query: what is the earth 's outer core made out of

pos: Outer core 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,

pos: Outer core 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,

pos: Spherical Earth 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

pos: Planetary core this by integrating the bulk density of the Earth with the missing iron and nickel as a core. The first detection of Earth's core occurred in 1906 by Richard Dixon Oldham upon discovery of the P-wave shadow zone; the liquid outer core. By 1936 seismologists had determined the size of the overall core as well as the boundary between the fluid outer core and the solid inner core. Planetary systems form from flattened disks of dust and gas that accrete rapidly (within thousands of years) into planetesimals around 10 km in diameter. From here gravity takes over to produce Moon

pos: Abundance of the chemical elements in the Sun and outer planets is similar to that in the universe. Due to solar heating, the elements of Earth and the inner rocky planets of the Solar System have undergone an additional depletion of volatile hydrogen, helium, neon, nitrogen, and carbon (which volatilizes as methane). The crust, mantle, and core of the Earth show evidence of chemical segregation plus some sequestration by density. Lighter silicates of aluminum are found in the crust, with more magnesium silicate in the mantle, while metallic iron and nickel compose the core. The abundance of elements in specialized environments, such as atmospheres, or

neg: Core–mantle boundary Core–mantle boundary The core–mantle boundary (CMB in the parlance of solid earth geophysicists) of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2891 km (1796 mi) depth beneath the Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of

neg: Geophysics S-waves in the outer core. This indicates that the outer core is liquid, because liquids cannot support shear. The outer core is liquid, and the motion of this highly conductive fluid generates the Earth's field. The inner core, however, is solid because of the enormous pressure. Reconstruction of seismic reflections in the deep interior indicate some major discontinuities in seismic velocities that demarcate the major zones of the Earth: inner core, outer core, mantle, lithosphere and crust. The mantle itself is divided into the upper mantle, transition zone, lower mantle and "D′′" layer. Between the crust and the mantle is

neg: History of Earth (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

neg: Broad-footed mole that run laterally and vertically up to the surface. The excess earth pushed out of these shafts form distinct volcano-shaped mounds with the older earth towards the outer base and the newer earth towards the core. Shallow surface tunnels are sometimes dug and form a ridge in the soil on the surface. How often exactly these tunnels are used is unknown seeing as they are used irregularly. Up to 12 subspecies of "S. latimanus" have been recognized, but a taxonomic revision published in 2004 recommended the southernmost subspecies, "S. l. anthonyi" (Anthony's Mexican mole) be elevated to full species, and

neg: SKS wave hits the core-mantle boundary as it leaves the core, some energy is converted back to shear energy before the wave travels through the mantle. SKS waves can be observed by seismometers roughly 60-141° from an earthquake according to the Preliminary reference Earth model. SKS wave An SKS wave is a type of seismic wave, with the three letters denoting the type of wave-motion through the mantle and outer core. The first S indicates that the wave travels as a shear or s-wave through the mantle, the K shows that the wave travels as a compressional or p-wave through the outer

neg: Seismic wave structures of the Earth interior. When an earthquake occurs, seismographs near the epicenter are able to record both P and S waves, but those at a greater distance no longer detect the high frequencies of the first S wave. Since shear waves cannot pass through liquids, this phenomenon was original evidence for the now well-established observation that the Earth has a liquid outer core, as demonstrated by Richard Dixon Oldham. This kind of observation has also been used to argue, by seismic testing, that the Moon has a solid core, although recent geodetic studies suggest the core is still molten.

neg: Geology of Venus structures of ilmenite and perovskite, and gradually becomes more like perovskite until the core boundary is reached. Venus is similar to Earth in size and density, and so probably also in bulk composition, but it does not have a significant magnetic field. Earth's magnetic field is produced by what is known as the core dynamo, consisting of an electrically conducting liquid, the nickel-iron outer core that rotates and is convecting. Venus is expected to have an electrically conductive core of similar composition, and although its rotation period is very long (243.7 Earth days), simulations show that this is adequate to

neg: Geochemical cycle As all closed systems, it follows the law of conservation of mass which states that matter cannot be created nor destroyed, thus, the matter, although transformed and migrated, remains the same as when the Earth was formed. The Earth system contains seven different reservoirs that are separated into surface reservoirs, which include atmosphere, hydrosphere, biosphere, pedosphere, and lithosphere and the isolated reservoirs that include deep Earth and outer space. Geochemical cycles are concerned with the interactions between deep earth which consists of Earth´s mantle and core, and the lithosphere which consists of the Earth´s crust. Flux in geochemical cycles is

neg: Seismology planet opposite the earthquake where no direct S-waves are observed. In addition, P-waves travel much slower through the outer core than the mantle. Processing readings from many seismometers using seismic tomography, seismologists have mapped the mantle of the earth to a resolution of several hundred kilometers. This has enabled scientists to identify convection cells and other large-scale features such as the large low-shear-velocity provinces near the core–mantle boundary. Forecasting a probable timing, location, magnitude and other important features of a forthcoming seismic event is called earthquake prediction. Various attempts have been made by seismologists and others to create effective systems

neg: Outer core measured to be 2.5 millitesla, 50 times stronger than the magnetic field at the surface. The outer core is not under enough pressure to be solid, so it is liquid even though it has a composition similar to the inner core. Sulfur and oxygen could be present in the outer core. As heat is transferred outward toward the mantle, the net trend is for the inner boundary of the liquid region to freeze, causing the solid inner core to grow. This growth rate is estimated to be 1 mm per year. Outer core The outer core of the Earth is

neg: S-wave from the fact that it is the second direct arrival on an earthquake seismogram, after the compressional primary wave, or P-wave, because S-waves travel slower in rock. Unlike the P-wave, the S-wave cannot travel through the molten outer core of the Earth, and this causes a shadow zone for S-waves opposite to where they originate. They can still appear in the solid inner core: when a P-wave strikes the boundary of molten and solid cores, S-waves will then propagate in the solid medium. And when the S-waves hit the boundary again they will in turn create P-waves. This property allows

