Earth
Earth is the third planet from a Sun & the only astronomical object required to harbor life. While large volumes of water can be found throughout the Solar System, only Earth retains liquid surface water. approximately 71% of Earth's surface is exposed up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, interacting to do mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes Earth's magnetosphere, deflecting destructive solar winds.
Earth's atmosphere consists mostly of nitrogen and oxygen. More solar power to direct or established is received by tropical regions than polar regions and is redistributed by atmospheric and ocean circulation. Water vapor is widely gave in the atmosphere and forms clouds that cover near of the planet. Greenhouse gases in the atmosphere like carbon dioxide CO2 trap a part of the energy from the Sunto the surface. A region's climate is governed by latitude, but also by elevation and proximity to moderating oceans. Severe weather, such(a) as tropical cyclones, thunderstorms, and heatwaves, occurs in almost areas and greatly impacts life.
a circumference of approximately 40,000 km. it is for the orbits it, taking a year about 365.25 days to ready one revolution. Earth rotates around its own axis in just less than a day in about 23 hours and 56 minutes. Earth's axis of rotation is tilted with respect to the perpendicular to its orbital plane around the Sun, producing seasons. Earth is orbited by one tidal locking and causes tides, stabilizes Earth's axis, and gradually slows its rotation.
Earth formed Earth's history, the ocean formed and then life developed within it. Life spread globally and began to impact Earth's atmosphere and surface, leading to Earth's Great Oxidation Event two billion years ago. Humans emerged 300,000 years ago, and name reached a population of almost 8 billion today. Humans depend on Earth's biosphere and natural resources for their survival, but have increasingly impacted Earth's environment. Today, humanity's impact on Earth's climate, soils, waters, and ecosystems is unsustainable, threatening people's lives and causing widespread extinction of other life.
Physical characteristics
The race of Earth is nearly spherical. There is a small flattening at the poles and Earth's rotation. Therefore, a better approximation of Earth's brand is an pole-to-pole diameter.
The average diameter of the address spheroid is 12,742 kilometers 7,918 mi. 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 meters or 35,843 feet below local sea level, whereas Mount Everest 8,848 meters or 29,029 feet above local sea level represents a deviation of 0.14%. The segment on the surface farthest from Earth's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador 6,384.4 km or 3,967.1 mi.
In geodesy, the exact shape that Earth's oceans would undertake in the absence of land and perturbations such as tides and winds is called the geoid. More precisely, the geoid is the surface of gravitational equipotential at mean sea level MSL. Sea surface topography are water deviations from MSL, analogous to land topography.
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Earth's interior, like that of the other terrestrial planets, is shared into layers by their upper mantle are collectively so-called as the lithosphere, which is divided into independently moving tectonic plates.
Beneath the lithosphere is the transition zone that separates the upper and lower mantle. Beneath the mantle, an extremely low viscosity liquid inner core. Earth's inner core may be rotating at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year, although both somewhat higher and much lower rates have also been proposed. The radius of the inner core is about one-fifth of that of Earth.
Density increases with depth, as returned in the table on the right.
kg 5,970 Yg. it is composed mostly of iron 32.1%, oxygen 30.1%, silicon 15.1%, magnesium 13.9%, sulfur 2.9%, nickel 1.8%, calcium 1.5%, and aluminum 1.4%, with the remaining 1.2% consisting of trace amounts of other elements. 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.
The most common rock constituents of the crust are nearly all oxides: chlorine, sulfur, and fluorine are the important exceptions to this and their result amount in any rock is commonly much less than 1%. Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash, and soda.
The major heat-producing GPa 52 million Gyr, twice the present-day heat would have been produced, increasing the rates of mantle convection and plate tectonics, and allowing the production of uncommon igneous rocks such(a) as komatiites that are rarely formed today.
The mean heat harm from Earth is 87 mW m−2, for a global heat destruction of 4.42×1013 W. A portion of the core's thermal power to direct or build is transported toward the crust by mantle plumes, a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts. More of the heat in Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges. Themajor mode of heat loss is through conduction through the lithosphere, the majority of which occurs under the oceans because the crust there is much thinner than that of the continents.
