when was the earth divided into continents

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when was the earth divided into continents

[214] The leakage of hydrogen into space contributes to the shifting of Earth's atmosphere and surface from an initially reducing state to its current oxidizing one. Water vapor, carbon dioxide, methane, nitrous oxide, and ozone are the primary greenhouse gases in the atmosphere. [74] This facilitated tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain, which led to the evolution of humans. [191] Shifts in the oceanic temperature distribution can cause significant weather shifts, such as the El Niño–Southern Oscillation. The presence of grains of the mineral zircon of Hadean age in Eoarchean sedimentary rocks suggests that at least some felsic crust existed as early as 4.4 Ga, only 140 Ma after Earth's formation. During the summer, the day lasts longer, and the Sun climbs higher in the sky. Since then, the combination of Earth's distance from the Sun, physical properties and geological history have allowed life to evolve and thrive. Earth's atmosphere consists mostly of nitrogen and oxygen. [201], The amount of solar energy reaching Earth's surface decreases with increasing latitude. [87] so that a better approximation of Earth's shape is an oblate spheroid, whose equatorial diameter is 43 kilometres (27 mi) larger than the pole-to-pole diameter. Earth has never had a planetwide government, but the United Nations is the leading worldwide intergovernmental organization. [199] Most of the water is then transported to lower elevations by river systems and usually returned to the oceans or deposited into lakes. The ozone layer blocks ultraviolet solar radiation, permitting life on land. [166] The same effect on the Moon has led to its tidal locking: its rotation period is the same as the time it takes to orbit Earth. The remaining 71% is covered with water, mostly by oceans but also by lakes, rivers, and other fresh water, which together constitute the hydrosphere. The crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, which is divided into independently moving tectonic plates.[103]. [68][69], During the Neoproterozoic, 1000 to 541 Ma, much of Earth might have been covered in ice. Africa is split into 54 countries, Asia 48, Australia/Oceania 7, Europe 51, North America 23, and South … The Australian Plate fused with the Indian Plate between 50 and 55 Ma. [196] Each layer has a different lapse rate, defining the rate of change in temperature with height. Though they are all interconnected, they are generally divided into 5 Oceans, namely, Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean and Antarctic Ocean. [n 6][94] [n 3] Earth's largest artificial satellite is the International Space Station. In the Northern Hemisphere, winter solstice currently occurs around 21 December; summer solstice is near 21 June, spring equinox is around 20 March and autumnal equinox is about 22 or 23 September. In many cultures it is a mother goddess that is also the primary fertility deity. [266] Lord Kelvin used thermodynamics to estimate the age of Earth to be between 20 million and 400 million years in 1864, sparking a vigorous debate on the subject; it was only when radioactivity and radioactive dating were discovered in the late 19th and early 20th centuries that a reliable mechanism for determining Earth's age was established, proving the planet to be billions of years old.[267][268]. This effect is much less significant than the total energy change due to the axial tilt, and most of the excess energy is absorbed by the higher proportion of water in the Southern Hemisphere. Due to this recycling, most of the ocean floor is less than 100 Ma old. [187], The average salinity of Earth's oceans is about 35 grams of salt per kilogram of sea water (3.5% salt). Aphelion is 103.4% of the distance to perihelion. [172][173], Viewed from Earth, the Moon is just far enough away to have almost the same apparent-sized disk as the Sun. [102] The thickness of the crust varies from about 6 kilometres (3.7 mi) under the oceans to 30–50 km (19–31 mi) for the continents. [246] Those termed non-renewable resources, such as fossil fuels, only renew over geological timescales. In the cartoons, there were two versions of the planet which … Three-quarters of the atmosphere's mass is contained within the first 11 km (6.8 mi) of the surface. [115] The tectonic plates ride on top of the asthenosphere, the solid but less-viscous part of the upper mantle that can flow and move along with the plates. He suggested that more than 200 million years ago Pangaea split apart to form the continents. [205] Atmospheric circulation also plays an important role: San Francisco and Washington DC are both coastal cities at about the same latitude. This causes a slow but steady loss of the atmosphere into space. [106] At the center, the temperature may be up to 6,000 Â°C (10,830 Â°F),[107] and the pressure could reach 360 GPa (52 million psi). [265], It was only during the 19th century that geologists realized Earth's age was at least many millions of years. Scientists since then have found evidence that this idea is correct. Alpine glaciers form in mountainous areas, whereas vast ice sheets form over land in polar regions. Within the first billion years of Earth's history, life appeared in the oceans and began to affect Earth's atmosphere and surface, leading to the proliferation of anaerobic and, later, aerobic organisms. At higher latitudes, the sunlight reaches the surface at lower angles, and it must pass through thicker columns of the atmosphere. [37] The