neg: Shadow zone Shadow zone A seismic shadow zone is an area of the Earth's surface where seismographs can only barely detect an earthquake after its seismic waves have passed through the Earth. When an earthquake occurs, seismic waves radiate out spherically from the earthquake's focus. The primary seismic waves are refracted by the liquid outer core of the Earth and are not detected between 104° and 140° (between approximately ) from the epicenter. The secondary seismic waves cannot pass through the liquid outer core and are not detected more than 104° (approximately ) from the epicenter. P waves that have been converted

neg: Structure of the Earth certain normally oxyphile elements existing either partially or wholly in the alloy portion that corresponds to the core of Earth. Dynamo theory suggests that convection in the outer core, combined with the Coriolis effect, gives rise to Earth's magnetic field. The solid inner core is too hot to hold a permanent magnetic field (see Curie temperature) but probably acts to stabilize the magnetic field generated by the liquid outer core. The average magnetic field strength in Earth's outer core is estimated to be 25 Gauss (2.5 mT), 50 times stronger than the magnetic field at the surface. Recent evidence has

neg: Structure of the Earth decay of radioactive elements, and freezing of the inner core. Structure of the Earth The internal structure of the Earth is layered in spherical shells: an outer silicate solid crust, a highly viscous asthenosphere and mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of the internal structure of the Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through the Earth, measurements of

neg: Future of Earth the mantle. The flow of heat will be concentrated, resulting in volcanism and the flooding of large areas with basalt. Rifts will form and the supercontinent will split up once more. The planet may then experience a warming period, as occurred during the Cretaceous period. The iron-rich core region of the Earth is divided into a radius solid inner core and a radius liquid outer core. The rotation of the Earth creates convective eddies in the outer core region that cause it to function as a dynamo. This generates a magnetosphere about the Earth that deflects particles from the solar

neg: Solar System fraction of the time it burned hydrogen in the core. The Sun is not massive enough to commence the fusion of heavier elements, and nuclear reactions in the core will dwindle. Its outer layers will move away into space, leaving a white dwarf, an extraordinarily dense object, half the original mass of the Sun but only the size of Earth. The ejected outer layers will form what is known as a planetary nebula, returning some of the material that formed the Sun—but now enriched with heavier elements like carbon—to the interstellar medium. The Sun is the Solar System's star and

neg: Structure of the Earth Structure of the Earth The internal structure of the Earth is layered in spherical shells: an outer silicate solid crust, a highly viscous asthenosphere and mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of the internal structure of the Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through the Earth, measurements of the gravitational and magnetic fields of the Earth, and experiments

neg: SKS wave SKS wave An SKS wave is a type of seismic wave, with the three letters denoting the type of wave-motion through the mantle and outer core. The first S indicates that the wave travels as a shear or s-wave through the mantle, the K shows that the wave travels as a compressional or p-wave through the outer core, and the final S indicates an s-wave, returning through the mantle. As shear waves cannot be transmitted through the liquid Outer core, some of the s-wave energy is converted to p-wave energy as the wave hits the Core–mantle boundary. When the wave

neg: Core–mantle boundary commonly used in reference to a decrease in seismic velocity with depth that is sometimes observed at about 100 km below the Earth's oceans. Core–mantle boundary The core–mantle boundary (CMB in the parlance of solid earth geophysicists) of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2891 km (1796 mi) depth beneath the Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities

neg: Seismology study referred to as forensic seismology). A major long-term motivation for the global seismographic monitoring has been for the detection and study of nuclear testing. Because seismic waves commonly propagate efficiently as they interact with the internal structure of the Earth, they provide high-resolution noninvasive methods for studying the planet's interior. One of the earliest important discoveries (suggested by Richard Dixon Oldham in 1906 and definitively shown by Harold Jeffreys in 1926) was that the outer core of the earth is liquid. Since S-waves do not pass through liquids, the liquid core causes a "shadow" on the side of the

neg: In situ resource utilization have return delta-v's from their surfaces to LEO which are less than the return from the Moon. Ceres is further out than Mars, with a higher delta-v, but launch windows and travel times are better, and the surface gravity is just 0.028 g, with a very low escape velocity of 510 m/s. Researchers have speculated that the interior configuration of Ceres includes a water-ice-rich mantle over a rocky core. Near Earth Asteroids and bodies in the asteroid belt could also be sources of raw materials for ISRU. Proposals have been made for "mining" for rocket propulsion, using what is called

neg: Centaurus and is very difficult to observe with an amateur telescope. It measures 7 arcminutes by 1 arcminute. It likely originated as a spiral galaxy and underwent a catastrophic gravitational interaction with Centaurus A around 500 million years ago, stopping its rotation and destroying its structure. NGC 4650A is a polar-ring galaxy located at a distance of 136 million light-years from Earth (redshift 0.01). It has a central core made of older stars that resembles an elliptical galaxy, and an outer ring of young stars that orbits around the core. The plane of the outer ring is distorted, which suggests that

neg: Geothermal gradient formed. Temperature within the Earth increases with depth. Highly viscous or partially molten rock at temperatures between are found at the margins of tectonic plates, increasing the geothermal gradient in the vicinity, but only the outer core is postulated to exist in a molten or fluid state, and the temperature at the Earth's inner core/outer core boundary, around deep, is estimated to be 5650 ± 600 Kelvin. The heat content of the Earth is 10 joules. In Earth's continental crust, the decay of natural radioactive isotopes makes a significant contribution to geothermal heat production. The continental crust is abundant in

neg: Mantle (geology) Mantle (geology) The mantle is a layer inside a planetary body bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density. All terrestrial planets (including Earth), a number of asteroids, and some planetary moons have mantles. The Earth's mantle is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 10 kg is 67% the mass of the Earth. It has

