Flat Earth is an archaic and scientifically disproven conception of the Earth's shape as a plane or disk. Many ancient societies subscribed to a flat-Earth cosmography. The model has undergone a recent resurgence as a conspiracy theory in the 21st century.
The idea of a spherical Earth appeared in ancient Greek philosophy with Pythagoras (6th century BC). However, the early Greek cosmological view of a flat Earth persisted among most pre-Socratics (6th–5th century BC). In the early 4th century BC, Plato wrote about a spherical Earth. By about 330 BC, his former student Aristotle had provided strong empirical evidence for a spherical Earth. Knowledge of the Earth's global shape gradually began to spread beyond the Hellenistic world. By the early period of the Christian Church, the spherical view was widely held, with some notable exceptions. In contrast, ancient Chinese scholars consistently describe the Earth as flat, and this perception remained unchanged until their encounters with Jesuit missionaries in the 17th century. Muslim scholars in early Islam maintained that the Earth is flat. However, since the 9th century, Muslim scholars have tended to believe in a spherical Earth.
It is a historical myth that medieval Europeans generally thought the Earth was flat. This myth was created in the 17th century by Protestants to argue against Catholic teachings, and gained currency in the 19th century.
Despite the scientific facts and obvious effects of Earth's sphericity, pseudoscientific flat-Earth conspiracy theories persist. Since the 2010s, belief in a flat Earth has increased, both as membership of modern flat Earth societies, and as unaffiliated individuals using social media. In a 2018 study reported on by Scientific American, only 82% of 18- to 24-year-old American respondents agreed with the statement "I have always believed the world is round". However, a firm belief in a flat Earth is rare, with less than 2% acceptance in all age groups.
History Belief in flat Earth Near East
In early Egyptian and Mesopotamian thought, the world was portrayed as a disk floating in the ocean. A similar model is found in the Homeric account from the 8th century BC in which "Okeanos, the personified body of water surrounding the circular surface of the Earth, is the begetter of all life and possibly of all gods."
The Pyramid Texts and Coffin Texts of ancient Egypt show a similar cosmography; Nun (the Ocean) encircled ("dry lands" or "islands").Pyramid Texts, Utterance 366, 629a–29c: "Behold, thou art great and round like the Great Round; Behold, thou are bent around, and art round like the Circle which encircles the nbwt; Behold, thou art round and great like the Great Circle which sets." (Faulkner 1969, 120)Ancient Near Eastern Texts, Pritchard, 1969, p. 374.Coffin Texts, Spell 714.
The Israelites also imagined the Earth to be a disc floating on water with an arched firmament above it that separated the Earth from the heavens. The sky was a solid dome with the Sun, Moon, planets, and stars embedded in it.
Greece Poets Both HomerIliad, 18. 606. and HesiodThe Shield of Heracles, pp. 314–6, transl. Hugh G. Evelyn-White, 1914. described a disc cosmography on the Shield of Achilles.The Shield of Achilles and the Poetics of Ekphrasis, Andrew Sprague Becker, Rowman & Littlefield, 1995, p. 148.Professor of Classics (Emeritus) Mark W. Edwards in his The Iliad. A Commentary (1991, p. 231) has noted of Homer's usage of the flat Earth disc in the Iliad: "Okeanos...surrounds the pictures on the shield and he surrounds the disc of the Earth on which men and women work out their lives." Quoted in The Shield of Achilles and the Poetics of Ekphrasis, Andrew Sprague Becker, Rowman & Littlefield, 1995, p. 148. This poetic tradition of an Earth-encircling (gaiaokhos) sea (Oceanus) and a disc also appears in Stasinus of Cyprus,Stasinus of Cyprus wrote in his Cypria (lost, only preserved in fragment) that Oceanus surrounded the entire Earth: deep eddying Oceanus and that the Earth was flat with furthest bounds, these quotes are found preserved in Athenaeus, Deipnosophistae, VIII. 334B. Mimnermus,Mimnermus of Colophon (630BC) details a flat-Earth model, with the sun (Helios) bathing at the edges of Oceanus that surround the Earth (Mimnermus, frg. 11). Aeschylus,Seven against Thebes, verse 305; Prometheus Bound, 1, 136; 530; 665 (which also describe the 'edges' of the Earth). and Apollonius Rhodius.Apollonius Rhodius, in his Argonautica (3rd century BC) included numerous flat-Earth references (IV. 590 ff): "Now that river, rising from the ends of the Earth, where are the portals and mansions of Nyx (Night), on one side bursts forth upon the beach of Okeanos."
Homer's description of the disc cosmography on the shield of Achilles with the encircling ocean is repeated far later in Quintus Smyrnaeus' Posthomerica (4th century AD), which continues the narration of the Trojan War.Posthomerica (V. 14). "Here [on the shield of Achilles] Tethys' all-embracing arms were wrought, and Okeanos fathomless flow. The outrushing flood of Rivers crying to the echoing hills all round, to right, to left, rolled o'er the land." Translation by Way, A.S. 1913.
