Outer core[change | change source]
The outer core of the Earth is a liquid layer about 2,266 kilometers thick. It is made of iron and nickel. This is above the Earth's solid inner core and below the mantle. Its outer boundary is 2,890 km (1,800 mi) beneath the Earth's surface. The transition between the inner core and outer core is approximately 5,150 km beneath the Earth's surface.
The temperature of the outer core ranges from 4400 °C in the outer regions to 6100 °C near the inner core. Eddy currents in the nickel iron fluid of the outer core are believed to influence the Earth's magnetic field.
Without the outer core, life on Earth would be very different. Convection of liquid metals in the outer core creates the Earth's magnetic field. This magnetic field extends outward from the Earth for several thousand kilometers, and creates a protective bubble around the Earth that deflects the Sun's solar wind. Without this field, the solar wind would directly strike the Earth's atmosphere. This might have removed the Earth's atmosphere, making the planet nearly lifeless. It may have happened to Mars.
Inner core[change | change source]
References[change | change source]
- Bruce A. Buffett 2010. Tidal dissipation and the strength of the Earth’s internal magnetic field. Nature 468, 952-954. doi:10.1038/nature09643
- Woodrow L. Shew, Daniel P. Lathrop 2005. Liquid sodium model of geophysical core convection. Physics of the Earth and Planetary Interiors 153 136–149
- Kent C. Condie 1997. Plate tectonics, Butterworth-Heinemann; 4th ed. p140 ISBN 978-0750633864
- E.R. Engdahl; E.A. Flynn and R.P. Massé (1974). "Differential PkiKP travel times and the radius of the core". Geophys. J. R. Astr. Soc. 39: 457–463. doi:10.1111/j.1365-246X.1974.tb05467.x.