"of the modern value. Seismic measurements show that the core is divided into two parts, a ""solid"" inner core with a radius of ≈1,220 km and a liquid outer core extending beyond it to a radius of ≈3,400 km. The densities are between 9,900 and 12,200 kg/m in the outer core and 12,600–13,000 kg/m in the inner core. The inner core was discovered in 1936 by Inge Lehmann and is generally believed to be composed primarily of iron and some nickel. Since this layer is able to transmit shear waves (transverse seismic waves), it must be solid. Experimental evidence has"
"Iron–nickel alloy An iron–nickel alloy or nickel–iron alloy, abbreviated FeNi or NiFe, is a group of alloys consisting primarily of the elements nickel (Ni) and iron (Fe). It is the main constituent of the ""iron"" planetary cores and iron meteorites. The acronym NiFe refers to various chemical reactions that involve an iron–nickel catalyst or component, or in geology, to the general composition of planetary cores (including Earth's). Some iron–nickel alloys are called nickel steel and usually contain additional elements, depending on the purpose. Iron and nickel are notable for being the final elements produced by stellar nucleosynthesis, and the heaviest"
"that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's inner core. Use of nickel (as a natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who initially mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden. The element's name comes from a"
"silicate mineral series. However, the sial ""actually has quite a diversity of rock types, including large amounts of basaltic rocks."" The name 'sial' was taken from the first two letters of silica and of alumina. The sial is often contrasted to the 'sima,' the next lower layer in the Earth, which is often exposed in the ocean basins; and the nickel-iron alloy core, sometimes referred to as the ""Nife"". These geochemical divisions of the Earth's interior (with these names) were first proposed by Eduard Suess in the 19th century. This model of the outer layers of the earth has been"
"Based on the relative prevalence of various chemical elements in the Solar System, the theory of planetary formation, and constraints imposed or implied by the chemistry of the rest of the Earth's volume, the inner core is believed to consist primarily of a nickel-iron alloy. Pure iron was found to be denser than the core by approximately 3%, implying the presence of light elements in the core (e.g. silicon, oxygen, sulfur) in addition to the probable presence of nickel. Further, if the primordial and mostly ""fluid"" (still forming) earth contained any significant mass(es) of elements denser than iron and nickel,"
"be dangerous in large enough quantities due to its radioactivity. Nickel (Ni) is an element in period 4, between cobalt and copper. Nickel is rare in the Earth's crust, mainly due to the fact that it reacts with oxygen in the air, with most of the nickel on Earth coming from nickel iron meteorites. However, nickel is incredibly common in the Earth's core; along with iron it is one of the two main components. Nickel is an important component of stainless steel, and in many superalloys. Copper (Cu) is an element in period 4, between nickel and zinc. Copper is"
"of Earth's volume but more than 30% of the mass, the mantle for 84% of the volume and close to 70% of the mass, while the crust accounts for less than 1% of the mass. About 90% of the mass of the Earth is composed of the iron–nickel alloy (95% iron) in the core (30%), and the silicon dioxides (c. 33%) and magnesium oxide (c. 27%) in the mantle and crust. Minor contributions are from iron(II) oxide (5%), aluminium oxide (3%) and calcium oxide (2%), besides numerous trace elements (in elementary terms: iron and oxygen c. 32% each, magnesium and"
"part of the iron core or mantle of a planetoid, which shattered into many pieces upon its fall on our planet. Since landing on Earth the meteorite has experienced four ice ages. It was unearthed from a glacial moraine in the northern tundra. It has a strongly weathered surface covered with cemented faceted pebbles. New analysis of this strongly shock-metamorphosed iron meteorite has shown a content of 8.4% nickel and trace amounts of rare elements—0.33 ppm gallium, 0.133 ppm germanium and 1.6 ppm iridium. It also contains the minerals chromite, daubréelite, schreibersite, akaganéite and inclusions of troilite. For the first"
"core. The gravitational potential energy released by the sinking of the dense NiFe globules, along with any cooler, denser solid material, is thought to have been a runaway process, increasing the temperature of the protoplanet above the melting point of most components, resulting in the rapid formation of a molten iron core covered by a deep global silicate magma. This event, an important process of planetary differentiation, occurred at about 500 million years into the formation of the planet. This large spinning mass of super-hot metal is responsible for the creation of the Earth's magnetic field, the magnetosphere, which protects"
"conventional view of the Earth's interior as a uniform molten liquid was false, and that the Earth is in fact composed of a nickel-iron core, a thin crust, and that aside from a thin layer of dunitic material between the Earth's crust and mantle, the rest of the Earth's interior is iron, magnesium, silicon, and oxygen. Leason Adams Leason Heberling Adams (January 16, 1887 – August 20, 1969) was an American geophysicist and researcher. His principal achievement was his research on the properties of materials exposed to very high pressures, which he used to derive information on the nature of"
