Scientists from Sweden, China and Chile have identified the likely type of crystal lattice occupied by the stable phase of iron in the Earth's inner core. A related study was published in the journal Nature Geoscience.
The inner solid core of the planet, according to the authors of the article, is formed by a body-centered cubic lattice (in one of its cells, eight atoms are spaced at the corners of the cube and one is in its center).
Scientists came to their conclusions by conducting computer modeling (by the method of molecular dynamics) of the conditions in the bowels of the planet using the VASP package (Vienna Abinitio Simulation Package). Thus, the specialists managed to track the evolution of a supercell consisting of 1024 iron atoms at a temperature of 6 thousand kelvin and under a pressure of 360 gigapascals.
According to the authors of the study, the body-centered cubic lattice of the solid core explains the observed anisotropy of the velocity of propagation of elastic waves through the inner core and its low shear modulus.
The core of the Earth with a radius of 3.5 thousand kilometers is under the mantle at a depth of 2.9 thousand kilometers from the surface of the planet. It is formed by a liquid outer layer 2.2 thousand kilometers thick and an inner solid core with a radius of 1.2 thousand kilometers. Its main components are iron and nickel.
An alternative hypothesis assumes that the Earth's interior is formed by a face-centered cubic lattice - in one of its cells, eight atoms are spaced at the corners of the cube, and six others are located in the centers of its sides.