bodies in the Solar System formed and evolved with the Sun. [72][73] Apart from the proposed current Holocene extinction event, the most recent was 66 Ma, when an asteroid impact triggered the extinction of the non-avian dinosaurs and other large reptiles, but largely spared small animals such as insects, mammals, lizards and birds. The orbital and axial planes are not precisely aligned: Earth's axis is tilted some 23.44 degrees from the perpendicular to the Earth–Sun plane (the ecliptic), and the Earth–Moon plane is tilted up to ±5.1 degrees against the Earth–Sun plane. [41], The gravitational attraction between Earth and the Moon causes tides on Earth. Solar System â†’ Local Interstellar Cloud â†’ Local Bubble â†’ Gould Belt â†’ Orion Arm â†’ Milky Way â†’ Milky Way subgroup â†’ Local Group → Local Sheet → Virgo Supercluster → Laniakea Supercluster â†’ Observable universe â†’ UniverseEach arrow (→) may be read as "within" or "part of". This hypothesis has been termed "Snowball Earth", and it is of particular interest because it preceded the Cambrian explosion, when multicellular life forms significantly increased in complexity. Over the period of hundreds of millions of years, tectonic forces have caused areas of continental crust to group together to form supercontinents that have subsequently broken apart. [98], The most common rock constituents of the crust are nearly all oxides: chlorine, sulfur, and fluorine are the important exceptions to this and their total amount in any rock is usually much less than 1%. Mammalian life has diversified over the past 66 Mys, and several million years ago an African ape gained the ability to stand upright. [179], As of April 2020[update], there are 2,666 operational, human-made satellites orbiting Earth. From early Middle English, its definite sense as "the globe" was expressed as the earth. These same latitudes also experience a midnight sun, where the sun remains visible all day. [95], Earth's mass is approximately 5.97×1024 kg (5,970 Yg). The earth is divided into four overlapping hemispheres that each represent one half of the earth from a different orientation. According to nebular theory, planetesimals formed by accretion, with the primordial Earth being estimated as likely taking anywhere from 70–100 million years to form. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends on dissolved nutrients washed down from the land. These dates change over time due to precession and other orbital factors, which follow cyclical patterns known as Milankovitch cycles. There is a small flattening at the poles and bulging around the equator due to Earth's rotation. It is the hardened part of the Earth with a depth of about 5 to 70 kilometers (~ 3 to 44 miles) and makes about less than 1% of the entire Earth’s volume. Please note: Text within images is not translated, some features may not work properly after translation, and the translation may not accurately convey the intended meaning. The poles of the dipole are located close to Earth's geographic poles. [49], The seven major plates are the Pacific, North American, Eurasian, African, Antarctic, Indo-Australian, and South American. These nutrients are constantly recycled between different species. [200] The Köppen system rates regions based on observed temperature and precipitation. Currently, there are 195 countries across the seven continents. [200] Ocean currents are also important factors in determining climate, particularly the thermohaline circulation that distributes thermal energy from the equatorial oceans to the polar regions. [40] It hit Earth with a glancing blow and some of its mass merged with Earth. Both of these motions are caused by the varying attraction of the Sun and the Moon on Earth's equatorial bulge. [183][184] Most fresh water, about 68.7%, is present as ice in ice caps and glaciers. [238][239], The first human to orbit Earth was Yuri Gagarin on 12 April 1961. The orbital speed of Earth averages about 29.78 km/s (107,200 km/h; 66,600 mph), which is fast enough to travel a distance equal to Earth's diameter, about 12,742 km (7,918 mi), in seven minutes, and the distance to the Moon, 384,000 km (239,000 mi), in about 3.5 hours. 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[5] The height of the troposphere varies with latitude, ranging between 8 km (5 mi) at the poles to 17 km (11 mi) at the equator, with some variation resulting from weather and seasonal factors. After translating an article, all tools except font up/font down will be disabled. [155] Above the Arctic Circle and below the Antarctic Circle there is no daylight at all for part of the year, causing a polar night, and this night extends for several months at the poles themselves. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. [112] More of the heat in Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges. In order from largest to smallest, they are Asia, Africa, North America, South America, Antarctica, Europe, and Australia. Model of a flat Earth, with the continents modeled in a disk-shape and Antarctica as an ice wall. Atmospheric circulation, topographic features, and temperature differences determine the average precipitation that falls in each region. [193] Water vapor content varies between 0.01% and 4%[193] but averages about 1%. [76][77], Because carbon dioxide (CO2) has a long life time in the atmosphere, moderate human CO2 emissions may postpone the next glacial inception by 100,000 years. [127], Erosion and tectonics, volcanic eruptions, flooding, weathering, glaciation, the growth of coral reefs, and meteorite impacts are among the processes that constantly reshape Earth's surface over geological time. See: Due to natural fluctuations, ambiguities surrounding, The ultimate source of these figures, uses the term "seconds of UT1" instead of "seconds of mean solar time".