"winds is called the geoid. More precisely, the geoid is the surface of gravitational equipotential at mean sea level. Earth's mass is approximately (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 aluminium (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:"
"to sink toward the center in a process called planetary differentiation (see also the iron catastrophe), while less-dense materials would have migrated to the crust. The core is thus believed to largely be composed of iron (80%), along with nickel and one or more light elements, whereas other dense elements, such as lead and uranium, either are too rare to be significant or tend to bind to lighter elements and thus remain in the crust (see felsic materials). Some have argued that the inner core may be in the form of a single iron crystal. Under laboratory conditions a sample"
"traditional sense, to Earth. It mainly comes from iron-nickel meteorites that formed millions of years ago but were preserved from chemical attack by the vacuum of space, and fell to the earth a relatively short time ago. Metallic meteorites are composed primarily of the iron-nickel alloys: taenite (high nickel content) and kamacite (low nickel content). However, there are a few areas on earth where truly native iron can be found. Native nickel has been described as serpentinite due to hydrothermal alteration of ultramafic rocks in New Caledonia and elsewhere. Metallic cobalt has been reported in the Canadian Lorraine Mine, Cobalt-Gowganda"
"Iron Iron is a chemical element with symbol Fe (from ) and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. Its abundance in rocky planets like Earth is due to its abundant production by fusion in high-mass stars, where it is the last element to be produced with release of energy before the violent collapse of a supernova, which scatters the iron into space. Like the other"
"level and reversed both the metal-induced stabilization of HIF-1- and HIF-1α-dependent gene expression. Nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion (passivation). Even so, pure native nickel is found in Earth's crust only in tiny"
"the double of known reserves). About 60% is in laterites and 40% in sulfide deposits. On geophysical evidence, most of the nickel on Earth is believed to be in the Earth's outer and inner cores. Kamacite and taenite are naturally occurring alloys of iron and nickel. For kamacite, the alloy is usually in the proportion of 90:10 to 95:5, although impurities (such as cobalt or carbon) may be present, while for taenite the nickel content is between 20% and 65%. Kamacite and taenite are also found in nickel iron meteorites. The most common oxidation state of nickel is +2, but"
"in ice and sediment. Nickel-78's half-life was recently measured at 110 milliseconds, and is believed an important isotope in supernova nucleosynthesis of elements heavier than iron. The nuclide Ni, discovered in 1999, is the most proton-rich heavy element isotope known. With 28 protons and 20 neutrons Ni is ""double magic"", as is with 28 protons and 50 neutrons. Both are therefore unusually stable for nuclides with so large a proton-neutron imbalance. On Earth, nickel occurs most often in combination with sulfur and iron in pentlandite, with sulfur in millerite, with arsenic in the mineral nickeline, and with arsenic and sulfur"
"elements formed with a supernova or similarly cataclysmic event. Iron and nickel are the most abundant metals in metallic meteorites and in the dense metal cores of planets such as Earth. Nickel–iron alloys occur naturally on Earth's surface as telluric or meteoric iron. The affinity of nickel atoms (atomic number 28) for iron (atomic number 26) results in natural occurring alloys and a large number of commercial alloys, and provides a complex electron environment for catalyzing chemical reactions. In steel metallurgy, nickel is alloyed with iron to produce maraging steel and some low-alloy steels. Other technological uses include Invar and"
"Outer core The outer core of the Earth is a fluid layer about thick and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. Its outer boundary lies beneath Earth's surface. The transition between the inner core and outer core is located approximately beneath the Earth's surface. Unlike the inner core, the outer core is liquid. The inner core is also referred to as the solid core. Seismic inversions of body waves and normal modes constrain the radius of the outer core to be 3483 km with an uncertainty of 5 km,"
"by a mantle that either is or was a fluid. The terrestrial planets are sealed within hard crusts, but in the giant planets the mantle simply blends into the upper cloud layers. The terrestrial planets have cores of elements such as iron and nickel, and mantles of silicates. Jupiter and Saturn are believed to have cores of rock and metal surrounded by mantles of metallic hydrogen. Uranus and Neptune, which are smaller, have rocky cores surrounded by mantles of water, ammonia, methane and other ices. The fluid action within these planets' cores creates a geodynamo that generates a magnetic field."
