at the centre and a wall of ice surrounding the edges of the disk to contain the oceans. The group was regarded as a harmless symbol of British eccentricity.
What would become the modern flat Earth concept emerged modestly in the 1950s as the Flat Earth Society, a small fringe group in Britain with a membership of fewer than 4,000 people. However, largely due to the rising influence of the Internet and social media in the early 2000s, the organization launched itself worldwide in October 2009, and annual conferences followed and catered to a variety of worldviews. Some of the society’s models echo the ancient view of Earth as a disk with a dome of stars rotating above it. The models of other groups, however, claim that the Sun and the Moon are only 50 km (31 miles) in diameter and that they circle the disk at a height of 5,500 km (3,417 miles). Others envision a world hemmed in by Antarctica (which is believed to extend infinitely in all directions), or they reject conventional laws of gravity, explaining that Earth exists as a disk that accelerates upward in order to give the illusion of gravity.
Scientists and researchers who study this growing movement have found that its appeal is rooted in four trends: the public’s mistrust of official scientific sources, the perpetuation of conspiracy theories, loyalty to the groups and community they identify with, and the use of social media to spread misinformation. Flat Earth ideas have gained a large enough audience worldwide to alarm some scientists, who have launched their own social media campaigns to debunk the flat Earth models promoted online. Other researchers are working to overcome these perceptions by combining the teaching of rigorous evidence-based science with a restoration of public trust in scientific institutions attained by taking the questions of flat Earth adherents seriously and refraining from taking aloof and dismissive positions.