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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 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]
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 is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust.
The ocean is a major driver of Earth's water cycle. Ocean water represents the largest body of water within the global water cycle (oceans contain 97% of Earth's water). Evaporation from the ocean moves water into the atmosphere to later rain back down onto land and the ocean. [68] Oceans have a significant effect on the biosphere.
Stars are known to get brighter as they age, and the Sun has become 30% brighter since its formation 4.5 billion years ago. [70] Many models indicate that the early Earth should have been covered in ice. [71] [66] A likely solution is that there was enough carbon dioxide and methane to produce a greenhouse effect. The carbon dioxide would have ...
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). Earth ...
The deep biosphere is the part of the biosphere that resides below the first few meters of the surface. It extends down below 10 kilometers below the continental surface and 21 kilometers below the sea surface, at temperatures that may reach beyond 120 °C (248 °F) [1] which is comparable to the maximum temperature where a metabolically active organism has been found.
The Pleistocene (/ ˈplaɪstəˌsiːn, - stoʊ -/ PLY-stə-seen, -stoh-; [ 5 ][ 6 ] often referred to colloquially as the Ice Age) is the geological epoch that lasted from c.2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International ...