"Telluric iron Telluric iron, also called native iron, is iron that originated on Earth, and is found in a metallic form rather than as an ore. Telluric iron is extremely rare, with only one known major deposit in the world, located in Greenland. Telluric iron resembles meteoric iron, in that it contains both a significant amount of nickel and Widmanstatten structures. However, telluric iron typically contains only around 3% nickel, which is too low for meteorites. There are two types of telluric iron. Both type 1 and type 2 contain comparable amounts of nickel and other impurities. The main difference"
"Nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion (passivation). Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites"
"Iron catastrophe The iron catastrophe was a postulated major geological event early in the history of Earth. The original accretion of the Earth's material into a spherical mass is thought to have resulted in a relatively uniform composition. While residual heat from the collision of the material that formed the Earth was significant, heating from radioactive materials in this mass gradually increased the temperature until a critical condition was reached. As material became molten enough to allow movement, the denser iron and nickel, evenly distributed throughout the mass, began to migrate to the center of the planet to form the"
"(metallic) core only 10 million years after the Earth began to form, producing the layered structure of Earth and setting up the formation of Earth's magnetic field. J. A. Jacobs was the first to suggest that the inner core—a solid center distinct from the liquid outer core—is freezing and growing out of the liquid outer core due to the gradual cooling of Earth's interior (about 100 degrees Celsius per billion years). The first eon in Earth's history, the ""Hadean"", begins with the Earth's formation and is followed by the ""Archean"" eon at 3.8 Ga. The oldest rocks found on Earth"
"matter that formed the Sun, but the planets acquired different compositions during the formation and evolution of the solar system. In turn, the natural history of the Earth caused parts of this planet to have differing concentrations of the elements. The mass of the Earth is approximately 5.98 kg. 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 aluminium (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Due to planetary differentiation, the core region is believed to be primarily composed of iron (88.8%), with smaller"
"planetary surfaces (as well as primitive meteorites) are largely made up of oxides like SiO (silicates, resulting in silicate planets). If the converse was true, carbides might be the dominant form of ""rock"" (resulting in carbon planets). Larger planetary bodies in the early Solar System were hot enough to experience melting and differentiation, with heavier elements (like nickel) finding their way into the core. The lighter silicate rocks presumably float to the surface. Thus this might explain why iron on Earth's surface is depleted in nickel, while iron meteorites (from the center of a differentiated planetoid) are rich in nickel."
"mischievous sprite of German miner mythology, Nickel (similar to Old Nick), who personified the fact that copper-nickel ores resisted refinement into copper. An economically important source of nickel is the iron ore limonite, which often contains 1–2% nickel. Nickel's other important ore minerals include pentlandite and a mixture of Ni-rich natural silicates known as garnierite. Major production sites include the Sudbury region in Canada (which is thought to be of meteoric origin), New Caledonia in the Pacific, and Norilsk in Russia. Nickel is slowly oxidized by air at room temperature and is considered corrosion-resistant. Historically, it has been used for"
"is the most stable element that can easily be made from alpha particles (being a product of decay of radioactive nickel-56, ultimately made from 14 helium nuclei). Elements heavier than iron are made in energy-absorbing processes in large stars, and their abundance in the universe (and on Earth) generally decreases with their atomic number. The abundance of the chemical elements on Earth varies from air to crust to ocean, and in various types of life. The abundance of elements in Earth's crust differs from that in the Solar system (as seen in the Sun and heavy planets like Jupiter) mainly"
"metals below the crust are generally higher, with most being found in the largely iron-silicon-nickel core. Platinum, for example, comprises approximately 1 part per billion of the crust whereas its concentration in the core is thought to be nearly 6,000 times higher. Recent speculation suggests that uranium (and thorium) in the core may generate a substantial amount of the heat that drives plate tectonics and (ultimately) sustains the Earth's magnetic field. The winning of heavy metals from their ores is a complex function of ore type, the chemical properties of the metals involved, and the economics of various extraction methods."
"was its ability to form compounds with hydrogen. Under these conditions, the s- and f-block metals were strongly enriched during the formation of the Earth. The most enriched elements are rubidium, strontium and barium, which between them account for over 50 percent by mass of all elements heavier than iron in the Earth's crust. The nonmetallic lithophiles – phosphorus and the halogens – exist on Earth as ionic salts with s-block metals in pegmatites and seawater. With the exception of fluorine, whose hydride forms hydrogen bonds and is therefore of relatively low volatility, these elements have had their concentrations on"
"of at least 1500 K and have an orthorhombic or a double hcp structure. These high-pressure phases of iron are important as endmember models for the solid parts of planetary cores. The inner core of the Earth is generally presumed to be an iron-nickel alloy with ε (or β) structure. Somewhat confusingly, the term ""β-iron"" is sometimes also used to refer to α-iron above its Curie point, when it changes from being ferromagnetic to paramagnetic, even though its crystal structure has not changed. The melting point of iron is experimentally well defined for pressures less than 50 GPa. For greater"
"of the orange spectrographic bands in the spectrum of the upper atmosphere. Meteoric iron Meteoric iron, sometimes meteoritic iron, is a native metal found in meteorites and made from the elements iron and nickel mainly in the form of the mineral phases kamacite and taenite. Meteoric iron makes up the bulk of iron meteorites but is also found in other meteorites. Apart from minor amounts of telluric iron, meteoric iron is the only naturally occurring native metal of the element iron on the Earth's surface. The bulk of meteoric iron consists of taenite and kamacite. Taenite is a face centered"
"most abundant heavier elements were iron and nickel, which now form the Earth's core. Though the surface rocks of the Earth have cooled enough to solidify, the outer core of the planet is still hot enough to remain liquid. Energy is still being released; volcanic and tectonic activity has pushed rocks into hills and mountains and blown them out of calderas. Meteors also create impact craters and surrounding ridges. However, if the energy release ceases from these processes, then they tend to erode away over time and return toward the lowest potential-energy curve of the ellipsoid. Weather powered by solar"