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The concept of a spherical Earth displaced earlier beliefs in a flat Earth: In early Mesopotamian mythology, the world was portrayed as a disk floating in the ocean with a hemispherical sky-dome above, [10] and this forms the premise for early world maps like those of Anaximander and Hecataeus of Miletus.
The Monge gauge has two obvious limitations: If the average surface is not plane, then the Monge gauge only makes sense on length scales smaller than the curvature of the average surface. And the Monge gauge fails completely if the surface is so strongly bent that there are overhangs (points x,y corresponding to more than one z).
The new forms of life, called Ediacara biota, were larger and more diverse than ever. Though the taxonomy of most Ediacaran life forms is unclear, some were ancestors of groups of modern life. [145] Important developments were the origin of muscular and neural cells. None of the Ediacaran fossils had hard body parts like skeletons.
Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System. Initially, Earth was molten due to extreme volcanism and frequent collisions with other bodies.
Some flat Earth conjectures that propose that Earth is a north-pole-centered disk conceive of Antarctica as an impenetrable ice wall that encircles the planet and hides any edges. [22] This disk model explains east-west circumnavigation as simply moving around the disk in a circle. (East-west paths form a circle in both disk and spherical ...
Earth is the only known place that has ever been habitable for life. Earth's life developed in Earth's early bodies of water some hundred million years after Earth formed. Earth's life has been shaping and inhabiting many particular ecosystems on Earth and has eventually expanded globally forming an overarching biosphere. [243]
The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
The Old Bedford River, photographed from the bridge at Welney, Norfolk (2008); the camera is looking downstream, south-west of the bridge. The Bedford Level experiment was a series of observations carried out along a 6-mile (10 km) length of the Old Bedford River on the Bedford Level of the Cambridgeshire Fens in the United Kingdom during the 19th and early 20th centuries to deny the curvature ...