Earth, also known as the Earth or Terra, is the third planet outward from the Sun. It is the largest of the solar systems terrestrial planets, and the only planetary body that modern science confirms as harboring life. The planet formed around 4.5 billion (4.5×109) years... Earth cutaway from The Congress of Racial Equality or CORE is a civil rights organization that played a pivotal role in the U.S. Civil Rights Movement of the 20th century. CORE was founded by a group of college students led by James L. Farmer, Jr., Berniece Fisher and George Houser. Bayard Rustin... core to The exosphere (from the Greek words exo = out(side) and sphaira = ball) is the uppermost layer of the atmosphere. On Earth, its lower boundary is estimated at 500 km to 1000 km above the Earths surface, and its upper boundary at about 10,000 km. It is only from... exosphere. Partially to scale.

Mapping the interior of the Earth, also known as the Earth or Terra, is the third planet outward from the Sun. It is the largest of the solar systems terrestrial planets, and the only planetary body that modern science confirms as harboring life. The planet formed around 4.5 billion (4.5×109) years... Earth with Global earthquake epicenters, 1963–1998. An earthquake is a trembling or a shaking movement of the Earths surface. Earthquakes typically result from the movement of faults, quasi-planar zones of deformation within its uppermost layers. The word earthquake is also widely used to indicate the source region itself... earthquake waves.

The Earth's mantle is the layer in the structure of the Earth, also known as the Earth or Terra, is the third planet outward from the Sun. It is the largest of the solar systems terrestrial planets, and the only planetary body that modern science confirms as harboring life. The planet formed around 4.5 billion (4.5×109) years... Earth that lies directly under the Earth's In geology, a crust is the outer layer of a planet, part of its lithosphere. Planetary crusts are generally composed of a less dense material than that of its deeper layers. On partially-molten planets, such as Earth, the lithosphere is floating on fluid interior layers. Because of the partially... crust and above the Earth, also known as the Earth or Terra, is the third planet outward from the Sun. It is the largest of the solar systems terrestrial planets, and the only planetary body that modern science confirms as harboring life. The planet formed around 4.5 billion (4.5×109) years... Earth's outer core. The term is also applied to the structure of other A planet (from the Greek πλανήτης, planetes or wanderers) is a body of considerable mass that orbits a star and that produces very little or no energy through nuclear fusion. Prior to the 1990s only nine were known (all of them in our... planets. Earth's mantle lies roughly between 30 and 2,900 km below the surface.

The boundary between the crust and the mantle is the The Mohorovicic discontinuity, usually referred to as the Moho, is the boundary between the Earths crust and the mantle. The Mohorovicic discontinuity was first identified in 1909 by Andrija Mohorovicic when he observed the abrupt increase in the velocity of earthquake waves at this point. The location of the... Mohorovičić discontinuity, named for its discoverer, and is usually called the Moho. The Moho is a boundary at which there is a sudden change in the speed of Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the movement of waves through the Earth. The field also includes studies of variants such as seaquakes, causes such as volcanoes and plate tectonics in general, and consequential phenomena such as tsunami. Earthquakes (and... seismic waves. At one time some thought that the Moho was the structure at which the earth's rigid crust moved relative to the mantle. Current research places this zone of movement within the mantle, from 70 km (43 mi) below the ocean crust to 150 km (93 mi) below the continental crust. The mantle just below the crust is composed of cold and therefore rigid mantle fused to the crust but at the same time separated from it by the Moho. This rigid layer of crust and the upper mantle forms the The lithosphere (from the Greek for rocky sphere) is the solid outermost shell of a rocky planet. On the Earth, the lithosphere includes the crust and the uppermost layer of the mantle. It floats on the more plastic asthenosphere. The thickness of the lithosphere varies from around 1.6 km... lithosphere.