—. [225] Many places are subject to earthquakes, landslides, tsunamis, volcanic eruptions, tornadoes, blizzards, floods, droughts, wildfires, and other calamities and disasters. In addition to an annual component to this motion, there is a 14-month cycle called the Chandler wobble. Fifty years ago, we finally saw it", "Apollo 8's Earthrise: The Shot Seen Round the World – Half a century ago today, a photograph from the moon helped humans rediscover Earth", "We Are All Riders on the Same Planet – Seen from space 50 years ago, Earth appeared as a gift to preserve and cherish. Beneath the lithosphere is the asthenosphere, a relatively low-viscosity layer on which the lithosphere rides. In 1912 a German scientist named Alfred Wegener came up with the idea that the continents were once all joined together. Almost 8 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Another convention capitalizes "Earth" when appearing as a name (for example, "Earth's atmosphere") but writes it in lowercase when preceded by the (for example, "the atmosphere of the earth"). [47] By 3.5 Ga, Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind. The wind transports the cold or the heat of the ocean to the land. While the Earth that appears in the Mario franchise has some features derived from the nonfictional entity, fictional alterations to the planet have been applied in the series. [57] High- and middle-latitude regions have since undergone repeated cycles of glaciation and thaw, repeating about every 21,000, 41,000 and 100,000 years. Know what are the 5 Oceans of the Planet earth and get more deeper into them. In order from largest to smallest, they are Asia , Africa , North America , South America , Antarctica , Europe , and Australia . [161][n 12] Because the Southern Hemisphere is tilted toward the Sun at about the same time that Earth reaches the closest approach to the Sun, the Southern Hemisphere receives slightly more energy from the Sun than does the northern over the course of a year. From 1980 to 2000, these events caused an average of 11,800 human deaths per year. Sometimes people think of Europe and Asia as a single continent called Eurasia. By continuing to use this site, you consent to the terms of our cookie policy, which can be found in our. [220] Estimates of the number of species on Earth today vary; most species have not been described. There are at least five quasi-satellites, including 469219 KamoÊ»oalewa. Earth's gravity interacts with other objects in space, especially the Sun and the Moon, which is Earth's only natural satellite. Earth is the third planet from the Sun and the only astronomical object known to harbor life. [153][n 11] This is the maximum distance at which Earth's gravitational influence is stronger than the more distant Sun and planets. The oldest oceanic crust is located in the Western Pacific and is estimated to be 200 Ma old. [162], The Moon is a relatively large, terrestrial, planet-like natural satellite, with a diameter about one-quarter of Earth's. At the other extreme, the slowest-moving plate is the South American Plate, progressing at a typical rate of 10.6 mm/a (0.42 in/year). Improved homework resources designed to support a variety of curriculum subjects and standards. [248] These deposits are used by humans both for energy production and as feedstock for chemical production. [198], Earth's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core. ", "Curious Kids: Why is the moon called the moon? A region's climate is not only determined by latitude, but also by elevation, and by proximity to moderating oceans, among other factors. [228] This is driving changes such as the melting of glaciers and ice sheets, a global rise in average sea levels, and significant shifts in weather. Earth's rotational velocity also varies in a phenomenon known as length-of-day variation. [137] Because the velocity of the solar wind is greater than the speed at which waves propagate through the solar wind, a supersonic bow shock precedes the dayside magnetosphere within the solar wind. Without this heat-retention effect, the average surface temperature would be −18 Â°C (0 Â°F), in contrast to the current +15 Â°C (59 Â°F),[197] and life on Earth probably would not exist in its current form. What happened? 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"[27], Occasionally, the name Terra /ˈtɛrə/ is used in scientific writing and especially in science fiction to distinguish humanity's inhabited planet from others,[28] while in poetry Tellus /ˈtɛləs/ has been used to denote personification of the Earth. In the history of life on Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinctions. [5][152], The Hill sphere, or the sphere of gravitational influence, of Earth is about 1.5 million km (930,000 mi) in radius. The most recent reversal occurred approximately 700,000 years ago. In the Southern Hemisphere, the situation is reversed, with the summer and winter solstices exchanged and the spring and autumnal equinox dates swapped. Energy from the Sun heats this layer, and the surface below, causing expansion of the air. [190] Sea water has an important influence on the world's climate, with the oceans acting as a large heat reservoir. Because unfixed hydrogen has a low molecular mass, it can achieve escape velocity more readily, and it leaks into outer space at a greater rate than other gases. Oxygenic photosynthesis evolved 2.7 Gya, forming the primarily nitrogen–oxygen atmosphere of today. To re-enable the tools or to convert back to English, click "view original" on the Google Translate toolbar. [4] Thus the sidereal day is shorter than the stellar day by about 8.4 ms.