Related Experiment Videos
The ab initio simulation of the Earth's core
D Alfè1, M J Gillan, L Vocadlo
1Research School of Geological and Geophysical Sciences, Birkbeck and University College London, Gower Street, London WC1E 6BT, UK.
Summary
Earth's inner core composition revealed: quantum simulations show it's hexagonal close-packed iron with sulfur, silicon, and oxygen. This provides new insights into planetary core structure and properties.
Area of Science:
- Geophysics
- Computational Materials Science
- Planetary Science
Background:
- Earth's core has a liquid outer and solid inner core, primarily iron alloyed with light elements like sulfur, oxygen, and silicon.
- Experimental determination of core-forming material properties at extreme pressures (300 GPa) and temperatures (5000-6000 K) is challenging.
Purpose of the Study:
- To utilize quantum mechanical methods and high-performance computing to simulate high-pressure/temperature properties of iron alloys.
- To determine the precise chemical and thermal structure of Earth's core.
Main Methods:
- Quantum mechanical simulations were employed to calculate Gibbs free energies for crystalline and liquid iron alloys.
- High-performance computing resources enabled these complex simulations at core-relevant conditions.
Main Results:
- The inner core is composed of hexagonal close-packed iron with approximately 8.5% sulfur (or silicon) and 0.2% oxygen.
- At the inner-outer core boundary (5600 K), the liquid outer core consists of iron with about 10% sulfur (or silicon) and 8% oxygen.
Conclusions:
- The study provides a detailed composition of Earth's inner and outer core based on advanced computational simulations.
- These findings advance our understanding of planetary core formation and evolution.