neg: Inge Lehmann Inge Lehmann Inge Lehmann (13 May 1888 – 21 February 1993) was a Danish seismologist and geophysicist. In 1936, she discovered that the Earth has a solid inner core inside a molten outer core. Before that, seismologists believed Earth's core to be a single molten sphere, being unable, however, to explain careful measurements of seismic waves from earthquakes, which were inconsistent with this idea. Lehmann analysed the seismic wave measurements and concluded that Earth must have a solid inner core and a molten outer core to produce seismic waves that matched the measurements. Other seismologists tested and then accepted Lehmann's

neg: Earth's magnetic field all generate magnetic fields through the motion of electrically conducting fluids. The Earth's field originates in its core. This is a region of iron alloys extending to about 3400 km (the radius of the Earth is 6370 km). It is divided into a solid inner core, with a radius of 1220 km, and a liquid outer core. The motion of the liquid in the outer core is driven by heat flow from the inner core, which is about , to the core-mantle boundary, which is about . The heat is generated by potential energy released by heavier materials sinking toward

neg: Astronomy by mutual gravitational attraction. As the Earth is located within the dusty outer arms, there are large portions of the Milky Way that are obscured from view. In the center of the Milky Way is the core, a bar-shaped bulge with what is believed to be a supermassive black hole at its center. This is surrounded by four primary arms that spiral from the core. This is a region of active star formation that contains many younger, population I stars. The disk is surrounded by a spheroid halo of older, population II stars, as well as relatively dense concentrations of

neg: Geology showed the existence of a liquid outer core (where shear waves were not able to propagate) and a dense solid inner core. These advances led to the development of a layered model of the Earth, with a crust and lithosphere on top, the mantle below (separated within itself by seismic discontinuities at 410 and 660 kilometers), and the outer core and inner core below that. More recently, seismologists have been able to create detailed images of wave speeds inside the earth in the same way a doctor images a body in a CT scan. These images have led to a

neg: Structure of the Earth of iron–nickel alloy was subjected to the corelike pressures by gripping it in a vise between 2 diamond tips (diamond anvil cell), and then heating to approximately 4000 K. The sample was observed with x-rays, and strongly supported the theory that Earth's inner core was made of giant crystals running north to south. The liquid outer core surrounds the inner core and is believed to be composed of iron mixed with nickel and trace amounts of lighter elements. Recent speculation suggests that the innermost part of the core is enriched in gold, platinum and other siderophile elements. The matter that

neg: Future of Earth wind, which prevents significant erosion of the atmosphere from sputtering. As heat from the core is transferred outward toward the mantle, the net trend is for the inner boundary of the liquid outer core region to freeze, thereby releasing thermal energy and causing the solid inner core to grow. This iron crystallization process has been ongoing for about a billion years. In the modern era, the radius of the inner core is expanding at an average rate of roughly per year, at the expense of the outer core. Nearly all of the energy needed to power the dynamo is being

neg: Structure of the Earth 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

neg: Planetary core 10–30 times the mass of the Earth, and this core is likely soluble in the gas envelope above, and so primordial in composition. Since the core still exists, the outer envelope must have originally accreted onto a previously existing planetary core. Thermal contraction/evolution models support the presence of metallic hydrogen within the core in large abundances (greater than Saturn). Saturn has an observed magnetic field generated within its metallic core. Metallic hydrogen is present within the core (in lower abundances than Jupiter). Saturn has a rock and or ice core 10–30 times the mass of the Earth, and this core

neg: Earth science shielding some of the Earth's surface from cosmic rays—of which are often incorrectly thought to be deflected by the magnetic field. The magnetic field—created by the internal motions of the core—produces the magnetosphere which protects the Earth's atmosphere from the solar wind. As the Earth is 4.5 billion years old, it would have lost its atmosphere by now if there were no protective magnetosphere. An electromagnet is a magnet that is created by an electric current. The Earth has a solid iron inner core surrounded by fluid outer core that convects; therefore, the Earth is an electromagnet. The motion of

neg: Foundationism Foundationism Foundationism is a fictional religion in depicted in the 1993 – 1998 American science fiction television series "Babylon 5". It is presented as an Earth religion, one of several that appeared around the time the Centauri aliens made first contact with the humans of the Earth Alliance in 2156. The intent behind the new religion was to get back to the roots of all Earth religions, past disparate doctrines to the core foundations of each belief system to find out what they have in common, proposing that they are more similar than might be expected. It further asserted that

neg: Phantom Zone all its levels are manifestations of the consciousness of a sentient universe called Aethyr. The Zone itself is an interface between the Earth-One dimension and Aethyr's mind, the outer layer representing its ability for abstract thought; the Zone is basically Aethyr's capacity to imagine other possibilities of existence. Only by entering Aethyr's core realm can they escape back to Earth, which is dangerous since any being who tries risks either being destroyed or merging with Aethyr's essence. While Quex-Ul is killed by Aethyr, Superman manages to make his way out of the Phantom Zone and return to Earth. Mister Mxyzptlk

neg: Hollow Earth illustration of the fact that any description of the physical world can be equivalently expressed in more than one way. The picture of the structure of the Earth that has been arrived at through the study of seismic waves is quite different from the Hollow Earth hypothesis. The time it takes for seismic waves to travel through and around the Earth directly contradicts a hollow sphere. The evidence indicates that the Earth is filled with solid rock (mantle and crust), liquid nickel-iron alloy (outer core), and solid nickel-iron (inner core). Another set of scientific arguments against a Hollow Earth or

neg: Don L. Anderson up from just above the Earth's core, Anderson showed that they can be explained entirely by chemical and mineralogical anomalies in the upper mantle. Moreover, Anderson pointed out that all demonstrations of the mantle plume hypothesis violate the basic laws of thermodynamics because they rely on a constant supply of heat coming from the deep Earth or even from outside the Earth. Anderson, on the other hand, accepted the classical view that the Earth's interior is cooling and that volcanoes simply tap a layer of melted rock that exists in the upper mantle, or outer shell of the Earth. It