The mantle differs substantially from the crust in its mechanical characteristics and its A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. A chemical element is a substance that cannot be divided or changed into different... chemical composition. It is chiefly the difference of -1... chemistry on which the distinction between crust and mantle is based. Mantle rock consists of Olivine The mineral olivine is a magnesium iron silicate with the formula (Mg,Fe)2SiO4 in which the ratio of magnesium and iron varies between the two endmembers of the series: forsterite (Mg-rich) and fayalite (Fe-rich). It gives its name to the group of minerals with a related... olivines, different The Pyroxenes are a group of important rock-forming silicate minerals found in many igneous and metamorphic rocks. They share a common structure which comprises of single chains of silica tetrahedra and they crystalise in the monoclinic and orthorhombic system. Pyroxenes have the general formula XY(Si,Al)2O6 (where... pyroxenes and other In geology, mafic minerals are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. The term is a combination of magnesium and ferric, the Latin word for iron (III), but mafic magmas also are rich in calcium and sodium. Mafic minerals... mafic Minerals are natural compounds formed through geological processes. The term mineral encompasses not only the materials chemical composition but also the mineral structures. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms (organic compounds are usually excluded). The study... minerals. Typified by Peridotite Peridotite is a dense, coarse grained ultrabasic rock, consisting mainly of the minerals olivine and pyroxene. Peridotite is also a group of mantle derived igneous rocks. They all are ultramafic or ultrabasic meaning the contain less than 45% silica and are high in iron and magnesium. Members of the... peridotite, Dunite is an igneous, plutonic rock, of ultramafic composition, with coarse grained or phaneritic texture. The mineral assemblage is typically greater than 90% olivine with minor pyroxene and chromite. Dunite is the olivine rich endmember of the peridotite group of mantle derived rocks. Dunite and other peridotite rocks are considered... dunite, and Eclogite is a coarse-grained, mafic-to-ultramafic grouping of metamorphic rocks of special interest on account of the variety of minerals they contain and their microscopic structures and geological relationships. The fresh rock can be very striking in appearance, with red to pink garnets, almandine-pyrope in a green... eclogite, mantle rocks also possesses a higher portion of General Name, Symbol, Number iron, Fe, 26 Chemical series transition metal Group, Period, Block 8 (VIIIB), 4 , d Density, Hardness 7874 kg/m3, 4.0 Appearance lustrous metallic with a greyish tinge Atomic properties Atomic weight 55.845 amu Atomic radius (calc.) 140 (156) pm Covalent radius 125 pm van... iron and General Name, Symbol, Number magnesium, Mg, 12 Series alkaline earth metals Group, Period, Block 2 (IIA), 3, s Density, Hardness 1738 kg/m³, 2.5 Appearance silvery white Atomic properties Atomic weight 24.305 amu Atomic radius (calc.) 150 pm (145 pm) Covalent radius 130 pm van der Waals radius... magnesium and a smaller portion of General Name, Symbol, Number silicon, Si, 14 Series metalloid Group, Period, Block 14 (IVA), 3, p Density, Hardness 2330 kg/m3, 6.5 Appearance dark grey, bluish tinge Atomic properties Atomic weight 28.0855 amu Atomic radius (calc.) 110 pm (111 pm) Covalent radius 111 pm van der Waals radius... silicon and General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13 (IIIA), 3, p Density, Hardness 2700 kg/m3, 2.75 Appearance silvery Atomic properties Atomic weight 26.981538 amu Atomic radius (calc.) 125 pm (118 pm) Covalent radius 118 pm van der Waals radius no... aluminium than the crust. In the mantle, temperatures range between 100°C at the upper boundary to over 3,500°C at the boundary with the Earth, also known as the Earth or Terra, is the third planet outward from the Sun. It is the largest of the solar systems terrestrial planets, and the only planetary body that modern science confirms as harboring life. The planet formed around 4.5 billion (4.5×109) years... core. Although these temperatures far exceed the The melting point of a solid is the temperature at which it changes state from solid to liquid. When considered as the temperature of the reverse change, it is referred to as the freezing point. For example, the melting point of the element mercury is 234.32 kelvins (−38... melting points of the mantle rocks, particularly in deeper ranges, they are almost exclusively solid. The enormous Overburden, or lithostatic pressure, is a term used in geology to denote the pressure imposed on a stratigraphic layer by the weight of overlying layers of material. If a given layer is in hydrostatic equilibrium, the lithostatic pressure at a depth z is given by where ρ(z) is the... lithostatic pressure exerted on the mantle prevents them from melting.

The subregion of the mantle extending about 250 km (155 mi) below the lithosphere is called the The asthenosphere (from the Greek asthenia, weakness) is the region of the Earth between 100-200 km below the surface, but may extend as deep as 400 km. It is the weak or soft zone in the upper mantle just below the lithosphere that is involved in plate movement and... asthenosphere. It some regions of the earth, this subregion of the mantle is associated with a region of the mantle that passes seismic waves more slowly. This region is called the low-velocity zone. The cause of this low velocity zone is still debated. Currently theories include the influence of temperature and pressure or the existance of a small amount of partial melt.

Due to the temperature difference between the Earth's crust and outer core there is a Convection is the transfer of heat by the motion of or within a fluid. It may arise from temperature differences either within the fluid or between the fluid and its boundary, or from the application of an external motive force. It is one of the three primary mechanisms of heat... convective material circulation in the asthenosphere. Hot material ascends as a Pluton redirects here. For the ancient Roman god, see Pluto. For the French nuclear missile system, see Pluton missile. In geology an intrusion is usually a body of igneous rock that has crystallized from a molten magma below the surface of the Earth. Intrusive rocks include all varieties of igneous... plutonic diapir from the border with the outer core, while cooler (and heavier) material sinks downward. This is often in the form of large-scale lithospheric downwellings at plate boundaries called subduction zones. During the ascent the material of the mantle cools down This article covers adiabatic processes in thermodynamics. For adiabatic processes in quantum mechanics, see adiabatic process (quantum mechanics). In thermodynamics, an adiabatic process is a process in which no heat is gained or lost in the working fluid. For example, there are no chemical processes taking place in the fluid... adiabatically. The temperature of the material falls with the pressure relief connected with the ascent, and its heat distributes itself over a larger volume. Near the lithosphere the pressure relief can lead to partial melting of the diapir, leading to This article is about volcanoes in geology. For the action movie, see Volcano (movie). A volcano (plural, volcanoes) is a geological landform (usually a mountain) where magma (rock of the earths interior made molten or liquid by high pressure and temperature) erupts through the surface of the planet. Although... volcanism and plutonism.

