Search results
Results from the WOW.Com Content Network
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 20% of Earth’s radius or 70% of the Moon 's radius. [1][2] There are no samples of Earth's core accessible for direct measurement, as there are for Earth's mantle. [3]
Geothermal gradient is the rate of change in temperature with respect to increasing depth in Earth 's interior. As a general rule, the crust temperature rises with depth due to the heat flow from the much hotter mantle; away from tectonic plate boundaries, temperature rises in about 25–30 °C/km (72–87 °F/mi) of depth near the surface in ...
The largest values of heat flux coincide with mid-ocean ridges, and the smallest values of heat flux occur in stable continental interiors. Earth's internal heat budget is fundamental to the thermal history of the Earth. The flow heat from Earth's interior to the surface is estimated at 47±2 terawatts (TW) [1] and comes from two main sources ...
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. [32][33] The inner core was discovered in 1936 by Inge Lehmann and is generally composed primarily of iron and some nickel.
The 1-dimensional velocity structure of the Earth, grey area indicating the transition zone. The change in velocity at the core-mantle boundary (CMB) represents changes in physical state from solid to fluid. At the inner-core boundary (ICB), the core changes from fluid to solid as reflected by the increase in velocity. [3]
The "New Core Paradox" [1] posits that the new upward revisions to the empirically measured thermal conductivity of iron [2] [3] [4] at the pressure and temperature conditions of Earth's core imply that the dynamo is thermally stratified at present, driven solely by compositional convection associated with the solidification of the inner core.
core–mantle boundary. outer core–inner core boundary. 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 ...
Lithosphere–asthenosphere boundary. A diagram of the internal structure of Earth. The lithosphere consists of the crust and upper solid mantle (). The green dashed line marks the LAB. The lithosphere–asthenosphere boundary (referred to as the LAB by geophysicists) represents a mechanical difference between layers in Earth's inner structure.