neg: Formation and evolution of the Solar System clear; although the Sun will envelop Earth's current orbit, the star's loss of mass (and thus weaker gravity) will cause the planets' orbits to move farther out. If it were only for this, Venus and Earth would probably escape incineration, but a 2008 study suggests that Earth will likely be swallowed up as a result of tidal interactions with the Sun's weakly bound outer envelope. Gradually, the hydrogen burning in the shell around the solar core will increase the mass of the core until it reaches about 45% of the present solar mass. At this point the density and temperature

neg: Core oligosaccharide A and an inner core (or less. ) is referred to as "deep-rough LPS". The outer core is made of hexose residues that are attached to the last heptose residue in the inner core. Hexoses often found in the outer core include: -glucose, -mannose, -galactose, "etc.". There is usually at least three hexoses bound β1→3, with the O antigen being ligated to the third hexose. Other hexose are often found attached to the outer core, branching from the main oligomer. LPS that include lipid A and a complete core oligosaccharide (inner and outer) is referred to as "rough LPS." Mechanism

neg: Flower Child (The Outer Limits) Flower Child (The Outer Limits) "Flower Child" is an episode of "The Outer Limits" television series. It aired during the seventh season. In this episode, a mysterious glowing green object hurtles towards Earth and lands in a flower bed. An old lady who tends to the flowers finds a new flower the next day. As she's trying to figure out what it is, the plant reaches out with its roots and sucks the life out of her. The plant uses her substance to form a new body: the body of a beautiful woman. A meteor enters Earth's atmosphere and a

neg: Structure of the Earth the crust, upper mantle, lower mantle, outer core, and inner core. The geologic component layers of Earth are at the following depths below the surface: The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. The core does not allow shear waves to pass through it, while the speed of travel (seismic velocity) is different in other layers. The changes in seismic velocity between different layers causes refraction owing to Snell's law, like light bending as it passes through a prism. Likewise, reflections are caused by a large

neg: Dynamo theory Earth's magnetism, proposed that this magnetic field resulted from electric currents induced in the fluid outer core of the Earth. He revealed the history of the Earth's magnetic field through pioneering the study of the magnetic orientation of minerals in rocks. In order to maintain the magnetic field against ohmic decay (which would occur for the dipole field in 20,000 years), the outer core must be convecting. The convection is likely some combination of thermal and compositional convection. The mantle controls the rate at which heat is extracted from the core. Heat sources include gravitational energy released by the compression

neg: Uranus model chosen; it must be between 9.3 and 13.5 Earth masses. Hydrogen and helium constitute only a small part of the total, with between 0.5 and 1.5 Earth masses. The remainder of the non-ice mass (0.5 to 3.7 Earth masses) is accounted for by rocky material. The standard model of Uranus's structure is that it consists of three layers: a rocky (silicate/iron–nickel) core in the centre, an icy mantle in the middle and an outer gaseous hydrogen/helium envelope. The core is relatively small, with a mass of only 0.55 Earth masses and a radius less than 20% of Uranus's; the

neg: Man-made structures visible from space far above sea level their hypothetical or actual observer in space is located. When just speaking of "space", an asker might mean anywhere from the edge of space (Kármán line) at an altitude of to low Earth orbit of 160–2,000 km (99-1200 mi) to Apollo 12's orbit at to the Moon, which orbits about away. The Kármán line is accepted by the World Air Sports Federation, an international standard setting and record-keeping body for aeronautics and astronautics, as the boundary between the Earth's atmosphere and outer space. However, a practical definition for the purpose of answering questions on what astronauts

neg: Structure of the Earth with crystalline solids at pressures and temperatures characteristic of the Earth's deep interior. The force exerted by Earth's gravity can be used to calculate its mass. Astronomers can also calculate Earth's mass by observing the motion of orbiting satellites. Earth’s average density can be determined through gravimetric experiments, which have historically involved pendulums. The mass of Earth is about . The structure of Earth can be defined in two ways: by mechanical properties such as rheology, or chemically. Mechanically, it can be divided into lithosphere, asthenosphere, mesospheric mantle, outer core, and the inner core. Chemically, Earth can be divided into

neg: Inner core had been difficult to establish because the elastic shear waves that are expected to pass through a solid mass are very weak and difficult for seismographs on the Earth's surface to detect, since they become so attenuated on their way from the inner core to the surface by their passage through the liquid outer core. Dziewonski and Gilbert established that measurements of normal modes of vibration of Earth caused by large earthquakes were consistent with a liquid outer core. In 2005, shear waves were detected passing through the inner core; these claims were initially controversial, but are now gaining acceptance.

neg: Seismology of elastic materials and in mathematics. In 1926, Harold Jeffreys was the first to claim, based on his study of earthquake waves, that below the mantle, the core of the Earth is liquid. In 1937, Inge Lehmann determined that within the earth's liquid outer core there is a solid "inner" core. By the 1960s, earth science had developed to the point where a comprehensive theory of the causation of seismic events had come together in the now well-established theory of plate tectonics. Seismic waves are elastic waves that propagate in solid or fluid materials. They can be divided into "body

neg: Super-Earth the relevant planet what the structural composition is. For Gliese 876 d, calculations range from 9,200 km (1.4 Earth radii) for a rocky planet and very large iron core to 12,500 km (2.0 Earth radii) for a watery and icy planet. Within this range of radii the super-Earth Gliese 876 d would have a surface gravity between 1.9g and 3.3g (19 and 32 m/s). However, this planet is not known to transit its host star. The limit between rocky planets and planets with a thick gaseous envelope is calculated with theoretical models. Calculating the effect of the active XUV saturation

neg: Asymptotic giant branch while HCN and SiS masers are generally found in carbon stars such as IRC +10216. S-type stars with masers are uncommon. After these stars have lost nearly all of their envelopes, and only the core regions remain, they evolve further into short-lived preplanetary nebulae. The final fate of the AGB envelopes are represented by planetary nebulae (PNe). As many as a quarter of all post-AGB stars undergo what is dubbed a "born-again" episode. The carbon–oxygen core is now surrounded by helium with an outer shell of hydrogen. If the helium is re-ignited a thermal pulse occurs and the star quickly