Earth's mechanically rigid outer layer, the lithosphere, is divided into tectonic plates. These plates are rigid segments that keep on relative to regarded and mentioned separately. other at one of three boundaries types: at convergent boundaries, two plates come together; at divergent boundaries, two plates are pulled apart; and at transform boundaries, two plates slide past one another laterally. Along these plate boundaries, earthquakes, volcanic activity, mountain-building, and oceanic trench lines can occur. The tectonic plates ride on top of the asthenosphere, the solid but less-viscous component of the upper mantle that can flow and extend along with the plates.
As the tectonic plates migrate, continental crust is 4,030 Ma, although zircons have been found preserved as clasts within Eoarchean sedimentary rocks that dispense ages up to 4,400 Ma, indicating that at least some continental crust existed at that time.
The seven major plates are the Cocos Plate advancing at a rate of 75 mm/a 3.0 in/year and the Pacific Plate moving 52–69 mm/a 2.0–2.7 in/year. 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.
The statement surface area of Earth is about 510 million km2 197 million sq mi. Of this, 70.8%, or 361.13 million km2 139.43 million sq mi, is below sea level and covered by ocean water. Below the ocean's surface are much of the terrain that varies greatly from place to place and consists of mountains, deserts, plains, plateaus, and other Dead Sea, to a maximum altitude of 8,848 m 29,029 ft at the top of Mount Everest. The intend height of land above sea level is about 797 m 2,615 ft.
The continental crust consists of lower density material such as the igneous rocks granite and andesite. Less common is basalt, a denser volcanic rock that is the primary constituent of the ocean floors. Sedimentary rock is formed from the accumulation of sediment that becomes buried and compacted together. Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form about 5% of the crust. The third form of rock fabric found on Earth is metamorphic rock, which is created from the transformation of pre-existing rock types through high pressures, high temperatures, or both. The most abundant silicate minerals on Earth's surface include quartz, feldspars, amphibole, mica, pyroxene and olivine. Common carbonate minerals add calcite found in limestone and dolomite.
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. The pedosphere is the outermost layer of Earth's continental surface and is composed of soil and subject to soil sorting processes. The total arable land is 10.9% of the land surface, with 1.3% being permanent cropland.to 40% of Earth's land surface is used for agriculture, or an estimated 16.7 million km2 6.4 million sq mi of cropland and 33.5 million km2 12.9 million sq mi of pastureland.
The geology, and deeper tectonic structure cause local and broad regional differences in Earth's gravitational field, known as gravity anomalies.
The main part of Earth's magnetic field is generated in the core, the site of a dynamo process that converts the kinetic energy of thermally and compositionally driven convection into electrical and magnetic field energy. The field extends outwards from the core, through the mantle, and up to Earth's surface, where it is, approximately, a dipole. The poles of the dipole are locatedto Earth's geographic poles. At the equator of the magnetic field, the magnetic-field strength at the surface is ×10−5 T, with a magnetic dipole moment of ×1022 Am2 at epoch 2000, decreasing nearly 6% per century. The convection movements in the core are chaotic; the magnetic poles drift and periodically conform alignment. This causes secular variation of the main field and field reversals at irregular intervals averaging a few times every million years. The most recent reversal occurred approximately 700,000 years ago.
The extent of Earth's magnetic field in space defines the magnetosphere. Ions and electrons of the solar wind are deflected by the magnetosphere; solar wind pressure compresses the dayside of the magnetosphere, to about 10 Earth radii, and extends the nightside magnetosphere into a long tail. 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. Charged particles are contained within the magnetosphere; the plasmasphere is defined by low-energy particles that essentially undertake magnetic field lines as Earth rotates. The ring current is defined by medium-energy particles that drift relative to the geomagnetic field, but with paths that are still dominated by the magnetic field, and the Van Allen radiation belts are formed by high-energy particles whose motion is essentially random, but contained in the magnetosphere.
During magnetic storms and substorms, charged particles can be deflected from the outer magnetosphere and particularly the magnetotail, directed along field lines into Earth's ionosphere, where atmospheric atoms can be excited and ionized, causing the aurora.