Flat Earth in the context of Eä

The earliest known world maps date to classical antiquity, the oldest examples of the 6th to 5th centuries BCE still based on the flat Earth paradigm. World maps assuming a spherical Earth first appear in the Hellenistic period. The developments of Greek geography during this time, notably by Eratosthenes and Posidonius culminated in the Roman era, with Ptolemy's world map (2nd century CE), which would remain authoritative throughout the Middle Ages. Since Ptolemy, knowledge of the approximate size of the Earth allowed cartographers to estimate the extent of their geographical knowledge, and to indicate parts of the planet known to exist but not yet explored as terra incognita.

With the Age of Discovery, during the 15th to 18th centuries, world maps became increasingly accurate; exploration of Antarctica, Australia, and the interior of Africa by western mapmakers was left to the 19th and early 20th century.

Spherical Earth or Earth's curvature refers to the approximation of the figure of the Earth as a sphere. The earliest documented mention of the concept dates from around the 5th century BC, when it appears in the writings of Greek philosophers. In the 3rd century BC, Hellenistic astronomy established the roughly spherical shape of Earth as a physical fact and calculated the Earth's circumference. This knowledge was gradually adopted throughout the Old World during Late Antiquity and the Middle Ages, displacing earlier beliefs in a flat Earth. A practical demonstration of Earth's sphericity was achieved by Ferdinand Magellan and Juan Sebastián Elcano's circumnavigation (1519–1522).

The realization that the figure of the Earth is more accurately described as an ellipsoid dates to the 17th century, as described by Isaac Newton in Principia. In the early 19th century, the flattening of the earth ellipsoid was determined to be of the order of 1/300 (Delambre, Everest). The modern value as determined by the US DoD World Geodetic System since the 1960s is close to 1/298.25. The scientific study of the shape of the Earth is known as geodesy.

Early Greek cosmology refers to beliefs about the origins, development, and structure of the universe in Ancient Greece that existed before the development of Ancient Greek astronomy. The basic elements of this early cosmology included a flat earth, heaven, a cosmic ocean, the afterworld (Hades), and the netherworld (Tartarus). The first three were represented by the gods Gaia, Uranus, and Oceanus (or sometimes Pontus). Ancient Greek cosmology was related to ancient Near Eastern cosmology, and was ultimately replaced by a more systematic and demythologized approach found in ancient Greek astronomy. Its main sources are the poetry of Homer (the Iliad and the Odyssey), Hesiod (the Theogony and the Works and Days), and surviving fragments from Mimnermus.

Beginning in the 5th century BC, elements of the traditional Greek cosmos began to be modified and challenged. One of the earliest of these challenges came from the emergence of the view that the cosmos as a whole was spherical (advocated by Xenophanes, Parmenides, Empedocles, and others). The rotation of the spherical cosmos was said to explain the visible rotation of the stars (an idea called "vortex"). Soon, a spherical model of the earth itself was proposed, which gradually gained acceptance, although the flat earth view never entirely disappeared during either classical antiquity or late antiquity, continuing to receive support from geographers and others like Ctesias, Ephorus, Strabo, Tacitus, and the Epicureans. The last Greek advocate of the traditional cosmology was Cosmas Indicopleustes.

Orlando Ferguson (November 6, 1846 – February 3, 1911) was a South Dakota resident best known today for a detailed flat Earth map he created in 1893.

Anti-scientific beliefs in a flat Earth are promoted by a number of organizations and individuals. The claims of modern flat Earth proponents are not based on scientific knowledge and are contrary to over two millennia of scientific consensus based on multiple confirming lines of evidence that Earth is roughly spherical. Flat Earth beliefs are classified by experts in philosophy and physics as a form of science denial.

Flat Earth groups of the modern era date from the middle of the 20th century; some adherents are serious and some are not. Those who are serious are often motivated by religion or conspiracy theories. Through the use of social media, flat Earth theories have been increasingly espoused and promoted by individuals unaffiliated with larger groups. Many believers make use of social media to spread their views.