neg: Heliophysics Science Division not only our lives on Earth, but Earth itself, and everything outside its atmosphere (astronauts and satellites out in space and even the other planets). SDO is helping us understand where the sun's energy comes from, how the inside of the sun works, and how energy is stored and released in the sun's atmosphere. By better understanding the sun and how it works, we will be able to better predict and better forecast space weather events. A joint ESA/NASA mission, the Solar and Heliospheric Observatory, or SOHO, studies the sun, from deep inside its core to the outer corona and

neg: Planetary core cores). Using the chondritic reference model and combining known compositions of the crust and mantle, the unknown component, the composition of the inner and outer core, can be determined; 85% Fe, 5% Ni, 0.9% Cr, 0.25% Co, and all other refractory metals at very low concentration. This leaves Earth's core with a 5–10% weight deficit for the outer core, and a 4–5% weight deficit for the inner core; which is attributed to lighter elements that should be cosmically abundant and are iron-soluble; H, O, C, S, P, and Si. Earth's core contains half the Earth's vanadium and chromium, and may

neg: The Stars Are Cold Toys up averagely — i.e. they fulfil all rules of the society, but are almost unable to violate any (such behaviour is even considered as illness). The core of this world conflicts with what Pyotr considers right — "you can violate laws of the society, but can't violate principles of the moral", "to be right is always an ordeal". Later Lukianenko supposes that the world of Geometers isn't free and really happy, due to both the hostile outer world and the kind inner world of the family are necessary to form a personality. Geometers can't be an ally for the Earth,

neg: Epsilon Librae the Earth to the Sun. The primary, component A, has been catalogued with stellar classifications of F3 V and F5 IV, suggesting that it is an F-type star that either belongs to the main sequence or has evolved into a subgiant as the hydrogen at its core nears exhaustion. The primary has an estimated 1.17 times the mass of the Sun and 1.5 times the Sun's radius. It is around 1.5 billion years old and is spinning with a projected rotational velocity of 10 km/s. The star radiates 9.3 times the solar luminosity from its outer atmosphere at an effective

neg: Inner core Inner core The Earth's inner core is the Earth's innermost part. It is primarily a solid ball with a radius of about , which is about 70% of the Moon's radius. It is composed of an iron–nickel alloy and some other elements. The temperature at the inner core's surface is approximately or 9806 °F, which is about the temperature at the surface of the Sun. The Earth was discovered to have a solid inner core distinct from its molten outer core in 1936, by the Danish seismologist Inge Lehmann, who deduced its presence by studying seismograms from earthquakes in New

neg: WR 3 be fusing hydrogen in its core. The emission lines of heavy elements in its spectrum are produced by strong convection and powerful stellar winds rather than complete loss of the outer layers of the star. The wind has been measured at 2,700 km/s leading to mass being lost at per year. WR 3 WR 3 is a Wolf-Rayet star located around 16,000 light years away from Earth in the constellation of Cassiopeia. WR 3 is a member of the nitrogen sequence of WR stars and has a spectrum with strong He and N lines, but weak N. He lines are

neg: Sun In about 5 billion years, when hydrogen fusion in its core has diminished to the point at which the Sun is no longer in hydrostatic equilibrium, its core will undergo a marked increase in density and temperature while its outer layers expand to eventually become a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable. After this, it will shed its outer layers and become a dense type of cooling star known as a white dwarf, and no longer produce energy by fusion, but

neg: Double-clad fiber outer cladding alter the waveguide dispersion of the core-guided signal. The second kind of fiber was developed in the late 1980s for use with high power fiber amplifiers and fiber lasers. In these fibers, the core is doped with active dopant material; it both guides and amplifies the signal light. The inner cladding and core together guide the pump light, which provides the energy needed to allow amplification in the core. In these fibers, the core has the highest refractive index and the outer cladding has the lowest. In most cases the outer cladding is made of a polymer material

neg: Earth's internal heat budget primordial heat, respectively. The structure of the Earth is a rigid outer crust that is composed of thicker continental crust and thinner oceanic crust, solid but plastically flowing mantle, a liquid outer core, and a solid inner core. The fluidity of a material is proportional to temperature; thus, the solid mantle can still flow on long time scales, as a function of its temperature and therefore as a function of the flow of Earth's internal heat. The mantle convects in response to heat escaping from Earth's interior, with hotter and more buoyant mantle rising and cooler, and therefore denser, mantle

neg: Mercury's magnetic field this is uncertain as yet. The origins of the magnetic field can be explained by the dynamo theory; i.e., by the convection of electrically conductive molten iron in the planet's outer core. A dynamo is generated by a large iron core that has sunk to a planet's center of mass, has not cooled over the years, an outer core that has not been completely solidified, and circulates around the interior. Before the discovery of its magnetic field in 1974, it was thought that because of Mercury′s small size, its core had cooled over the years. There are still difficulties with

neg: Thermoplastic-sheathed cable Thermoplastic-sheathed cable Thermoplastic-sheathed cable (TPS) consists of an outer toughened sheath of polyvinyl chloride (PVC) (the thermoplastic element) covering one or more individual cables which are PVC insulated annealed copper conductors. It is a commonly used type of wiring for residential and light commercial construction in many countries. The flat version of the cable with two insulated conductors and an uninsulated earth conductor all within the outer sheath is referred to as twin and earth. In mainland Europe, a round equivalent is more common. Each of the current carrying conductors in the "core" is insulated by an individual thermoplastic sheath,

neg: Shadow zone overall zero and as such S-waves lose all velocity when travelling through a liquid. P-waves, however, are only partially dependent on rigidity and as such still maintain some velocity (if greatly reduced) when travelling through a liquid. Analysis of the seismology of various recorded earthquakes and their shadow zones led geologist Richard Oldham to deduce in 1906 the liquid nature of the Earth's outer core. Shadow zone A seismic shadow zone is an area of the Earth's surface where seismographs can only barely detect an earthquake after its seismic waves have passed through the Earth. When an earthquake occurs, seismic

