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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.
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]
Computer simulation of the Earth's magnetic field in a period of normal polarity between reversals [2] Geophysics (/ ˌdʒiːoʊˈfɪzɪks /) is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis.
In physics, the dynamo theory proposes a mechanism by which a celestial body such as Earth or a star generates a magnetic field. The dynamo theory describes the process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time scales. A dynamo is thought to be the source of the ...
The inner Van Allen Belt extends typically from an altitude of 0.2 to 2 Earth radii (L values of 1.2 to 3) or 1,000 km (620 mi) to 12,000 km (7,500 mi) above the Earth. [ 4 ] [ 16 ] In certain cases, when solar activity is stronger or in geographical areas such as the South Atlantic Anomaly , the inner boundary may decline to roughly 200 km ...
The gravity of Earth, denoted by g, is the net acceleration that is imparted to objects due to the combined effect of gravitation (from mass distribution within Earth) and the centrifugal force (from the Earth's rotation). [2][3] It is a vector quantity, whose direction coincides with a plumb bob and strength or magnitude is given by the norm .
Notes Sources (most suitable unit) (km, with scientific notation) (km, as a power of 10, Logarithmic scale) Earth: 12,756.2 km (equatorial) 1.28×10 4: 4.11: Measurement comprises just the solid part of the Earth; there is no agreed upper boundary for Earth's atmosphere. The geocorona, a layer of UV-luminescent hydrogen atoms, lies at 100,000 km.
Earth science or geoscience includes all fields of natural science related to the planet Earth. [1] This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres: the biosphere , hydrosphere / cryosphere , atmosphere , and geosphere (or lithosphere ).