The cosmology of the ancient Near East refers to beliefs about where the universe came from, how it developed, and its physical layout, in the ancient Near East, an area that corresponds with the Middle East today (including Mesopotamia, Egypt, Persia, the Levant, Anatolia, and the Arabian Peninsula). The basic understanding of the world in this region from premodern times included a flat earth, a solid layer or barrier above the sky (the firmament), a cosmic ocean located above the firmament, a region above the cosmic ocean where the gods lived, and a netherworld located at the furthest region in the direction down. Creation myths explained where the universe came from, including which gods created it (and how), as well as how humanity was created. These beliefs are attested as early as the fourth millennium BC and dominated until the modern era, with the only major competing system being the Hellenistic cosmology that developed in Ancient Greece in the mid-1st millennium BC.

Geographically, these views are known from the Mesopotamian cosmologies from Babylonia, Sumer, and Akkad; the Levantine or West Semitic cosmologies from Ugarit and ancient Israel and Judah (the biblical cosmology); the Egyptian cosmology from Ancient Egypt; and the Anatolian cosmologies from the Hittites. This system of cosmology went on to have a profound influence on views in early Greek cosmology, later Jewish cosmology, patristic cosmology, and Islamic cosmology (including Quranic cosmology).

Biblical cosmology is the biblical writers' conception of the cosmos as an organised, structured entity, including its origin, order, meaning and destiny. The Bible was formed over many centuries, involving many authors, and reflects shifting patterns of religious belief; consequently, its cosmology is not always consistent. Nor do the biblical texts necessarily represent the beliefs of all Jews or Christians at the time they were put into writing: the majority of the texts making up the Hebrew Bible or Old Testament in particular represent the beliefs of only a small segment of the ancient Israelite community, the members of a late Judean religious tradition centered in Jerusalem and devoted to the exclusive worship of Yahweh.

The ancient Israelites envisaged the universe as a flat disc-shaped Earth floating on water, heaven above, underworld below. Humans inhabited Earth during life and the underworld after death; there was no way that mortals could enter heaven, and the underworld was morally neutral; only in Hellenistic times (after c. 330 BCE) did Jews begin to adopt the Greek idea that it would be a place of punishment for misdeeds, and that the righteous would enjoy an afterlife in heaven. In this period too the older three-level cosmology in large measure gave way to the Greek concept of a spherical Earth suspended in space at the center of a number of concentric heavens.

Discworld is a fantasy comedy book series written by English author Terry Pratchett, set on the Discworld, a flat planet balanced on the backs of four elephants which in turn stand on the back of a giant turtle. The series began in 1983 with The Colour of Magic and continued until the final novel The Shepherd's Crown, which was published in 2015, following Pratchett's death. The books frequently parody or take inspiration from classic works, usually fantasy or science fiction, as well as mythology, folklore and fairy tales, and often use them for satirical parallels with cultural, political and scientific issues.

Forty-one Discworld novels were published. Apart from the first novel in the series, The Colour of Magic, the original British editions of the first 26 novels, up to Thief of Time (2001), had cover art by Josh Kirby. After Kirby's death in 2001, the covers were designed by Paul Kidby. The American editions, published by HarperCollins, used their own cover art. Companion publications include eleven short stories (some only loosely related to the Discworld), four popular science books, and a number of supplementary books and reference guides. The series has been adapted for graphic novels, theatre, computer and board games, and television.

The fictional cosmology of J. R. R. Tolkien's legendarium combines aspects of Christian theology and metaphysics with pre-modern cosmological concepts in the flat Earth paradigm, along with the modern spherical Earth view of the Solar System.

The created world, Eä, includes the planet Arda, corresponding to the Earth. It is created flat, with the dwelling of the godlike Valar at its centre. When this is marred by the evil Vala Melkor, the world is reshaped, losing its perfect symmetry, and the Valar move to Valinor, but the Elves can still sail there from Middle-earth. When Men try to go there, hoping for immortality, Valinor and its continent of Aman are removed from Arda, which is reshaped as a round world. Scholars have compared the implied cosmology with that of Tolkien's religion, Catholicism, and of medieval poetry such as Pearl or Dante's Paradiso, where there are three parts, Earth, Purgatory or the Earthly Paradise, and Heaven or the Celestial Paradise. Scholars have debated the nature of evil in Middle-earth, arguing whether it is the absence of good (the Boethian position) or equally as powerful as good (the Manichaean view).