neg: Algorithm remainder "r" to measure what was previously smaller number "s"; L serves as a temporary location. OUTPUT: DONE: The following version of Euclid's algorithm requires only six core instructions to do what thirteen are required to do by "Inelegant"; worse, "Inelegant" requires more "types" of instructions. The flowchart of "Elegant" can be found at the top of this article. In the (unstructured) Basic language, the steps are numbered, and the instruction is the assignment instruction symbolized by ←. The following version can be used with Object Oriented languages: "How "Elegant" works": In place of an outer "Euclid loop", "Elegant" shifts

neg: Magnetohydrodynamics seismology). Beneath the Earth's mantle lies the core, which is made up of two parts: the solid inner core and liquid outer core. Both have significant quantities of iron. The liquid outer core moves in the presence of the magnetic field and eddies are set up into the same due to the Coriolis effect. These eddies develop a magnetic field which boosts Earth's original magnetic field—a process which is self-sustaining and is called the geomagnetic dynamo. Based on the MHD equations, Glatzmaier and Paul Roberts have made a supercomputer model of the Earth's interior. After running the simulations for thousands

neg: Future of Earth trajectory towards the Sun may remove Earth's mantle, leaving just its core, which will finally be destroyed after at most 200 years. Following this event, Earth's sole legacy will be a very slight increase (0.01%) of the solar metallicity. After fusing helium in its core to carbon, the Sun will begin to collapse again, evolving into a compact white dwarf star after ejecting its outer atmosphere as a planetary nebula. The predicted final mass is 54.1% of the present value, most likely consisting primarily of carbon and oxygen. Currently, the moon is moving away from Earth at a rate of

neg: Geomagnetic jerk at Chambon la Forêt (Europe, long. 2.27°). Moreover, the global jerks seem to occur at slightly different times in different regions; often earlier in the Northern hemisphere than in the Southern hemisphere. These events are believed to be caused by changes in the flow patterns of the liquid outer core of the Earth. Another theory is that they are due to torsional oscillations in the solid inner core of the Earth. There have been claims that they are connected to strong earthquakes. Geomagnetic jerk In geophysics, a geomagnetic jerk or secular geomagnetic variation impulse is a relatively sudden change in

neg: Extinction event die out, although simpler plants like grasses and mosses can survive much longer, until levels drop to 10 ppm. With all photosynthetic organisms gone, atmospheric oxygen can no longer be replenished, and is eventually removed by chemical reactions in the atmosphere, perhaps from volcanic eruptions. Eventually the loss of oxygen will cause all remaining aerobic life to die out via asphyxiation, leaving behind only simple anaerobic prokaryotes. When the Sun becomes 10% brighter in about a billion years, Earth will suffer a moist greenhouse effect resulting in its oceans boiling away, while the Earth's liquid outer core cools due to

neg: Geochemistry of carbon core, however the conditions at the formation of the core would not be suitable for its inclusion. Carbon is a very likely constituent of the core. Preferential partitioning of the carbon isotopeC into the metallic core, during its formation, may explain why there seems to be more C on the surface and mantle of the Earth compared to other solar system bodies (−5‰ compared to -20‰). The difference can also help to predict the value of the carbon proportion of the core. The outer core has a density around 11 cm, and a mass of 1.3×10kg. It contains roughly 10

neg: Future of Earth functioning dynamo, the magnetic field of the Earth will decay in a geologically short time period of roughly 10,000 years. The loss of the magnetosphere will cause an increase in erosion of light elements, particularly hydrogen, from the Earth's outer atmosphere into space, resulting in less favorable conditions for life. The energy generation of the Sun is based upon thermonuclear fusion of hydrogen into helium. This occurs in the core region of the star using the proton–proton chain reaction process. Because there is no convection in the solar core, the helium concentration builds up in that region without being distributed

neg: Future of Earth This is sufficient to melt the surface of the planet. However, most of the atmosphere will be retained until the Sun has entered the red giant stage. With the extinction of life, 2.8 billion years from now it is also expected that Earth biosignatures will disappear, to be replaced by signatures caused by non-biological processes. Once the Sun changes from burning hydrogen at its core to burning hydrogen around its shell, the core will start to contract and the outer envelope will expand. The total luminosity will steadily increase over the following billion years until it reaches 2,730 times the

neg: Summit (The Outer Limits) Grandmother and then prepares to land. After making planet-fall and disembarking the delegation from Earth enters their portion of the habitat. The shuttle carrying the Dregocian delegation malfunctions and crashes, while the delegation from Earth watches in horror. After some tense moments and the destruction of both the Earth and Dregocian motherships the Earth delegation attempts to figure out what went wrong. The last transmission from the Dregocian shuttle mentioned that it was sabotaged but by whom is the mystery. Before anymore questions can be answered a warhead launched from one of the motherships toward the planet explodes some distance

neg: Metal rhodium, palladium, osmium, iridium, and platinum), germanium, and tin—can be counted as siderophiles but only in terms of their primary occurrence in the Earth (core, mantle and crust), rather the crust. These metals otherwise occur in the crust, in small quantities, chiefly as chalcophiles (less so in their native form). The rotating fluid outer core of the Earth's interior, which is composed mostly of iron, is thought to be the source of Earth's protective magnetic field. The core lies above Earth's solid inner core and below its mantle. If it could be rearranged into a column having a 5m footprint

neg: Outer core while that of the inner core is 1220±10 km. Estimates for the temperature of the outer core are about in its outer regions and near the inner core. Evidence for a fluid outer core includes from seismology which shows that seismic shear-waves are not transmitted through the outer core Because of its high temperature, modeling work has shown that the outer core is a low viscosity fluid that convects turbulently. Eddy currents in the nickel iron fluid of the outer core are believed to influence the Earth's magnetic field. The average magnetic field strength in the Earth's outer core was

neg: Cornelius Castoriadis since been promoted to a scientific term, but Castoriadis is inclined to believe that although the Greeks "had" sometimes expressed Chaos in that way (as a system too complex to be understood), they mainly referred to it as "nothingness". He then concludes what made the ancient Greek society different to other societies is exactly that core imaginary, which essentially says that if the world is created out of nothing then man can indeed, in his brief time on earth, model it as he sees fit, without trying to conform on some pre-existing order like a divine law. He contrasted that