[148], Apart from meteors within the atmosphere and low-orbiting satellites, the main apparent motion of celestial bodies in Earth's sky is to the west at a rate of 15°/h = 15'/min. [49] There are two main models of how this initial small volume of continental crust evolved to reach its current abundance:[50] (1) a relatively steady growth up to the present day,[51] which is supported by the radiometric dating of continental crust globally and (2) an initial rapid growth in the volume of continental crust during the Archean, forming the bulk of the continental crust that now exists,[52][53] which is supported by isotopic evidence from hafnium in zircons and neodymium in sedimentary rocks. A nebula contains gas, ice grains, and dust (including primordial nuclides). Earth’s surface is traditionally subdivided into seven continental masses: Africa, Antarctica, Asia, Australia, Europe, North America, and South America.These continents are surrounded by four major bodies of water: the Arctic, Atlantic, Indian, and Pacific oceans. Australia is part of a larger area called Oceania or Australasia. [89][90][91] The average diameter of the reference spheroid is 12,742 kilometres (7,918 mi). [60] The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. [48], As the molten outer layer of Earth cooled it formed the first solid crust, which is thought to have been mafic in composition. In its earliest attestation, the word eorðe was already being used to translate the many senses of Latin terra and Greek γῆ gē: the ground, its soil, dry land, the human world, the surface of the world (including the sea), and the globe itself. The oceans cover an area of 361.8 million km2 (139.7 million sq mi) with a mean depth of 3,682 m (12,080 ft), resulting in an estimated volume of 1.332 billion km3 (320 million cu mi). At approximately 750 Ma, one of the earliest known supercontinents, Rodinia, began to break apart. Terrestrial biomes lying within the Arctic or Antarctic Circles, at high altitudes or in extremely arid areas are relatively barren of plant and animal life; species diversity reaches a peak in humid lowlands at equatorial latitudes. [58] The Last Glacial Period, colloquially called the "last ice age", covered large parts of the continents, up to the middle latitudes, in ice and ended about 11,700 years ago. [250] These metals and other elements are extracted by mining, a process which often brings environmental and health damage. The continents then drifted apart to their current locations. By Early Modern English, many nouns were capitalized, and the earth was also written the Earth, particularly when referenced along with other heavenly bodies. [243] The farthest that humans have traveled from Earth is 400,171 km (248,655 mi), achieved during the Apollo 13 mission in 1970. [75] Over 99% of all species that ever lived on Earth are extinct. [109][110], The mean heat loss from Earth is 87 mW m−2, for a global heat loss of 4.42×1013 W.[111] A portion of the core's thermal energy is transported toward the crust by mantle plumes, a form of convection consisting of upwellings of higher-temperature rock. [181] If all of Earth's crustal surface were at the same elevation as a smooth sphere, the depth of the resulting world ocean would be 2.7 to 2.8 km (1.68 to 1.74 mi). [235], It is estimated that one-eighth of Earth's surface is suitable for humans to live on—three-quarters of Earth's surface is covered by oceans, leaving one-quarter as land. [217], A planet's life forms inhabit ecosystems, whose total forms the biosphere. [153], Earth, along with the Solar System, is situated in the Milky Way and orbits about 28,000 light-years from its center. The two models and the data that support them can be reconciled by large-scale recycling of the continental crust, particularly during the early stages of Earth's history. [223] The distance of Earth from the Sun, as well as its orbital eccentricity, rate of rotation, axial tilt, geological history, sustaining atmosphere, and magnetic field all contribute to the current climatic conditions at the surface. Beyond these, the exosphere thins out into the magnetosphere, where the geomagnetic fields interact with the solar wind. Local topography deviates from this idealized spheroid, although on a global scale these deviations are small compared to Earth's radius: the maximum deviation of only 0.17% is at the Mariana Trench (10,925 metres or 35,843 feet below local sea level),[92] whereas Mount Everest (8,848 metres or 29,029 feet above local sea level) represents a deviation of 0.14%. Local differences in topography, geology, and deeper tectonic structure cause local and broad, regional differences in Earth's gravitational field, known as gravity anomalies. Viewed from a vantage point above the north poles of both the Sun and Earth, Earth orbits in a counterclockwise direction about the Sun. Viewed from the celestial north pole, the motion of Earth, the Moon, and their axial rotations are all counterclockwise. The geological time scale organizes Earth’s history into the increasingly long time intervals of eras, periods, and epochs. [121], The total surface area of Earth is about 510 million km2 (197 million sq mi). This lower-density air then rises and is replaced by cooler, higher-density air.

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