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Earth and Space > Earth Structure and Measurements

The overall composition of the Earth is made up of the following elements, including core, crust and mantle.
  • Iron (Fe) 35.9%
  • Oxygen (O) 28.5%
  • Silicon (Si) 14.3%
  • Magnesium (Mg) 13.2%
  • Nickel (Ni) 2.0%
  • Calcium (C) 1.9%
  • Sulfur (S) 1.8%
  • Aluminium (Al) 1.8%
  • Other 0.6%
Fig 1: Overall composition of the Earth
Fig 1:
Overall composition of the Earth


The temperature at the centre of the Earth is estimated to be 4530°C

The average density of the Earth is 5.517g/cm3

The mass of the Earth including the atmosphere is 5.976 x 1021 tonnes.

The Earth is made up of several layers. The measurements of which are below.

 

polymorph melting point (°C) comments
form I 17.3 Produced by rapid cooling of melt. Successive polymorphs are then obtained by heating at 0.5 °C/min.
form 2 23.3 Produced by cooling melt at 2 °C/min or rapid cooling of melt followed by storing from several minutes up to one hour at 0 °C. This form is stable at 0 °C for up to 5 hours.
form 3 25.5 Produced by solidification of melt at 5-10 °C or transformation of form 2 by storing at 5-10 °C.
form 4 27.3 Produced by solidification of melt at 16-21 °C or transformation of form 3 by storing at 16-21 °C.
form 5 33.8 Produced by tempering (cooling then reheating slightly while mixing). The most desirable form with good gloss, texture, and "snap".
form 6 36.3 The transformation of form 5 after spending 4 months at room temperature. Leads to the white, dusty appearance.



  Density g/cm3 % of mass % of volume Thickness (km)
Ocean 1.020 0.03 0.14 3
Upper Crust 2.6 0.27 1 (with lower crust) 21 (with lower crust)
Lower Crust 2.9 0.23 1 (with upper crust) 21 (with upper crust)
Mantle Variable 65.99* 82.54 2,865
Outer Core 11.238 31.82 15.62 2,260
Inner Core 12.980 1.66 0.70 1,222

*The % of mass is calculated as a remainder.