neg: Epicenter 330 km away at the eastern end. Focal depths of earthquakes occurring in continental crust mostly range from 2 to 20 km.Continental earthquakes below 20 km are rare whereas in subduction zones earthquakes can originate at depths deeper than 600 km. During an earthquake, seismic waves propagate in all directions from the hypocenter. Seismic shadowing occurs on the opposite side of the Earth from the earthquake epicenter because the planet's liquid outer core refracts the longitudinal or compressional (P-waves) while it absorbs the transverse or shear waves (S-waves). Outside the seismic shadow zone, both types of wave can be detected

neg: Serpens known as ring galaxies. The outer ring is largely composed of young blue stars while the core is made up of older yellow stars. The predominant theory regarding its formation is that the progenitor galaxy was a barred spiral galaxy whose arms had velocities too great to keep the galaxy's coherence and therefore detached. Arp 220 is another unusual galaxy in Serpens. The prototypical ultraluminous infrared galaxy, Arp 220 is somewhat closer than Hoag's Object at 250 million light-years from Earth. It consists of two large spiral galaxies in the process of colliding with their nuclei orbiting at a distance

neg: Large low-shear-velocity provinces Large low-shear-velocity provinces Large low-shear-velocity provinces, LLSVPs, also called LLVPs or superplumes, are characteristic structures of parts of the lowermost mantle (the region surrounding the outer core) of the Earth. These provinces are characterized by slow shear wave velocities and were discovered by seismic tomography of the deep Earth. There are two main provinces: the African LLSVP and the Pacific LLSVP. Both extend laterally for thousands of kilometers and possibly up to 1000 km vertically from the core-mantle boundary. The Pacific LLSVP has specific dimensions of 3000 km across and 300 m higher than the surrounding ocean-floor, and is situated

neg: Ihuatzio (archaeological site) times. The Yácatas walls are built with horizontally set slabs which cover a rock and earth core. The outer coating consisted of Janamus blocks which once fully covered the structures but have since weathered completely. Some vestiges can be seen on the east face of rectangular structure no. 1. The Huatziris or walled causeway (Muro-Calzada), is a most infrequent element in western Mexico's archaeology. It consists of a structure built with a system similar to that used in the rectangular buildings, namely, a rock and earth core covered by stone slabs. It displays a stuccoed-upper part, stepped tiers, and an

neg: Chandler wobble its discovery, reaching its largest size in 1910 and fluctuating noticeably from one decade to another. In 2009, Malkin & Miller's analysis of International Earth Rotation and Reference Systems Service (IERS) Pole coordinates time series data from January 1946 to January 2009 showed three phase reversals of the wobble, in 1850, 1920, and 2005. While it has to be maintained by changes in the mass distribution or angular momentum of the Earth's outer core, atmosphere, oceans, or crust (from earthquakes), for a long time the actual source was unclear, since no available motions seemed to be coherent with what was

neg: Mercury (planet) 2015. The "BepiColombo" spacecraft will arrive at Mercury in 2025. Mercury appears to have a solid silicate crust and mantle overlying a solid, iron sulfide outer core layer, a deeper liquid core layer, and possibly a solid inner core. Mercury is one of four terrestrial planets in the Solar System, and is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of . Mercury is also smaller—albeit more massive—than the largest natural satellites in the Solar System, Ganymede and Titan. Mercury consists of approximately 70% metallic and 30% silicate material. Mercury's

neg: Nitra Castle the 9th century, the top of the hill was protected by the wooden palisade. In the second half of the same century, the Slavs built massive rampart made of two outer drystone walls (thickness 2 x 3m) with an internal timber structure filled with earth (3m). The original rampart was destroyed before early 11th century. The castle was built in the 11th century on the place of an earlier fort. The core of the castle is St. Emmeram's Cathedral with the Bishop's residence, with several different parts. The oldest surviving part is the Romanesque Church of St. Emmeram from the

neg: Delta Crateris at its core. The star has an estimated 1.56 times the mass of the Sun but has expanded to times the Sun's radius. The metallicity of the star – what astronomers term the abundance of elements other than hydrogen and helium – is only 33% that of the Sun. It is around 2.89 billion years old with a rotation rate that is too small to measure; the projected rotational velocity is 0.0 km/s. Delta Crateris is radiating as much luminosity as the Sun from its outer envelope at an effective temperature of K. Delta Crateris Delta Crateris (δ Crt, δ

neg: Question (comics) from DC Comics previous Elseworlds stories or from variant "themed" universes, such as the gender-reversed world of Earth-11. In Grant Morrison's "Multiversity" series, the Vic Sage/Question is one of the core protagonists in Pax Americana, an issue of that limited series set in the New 52's Earth 4 continuity, along with the Blue Beetle, Peacemaker, Nightshade, and Captain Atom. On Earth-9, "The Question" is the name given to a global surveillance network. In the alternate universe of "Flashpoint", Question is a member of the Resistance. References to the character and his city are made in the shared universe television series

neg: Earth about under the oceans to for the continents. The crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, and it is of the lithosphere that the tectonic plates are composed. Beneath the lithosphere is the asthenosphere, a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core. The Earth's inner core might rotate at a

neg: The Universal Solvent (comics) comical misery. Their platform is also slightly damaged by a falling pebble (which, due to the vacuum having no air to slow it down, was essentially travelling at bullet speed). Scrooge also finds his diamonds, although he is nearly burned by the massive heat of the diamonds, as they were in the outer core. Later, as Scrooge finds out, they become essentially weightless, due to their weight being their attraction to the Earth's mass, and as they travel deeper, more of the Earth is above them than below them, making them almost weightless. They also find that they have reached

neg: Space Pirates and Zombies the new element found near the galactic core, the outer worlds, including Earth, have become neglected backwaters. With humanity now numbering in the thousands of trillions across thousands of planets, the spread of interplanetary diseases caused the collapse of many human governments. A totalitarian militaristic police force called the United Terran Alliance (or UTA) stepped in to fill the void and began to strictly police access to the warp gates. Civilian access to interstellar travel was abolished in what was described as a 'temporary move' but this state of affairs has existed for over 1000 years. With humanity living in

neg: Sin & Punishment: Star Successor by humans to defend against Outer Space. Whenever humans stray from their intended path by attempting to bring peace, the Creators wipe them out and create a new Earth. Outer Space sends a reconnaissance unit in the form of a human girl to investigate humans. However, in the process of infiltration she loses her memory and wanders to the ruins of Earth-4 instead of the human-populated Earth-5. An agent of Earth-5, Isa Jo, is sent to find and kill the Outer Space infiltrator, but after observing her he concludes she is harmless. Naming her "Kachi," Isa decides to protect her.

