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The stories vary on the other details about humanity's creation, but it was a tradition commonly believed in ancient China that she created commoners from brown mud. [5] A story holds that she was tired when she created "the rich and the noble", so all others, or "cord-made people", were created from her "dragg[ing] a string through mud". [6]
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth itself.
Earth formed approximately 4.6 billion years ago from a disk of dust and gas orbiting the newly formed Sun. It formed via accretion, where planetesimals and other smaller rocky bodies collided and stuck, gradually growing into a planet. This process generated an enormous amount of heat, which caused early Earth to melt completely.
The Earth's crust is one "reservoir" for measurements of abundance. A reservoir is any large body to be studied as unit, like the ocean, atmosphere, mantle or crust. Different reservoirs may have different relative amounts of each element due to different chemical or mechanical processes involved in the creation of the reservoir. [1]: 18
German chemist Andreas Sigismund Marggraf synthesized the earth of alum by boiling clay in sulfuric acid and adding potash in 1754. [16] He realized that adding soda, potash, or an alkali to a solution of the new earth in sulfuric acid yielded alum. [21] He described the earth as alkaline, as he had discovered it dissolved in acids when dried.
Earth's outer core is a fluid layer about 2,260 km (1,400 mi) thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. [ 1 ] [ 2 ] [ 3 ] The outer core begins approximately 2,889 km (1,795 mi) beneath Earth's surface is at the core-mantle boundary and ends 5,150 km (3,200 mi) beneath Earth's ...
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.
It uses a liquid iron cathode, an anode formed from an alloy of chromium, aluminium and iron, [123] and the electrolyte is a mixture of molten metal oxides into which iron ore is dissolved. The current keeps the electrolyte molten and reduces the iron oxide. Oxygen gas is produced in addition to liquid iron.