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 the core accessible for direct measurement, as there are for Earth's mantle. [3]
A diagram of Earth's geodynamo and magnetic field, which could have been driven in Earth's early history by the crystallization of magnesium oxide, silicon dioxide, and iron(II) oxide. Earth's outer core is a fluid layer about 2,260 km (1,400 mi) in height (i.e. distance from the highest point to the lowest point at the edge of the inner core ...
The variety of light elements present in Earth's outer core is constrained in part by Earth's accretion. [16] Namely, the light elements contained must have been abundant during Earth's formation, must be able to partition into liquid iron at low pressures, and must not volatilize and escape during Earth's accretionary process. [14] [16]
The core contains half the Earth's vanadium and chromium, and may contain considerable niobium and tantalum. [26] The core is depleted in germanium and gallium. [26] Core mantle differentiation occurred within the first 30 million years of Earth's history. [26] Inner core crystallization timing is still largely unresolved. [26]
While iron is the most abundant element on Earth, most of this iron is concentrated in the inner and outer cores. [43] [44] The fraction of iron that is in Earth's crust only amounts to about 5% of the overall mass of the crust and is thus only the fourth most abundant element in that layer (after oxygen, silicon, and aluminium). [45]
Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 10 24 kg (8.84 × 10 24 lb) and makes up 67% of the mass of Earth. [ 1 ] It has a thickness of 2,900 kilometers (1,800 mi) [ 1 ] making up about 46% of Earth's radius and 84% of Earth's volume.
The iron cycle is an important component of the terrestrial ecosystems. The ferrous form of iron, Fe 2+, is dominant in the Earth's mantle, core, or deep crust. The ferric form, Fe 3+, is more stable in the presence of oxygen gas. [22] Dust is a key component in the Earth's iron cycle.
The heavier alkaline earth metals react more vigorously than the lighter ones. [2] The alkaline earth metals have the second-lowest first ionization energies in their respective periods of the periodic table [4] because of their somewhat low effective nuclear charges and the ability to attain a full outer shell configuration by losing just two ...