neg: Summit (The Outer Limits) Summit (The Outer Limits) "Summit" is an episode of "The Outer Limits" television show. It first aired on 21 May 1999, during the fifth season. On a barren planetoid, diplomats from Earth and Dregocia meet to discuss peace. Several centuries in the future, Humans from Earth (the United Coalition) and a genetically-engineered race from Dregocia (Dregocian High Command) agree to meet to work out a peace accord on a neutral planetoid. An envoy named Kate Woods is part of the Earth delegation. She leaves a love message to her son that she left on Earth in the care of his

neg: Geomagnetic pole Geomagnetic pole The geomagnetic poles are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth. This theoretical dipole is equivalent to a powerful bar magnet at the center of Earth and comes closer than any other model to accounting for the magnetic field observed at Earth's surface. In contrast, the magnetic poles of the actual Earth are not antipodal; that is, the line on which they lie does not pass through Earth's center. Owing to motion of fluid in the Earth's outer core, the actual magnetic poles are constantly moving. However, over thousands of years

neg: Allotropes of iron the solid parts of planetary cores. The inner core of the Earth is generally assumed to consist essentially of a crystalline iron-nickel alloy with ε structure. The outer core surrounding the solid inner core is believed to be composed of liquid iron mixed with nickel and trace amounts of lighter elements. As molten iron cools down, it solidifies at 1,538 °C (2,800 °F) into its δ allotrope, which has a body-centered cubic (BCC) crystal structure. δ-iron can dissolve as much as 0.08% of carbon by mass at 1,475 °C. As the iron cools further to 1,394 °C its crystal structure

neg: Earth's internal heat budget loss, and the heat loss rate would slow once the mantle solidified. Heat flow from the core is necessary for maintaining the convecting outer core and the geodynamo and Earth's magnetic field, therefore primordial heat from the core enabled Earth's atmosphere and thus helped retain Earth's liquid water. Controversy over the exact nature of mantle convection makes the linked evolution of Earth's heat budget and the dynamics and structure of the mantle difficult to unravel. There is evidence that the processes of plate tectonics were not active in the Earth before 3.2 billion years ago, and that early Earth's internal

neg: Confidence she does not have a personal certainty belief that s/he can handle what it takes or what needs to be done. Stajkovic (2006) argues that all three – skill, will, and confidence – are needed for action to unfold. The opposite of confidence is doubt. Alexander Stajkovic argues that confidence is not actually an observable variable, however, confidence sits at the core of four other manifestations: Hope, Efficacy, Optimism and Resilience. Core confidence impacts hope by allowing one to figure out what needs to be done and how to do it. It affects self-efficacy as one gains the belief that

neg: Red giant will begin to expand into a subgiant. Eventually, the pressure builds up so much that the core will begin to fuse helium, and will expand even more into a red giant. At its largest, its surface (photosphere) will approximately reach the current orbit of Earth. It will then lose its atmosphere completely; its outer layers forming a planetary nebula and the core a white dwarf. The evolution of the Sun into and through the red-giant phase has been extensively modelled, but it remains unclear whether Earth will be engulfed by the Sun or will continue in orbit. The uncertainty arises

neg: Delta Canis Majoris may take a year to rotate fully. Only around 10 million years old, Wezen has stopped fusing hydrogen in its core. Its outer envelope is beginning to expand and cool, and in the next 100,000 years it will become a red supergiant as its core fuses heavier and heavier elements. Once it has a core of iron, it will collapse and explode as a supernova. If Wezen were as close to Earth as Sirius is, it would be as bright as a half-full moon. Wezen appears on the flag of Brazil, symbolising the state of Roraima. Delta Canis Majoris Delta

neg: Geology of solar terrestrial planets Earth, though these observations may also be explained by silica glass, phyllosilicates, or opal. Much of the surface is deeply covered by dust as fine as talcum powder. The red/orange appearance of Mars' surface is caused by iron(III) oxide (rust). Mars has twice as much iron oxide in its outer layer as Earth does, despite their supposed similar origin. It is thought that Earth, being hotter, transported much of the iron downwards in the deep, , lava seas of the early planet, while Mars, with a lower lava temperature of was too cool for this to happen. The core is

neg: Thermoplastic-sheathed cable 6 mm² Cross Sectional Area (CSA) are available with the outer sheath covering a "core" of either a single conductor, twin conductors, "twin and earth" conductors, or "three and earth" conductors. Although available in the larger sizes, solid conductors are rarely used with wire sizes greater than 1 mm² CSA, since the small extra expense of multi-stranded conductors is far outweighed by the relative ease of working with them, especially at the points of termination. Unlike in North America, the existence of the Earth wire within the sheath is always specified if it is present (e.g. twin cable has two

neg: Future of Earth supplied by this process of inner core formation. The growth of the inner core may be expected to consume most of the outer core by some 3–4 billion years from now, resulting in a nearly solid core composed of iron and other heavy elements. The surviving liquid envelope will mainly consist of lighter elements that will undergo less mixing. Alternatively, if at some point plate tectonics comes to an end, the interior will cool less efficiently, which may end the growth of the inner core. In either case, this can result in the loss of the magnetic dynamo. Without a