Philosophers
Several pre-Socratic philosophers believed that the world was flat: Thales (c. 550 BC) according to several sources, and Leucippus (c. 440 BC) and Democritus (c. 460–370 BC) according to Aristotle.Aristotle, De Caelo, 294b13–21
Thales thought that the Earth floated in water like a log.Aristotle, De Caelo, II. 13. 3; 294a 28: "Many others say the Earth rests upon water. This... is the oldest theory that has been preserved, and is attributed to Thales of Miletus." It has been argued, however, that Thales actually believed in a spherical Earth. Anaximander (c. 550 BC) believed that the Earth was a short cylinder with a flat, circular top that remained stable because it was the same distance from all things.Hippolytus, Refutation of all Heresies, i. 6. (Plut., Strom. 2; Dox. 579). Anaximenes of Miletus believed that "the Earth is flat and rides on air; in the same way the Sun and the Moon and the other heavenly bodies, which are all fiery, ride the air because of their flatness".Hippolytus, Refutation of all Heresies, i. 7; Cf. Aristotle, De Caelo, 294b13–21. Xenophanes (c. 500 BC) thought that the Earth was flat, with its upper side touching the air, and the lower side extending without limit.Xenophanes DK 21B28, quoted in Achilles, Introduction to Aratus 4.
Belief in a flat Earth continued into the 5th century BC. Anaxagoras (c. 450 BC) agreed that the Earth was flat,Diogenes Laërtius, ii. 8. and his pupil Archelaus believed that the flat Earth was depressed in the middle like a saucer, to allow for the fact that the Sun does not rise and set at the same time for everyone.Hippolytus, Refutation of all Heresies, i. 9.
Historians Hecataeus of Miletus believed that the Earth was flat and surrounded by water.FGrH F 18a. Herodotus in his Histories ridiculed the belief that water encircled the world,Herodotus knew of the conventional view, according to which the river Ocean runs around a circular flat Earth (4.8), and of the division of the world into three – Jacoby, RE Suppl. 2.352 ff, yet rejected this personal belief (Histories, 2. 21; 4. 8; 4. 36). yet most classicists agree that he still believed Earth was flat because of his descriptions of literal "ends" or "edges" of the Earth.The history of Herodotus, George Rawlinson, Appleton and company, 1889, p. 409.
Northern Europe The ancient Norse and Germanic peoples believed in a flat-Earth cosmography with the Earth surrounded by an ocean, with the axis mundi, a world tree (Yggdrasil), or pillar (Irminsul) in the centre. In the world-encircling ocean sat a snake called Jormungandr.One of the earliest literary references to the world encircling water snake comes from Bragi Boddason who lived in the 9th century, in his Ragnarsdrápa (XIV). The Norse creation account preserved in Gylfaginning (VIII) states that during the creation of the Earth, an impassable sea was placed around it:
The late Norse Konungs skuggsjá, on the other hand, explains Earth's shape as a sphere:
East Asia
In ancient China, the prevailing belief was that the Earth was flat and square, while the heavens were round, an assumption virtually unquestioned until the introduction of European astronomy in the 17th century. The English sinologist Cullen emphasizes the point that there was no concept of a round Earth in ancient Chinese astronomy:
The model of an egg was often used by Chinese astronomers such as Zhang Heng (78–139 AD) to describe the heavens as spherical:
This analogy with a curved egg led some modern historians, notably Joseph Needham, to conjecture that Chinese astronomers were, after all, aware of the Earth's sphericity. The egg reference, however, was rather meant to clarify the relative position of the flat Earth to the heavens:
Further examples cited by Needham supposed to demonstrate dissenting voices from the ancient Chinese consensus actually refer without exception to the Earth being square, not to it being flat. Accordingly, the 13th-century scholar Li Ye, who argued that the movements of the round heaven would be hindered by a square Earth, did not advocate a spherical Earth, but rather that its edge should be rounded off so as to be circular. However, Needham disagrees, affirming that Li Ye believed the Earth to be spherical, similar in shape to the heavens but much smaller.Needham, Joseph; Wang, Ling. (1995) . Science and Civilization in China: Mathematics and the Sciences of the Heavens and the Earth, vol. 3, reprint edition. Cambridge: Cambridge University Press. , p. 498. This was preconceived by the 4th-century scholar Yu Xi, who argued for the infinity of outer space surrounding the Earth and that the latter could be either square or round, in accordance to the shape of the heavens.Needham, Joseph; Wang, Ling. (1995) . Science and Civilization in China: Mathematics and the Sciences of the Heavens and the Earth, vol. 3, reprint edition. Cambridge: Cambridge University Press. , pp. 220, 498. When Chinese geographers of the 17th century, influenced by European cartography and astronomy, showed the Earth as a sphere that could be circumnavigated by sailing around the globe, they did so with formulaic terminology previously used by Zhang Heng to describe the spherical shape of the Sun and Moon (i.e. that they were as round as a crossbow bullet).Needham, Joseph; Wang, Ling. (1995) . Science and Civilization in China: Mathematics and the Sciences of the Heavens and the Earth, vol. 3, reprint edition. Cambridge: Cambridge University Press. , pp. 227, 499.
As noted in the book Huainanzi,Joseph Needham, p. 225. in the 2nd century BC, Chinese astronomers effectively inverted Eratosthenes' calculation of the curvature of the Earth to calculate the height of the Sun above the Earth. By assuming the Earth was flat, they arrived at a distance of (approximately ). The Zhoubi Suanjing also discusses how to determine the distance of the Sun by measuring the length of noontime shadows at different latitudes, a method similar to Eratosthenes' measurement of the circumference of the Earth, but the Zhoubi Suanjing assumes that the Earth is flat.
Alternate or mixed theories
Mesopotamia