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Earth cutaway from core to exosphere Geothermal drill machine in Wisconsin, USA. Temperature within Earth increases with depth. Highly viscous or partially molten rock at temperatures between 650 and 1,200 °C (1,200 and 2,200 °F) 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 ...
The average magnetic field strength in Earth's outer core is estimated to be 2.5 millitesla, 50 times stronger than the magnetic field at the surface. [9] [10] As Earth's core cools, the liquid at the inner core boundary freezes, causing the solid inner core to grow at the expense of the outer core, at an estimated rate of 1 mm per year.
The transition between the inner core and outer core is located approximately 5,150 km (3,200 mi) beneath Earth's surface. Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 19% of Earth's radius [0.7% of volume] or 70% of the Moon's radius.
The sharp decline in P-wave velocity at the mantle-core boundary suggests a liquid outer core, transitioning from 7.7 km/s in the mantle to 4 km/s in the outer core. [59] The inability of S-waves to traverse this zone further confirms its fluid nature with molten iron sulphate .
Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core. [132] Earth's inner core may be rotating at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year, although both somewhat higher and much lower rates have also been proposed. [133]
What are the light alloying elements in the Earth's outer core and how are they distributed? [16] [17] What are the heterogeneities of the core and their dynamical significance? [17] Does the internal mantle structure provide the resonance for the Chandler wobble of the Earth's axis or is it some other external mechanism? No available motions ...
Earth’s inner core, a red-hot ball of iron 1,800 miles below our feet, stopped spinning recently, and it may now be reversing directions, according to an analysis of seismic activity.
The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron–nickel outer core, at a depth of 2,891 km (1,796 mi) below 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 ...