The Convection is the transfer of heat by the motion of or within a fluid. It may arise from temperature differences either within the fluid or between the fluid and its boundary, or from the application of an external motive force. It is one of the three primary mechanisms of heat... convection of the Earth's mantle is a Chaos theory, in mathematics and physics, deals with the behaviour of certain nonlinear dynamical systems that (under certain conditions) exhibit the phenomenon known as chaos, most famously characterised by sensitivity to initial conditions (see butterfly effect). Examples of such systems include the atmosphere, the solar system, plate tectonics, turbulent fluids... chaotic process (in the sense of fluid dynamics), which is thought to drive the motion of plates. Plate motion should not be confused with the older term The concept of continental drift was first proposed by Alfred Wegener. In 1912 he noticed that the shapes of continents on either side of the Atlantic Ocean seem to fit together (for example, Africa and South America). Benjamin Franklin and others had noted much the same thing earlier. The similarity... continental drift which applies purely to the movement of the crustal components of the continents. The movements of the lithosphere and the underlying mantle are thereby partially decoupled, since due to the rigidity of the lithosphere, a The tectonic plates of the world were mapped in the second half of the 20th century. Plate tectonics (from the Greek word for one who constructs, τεκτων (tekton)) is a theory of geology developed to explain the phenomenon of continental drift. In the theory of... tectonic plate can only move as a whole. Continental drift is therefore only a diffuse image of the movements at the upper limit of the Earth's mantle. The convection of the mantle is not yet clarified in detail. There are different theories, according to which the Earth's mantle is divided into different floors of separate convection.

Although there is a tendency to larger viscosity at greater depth, this relation is far from linear, and shows layers with dramatically decreased viscosity, in particular in the upper mantle and at the boundary with the core [1]  (http://www2.uni-jena.de/chemie/geowiss/geodyn/poster2.html).

Due to the low viscosity in the upper mantle one could reason that there should be no Global earthquake epicenters, 1963–1998. An earthquake is a trembling or a shaking movement of the Earths surface. Earthquakes typically result from the movement of faults, quasi-planar zones of deformation within its uppermost layers. The word earthquake is also widely used to indicate the source region itself... earthquakes below approximately 300 km depth. However, in subduction zones, the geothermal gradient can be lowered, increasing the strength of the surrounding mantle, and allowing earthquakes to occur down to a depth of 400 km and 670 km.

The Pressure (symbol: p or P) is the measure of the force that acts on a unit area. where: p is the pressure F is the force A is the area Often F is taken to be the of the magnitude of the mean vector force normal to the surface of... pressure at the bottom of the mantle is ~140 G The pascal (symbol Pa) is the SI unit of pressure. It is equivalent to one newton per square metre. The unit is named after Blaise Pascal, the eminent French mathematician, physicist and philosopher. 1 Pa = 1 N/m² = 1 (kg·m/s²)/m² = 1 kg/m·s² = 0.01 millibar... Pa (1.4 M Atmospheric pressure is the pressure caused by the weight of air above any area in the Earths atmosphere. Standard atmospheric pressure (atm) is discussed in the next section. Air masses are affected by the general atmospheric pressure within the mass, creating areas of high and low pressure. As elevation... atm). As there is intense and increasing pressure as one travels deeper into the mantle, the lower part of this region is thought solid while the upper mantle is The term plastics covers a range of synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or fibers. Their name is derived from the fact that in their semi-liquid state they are malleable, or have the property of plasticity... plastic (semi-molten). The viscosity of the upper mantle ranges between 10²¹ and 10²⁴ Pa·s, depending on depth [2]  (http://www2.uni-jena.de/chemie/geowiss/geodyn/poster2.html). Thus, the upper mantle can only flow very slowly.

Why is the inner core thought solid, the outer core thought liquid, and the mantle solid/plastic? The melting point of iron rich substances are higher than pure iron. The core is composed almost entirely of pure iron, while iron rich substances are more common outside the core. So, surface iron-substances are solid, upper mantle iron-substances are semi-molten (as it is hot and they are under relatively little pressure), lower mantle iron-substances are solid (as they are under tremendous pressure), outer core pure iron is liquid as it has a very low melting point (despite enormous pressure), and the inner core is solid due to the overwhelming pressure found at the center of the planet.